Cut Emissions and Remove Carbon FALO & Nature-Based Carbon Removal Protect & Manage Ecosystems

Protect Seaweed Ecosystems

Highly Recommended
Seaweed

Seaweed ecosystem protection is the long-term protection from degradation of wild subtidal brown and red seaweed ecosystems. Seaweeds, also called macroalgae, are photosynthetic marine organisms that absorb CO₂ from the water and convert it into biomass. This can lower surface-water CO₂ concentrations, allowing additional CO₂ from the atmosphere to be dissolved in the ocean. Some of the fixed carbon can be sequestered through export to the deep sea or burial in the seafloor, while a portion may persist in forms that resist degradation even at the ocean surface. 

Protecting seaweed ecosystems can reduce a range of human impacts (wild harvesting, coastal development, overgrazing, and poor water quality) and improve resilience to other stressors (warming), which helps preserve carbon removal by the seaweed and avoid CO₂ emissions from biomass losses. 

This solution focuses on legal mechanisms of protection through the establishment of Marine Protected Areas (MPAs), which are managed with the primary goal of conserving nature. This solution does not include cultivated seaweed (see Deploy Seaweed Farming for Food).

Last updated April 2, 2026

Solution Basics

ha of seaweed ecosystem protected

t CO₂-eq (100-yr)/unit/yr
00.110.32estimate
units
Current 7.88×10⁷ 02.163×10⁸3.029×10⁸
Achievable (Low to High)

Climate Impact

Gt CO₂-eq (100-yr)/yr
Current 0.03 0.070.1
US$ per t CO₂-eq
-72
Emergency Brake

CO₂

Additional Benefits

180
183,184,188
    183
    • 184
    • 185
    • 186
    • 187
    • 188
189,193

Overview

Seaweeds are diverse marine photosynthetic organisms composed of three groups: brown (Phaeophyceae), green (Chlorophyta), and red algae (Rhodophyta). They can form ecosystems, such as kelp forests, and contribute to other marine ecosystems by providing habitat and food. Seaweeds are distinguished from other algae, such as phytoplankton, based on their larger size and because most are attached to substrate rather than free-floating. Seaweeds cover an estimated 600 Mha of the ocean (Duarte et al., 2022), an area that is an order of magnitude greater than the area associated with coastal wetlands (~55 Mha, see Protect Coastal Wetlands). 

This solution focuses on wild subtidal (always submerged) brown and red seaweed ecosystems, which together account for over 75% of global seaweed extent (Duarte et al., 2022) (Figure 1). We do not include green seaweeds due to their smaller extent and data limitations. We also do not include seaweeds that occur in intertidal zones, as free-floating colonies (e.g., some species of Sargassum) or are cultivated due to data limitations or coverage in other Explorer solutions (e.g., Deploy Seaweed Farming for Food).

Figure 1. Seaweed ecosystem types considered in this solution (left to right): subtidal brown (central California, USA) and subtidal red (Atlantic coast of Spain)

Two photos demonstrating seaweed ecosystem types. Left: subtidal brown. Right: subtidal red.

fdastudillo | iStock; Damocean | iStock

Seaweed ecosystems exhibit high net primary productivity (NPP) rates, comparable to those of terrestrial forests (Filbee-Dexter, 2020). Unlike many terrestrial ecosystems, however, nearly all carbon storage in seaweed ecosystems occurs as above-ground biomass, since seaweeds lack below-ground roots. A smaller amount can be buried on site in sediment (Krause-Jensen & Duarte, 2016). Most long-term carbon storage attributable to seaweeds occurs largely outside of seaweed ecosystems, through the export of carbon in dissolved and suspended forms (Figure 2). Some of this carbon reaches the deep sea, where it can persist for more than 100 years (Krause-Jensen & Duarte, 2016; Krause-Jensen et al., 2018; Ortega et al., 2019). Roughly 11.4% (25th quartile, 6.0%; 75th quartile, 13.7%) of NPP from global seaweed ecosystems is estimated to contribute to long-term carbon storage in the deep sea, equivalent to as much as 0.62 Gt CO₂‑eq/yr (173 Tg C/yr, Krause-Jensen & Duarte, 2016). While uncertain and requiring more research, recent modeling efforts support these estimates, suggesting that more than 12.5% of NPP may be removed on 100-yr timescales (Filbee-Dexter et al., 2024b).

Figure 2. Overview of a seaweed ecosystem showing carbon fluxes into and out of the ecosystem (g=gaseous, aq=aqueous) that can result in carbon removal. Some carbon is exported to the shallow sea, where it may be recycled or persist for longer periods depending on its form, some is exported to the deep sea (~1000 m), and some is buried in seafloor sediments. 

diagram illustration of seaweed ecosystem, showing carbon fluxes into and out of the ecosystem

Adapted from: Hurd, C. L., Gattuso, J.-P., & Boyd, P. W. (2024). Air-sea carbon dioxide equilibrium: Will it be possible to use seaweeds for carbon removal offsets? Journal of Phycology, 60(1), 4–14. 

Seaweed ecosystems face growing threats from a range of climate change impacts (Harley et al., 2012), such as increasing sea surface temperatures, marine heat waves, ocean acidification, and extreme storm events, as well as local drivers, such as overfishing, overgrazing, pollution, disease outbreaks, invasive species, and bottom fishing (Corrigan et al., 2025; Filbee-Dexter et al., 2024a; Hanley et al., 2024). For instance, overfishing can deplete top predators in ecosystems, leading to increases in herbivores, such as sea urchins, that overgraze seaweed (Steneck et al., 2002). 

In this solution, we calculate how legal protection of seaweed ecosystems via MPAs can reduce CO₂ emissions and preserve carbon removal through avoided ecosystem loss. In addition to preventing direct losses from impacts such as wild harvest, MPAs can help restore predator populations that keep herbivores in balance. For instance, many MPAs include no-take zones that allow predatory fish populations to recover, thereby lessening overgrazing impacts over time. MPAs can also increase the resilience of seaweed ecosystems against climate change stressors, such as marine heat waves (Kumagai et al., 2024; Ortiz-Villa et al., 2025). While some seaweed can release methane, offsetting CO₂ removal (Roth et al., 2023), we exclude this process from our analysis due to existing data limitations. We also do not consider nitrous oxide, though protection might provide additional climate benefits because enhanced nitrous oxide production has been tied to nutrient-polluted seaweed systems (Wong et al., 2021). 

We present estimates of climate impact as likely upper bounds under several key assumptions (see Appendix and Caveats), which can be improved upon as more research unfolds. We consider subtidal brown and red seaweed to be protected if they are within designated MPAs based on global datasets from UNEP-WCMC and IUCN (2024). Importantly, protection can help reduce – but will not eliminate – ecosystem loss in MPAs relative to unprotected areas (see Effectiveness). 

Impact Calculator

Adjust effectiveness and adoption using range sliders to see resulting climate impact potential.

Effectiveness

0.32
t CO2-eq/unit/yr
25th
percentile
0.11
75th
percentile
0.52
0.32
estimate

Adoption

7.88×10⁷
ha of seaweed ecosystem protected
Low
2.163×10⁸
High
3.029×10⁸
7.88×10⁷
current
Achievable Range

Climate Impact

0.03
Gt CO₂-eq/yr (100-yr)
05
which is the equivalent of
0.04%
of global emissions

The Details

Current State

The globally weighted average effectiveness of seaweed ecosystem protection is 0.32 tCO₂‑eq /ha/yr. Protecting 1 ha of seaweed ecosystem avoids emissions of 0.043–0.13 tCO₂‑eq /ha/yr while also sequestering an additional 0.083–0.43 tCO₂‑eq /ha/yr, with effectiveness higher in subtidal brown than subtidal red seaweed ecosystems (100-yr GWP; Table 1; Appendix).

We estimated effectiveness as the avoided emissions and retained carbon sequestration capacity attributable to the reduction in seaweed ecosystem loss conferred by protection, as detailed in Equation 1. First, we calculated the difference between the rate of seaweed ecosystem loss outside and inside MPAs (Seaweed lossbaseline). We assumed a reduction in loss of 53% (Reduction in loss), which is based on estimates for a range of ecosystems in MPAs (Rodríguez-Rodríguez & Martínez-Vega, 2022). Importantly, this number is highly uncertain and likely to be highly variable, too. 

Next, we multiplied this product by the sum of the avoided CO₂ emissions associated with the one-time loss of all above ground biomass carbon in 1 ha of seaweed ecosystem each year over 30 years (Carbonavoided emissions) and the amount of carbon sequestered via long-term storage (on-site or off-site) in 1 ha of protected seaweed ecosystem each year over 30 years (Carbonsequestration). 

We based these rates on original analysis of a subset of studies conducted over, at least, 20 years, collated from Krumhansl et al. (2016), that show a median loss rate of 1.2% per year for kelp forests. Due to data limitations, we applied this loss rate to subtidal red seaweed ecosystems as well, but recognize that loss rates are likely to be highly variable. We did this calculation separately for red and brown seaweed ecosystems due to their distinct biomass densities and sequestration capacities, and then averaged the results with accommodations for their relative global areas.

Equation 1.

\[ \text{Effectiveness} = \left( \text{Seaweed loss}_{\text{baseline}} \times \text{Reduction in loss} \right) \times \left( \text{Carbon}_{\text{avoided emissions}} + \text{Carbon}_{\text{sequestration}} \right) \]

Table 1. Effectiveness of seaweed ecosystem protection in avoiding emissions and sequestering carbon.

Unit: tCO₂‑eq /ha/yr, 100-year basis

Avoided emissions, estimate 0.13
Sequestration 0.43
Total effectiveness, estimate 0.56
Total effectiveness, 25th percentile 0.21
Total effectiveness, 75th percentile 0.91

Unit: tCO₂‑eq /ha/yr, 100-year basis

Avoided emissions, estimate 0.043
Sequestration 0.083
Total effectiveness, estimate 0.13
Total effectiveness, 25th percentile 0.034
Total effectiveness, 75th percentile 0.22

Unit: tCO₂‑eq /ha/yr, 100-year basis

Avoided emissions, estimate 0.080
Sequestration 0.24
Total effectiveness, estimate 0.32
Total effectiveness, 25th percentile 0.11
Total effectiveness, 75th percentile 0.52

We estimate that seaweed ecosystem protection might save approximately US$72/tCO₂‑eq , but emphasize that these estimates are highly uncertain due to existing data limitations. This is based on protection costs of roughly US$14/ha/yr and revenue of US$43/ha/yr compared with the baseline (Table 2). The costs of seaweed ecosystem protection also include up-front one-time expenditures of US$208 (surveys, administrative setup, legal fees, etc.), estimated from McCrea-Strub et al. (2011). However, data related to the costs of seaweed ecosystem protection are limited, and these estimates are uncertain. For consistency across solutions, we did not include revenue associated with other ecosystem services. 

We estimated costs of MPA maintenance at US$14/ha/yr based on data from existing MPAs, though only 16% of MPAs surveyed reported their current funding was sufficient (Balmford et al., 2004). Maintenance is critical for seaweed ecosystems, especially those prone to overgrazing. Tourism revenues directly attributable to protection were estimated to be $43/ha/yr (Waldron et al., 2020) based on estimates for all MPAs (and PAs) and not including downstream revenues. However, estimates of tourism revenues are highly uncertain for seaweed ecosystems. In some seaweed ecosystems, such as kelp forests, tourism is likely a real revenue generator through diving or other recreational activities, but the financial contribution is generally unclear and poorly documented across all seaweed ecosystems. 

Table 2. Cost per unit of climate impact. Negative values indicate cost savings.

Unit: 2023 US$/tCO₂‑eq , 100-yr basis

Estimate -72

A learning curve is defined here as falling costs with increased adoption. The costs of seaweed ecosystem protection do not fall with increasing adoption, so there is no learning curve for this solution.

Speed of action refers to how quickly a climate solution physically affects the atmosphere after it is deployed. This is different from speed of deployment, which is the pace at which solutions are adopted.

At Project Drawdown, we define the speed of action for each climate solution as emergency brake, gradual, or delayed.

Protect Seaweed Ecosystems is an EMERGENCY BRAKE climate solution. It has the potential to deliver a more rapid impact than gradual and delayed solutions. Because emergency brake solutions can deliver their climate benefits quickly, they can help accelerate our efforts to address dangerous levels of climate change. For this reason, they are a high priority.

Adoption

A total of 78.80 Mha of seaweed ecosystems are currently within MPAs (Table 3). Cumulatively, roughly 18% of seaweed ecosystems are under some form of protection, with 4% located in strictly protected MPAs, 6% in nonstrict MPAs, and 8% in other IUCN protection categories. Subtidal brown and red seaweed ecosystems have similar rates of existing protection in all protection categories (Figure 3).

Table 3. Current (circa 2024) extent of seaweed ecosystems under legal protection. “Strict protection” includes land within IUCN categories I–II Marine Protected Areas (MPAs). “Nonstrict protection” includes land within IUCN Categories III–VI MPAs. “Other” includes land within all remaining IUCN MPA categories. Values may not sum to global totals due to rounding.

Unit: Mha protected

Strict protection 8.43
Nonstrict protection 11.4
Other 15.5
Total 35.3

Unit: Mha protected

Strict protection 9.28
Nonstrict protection 16.3
Other 18.0
Total 43.5

Unit: Mha protected

Strict protection 17.7
Nonstrict protection 27.6
Other 33.4
Total 78.8

We calculated the rate of MPA expansion in seaweed ecosystems based on recorded year of establishment (UNEP-WCMC & IUCN, 2024). Protection expanded by a median of 0.74 Mha/yr in subtidal brown seaweed ecosystems and 0.97 Mha/yr in subtidal red seaweed ecosystems (Table 4; Figure 3a). The global average rate of expansion was roughly 2.13 Mha/yr, with a median of 1.71 Mha/yr. The adoption trend for subtidal brown and red seaweed was relatively similar, with both expanding 0.46–0.55%/yr, on average (median of 0.39–0.40%/yr) (Figure 3b).

Table 4. 2000–2024 adoption trend. Global totals reflect independent statistics, not sums of subtidal brown and red values.

Unit: Mha/yr

25th percentile 0.40
Median (50th percentile) 0.74
Mean 1.01
75th percentile 1.31

Unit: Mha/yr

25th percentile 0.62
Median (50th percentile) 0.97
Mean 1.12
75th percentile 1.45

Unit: Mha/yr

25th percentile 1.02
Median (50th percentile) 1.71
Mean 2.13
75th percentile 2.76

Figure 3. Trend in seaweed ecosystem protection (2000–2024) in terms of (A) total hectares protected and (B) the percent of the current adoption ceiling that is currently protected. These values reflect only the area located within Marine Protected Areas. Units: million hectares protected and percent protected relative to the adoption ceiling.

We estimated that approximately 430 Mha of wild seaweed ecosystems are available for protection (Table 5). Subtidal red seaweeds compose ~240 Mha, with subtidal brown seaweeds occupying the remaining ~190 Mha. These adoption areas do not include other types of seaweed habitats/ecosystems, such as those found in the intertidal zone, rhodolith beds, Halimeda bioherms, coral reefs, and pelagic, free-floating seaweed, which could account for an additional ~150 Mha (Duarte et al., 2022). These adoption areas are highly uncertain due to data limitations and are also likely to shift with climate change.

Table 5. Adoption ceiling: upper limit for the adoption of legal protection of seaweed ecosystems.

Unit: Mha

Estimate 189.6

Unit: Mha

Estimate 243.0

Unit: Mha

Estimate 432.6

We defined the lower end of the achievable range for seaweed ecosystem protection (across all IUCN categories) as 50% of the adoption ceiling and the upper end of the achievable range as 70% of the adoption ceiling (Table 6). These adoption levels are ambitious relative to existing levels of protection (~18%), but align with targets to protect 30% of ecosystems by 2030 (Eger et al., 2024) and serve as an optimistic benchmark for the 30-year time horizon considered in our analysis. Several countries already protect more than 30% of subtidal brown seaweed ecosystems, such as kelp forests (Kelp Forest Alliance, 2024). For example, the United Kingdom, Japan, China, and France protect over 41%, 68%, 68%, and 47% of their kelp beds, respectively. 
 

Table 6: Range of achievable adoption levels for seaweed ecosystems.

Unit: Mha

Current adoption 78.8
Achievable – low 216.3
Achievable – high 302.9
Adoption ceiling 432.6

Impacts

We estimated that MPAs currently avoid emissions of 0.03 GtCO₂‑eq/yr in seaweed ecosystems, with potential impacts of 0.14 GtCO₂‑eq/yr at the adoption ceiling (Table 7). Achievable levels of seaweed ecosystem protection could safeguard 0.07 to 0.10 GtCO₂‑eq/yr by reducing emissions from biomass loss and retaining sequestration fluxes (Table 7). However, these estimates are highly uncertain and will benefit from more research (see Caveats).

Limited data exist on the potential climate impacts of seaweed ecosystem protection for comparison. However, a rough estimate of the benefits of conservation, restoration, and afforestation interventions of seaweeds suggests carbon benefits of at least 0.04 GtCO₂‑eq/yr (Pessarrodona et al., 2023). Other estimates suggest that total carbon sequestration in seaweed ecosystems could be on the order of 0.22–0.98 GtCO₂‑eq/yr (Krause-Jensen & Duarte, 2016). This is higher than our estimates because we account only for the carbon benefits of protection in seaweed ecosystems at risk of loss.

Table 7. Climate impact at different levels of adoption. Values may not sum to global totals due to rounding.

Unit: GtCO₂‑eq/yr, 100-year basis

Current adoption 0.02
Achievable – low 0.05
Achievable – high 0.07
Adoption ceiling 0.11

Unit: GtCO₂‑eq/yr, 100-year basis

Current adoption 0.01
Achievable – low 0.02
Achievable – high 0.02
Adoption ceiling 0.03

Unit: GtCO₂‑eq/yr, 100-year basis

Current adoption 0.03
Achievable – low 0.07
Achievable – high 0.10
Adoption ceiling 0.14

Extreme Weather Events

Seaweeds can provide coastal resilience to the impacts of storms by lowering wave heights before they reach shorelines (Corrigan et al., 2025; Cotas et al., 2023). The magnitude of this benefit can vary based on the species and location of seaweed, and some evidence suggests that severe storms can harm seaweed habitats (Earp et al., 2024). Evidence suggests that kelp forests can attenuate wave heights locally, especially in the summer at peak kelp growth, but protection varies at larger spatial scales (Elsmore et al., 2024; Lindhart et al., 2024). Emerging research has found that protected seaweed ecosystems show more resilience to marine heat waves than unprotected areas (Kumagai et al., 2024). During heat waves, protected ecosystems maintain a habitat for species such as sea urchins that consume species that might degrade kelp ecosystems (Bauer et al., 2025; Kumagai et al., 2024).

Income and Work

Seaweeds support species that are important for tourism and fishing (Cuba et al., 2022; Eger et al., 2023). Many species that are supported by seaweeds have high economic value for fishing, such as crabs, lobsters, and abalones (Corrigan et al., 2025). For example, Eger et al. (2023) estimated that 1 ha of kelp forest where about 900 kg of fish biomass is harvested could yield about US$29,900 a year. The same study estimated that the global value of kelp forests that support fisheries is about US$465–562 billion (Eger et al., 2023). Seaweed habitats can also be tourist destinations for snorkeling and diving (UNEP, 2023), providing income-earning opportunities for nearby communities.

Food Security

The contribution of seaweeds to fisheries production can play a role in global food security (Cottier-Cook et al., 2023; Eger et al., 2023). Additionally, seaweeds are an essential part of many diets, especially in East Asia (FAO, 2024). Because seaweeds are a culturally important food in many geographies, protecting seaweeds can play an important role in equitably improving global food security (FAO, 2024).

Equality

For some cultures, seaweeds and their habitats shape shared identities and livelihoods (Cotas et al., 2023). For example, seaweeds are a source of traditional foods, medicines, art, and knowledge for many coastal communities and Indigenous peoples (Thurstan et al., 2018). Protecting seaweeds can preserve the cultural identities, practices, and knowledge of Indigenous communities that are often vulnerable (Corrigan et al., 2025).

Nature Protection

Seaweeds support biodiversity by providing habitat for a variety of marine species (Best et al., 2014; Cuba et al., 2022; Gibbons & Quijón, 2023; Tano et al., 2016). Literature reviews of the ecosystem services of seaweeds find that they contribute to increases in biodiversity (Gibbons & Quijón, 2023). Seaweeds can provide habitat and refuge from large predators (Best et al., 2014; Gibbons & Quijón, 2023). Invertebrates, detritivores, and other small species found in seaweed forests are essential food sources for other marine species (Cuba et al., 2022; Tano et al., 2016). 

Water Quality

Seaweeds improve water quality by supporting nutrient cycling and reducing pollutants (Cotas et al., 2023; Heckwolf et al., 2021). Evidence suggests that seaweeds can reduce eutrophication by filtering excess nutrients from the water (Corrigan et al., 2025; Gao et al., 2022; Heckwolf et al., 2021). 

Other

Additionality is an important caveat for ecosystem protection. In our analysis, we used baseline rates of seaweed ecosystem loss to calculate the effectiveness of protection, which are highly uncertain and understudied. This assumes that seaweed ecosystems would continue to be lost at these rates in the absence of protection and thus that protection provides additional carbon benefits from the ecosystems whose loss is avoided. 

Importantly, effective protection depends on adequate funding and management. Poorly managed MPAs can fail to prevent key stressors, such as urchin overgrazing, from increasing and undermine the viability of seaweed ecosystems. Similar dynamics have been documented in kelp restoration efforts, where inadequate management has led to overgrazing and project failure (Eger et al., 2022).

The permanence of ecosystem carbon benefits is another key caveat. While seaweed ecosystems are expanding or expected to expand with climate change, in some regions many will contract (Corrigan et al., 2025). Protection may increase resilience to some climate change stressors, but it will not fully prevent ecosystem loss in many regions. Additionally, because seaweed ecosystems sequester carbon both on-site and off-site, the effectiveness of protection partly depends on downstream activities. For instance, carbon at the seafloor is threatened by disturbances such as bottom fishing and mining (see Protect Seafloors). Protection of seaweed ecosystems does not prevent loss of downstream stored carbon, some of which is contributed by seaweed ecosystems (Ortega et al., 2019). Additionally, seaweed biomass extent can change dramatically from year to year, which could result in substantial variability in carbon removal rates despite protection.

Another caveat in this solution lies in our assumptions about carbon dynamics at the ocean surface. We assume that seaweed NPP results in an equivalent removal of CO₂ from the atmosphere. In reality, this influx may not be fully efficient (Hurd et al., 2024). In some regions of the ocean, water carrying a CO₂ deficit from seaweed photosynthesis might be subducted before it reaches equilibrium with the atmosphere, which would reduce the atmospheric removal attributed to seaweed productivity in our calculations.

In our analysis, avoided emissions are calculated under the assumption that destruction of a seaweed ecosystem results in the loss of all biomass carbon This likely overestimates near-term emissions, as some carbon may remain in the ocean for long periods. However, this fraction is expected to be small given that an estimated 6.0–13.7% (average: 11.4%) of NPP is thought to be stored long term (Krause-Jensen & Duarte, 2016). 

Finally, the relative fraction of NPP removed and durably stored (>100 years) is also uncertain (Pessarrodona et al., 2023). Despite this uncertainty, our use of 11.4% is supported by recent modeling of particulate carbon fluxes that suggest ~12.5% of NPP could be sequestered on a 100-year timescale (based on 44 Tg C of particulate organic carbon export to 1,000 m, where carbon is less likely to return to the atmosphere within a century, and ~353 Tg C as NPP; Filbee-Dexter et al., 2024b), but requires more research.

Leakage, in which protecting one ecosystem results in the degradation of another, could offset the climate impact of seaweed ecosystem protection. For instance, restricting wild harvesting through the establishment of an MPA could shift pressure to other unprotected areas. Another key risk is weakly enforced or poorly managed MPAs. This is a real concern with existing MPAs due to a lack of funding, and can result in low protection effectiveness. Finally, climate change stressors, such as ocean warming and marine heat waves, are a major risk to permanence because they could lead to widespread mortality, even in protected areas.

Seaweed ecosystems can release methane, which could reduce the climate benefits of protection estimated in this solution. While data are scarce, a recent study suggests that methane emissions could offset 28–35% of the carbon sink capacity in some seaweed ecosystems (Roth et al., 2023) if they escape to the atmosphere, which may be unlikely if methane production occurs at depth in sediments (Pessarrodona et al., 2023). 

Reinforcing

Intact and healthy seaweed ecosystems can enhance fish stocks, biodiversity, and habitat quality, which benefits all connected coastal and marine ecosystems.

Protecting seaweed ecosystems can help ensure the underlying areas of the seafloor remain intact.

Competing

Protection of seaweed ecosystems could potentially reduce the adoption of offshore wind in some regions.

Consensus of effectiveness at reducing emissions and maintaining carbon removal: Mixed

There is mixed scientific consensus that protection prevents the degradation of seaweed ecosystems, but high consensus that degradation leads to losses in biomass carbon stocks and sequestration capacity. Seaweed ecosystems can be degraded by diverse stressors that directly or indirectly affect biomass stocks. Management actions, such as establishment of MPAs, can help prevent both direct and indirect habitat loss and thereby maintain the carbon removal capacity of seaweed ecosystems with relatively high certainty against stressors such as wild harvesting, coastal development, overgrazing, and poor water quality (Pessarrodona et al., 2023). However, some stressors, such as marine heat waves and ocean warming, are less effectively addressed by protection alone (Filbee-Dexter et al., 2024a). Benefits are still expected in some systems because MPAs can enhance resilience and recovery by reducing co-occurring stressors common that contribute to seaweed ecosystem degradation (Krumhansl et al., 2016; Ortiz-Villa et al., 2025). Moreover, MPAs, even when established in areas with addressable stressors, are typically not fully effective. Here, we applied a protection effectiveness of 53%, based on aggregated estimates from MPAs beyond seaweed ecosystems (Rodríguez-Rodríguez & Martínez-Vega, 2022). If the effectiveness of protection is lower (higher), climate impacts could likewise be lower (higher).

There is high scientific consensus that degradation of seaweed ecosystems leads to losses in biomass carbon stocks and sequestration capacity. While direct estimates of CO₂ emissions from biomass are limited, degradation has been shown to remove biomass carbon and reduce sequestration. For instance, drivers of habitat loss and degradation, such as overharvesting (González-Roca et al., 2021; Steen et al., 2016), overgrazing (Akaike & Mizuta, 2024), and poor water quality (Filbee-Dexter & Wernberg, 2020), reduce standing biomass and therefore associated carbon export from seaweed ecosystems (Pessarrodona et al., 2023). 

The carbon sink capacity of seaweed ecosystems, such as kelp forests, is also expected to decline with climate change stressors such as warming, which can increase rates of decomposition by 9–42% (Filbee-Dexter et al., 2022) and drive habitat loss, both of which reduce the likelihood that carbon makes its way to the deep sea for long-term storage. Off the coast of Australia, over 140,000 ha of subtidal brown seaweed forests have already been lost to warming over two decades, representing a decline of 2–4% of regional seaweed biomass carbon stocks and sequestration capacity (Filbee-Dexter & Wernberg, 2020).

The results presented in this assessment synthesize findings from 5 global datasets. We recognize that geographic bias in the information underlying global data products creates bias, and hope this work inspires research and data sharing on this topic in underrepresented regions and on understudied aspects of these ecosystems.

Take Action

Looking to get involved? Below are some key actions for this solution that can get you started, arranged according to different roles you may play in your professional or personal life.

These actions are meant to be starting points for involvement and are not intended to be prescriptive or necessarily suggest they are the most important or impactful actions to take. We encourage you to explore and get creative!

Lawmakers and Policymakers

  • Set achievable targets and pledges for seaweed protection with clear effectiveness goals; regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; incorporate statutory protections for seaweeds in existing MPAs; expand MPA designations to meet international goals.
  • Create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Seek to identify local drivers of seaweed decline, address drivers of decline through stringent legal protections, ensure strict enforcement of regulations, and allow for restoration activities.
  • When designating new MPAs, prioritize strategies such as no-take-fishing regulations and strong enforcement measures with high penalties for noncompliance; target large (>100 km2) areas that can be protected over the long term (>10 years) and are ecologically isolated by natural barriers such as deep water and/or sand.
  • Consider placing MPAs near protected or undisturbed terrestrial areas to help avoid nutrient and other land pollution.
  • Codesign seaweed protection projects with the local community; ensure the community engagement process starts early and is transparent, inclusive, and ongoing; solicit feedback from the local community – including from opposition groups – on location, design, finance, and management; ensure finalized protections address sociological, economic, and ecological considerations.
  • Coordinate seaweed protection and restoration policies horizontally (e.g., across agencies) and vertically (e.g., across subnational, national, and international efforts); seek to align social and environmental safeguards with seaweed protection policies and goals.
  • Develop regional and transboundary coordination mechanisms for seaweed protection, especially when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Ensure projects operating in or with Indigenous communities only do so under Free, Prior, and Informed Consent (FPIC); codify FPIC into legal systems.
  • Strengthen land tenure rights; grant Indigenous communities full property rights and autonomy to protect coastal areas and watersheds.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Create programs to monitor for activity and market leakage from protected sites; adjust enforcement and policies to reduce leakage, if necessary.
  • Maintain up-to-date records of seaweed harvesting and populations; monitor impacts; adjust regulations and enforcement to ensure harvesting is sustainable.
  • Remove harmful agriculture subsidies, particularly those that incentivize livestock and overuse of fertilizers that can impact seaweed habitats and MPAs.
  • Put into place locally relevant laws and regulations that help indirectly protect seaweed ecosystems, such as bans on sea otter trapping or bottom trawling.
  • Create “climate-smart” MPAs that connect seaweed ecosystems, allow for gene exchanges, and adjust boundaries to address changing oceanic conditions; target protection of taxa such as brown seaweedss that maximize climate benefits while not neglecting others such as red seaweeds; incorporate climate refugia into MPAs; create strategies for MPAs to address both climate mitigation and adaptation.
  • Invest in research on seaweed biodiversity seeking to document new species, sample from underrepresented regions, and use the most up-to-date techniques to assess taxonomies; support efforts to update key databases such as the IUCN Red List; support research to improve confidence in estimates of global seaweed ecosystem extent, biomass, composition, productivity, and loss rates; monitor related long-term trends.
  • Create educational and volunteer programs that work with schools, universities, NGOs, and the general public to inform communities how to participate in seaweed protection efforts, benefits, and opportunities; expand extension services to develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Practitioners

  • Set achievable targets and pledges for seaweed protection with clear effectiveness goals; regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long term impacts, including metrics to capture social and biodiversity impacts.
  • Establish MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; incorporate statutory protections for seaweeds in existing MPAs; expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Seek to identify local drivers of seaweed decline, address drivers of decline through stringent legal protections, ensure strict enforcement of regulations, and allow for restoration activities.
  • When designating new MPAs, prioritize strategies such as no-take-fishing regulations and strong enforcement measures with high penalties for noncompliance; target large (>100 km2) areas that can be protected over the long term (>10 years) and are ecologically isolated by natural barriers such as deep water and/or sand.
  • Create “climate-smart” MPAs that connect seaweed ecosystems, allow for gene exchanges, and adjust boundaries to address changing oceanic conditions, target protection of taxa such as brown seaweeds that maximize climate benefits while not neglecting others such as red seaweeds; incorporate climate refugia into MPAs; create specific strategies for MPAs to address both climate mitigation and adaptation.
  • Consider placing MPAs near protected or undisturbed terrestrial areas to help avoid nutrient and other land pollution.
  • Codesign seaweed protection projects with the local community; ensure the community engagement process starts early and is transparent, inclusive, and ongoing; solicit feedback from the local community – including from opposition groups – on location, design, finance, and management; ensure finalized protections address sociological, economic, and ecological considerations.
  • Develop regional and transboundary coordination mechanisms for seaweed protection - especially, when working across international borders; consider using proven methods from adjacent issue areas such as fresh-water management or combining MPA management with existing coordinating bodies.
  • Review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Maintain detailed financial records of activities related to MPA designation and management; share costs publicly and provide recommendations for best practices.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweed and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; adjust enforcement and strategies to reduce leakage, if necessary.
  • Maintain up-to-date records of seaweed harvesting and existing populations; monitor impacts; adjust regulations and enforcement to ensure harvesting is sustainable.
  • Invest in research on seaweed biodiversity seeking to document new species, sample from underrepresented regions, and use the most up-to-date techniques to assess taxonomies; support efforts to update key databases such as the IUCN Red List; support research to improve confidence in estimates of global seaweed ecosystem extent, biomass, composition, productivity, and loss rates; monitor related long-term trends.
  • Create educational and volunteer programs that work with schools, universities, NGOs, and the general public to inform communities of how to participate in seaweed protection efforts, benefits, and opportunities; expand extension services to develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Business Leaders

  • Ensure operations, development, and supply chains are not degrading seaweed communities or interfering with MPA management.
  • Develop markets for native species products and other sustainable uses of seaweed and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Consider offering company grants to suppliers or other partners to improve resource management within your supply chain.
  • Offer incubator services for those working on seaweed protection; offer pro bono business advice or general support for community protection efforts.
  • Enter into outgrower schemes to support sustainable harvesters; make long-term commitments to help stabilize projects.
  • Consider donating or contributing to local seaweed protection efforts; consider using an internal carbon fee or setting aside a percentage of revenue to fund protection projects.
  • Amplify the voices of local communities and civil society to promote robust media coverage.
  • Invest in and support Indigenous and local communities' capacity for management, legal protection, and public relations.
  • Leverage political influence to advocate for stronger seaweed protection policies at national and international levels.
  • Offer employee professional development funds to be used for certification in seaweed protection or related fields such as curricular economies.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Nonprofit Leaders

  • Ensure operations, development, and supply chains are not degrading seaweed communities or interfering with MPA management, if relevant.
  • Assist in managing restoration projects; consider using alternative business structures such as cooperatives.
  • Develop seaweed protection tool kits specific for nations or regions; include best practices, management strategies, typical interventions, recommendations for regulations, and strategies for civil society to impact legal classifications and MPA designations.
  • Advocate for achievable targets and pledges for seaweed protection with clear effectiveness goals; help regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish or advocate for the establishment of MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; advocate for statutory protections for seaweeds in existing MPAs; help expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Seek to identify local drivers of seaweed decline, help address causes when possible, and advocate for stringent legal protections with strict enforcement.
  • Help develop or advocate for regional and transboundary coordination mechanisms for protecting seaweeds, especially when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Help review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Codesign seaweed protection projects with the local community; ensure the community engagement process starts early and is transparent, inclusive, and ongoing; solicit feedback from the local community – including from opposition groups–- on location, design, finance, and management strategies; ensure finalized protections address relevant sociological, economic, and ecological considerations.
  • Help maintain and/or audit detailed financial records of activities related to MPA designation and management; share costs publicly and provide recommendations for best practices.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; advocate to codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweed and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Help establish outgrower schemes and negotiate contracts to support sustainable harvesters to ensure they receive the most favorable terms possible.
  • Assist in maintaining up-to-date records of seaweed harvesting and existing ecosystems; monitor impacts; advocate for adjustments to regulations and enforcement to ensure harvesting is sustainable.
  • Help create educational and volunteer programs that work with schools, universities, other NGOs, and the general public to inform communities of how to participate in seaweed protection efforts, benefits, and opportunities; develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Investors

  • Create investment portfolios that support seaweed protection and sustainable use; use current data and the latest technology to guide sustainable investments.
  • Apply environmental and social standards to existing investments; divest from destructive industries and/or work with portfolio companies to improve practices.
  • Offer specific credit lines for seaweed protection projects with long-term timelines; offer low-interest loans, microfinancing, and specific financial products for small and medium-sized projects.
  • Own equity in sustainable projects that manage or support seaweed protection, especially during the early and middle phases.
  • Offer incubator services for those working on seaweed protection; offer pro bono business advice or general support for community protection projects.
  • Provide catalytic financing for businesses developing sustainable products made from native species, local ecotourism, or other sustainable uses of seaweed and MPAs.
  • Invest in blue bonds or high-integrity carbon credits for seaweed protection or supportive efforts.
  • Support seaweed protection, other investors, and NGOs by sharing data, information, and investment frameworks that successfully avoid investments that drive declines in seaweeds and damage their habitats.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Philanthropists and International Aid Agencies

  • Ensure operations, development, and supply chains are not degrading seaweed communities or interfering with MPA management, if relevant.
  • Help manage restoration projects; consider using alternative business structures such as cooperatives.
  • Offer grants or specific credit lines for seaweed protection projects with long-term timelines; offer low-interest loans, microfinancing options, and favorable financial products for small and medium-sized projects.
  • Own equity in sustainable projects that manage or support seaweed protection, especially during the early and middle phases.
  • Offer incubator services for those working on seaweed protection; offer free business advice or general support for community protection projects.
  • Provide catalytic financing for business developing sustainable products made from native species, local ecotourism, or other sustainable uses of reforested lands.
  • Develop seaweed protection tool kits specific for nations or regions; include best practices, management strategies, typical interventions, recommendations for regulations, and strategies for civil society to impact legal classifications and MPA designations.
  • Advocate for achievable targets and pledges for seaweed protection with clear effectiveness goals; help regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish or advocate for the establishment of MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting other taxa such as red seaweeds; advocate for statutory protections for seaweeds in existing MPAs; help expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Help develop or advocate for regional and transboundary coordination mechanisms for protecting seaweeds, especially when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Help review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Help maintain and/or audit detailed financial records of activities related to MPA designation and management; share costs publicly and provide recommendations for best practices.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; advocate to codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweeds and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Help establish outgrower schemes and negotiate contracts to support sustainable harvesters to ensure they receive the most favorable terms possible.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Thought Leaders

  • If possible, initiate seaweed protection projects in your area; work with local experts, share your experience, and document your progress.
  • Advocate for achievable targets and pledges for seaweed protection with clear effectiveness goals; help regularly measure and report on protection status, seaweed ecosystems, challenges, and related data points.
  • Help develop definitions, standards, strategies, and commitments at the international level for seaweed protection along with frameworks for measurement and monitoring; design indicators to capture long-term impacts, including metrics to capture social and biodiversity impacts.
  • Establish or advocate for the establishment of MPAs specifically for seaweeds and their habitats; target subtidal brown seaweeds for maximum climate benefits while not neglecting others such as red seaweeds; advocate for statutory protections for seaweeds in existing MPAs; help expand MPA designations to meet international goals.
  • Help create strong regulatory frameworks with clear goals and definitions for activities related to seaweed protection such as sustainable harvesting, protection, management, and restoration; ensure the framework is gender responsive and seeks to include women throughout the protection process.
  • Help develop or advocate for regional and transboundary coordination mechanisms for protecting seaweeds, especially, when working across international borders; consider using proven methods from adjacent issue areas such as freshwater management or combining MPA management with existing coordinating bodies.
  • Help review MPA management plans, regulations, designs, and implementation strategies frequently to adjust for changing conditions; update as needed and ensure protections allow for changes to respond to climatic conditions.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; advocate to codify FPIC into legal systems.
  • Center Indigenous communities and knowledge in MPA management strategies; help document and amplify Indigenous wisdom and practices.
  • Work with businesses to develop markets for native species products and other sustainable uses of seaweeds and MPAs.
  • Develop or support opportunities for ecotourism industries in local MPAs with particular emphasis on educating tourists of the importance of seaweed.
  • Create programs to monitor for activity and market leakage from protected sites; advocate for adjustments to enforcement and policies to reduce leakage, if necessary.
  • Help establish outgrower schemes and negotiate contracts to support sustainable harvesters to ensure they receive the most favorable terms possible.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

Technologists and Researchers

  • Help develop spatial distribution models of seaweed ecosystems combining field surveys, satellite data, and machine learning to help identify likely locations of seaweed and vulnerable ecosystems; conduct field observations to validate and/or improve models; update existing or create new databases with the information.
  • Help improve confidence in estimates of global seaweed ecosystems and monitor related long-term trends, including impacts of harvesting and adaptive capacity of seaweeds.
  • Conduct research on seaweed biodiversity seeking to document new species, sample from underrepresented regions, and use the most up-to-date techniques to assess taxonomies; help update key databases such as the IUCN Red List.
  • Help develop national seedstocks and biosecure nurseries for local and vulnerable seaweed.
  • Research the interactions of disturbances such as overfishing, eutrophication, coastal darkening, invasive species, climate change, and other related variables on seaweed ecosystems; identify loss rates and protection strategies to mitigate impacts from these events.
  • Examine and document ecosystem functions of various seaweed varieties, including their productivity and potential contributions to carbon removal; research the benefits of seaweed protection for human well-being.
  • Help classify existing MPAs according to IUCN categories; monitor ongoing efforts; use learnings to inform management.
  • Help gather accurate financial data on MPAs; assess average and global costs; provide cost projections for potential MPA sites; assess financial gains provided by MPAs, such as increased tourism and economic activity.
  • Work with Indigenous communities under FPIC to help document, examine, and apply traditional practices; help amplify relevant Indigenous knowledge.

Further information:

Communities, Households, and Individuals

  • If possible, initiate seaweed protection projects in your area; work with local experts, share your experience, and document your progress.
  • Help establish and participate in local protection efforts; consider volunteering with a local nonprofit or establishing one if none exists.
  • Conduct citizen science research to map and monitor local seaweed communities; share your findings with policymakers, local experts, and the public.
  • If seaweed communities are being damaged in your area and no action is being taken, conduct individual advocacy by speaking to local officials, handing out fliers, and other relevant methods.
  • Help identify local sources of degradation and distribute findings to policymakers and the public; help address causes when possible and advocate for stringent legal protections with strict enforcement.
  • Call on governments and administrators to use transparent, inclusive, and ongoing community engagement processes to codesign seaweed protection projects; help solicit community feedback on area designations, finance, monitoring, and distribution of benefits; help ensure finalized projects address relevant sociological, economic, and ecological considerations.
  • Reduce and/or eliminate use of chemicals on your lawn and/or property to reduce pollution runoff, especially if your property contains or is located on a coastally connected watershed; set up a sign that indicates your lawn is chemical-free.
  • Have community conversations about local seaweed habitats, MPAs, and local drivers of damage; seek to reduce harmful practices such as overuse of fertilizers and pesticides; educate friends and neighbors about local degraded seaweed habitats and potential solutions.
  • Consider donating or contributing to local protection efforts.
  • Try to purchase sustainable seaweed products that support local protection efforts.
  • When traveling, look for opportunities to support seaweed protection projects and ecotourism.
  • Advocate for strong land tenure rights; support Indigenous property rights and autonomy to protect watersheds and adjacent terrestrial systems to seaweed habitats.
  • Ensure projects operating in or with Indigenous communities only do so under FPIC; help codify FPIC into legal systems.
  • Help document and develop knowledge-sharing opportunities for Indigenous and local knowledge.
  • Help create educational and volunteer programs that work with schools, universities, NGOs, and the general public to inform communities of how to participate in seaweed protection efforts, benefits, and opportunities; develop local capacity in seaweed protection, especially in community-led monitoring and evaluation; establish knowledge-sharing initiatives with Indigenous peoples.
  • Join, create, or participate in public-private partnerships dedicated to mobilizing financing, protection activities, knowledge transfers, general education, and other relevant areas.
  • Join, support, or create certification schemes that verify protected areas and sustainable use of seaweed products.

Further information:

“Take Action” Sources

References

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Balmford, A., Gravestock, P., Hockley, N., McClean, C. J. and Roberts, C. M. (2004). The worldwide costs of marine protected areas. Proceedings of the National Academy of Sciences, 101(26), 9694–9697. Link to source: https://doi.org/10.1073/pnas.0403239101

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Earp, H. S., Smale, D. A., Almond, P. M., Catherall, H. J. N., Gouraguine, A., Wilding, C., & Moore, P. J. (2024). Temporal variation in the structure, abundance, and composition of Laminaria hyperborea forests and their associated understorey assemblages over an intense storm season. Marine Environmental Research, 200, Article 106652. Link to source: https://doi.org/10.1016/j.marenvres.2024.106652

Eger, A. M., Eddy, N., McHugh, T. A., Arafeh-Dalmau, N., Wernberg, T., Krumhansl, K., Verbeek, J., Branigan, S., Kuwae, T., Caselle, J. E., Ospina, A. G., & Vergés, A. (2024). State of the world’s kelp forests. One Earth, 7(11), 1927–1931. Link to source: https://doi.org/10.1016/j.oneear.2024.10.008

Eger, A. M., Marzinelli, E. M., Christie, H., Fagerli, C. W., Fujita, D., Gonzalez, A. P., Hong, S. W., Kim, J. H., Lee, L. C., McHugh, T. A., Nishihara, G. N., Tatsumi, M., Steinberg, P. D., & Vergés, A. (2022). Global kelp forest restoration: Past lessons, present status, and future directions. Biological Reviews, 97(4), 1449–1475. Link to source: https://doi.org/10.1111/brv.12850

Eger, A. M., Marzinelli, E. M., Beas-Luna, R., Blain, C. O., Blamey, L. K., Byrnes, J. E. K., Carnell, P. E., Choi, C. G., Hessing-Lewis, M., Kim, K. Y., Kumagai, N. H., Lorda, J., Moore, P., Nakamura, Y., Pérez-Matus, A., Pontier, O., Smale, D., Steinberg, P. D., & Vergés, A. (2023). The value of ecosystem services in global marine kelp forests. Nature Communications, 14(1), Article 1894. Link to source: https://doi.org/10.1038/s41467-023-37385-0

Elsmore, K., Nickols, K. J., Miller, L. P., Ford, T., Denny, M. W., & Gaylord, B. (2024). Wave damping by giant kelp, Macrocystis pyrifera. Annals of Botany, 133(1), 29–40. Link to source: https://doi.org/10.1093/aob/mcad094

Food and Agriculture Organization of the United Nations. (2024). The state of world fisheries and aquaculture 2024: Blue transformation in action [Report]. Link to source: https://doi.org/10.4060/cd0683en

Filbee-Dexter, K. (2020). Ocean forests hold unique solutions to our current environmental crisis. One Earth, 2(5), 398–401. Link to source: https://doi.org/10.1016/j.oneear.2020.05.004

Filbee-Dexter, K., & Wernberg, T. (2020). Substantial blue carbon in overlooked Australian kelp forests. Scientific Reports, 10, Article 12341. Link to source: https://doi.org/10.1038/s41598-020-69258-7

Filbee-Dexter, K., Feehan, C. J., Smale, D. A., Krumhansl, K. A., Augustine, S., de Bettignies, F., Burrows, M. T., Byrnes, J. E. K., Campbell, J., Davoult, D., Dunton, K. H., Franco, J. N., Garrido, I., Grace, S. P., Hancke, K., Johnson, L. E., Konar, B., Moore, P. J., Norderhaug, K. M., … Wernberg, T. (2022). Kelp carbon sink potential decreases with warming due to accelerating decomposition. PLOS Biology, 20(8), Article e3001702. Link to source: https://doi.org/10.1371/journal.pbio.3001702

Filbee‐Dexter, K., Starko, S., Pessarrodona, A., Wood, G., Norderhaug, K. M., Piñeiro‐Corbeira, C., & Wernberg, T. (2024a). Marine protected areas can be useful but are not a silver bullet for kelp conservation. Journal of Phycology, 60(2), 203–213. Link to source: https://doi.org/10.1111/jpy.13446

Filbee-Dexter, K., Pessarrodona, A., Pedersen, M. F., Wernberg, T., Duarte, C. M., Assis, J., Bekkby, T., Burrows, M. T., Carlson, D. F., Gattuso, J.-P., Gundersen, H., Hancke, K., Krumhansl, K. A., Kuwae, T., Middelburg, J. J., Moore, P. J., Queirós, A. M., Smale, D. A., Sousa-Pinto, I., … Krause-Jensen, D. (2024b). Carbon export from seaweed forests to deep ocean sinks. Nature Geoscience, 17(6), 552–559. Link to source: https://doi.org/10.1038/s41561-024-01449-7

Gao, G., Gao, L., Jiang, M., Jian, A., & He, L. (2022). The potential of seaweed cultivation to achieve carbon neutrality and mitigate deoxygenation and eutrophication. Environmental Research Letters, 17(1), Article 014018. Link to source: https://doi.org/10.1088/1748-9326/ac3fd9

Gibbons, E. G., & Quijón, P. A. (2023). Macroalgal features and their influence on associated biodiversity: Implications for conservation and restoration. Frontiers in Marine Science, 10, Article 1304000. Link to source: https://doi.org/10.3389/fmars.2023.1304000

González-Roca, F., Gelcich, S., Pérez-Ruzafa, Á., Vega, J. M. A., & Vásquez, J. A. (2021). Exploring the role of access regimes over an economically important intertidal kelp species. Ocean & Coastal Management, 212, Article 105811. Link to source: https://doi.org/10.1016/j.ocecoaman.2021.105811

Hanley, M. E., Firth, L. B., & Foggo, A. (2024). Victim of changes? Marine macroalgae in a changing world. Annals of Botany, 133(1), 1–16. Link to source: https://doi.org/10.1093/aob/mcad185

Harley, C. D. G., Anderson, K. M., Demes, K. W., Jorve, J. P., Kordas, R. L., Coyle, T. A., & Graham, M. H. (2012). Effects of climate change on global seaweed communities. Journal of Phycology, 48(5), 1064–1078. Link to source: https://doi.org/10.1111/j.1529-8817.2012.01224.x

Heckwolf, M. J., Peterson, A., Jänes, H., Horne, P., Künne, J., Liversage, K., Sajeva, M., Reusch, T. B. H., & Kotta, J. (2021). From ecosystems to socio-economic benefits: A systematic review of coastal ecosystem services in the Baltic Sea. Science of the Total Environment, 755, Article 142565. Link to source: https://doi.org/10.1016/j.scitotenv.2020.142565

Hurd, C. L., Gattuso, J.-P., & Boyd, P. W. (2024). Air-sea carbon dioxide equilibrium: Will it be possible to use seaweeds for carbon removal offsets? Journal of Phycology, 60(1), 4–14. Link to source: https://doi.org/10.1111/jpy.13405

Kelp Forest Alliance. (2024). State of the world’s kelp report [Report]. Link to source: https://kelpforestalliance.com/state-of-the-worlds-kelp-report/

Krause-Jensen, D., & Duarte, C. M. (2016). Substantial role of macroalgae in marine carbon sequestration. Nature Geoscience, 9(10), 737–742. Link to source: https://doi.org/10.1038/ngeo2790

Krause-Jensen, D., Lavery, P., Serrano, O., Marbà, N., Masque, P., & Duarte, C. M. (2018). Sequestration of macroalgal carbon: The elephant in the blue carbon room. Biology Letters, 14(6), Article 20180236. Link to source: https://doi.org/10.1098/rsbl.2018.0236

Krumhansl, K. A., Okamoto, D. K., Rassweiler, A., Novak, M., Bolton, J. J., Cavanaugh, K. C., Connell, S. D., Johnson, C. R., Konar, B., Ling, S. D., Micheli, F., Norderhaug, K. M., Pérez-Matus, A., Sousa-Pinto, I., Reed, D. C., Salomon, A. K., Shears, N. T., Wernberg, T., Anderson, R. J., … Byrnes, J. E. K. (2016). Global patterns of kelp forest change over the past half-century. Proceedings of the National Academy of Sciences, 113(48), 13785–13790. Link to source: https://doi.org/10.1073/pnas.1606102113

Kumagai, J. A., Goodman, M. C., Villaseñor-Derbez, J. C., Schoeman, D. S., Cavanuagh, K. C., Bell, T. W., Micheli, F., De Leo, G., & Arafeh-Dalmau, N. (2024). Marine protected areas that preserve trophic cascades promote resilience of kelp forests to marine heatwaves. Global Change Biology, 30(12), Article e17620. Link to source: https://doi.org/10.1111/gcb.17620

Lindhart, M., Daly, M. A., Walker, H., Arzeno-Soltero, I. B., Yin, J. Z., Bell, T. W., Monismith, S. G., Pawlak, G., & Leichter, J. J. (2024). Short wave attenuation by a kelp forest canopy. Limnology and Oceanography Letters, 9(4), 478–486. Link to source: https://doi.org/10.1002/lol2.10401

McCrea-Strub, A., Zeller, D., Rashid Sumaila, U., Nelson, J., Balmford, A., & Pauly, D. (2011). Understanding the cost of establishing marine protected areas. Marine Policy, 35(1), 1–9. Link to source: https://doi.org/10.1016/j.marpol.2010.07.001

Ortega, A., Geraldi, N. R., Alam, I., Kamau, A. A., Acinas, S. G., Logares, R., Gasol, J. M., Massana, R., Krause-Jensen, D., & Duarte, C. M. (2019). Important contribution of macroalgae to oceanic carbon sequestration. Nature Geoscience, 12(9), 748–754. Link to source: https://doi.org/10.1038/s41561-019-0421-8

Ortiz‐Villa, E. M., Rassweiler, A., Caselle, J. E., Cavanaugh, K. C., Arafeh‐Dalmau, N., Bell, T. W., & Cavanaugh, K. C. (2025). Marine protected areas enhance climate resilience to severe marine heatwaves for kelp forests. Journal of Applied Ecology, 62(9), 2439–2453. Link to source: https://doi.org/10.1111/1365-2664.70112

Pessarrodona, A., Franco-Santos, R. M., Wright, L. S., Vanderklift, M. A., Howard, J., Pidgeon, E., Wernberg, T., & Filbee-Dexter, K. (2023). Carbon sequestration and climate change mitigation using macroalgae: A state of knowledge review. Biological Reviews, 98(6), 1945–1971.  Link to source: https://doi.org/10.1111/brv.12990

Rodríguez-Rodríguez, D., & Martínez-Vega, J. (2022). Chapter three—Ecological effectiveness of marine protected areas across the globe in the scientific literature. In C. Sheppard (Ed.), Advances in marine biology (Vol. 92, pp. 129–153). Academic Press. Link to source: https://doi.org/10.1016/bs.amb.2022.07.002

Roth, F., Broman, E., Sun, X., Bonaglia, S., Nascimento, F., Prytherch, J., Brüchert, V., Lundevall Zara, M., Brunberg, M., Geibel, M. C., Humborg, C., & Norkko, A. (2023). Methane emissions offset atmospheric carbon dioxide uptake in coastal macroalgae, mixed vegetation and sediment ecosystems. Nature Communications, 14(1), Article 42. Link to source: https://doi.org/10.1038/s41467-022-35673-9

Steen, H., Moy, F. E., Bodvin, T., & Husa, V. (2016). Regrowth after kelp harvesting in Nord-Trøndelag, Norway. ICES Journal of Marine Science, 73(10), 2708–2720. Link to source: https://doi.org/10.1093/icesjms/fsw130

Steneck, R. S., Graham, M. H., Bourque, B. J., Corbett, D., Erlandson, J. M., Estes, J. A., & Tegner, M. J. (2002). Kelp forest ecosystems: Biodiversity, stability, resilience and future. Environmental Conservation, 29(4), 436–459. Link to source: https://doi.org/10.1017/S0376892902000322

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Thurstan, R. H., Brittain, Z., Jones, D. S., Cameron, E., Dearnaley, J., & Bellgrove, A. (2018). Aboriginal uses of seaweeds in temperate Australia: An archival assessment. Journal of Applied Phycology, 30(3), 1821–1832. Link to source: https://doi.org/10.1007/s10811-017-1384-z

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Waldron, A., Adams, V., Allan, J., Arnell, A., Asner, G., Atkinson, S., Baccini, A., Baillie, J. E. M., Balmford, A., Beau, J. A., Brander, L., Brondizio, E., Bruner, A., Burgess, N., Burkart, K., Butchart, S., Button, R., Carraso, R., Cheung, W., … Zhang, Y. P. (2020). Protecting 30% of the planet for nature: Costs, benefits and economic implications [Report]. Campaign for Nature. Link to source: https://www.conservation.cam.ac.uk/files/waldron_report_30_by_30_publish.pdf

Wong, W. W., Greening, C., Shelley, G., Lappan, R., Leung, P. M., Kessler, A., Winfrey, B., Poh, S. C., & Cook, P. (2021). Effects of drift algae accumulation and nitrate loading on nitrogen cycling in a eutrophic coastal sediment. Science of The Total Environment, 790, Article 147749. Link to source: https://doi.org/10.1016/j.scitotenv.2021.147749

Appendix

This analysis quantifies emissions that can be avoided by protecting seaweed ecosystems via the establishment of Marine Protected Areas (MPAs). We leveraged two global seaweed distribution maps alongside a shapefile of MPAs, available data on rates of avoided ecosystem loss attributable to MPA establishment, and global data on biomass carbon stores and carbon sequestration rates to calculate climate impacts. This appendix describes the source data products and how they were integrated.

Seaweed Ecosystem Extent

We relied on the global maps of seaweed extent developed by Duarte et al. (2022), which classify subtidal brown and red seaweeds (among others). We used the “LT2 Brown Algae Benthic” raster to calculate subtidal brown seaweed extent and the “LT2 Red Algae Benthic” raster to calculate subtidal red seaweed extent. We did not consider red seaweed in subtidal brown-dominant environments, such as kelp forests, due to existing limitations with the global maps. 

Protected Seaweed Ecosystem Areas

We identified protected seaweed ecosystem areas using the World Database on Protected Areas (UNEP-WCMC & IUCN, 2024), which contains boundaries for each MPA and additional information, including the establishment year and IUCN management category (Ia to VI, not applicable, not reported, or not assigned). In this analysis, we considered all categories. While some MPA categories likely allow for wild harvest, which can be unsustainably conducted, wild seaweed harvest is currently estimated at 1.3 Mt/yr (wet weight) (FAO, 2024), which represents a relatively small portion of the global loss rate used (<0.2%/yr). We converted the MPA boundary data to a raster and used them to calculate the seaweed area within MPA boundaries for each seaweed type analyzed (subtidal brown and red) and each MPA category. To evaluate trends in adoption over time, we also aggregated protected areas by establishment year as reported in the WDPA. 

Calculation of Effectiveness

The following equations show a detailed breakdown of the stepwise set of calculations used to implement Equation 1, including estimation of avoided seaweed loss and of emissions and retained sequestration across the 30-year time horizon considered.

Avoided Seaweed Ecosystem Conversion

We compiled baseline estimates of seaweed ecosystem loss (%/yr) from existing literature and used them in conjunction with an estimate of reductions in loss associated with protection of 53% (derived from Rodríguez-Rodríguez & Martínez-Vega, 2022) to calculate the rate of avoidable macroalgae loss (Seaweed lossavoided). Seaweed ecosystem loss rates were based on the original analysis of data aggregated from Krumhansl et al. (2016) for studies over 20 years long (Seaweed lossbaseline; median loss rate of 1.2%/yr). 

Equation A1.

\[ Seaweed\ loss_{avoided}=Seaweed\ loss_{baseline} \times Reduction\ in\ loss\]

We then used the avoidable seaweed loss rates to calculate avoided CO₂ emissions and additional carbon sequestration for each adoption unit. Specifically, we estimated the carbon benefits of avoided seaweed ecosystem loss by multiplying avoided seaweed ecosystem loss by avoided CO₂ emissions (Equation A2) and by applying carbon sequestration rates over 30 years (Equation A3) for each seaweed type. 

We estimated avoided CO₂ emissions by assuming a one-time release of all aboveground biomass carbon upon loss. We derived our estimates of retained carbon sequestration from global databases on NPP for each seaweed type from Duarte et al. (2022) and a global estimate of NPP-derived sequestration (11.4%) from NPP based on Krause-Jensen and Duarte (2016). 

Equation A2.

\[Avoided\ emissions= Seaweed\ loss_{avoided} \times \sum_{t=1}^{30}(Emissions)\]

Equation A3.

\[Sequestration= Seaweed\ loss_{avoided} \times \sum_{t=1}^{30}(Sequestration)\]

We then estimated effectiveness (Equation A4) as the avoided CO₂ emissions and retained carbon sequestration capacity attributable to the reduction in seaweed ecosystem loss conferred by protection estimated in Equations A1–3.

Equation A4.

\[Effectiveness = (Carbon_{avoided\ emissions}+ Carbon_{sequestration})\]

Credits

Lead Fellow

  • Christina Richardson, Ph.D.

Contributors

  • Ruthie Burrows, Ph.D.

  • Avery Driscoll, Ph.D.

  • James Gerber, Ph.D.

  • Daniel Jasper

  • Alex Sweeney

Internal Reviewers

  • Aiyana Bodi

  • Avery Driscoll, Ph.D.

  • Christina Swanson, Ph.D.

  • Paul C. West, Ph.D.

Methods and Supporting Data

Methods and Supporting Data

Comments / Questions

  • Greenhouse gas quantity expressed relative to CO₂ with the same warming impact over 100 years, calculated by multiplying emissions by the 100-yr GWP for the emitted gases.

  • Greenhouse gas quantity expressed relative to CO₂ with the same warming impact over 20 years, calculated by multiplying emissions by the 20-yr GWP for the emitted gases.

  • 8th World Congress on Conservation Agriculture

  • Reducing greenhouse gas concentrations in the atmosphere by preventing or reducing emissions.

  • Air conditioning

  • A liquid with a low pH (below 7).

  • The process of increasing acidity.

  • The extent to which emissions reduction or carbon removal is above and beyond what would have occurred without implementing a particular action or solution.

  • An upper limit on solution adoption based on physical or technical constraints, not including economic or policy barriers. This level is unlikely to be reached and will not be exceeded.

  • The quantity and metric to measure implementation for a particular solution that is used as the reference unit for calculations within that solution.

  • A composting method in which organic waste is processed in freestanding piles that can be aerated actively with forced air or passively by internal convection.

  • The interactions of aerodynamic forces and flexible structures, often including the stucture's control system.

  • A process in which microbes break down organic materials in the presence of oxygen. This process converts food and green waste into nutrient-rich compost.

  • Establishment of new forests in areas that did not historically support forests.

  • Farming practices that work to create socially and ecologically sustainable food production.

  • Addition of trees and shrubs to crop or animal farming systems.

  • Artificial intelligence

  • Spread out the cost of an asset over its useful lifetime.

  • A process in which microorganisms break down organic material in the absence of oxygen. Methane and CO₂ are the main byproducts.

  • A crop that live one year or less from planting to harvest; also called annual.

  • aerated static piles

  • Electric power delivered at a steady, around-the-clock rate, to cover power demand that exists at all times. Baseload power is typically supplied by high availability, low operating-cost plants, such as nuclear or geothermal.

  • A liquid with a high pH (above 7).

  • black carbon

  • Solar panels that generate electricity from sunlight captured on both sides, increasing energy output by reflecting light from the ground and surroundings.

  • Made from material of biological origin, such as plants, animals, or other organisms.

  • A renewable energy source generated from organic matter from plants and/or algae.

  • An energy source composed primarily of methane and CO₂ that is produced by microorganisms when organic matter decomposes in the absence of oxygen.

  • Carbon stored in biological matter, including soil, plants, fungi, and plant products (e.g., wood, paper, biofuels). This carbon is sequestered from the atmosphere but can be released through decomposition or burning.

  • Living or dead renewable matter from plants or animals, not including organic material transformed into fossil fuels. Peat, in early decay stages, is partially renewable biomass.

  • Biogas refined to the same quality as natural gas. CO₂ and impurities are removed, and the biomethane can be distributed and used in existing natural gas technologies.
     

  • A type of carbon sequestration that captures carbon from CO₂ via photosynthesis and stores it in soils, sediments, and biomass, distinct from sequestration through chemical or industrial pathways.

  • A synthetic organic compound used to make a type of hard, clear plastic for food and drink packaging and many consumer goods.

  • A climate pollutant, also called soot, produced from incomplete combustion of organic matter, either naturally (wildfires) or from human activities (biomass or fossil fuel burning).

  • A secure, decentralized way of digitally tracking transactions that could be used to improve the transparency and efficiency of carbon markets. 

  • Fixed income debt instruments focused on sustainable ocean projects. Blue bonds work in the same manner as traditional bonds and may be issued by corporations, financial institutions, and governments.

  • A global initiative launched by Germany and the IUCN in 2011 to restore 150 Mha of land by 2020 and 350 Mha by 2030.

  • High-latitude (>50°N or >50°S) climate regions characterized by short growing seasons and cold temperatures.

  • bisphenol A

  • Revenue from carbon credits reserved for payout to land- and rights-holders in the event of a disturbance such as a fire; similar to insurance scheme.

  • The components of a building that physically separate the indoors from the outdoor environment.

  • Businesses involved in the sale and/or distribution of solution-related equipment and technology, and businesses that want to support adoption of the solution.

  • Compound annual growth rate

  • A chemical reaction involving heating a solid to a high temperature; to make cement clinker, limestone is calcined into lime in a process that requires high heat and produces CO₂.

  • The ratio of the actual electricity an energy technology generates over a period of time to the maximum it could have produced if it operated continuously at full capacity.

  • A four-wheeled passenger vehicle.

  • Average number of people traveling in a car per trip.

  • Technologies that collect CO₂ before it enters the atmosphere, preventing emissions at their source. Collected CO₂ can be used onsite or in new products, or stored long term to prevent release.

  • A greenhouse gas that is naturally found in the atmosphere. Its atmospheric concentration has been increasing due to human activities, leading to warming and climate impacts.

  • Total GHG emissions resulting from a particular action, material, technology, or sector.

  • Amount of GHG emissions released per activity or unit of production. 

  • A marketplace where carbon credits are purchased and sold. One carbon credit represents activities that avoid, reduce, or remove one metric ton of GHG emissions.

  • A colorless, odorless gas released during the incomplete combustion of fuels containing carbon. Carbon monoxide can harm health and be fatal at high concentrations.

  • The time it takes for the emissions reduction from a measure to equal the emissions invested in implementing the measure.

  • Activities or technologies that pull CO₂ out of the atmosphere, including enhancing natural carbon sinks and deploying engineered sinks.

  • Long-term storage of carbon in soils, sediment, biomass, oceans, and geologic formations after removal of CO₂ from the atmosphere or CO₂ capture from industrial and power generation processes.

  • The interconnected pool of dissolved inorganic carbon forms in water. Composed of dissolved CO₂, carbonic acid, bicarbonate ions, and carbonate ions.

  • carbon capture and storage

  • carbon capture, utilization, and storage

  • Cooling degree days

  • A binding ingredient in concrete responsible for most of concrete’s life-cycle emissions. Cement is made primarily of clinker mixed with other mineral components.

  • chlorofluorocarbon

  • Processes that use chemical reactions or heat to break down plastic waste into basic molecular components or feedstocks that can then be used to make new plastic products.

  • Process that uses chemical reactions or heat to break down plastic waste into basic molecular components that can be used to make new plastic products.

  • methane

  • A system in which resources, materials, and products are used for as long as possible through reuse, repair, refurbishment, and recycling.

  • Energy sources that have little to no negative environmental or climate impacts during operation relative to fossil fuel–based energy sources.

  • Gases or particles that have a planet-warming effect when released to the atmosphere. Some climate pollutants also cause other forms of environmental damage.

  • Areas that have natural buffers from local climate change impacts, offering safe havens for species and ecosystems.

  • A binding ingredient in cement responsible for most of the life-cycle emissions from cement and concrete production.

  • A waste management process where waste is made into the same original product, preserving quality and value so materials can be reused multiple times while keeping resources in continuous use.

  • A system that encompasses both forward supply chains (from producer to consumer) and reverse logistics for reuse, recycling, or proper disposal.

  • Neighbors, volunteer organizations, hobbyists and interest groups, online communities, early adopters, individuals sharing a home, and private citizens seeking to support the solution.

  • A solution that potentially lowers the benefit of another solution through reduced effectiveness, higher costs, reduced or delayed adoption, or diminished global climate impact.

  • The average annual rate at which a value grows over a specified period, assuming profits are reinvested and growth occurs steadily each year.

  • Funding with substantially more generous terms than market loans (typically due to lower interest rates, longer repayment periods, or partial grants) used to support projects with public or development benefits.

  • A farming system that combines reduced tillage, cover crops, and crop rotations.

  • The proportion of water used or applied that is evaporated, transpired, or incorporated into a product and therefore is not returned to the local hydrological system through runoff or leaching.

  • Risk-sharing financial agreements in which two parties (e.g., renewable generator, government) guarantee a fixed price (e.g., electricity price). If market prices fluctuate, one party pays the other the difference.

  • Persistent long, thin clouds that form behind aircraft when water vapor in the exhaust condenses, then freezes into ice crystals at high altitudes. 

  • A measure of the total space cooling demand to maintain an indoor temperature below 24 °C

  • carbon dioxide

  • A  measure standardizing the warming effects of greenhouse gases relative to CO₂. CO₂-eq is calculated as quantity (metric tons) of a particular gas multiplied by its GWP.

  • carbon dioxide equivalent

  • Plant materials left over after a harvest, such as stalks, leaves, and seed husks.

  • A granular material made by crushing broken or waste glass.

  • direct air capture

  • Financial agreements in which government creditors forgive a portion of debt in exchange for specific conservation commitments.

  • The process of cutting greenhouse gas emissions (primarily CO₂) from a particular sector or activity.

  • An industrial process that removes printing ink from used or waste paper fibers, creating clean pulp that can be turned into new paper products.

  • A solution that works slower than gradual solutions and is expected to take longer to reach its full potential.

  • Microbial conversion of nitrate into inert nitrogen gas under low-oxygen conditions, which produces the greenhouse gas nitrous oxide as an intermediate compound.

  • Electronic document that verifies whether a product has been manufactured according to environmental and social standards and/or material origins, environmental impact, and disposal recommendations.

  • Electronic documents that verify whether or not a product has been manufactured according to environmental and social standards and/or material origins, environmental impact, and disposal recommendations.

  • Greenhouse gas emissions produced as a direct result of the use of a technology or practice.

  • Electric power that can be increased, decreased, or turned on/off to match real-time fluctuations in grid conditions. Typically supplied by fast-responding plants such as natural gas, hydroelectric, or battery storage.

  • The inorganic forms of carbon dissolved in seawater. Composed of dissolved CO₂, carbonic acid, bicarbonate ions, and carbonate ions.

  • A system of underground distribution pipes that supply heat from centralized sources to a large number of buildings for space and water heating or industrial use.

  • A window consisting of two glass panes separated by a sealed gap and typically filled with air or an inert gas to improve the heat flow resistance.

  • A waste management system that transforms waste into different products of lower quality and value, making materials harder to recycle again and limiting reuse.

  • Flexible benchmarks derived from independent, publicly available, frequently updated data sets.

  • European Energy Agency

  • Ability of a solution to reduce emissions or remove carbon, expressed in CO₂-eq per installed adoption unit. Effectiveness is quantified per year when the adoption unit is cumulative over time.

  • Enhanced geothermal system

  • Exajoule (one quintillion joules)

  • A process that uses electric current to drive a reaction, such as using electricity to split water molecules into hydrogen and oxygen.

  • Produced by electrolysis.

  • Greenhouse gas emissions accrued over the lifetime of a material or product, including as it is produced, transported, used, and disposed of.

  • Solutions that work faster than gradual solutions, front-loading their impact in the near term.

  • Methane produced by microbes in the digestive tracts of ruminant livestock, such as cattle, sheep and goats.

  • The unintended capture of organisms in intake flows.

  • Environmental Protection Agency

  • Extended Producer Responsibility

  • expanded polystyrene

  • Environmental Research & Education Foundation

  • environmental, social, and governance

  • exchange-traded fund

  • A process triggered by an overabundance of nutrients in water, particularly nitrogen and phosphorus, that stimulates excessive plant and algae growth and can harm aquatic organisms.

  • Electric vehicle

  • The movement of water from the earth’s surface to the atmosphere directly from land or water surfaces (evaporation) and through plant tissues (transpiration).

     

  • The scientific literature that supports our assessment of a solution's effectiveness.

  • A policy framework that assigns responsibility to producers for the end-of-life servicing of their products.

  • A group of human-made molecules that contain fluorine atoms. They are potent greenhouse gases with GWPs that can be hundreds to thousands times higher than CO₂.

  • Food, agriculture, land, and ocean

  • Food and Agriculture Organization of the United Nations

  • feed conversion ratio

  • The efficiency with which an animal converts feed into increased body mass, measured as the ratio of the weight of the feed given to weight gain. Lower FCR means less feed for the same growth.

  • Raw material inputs for manufacturing, processing, and managing waste.

  • Containing or consisting of iron.

  • A measure of fishing activity over time and area, commonly measured by number of trips, vessel time, or gear deployed.

  • A solar PV system with panels mounted at a constant angle.

  • Glass is manufactured by floating molten glass on a molten tin bath, producing a smooth, flat product with high optical clarity, often used for window applications.

  • food loss and waste

  • Food discarded during pre-consumer supply chain stages, including production, harvest, and processing.

  • Food discarded during pre-consumer supply chain stages, including production, harvest, and processing, along with food discarded wt the retail and consumer stages of the supply chain.

  • Food discarded at the retail and consumer stages of the supply chain.

  • Combustible materials found in Earth's crust that can be burned for energy, including oil, natural gas, and coal. They are formed from decayed organisms through prehistoric geological processes.

  • Free, prior, and informed consent

  • A principled process of working with Indigenous communities that requires consent from Indigenous peoples for any decision, action, or activity that impacts their community and/or lands.

  • Unintentional leaks of gases or vapor into the atmosphere.

  • A group of countries representing the majority of the world's population, trade, and GDP. There are 19 member countries plus the European Union and the African Union

  • Gas collection and control system

  • A design or approach to policy, programs, or activities that addresses the different situations, roles, needs, and interests of women, men, girls, and boys.

  • Manipulating the environment to influence the quantities or impact of climate pollutants in the atmosphere.

  • greenhouse gas

  • Global Horizontal Irradiance

  • gigajoule or billion joules

  • The glass layers or panes in a window.

  • A measure of how effectively a gas traps heat in the atmosphere relative to CO₂. GWP converts greenhouse gases into CO₂-eq emissions based on their 20- or 100-year impacts.

  • A solution that has a steady impact on the atmosphere. Effectiveness is expected to be constant over time rather than having a higher impact in the near or long term.

  • A system that uses the slope of a field and furrows, borders, or flooding to apply water without pumping.

  • Hydrogen produced from natural gas, most commonly by combining heated steam with methane. Producing grey hydrogen emits CO₂ and leaks methane. Most hydrogen made today is grey.

  • A fixed income debt instrument focused on sustainable projects. Green bonds work in the same manner as traditional bonds and may be issued by corporations, financial institutions, and governments.

  • A fixed income debt instrument focused on sustainable projects. They work in the same manner as traditional bonds and may be issued by corporations, financial institutions, and governments.

  • Hydrogen gas made through electrolysis using electricity produced onsite using renewable energy sources.

  • The practice of charging more for renewable energy than for conventional energy to cover added costs .

  • Roofs that are designed to be partially or completely covered in vegetation.

  • Biomass discarded during landscaping and gardening.

  • A gas that traps heat in the atmosphere, contributing to climate change.

  • The makeup of electricity generation on a power grid, showing the share contributed by various energy sources (e.g., coal, natural gas, nuclear, wind, solar, hydro) relative to total electricity production.

  • A process by which GHGs dissolved in groundwater are released to the atmosphere when the groundwater is extracted from the aquifer.

  • metric gigatons or billion metric tons

  • global warming potential

  • A low-carbon steel-making technology that uses hydrogen from water, direct reduction of iron, and electric arc furnaces. 

  • hectare

  • household air pollution

  • A sector or process that is exceptionally challenging to decarbonize, often because of a lack of mature technology options.  

  • hydrochlorofluorocarbon

  • Number of years a person is expected to live without disability or other limitations that restrict basic functioning and activity.

  • A measure of the total space heating demand to maintain an indoor temperature above 18 °C

  • A unit of land area comprising 10,000 square meters, roughly equal to 2.5 acres.

  • Hybrid electric car

  • hydrofluorocarbon

  • hydrofluoroolefin

  • hydrofluoroolefin

  • high-income countries

  • Metal waste that is produced at a mill or foundry during the metal production process and recycled internally.

  • Particles and gases released from use of polluting fuels and technologies such as biomass cookstoves that cause poor air quality in and around the home.

  • heating, ventilation, air conditioning, and refrigeration

  • Organic compounds that contain hydrogen and carbon.

  • Human-made F-gases that contain hydrogen, fluorine, and carbon. They typically have short atmospheric lifetimes and GWPs hundreds or thousands times higher than CO₂. 

  • Human-made F-gases that contain hydrogen, fluorine, and carbon, with at least one double bond. They have low GWPs and can be climate-friendly alternatives to HFC refrigerants.

  • Hydrogen is a gas that can be a fuel, feedstock, or means of storing energy. It generates water instead of GHG when burned, but the process of producing it can emit high levels of GHGs. 

  • A recycling process that separates fibers from contaminants for reuse. Paper or cardboard is mixed with water to break down fibrous materials into pulp.

  • internal combustion engine

  • International Energy Agency

  • Aerobic decomposition of organic waste in a sealed container or bin/bay system. 

  • Greenhouse gas emissions produced as a result of a technology or practice but not directly from its use.

  • A solid block of purified silicon formed by melting and crystallizing raw silicon; it serves as the base material for slicing into wafers used in solar cells.

  • Device used to power vehicles by the intake, compression, combustion, and exhaust of fuel that drives moving parts.

  • The annual discount rate that balances net cash flows for a project over time. Also called IRR, internal rate of return is used to estimate profitability of potential investments.

  • Individuals or institutions willing to lend money in search of a return on their investment.

  • Intergovernmental Panel on Climate Change

  • Indigenous peoples’ land

  • Integrated pest management.

  • internal rate of return

  • The timing and amount of irrigation water applied.

  • International Union for Conservation of Nature

  • The most comprehensive global list of species threatened with extinction, maintained by the International Union for Conservation of Nature.

  • International agreement adopted in 2016 to phase down the use of high-GWP HFC F-gases over the time frame 2019–2047.

  • A measure of energy equivalent to the energy delivered by 1,000 watts of power over one hour.

  • kiloton or one thousand metric tons

  • kilowatt-hour

  • The intentional or unintentional act of property use crossing ownership boundaries without permission.

  • A land-holding system, e.g. ownership, leasing, or renting. Secure land tenure means farmers or other land users will maintain access to and use of the land in future years.

  • Gases, mainly methane and CO₂, created by the decomposition of organic matter in the absence of oxygen.

  • levelized cost of electricity

  • leak detection and repair

  • Regular monitoring for fugitive methane leaks throughout oil and gas, coal, and landfill sector infrastructure and the modification or replacement of leaking equipment.

  • Relocation of emissions-causing activities outside of a mitigation project area rather than a true reduction in emissions.

  • The rate at which solution costs decrease as adoption increases, based on production efficiencies, technological improvements, or other factors.

  • Percent decrease in costs per doubling of adoption.

  • A metric describing the expected break-even cost of generating electricity per megawatt-hour ($/MWh), combining costs related to capital, operation, and fuel (if used) and dividing by total output over the generator's lifetime.

  • landfill gas

  • Greenhouse gas emissions from the sourcing, production, use, and disposal of a technology or practice.

  • A process that converts biomass, plastics, or other solid wastes into liquid fuel or chemicals.

  • The total weight of an organism before any meat processing.

  • low- and middle-income countries

  • liquefied petroleum gas

  • land use change

  • A measure of the amount of light produced by a light source per energy input.

  • live weight

  • Mobility as a Service

  • marginal abatement cost curve

  • Livestock grazing practices that strategically manage livestock density, grazing intensity, and timing. Also called improved grazing, these practices have environmental, soil health, and climate benefits, including enhanced soil carbon sequestration.

  • A tool to measure and compare the financial cost and abatement benefit of individual actions based on the initial and operating costs, revenue, and emission reduction potential.

  • Periods of unusually warm ocean temperatures that typically last from days to months and can affect large areas of the ocean.

  • Defined by the International Union for Conservation of Nature as: "A clearly defined geographical space, recognised, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values." References to PAs here also include other effective area-based conservation measures defined by the IUCN. 

  • The transfer of economic activity or environmental impact from one area to another as a result of conservation activities, often having the effect of reducing or offsetting intended benefits.

  • The transfer of economic activity or environmental impact from one location to another as a result of conservation activities, often having the effect of reducing or offsetting intended benefits.

  • A facility that receives recyclable waste from residential, commercial, and industrial sources; separates, processes, and prepares them; and then sells them to manufacturers for reuse in new products.

  • A measure of energy equivalent to the energy delivered by one million watts of power over one hour.

  • A greenhouse gas with a short lifetime and high GWP that can be produced through a variety of mechanisms including the breakdown of organic matter.

  • A measure of mass equivalent to 1,000 kilograms (~2,200 lbs).

  • million hectares

  • The natural process by which microbes convert matter to energy, often producing CO₂ or other GHGs as a byproduct.

  • Soils mostly composed of inorganic materials formed through the breakdown of rocks. Most soils are mineral soils, and they generally have less than 20% organic matter by weight.

  • A localized electricity system that independently generates and distributes power. Typically serving limited geographic areas, mini-grids can operate in isolation or interconnected with the main grid.

  • Reducing the concentration of greenhouse gases in the atmosphere by cutting emissions or removing CO₂.

  • megajoule or one million joules

  • Digital platform that integrates transport modes such as public transit, carpooling, and bike sharing into a single service, allowing users to plan, book, and pay for multimodal trips through one application.

  • Percent of trips made by different passenger and freight transportation modes.

  • A condition of being diseased, unhealthy, or injured.

  • Marine Protected Area

  • materials recovery facility

  • Municipal solid waste

  • megaton or million metric tons

  • Materials discarded from residential and commercial sectors, including organic waste, glass, metals, plastics, paper, and cardboard.

  • megawatt

  • Megawatt-hour

  • micro wind turbine

  • square meter kelvins per watt (a measure of thermal resistance, also called R-value)

  • nitrous oxide

  • The enclosed housing at the top of a wind turbine tower that contains the main mechanical and electrical components of the turbine.

  • A commitment from a country to reduce national emissions and/or sequester carbon in alignment with global climate goals under the Paris Agreement, including plans for adapting to climate impacts.

  • A gaseous form of hydrocarbons consisting mainly of methane.

  • Chemicals found in nature that are used for cooling and heating, such as CO₂, ammonia, and some hydrocarbons. They have low GWPs and are ozone friendly, making them climate-friendly refrigerants.

  • The rate of primary production for photosynthetic organisms, excluding the carbon they respire for their own metabolic processes.

  • The rate at which photosynthetic organisms convert carbon dioxide into organic matter, minus the carbon they respire for their own metabolic processes.

  • Microbial conversion of ammonia or ammonium to nitrite and then to nitrate under aerobic conditions.

  • A group of air pollutant molecules composed of nitrogen and oxygen, including NO and NO₂.

  • A greenhouse gas produced during fossil fuel combustion and agricultural and industrial processes. N₂O is hundreds of times more potent than CO₂ at trapping atmospheric heat, and it depletes stratospheric ozone.

  • Metals or alloys that do not contain significant amounts of iron.

  • Social welfare organizations, civic leagues, social clubs, labor organizations, business associations, and other not-for-profit organizations.

  • A material or energy source that relies on resources that are finite or not naturally replenished at the rate of consumption, including fossil fuels like coal, oil, and natural gas.

  • nitrogen oxides

  • Net primary production

  • nitrous oxide

  • The process of increasing the acidity of seawater, primarily caused by absorption of CO₂ from the atmosphere.

  • Organisation for Economic Co-operation and Development

  • An agreement between a seller who will produce future goods and a purchaser who commits to buying them, often used as project financing for producers prior to manufacturing.

  • Waste made of plant or animal matter, including food waste and green waste.

  • Systems to connect buyers with a network of smallholder farmers to stabilize supply and demand (sometimes called "contract farming.”

  • organic waste

  • Protected area

  • Protected Area

  • A certification that verifies a metric ton of packaging waste has been recovered and is being exported for reprocessing.

  • A certification that verifies a metric ton of packaging waste has been recovered and reprocessed.

  • Productive use of wet or rewetted peatlands that does not disturb the peat layer, such as for hunting, gathering, and growing wetland-adapted crops for food, fiber, and energy.

  • A legally protected area that lacks effective enforcement or management, resulting in minimal to no conservation benefit.

  • Airborne particles composed of solids and liquids.

  • A measure of transporting one passenger over a distance of one kilometer.

  • Incentive payments to landowners or managers to conserve natural resources and promote healthy ecological functions or ecosystem services.

  • Small, hardened pieces of plastic made from cooled resin that can be melted to make new plastic products.

  • The longevity of any greenhouse gas emission reductions or removals. Solution impacts are considered permanent if the risk of reversing the positive climate impacts is low within 100 years.

  • Packaging waste export recovery note

  • Advanced solar cells combining perovskite and silicon layers to capture more of the solar spectrum, achieving higher efficiency than conventional silicon cells.

  • Payments for ecosystem services

  • A mixture of hydrocarbons, small amounts of other organic compounds, and trace amounts of metals used to produce products such as fuels or plastics.

  • Per- and polyfluoroalkyl substances, a class of synthetic chemicals that do not degrade easily in the environment. They can pollute the environment and can have negative impacts on human health.

  • A measure of the acidity (pH<7) or alkalinity (pH>7) of a solution.

  • Reduce the use of a material or practice over time.

  • Eliminate the use of a material or practice over time.

  • Plug-in hybrid electric car

  • Private, national, or multilateral organizations dedicated to providing aid through in-kind or financial donations.

  • An atmospheric reaction among sunlight, VOCs, and nitrogen oxide that leads to ground-level ozone formation. Ground-level ozone, a component of smog, harms human health and the environment.

  • The process by which certain materials, such as those in solar cells, convert sunlight into electricity by releasing electrons.

  • The process by which sunlight is converted into electricity. When light hits certain materials, such as those in solar panels, it mobilizes electrons, creating an electric current.

  • A family of synthetic organic compounds used to make plastics softer, more flexible, and durable. They are added to a wide range of plastics for consumer and industrial uses.

  • polyisocyanurate

  • The adjustment of turbine blade angles around their long axis in which a control system rotates blades slightly forward or backward to regulate wind capture and optimize electricity generation.

  • passenger kilometer

  • particulate matter

  • Particulate matter 2.5 micrometers or less in diameter that can harm human health when inhaled.

  • Elected officials and their staff, bureaucrats, civil servants, regulators, attorneys, and government affairs professionals.

  • System in a vehicle that generates power and delivers it to the wheels. It typically includes an engine and/or motor, transmission, driveshaft, and differential.

  • Purchase Power Agreements

  • Purchase Power Agreement.

  • People who most directly interface with a solution and/or determine whether the solution is used and/or available. 

  • A chemical reaction that creates a solid from a solution.

  • A substance that is the starting material for a chemical reaction that forms a different substance.

  • Extraction of naturally occurring resources from the Earth, including mining, logging, and oil and gas refining. These resources can be used in raw or minimally processed forms to produce materials.

  • The process of converting inorganic matter, including carbon dioxide, into organic matter (biomass), primarily by photosynthetic organisms such as plants and algae.

  • Packaging waste recovery note

  • Defined by the International Union for the Conservation of Nature as "A clearly defined geographical space, recognised, dedicated and managed, through legal or other effective means, to achieve the long-term conservation of nature with associated ecosystem services and cultural values". References to PAs here also include other effective area-based conservation measures defined by the IUCN. 

  • A process that separates and breaks down wood and other raw materials into fibers that form pulp, the base ingredient for making paper products.

  • polyurethane

  • Long-term contract between a company (the buyer) and a renewable energy producer (the seller).

  • Long-term contracts between a company (the buyer) and a renewable energy producer (the seller).

  • photovoltaic

  • research and development

  • A situation in which improvements in efficiency or savings lead to consumers increasing consumption, partially or fully offsetting or exceeding the emissions or cost benefits.

  • renewable energy certificate

  • Chemical or mixture used for cooling and heating in refrigeration, air conditioning, and heat pump equipment. Refrigerants absorb and release heat as they move between states under changing pressure.

  • The amount of refrigerant needed for a particular refrigeration, air conditioning, or heat pump system.

  • A group of approaches to farming and ranching that emphasizes enhancing the health of soil by restoring its carbon content and providing other benefits to the farm and surrounding ecosystem.

  • A solution that can increase the beneficial impact of another solution through increased effectiveness, lower costs, improved adoption, enhanced global climate impact, and/or other benefits to people and nature.

  • A material or energy source that relies on naturally occuring and replenishing resources such as plant matter, wind, or sunlight.

  • A market-based instrument that tracks ownership of renewable energy generation.

  • The moldable form of raw plastic material, created by melting down waste or virgin plastics and serving as the building block for creating new plastic goods.

  • The process of moving items from end users (e.g., consumers) back to the sellers or manufacturers to reuse, recycle, or dispose of. This can include transportation, cleaning, sorting, and more.

  • Hiring a vehicle to take a passenger or passengers to a particular destination.

  • U.N. treaties to combat climate change, biodiversity loss, and desertification. They include the U.N. Framework Convention on Climate Change (UNFCCC), the Convention on Biological Diversity (CBD), and the U.N. Convention to Combat Desertification (UNCCD).

  • A class of animals with complex stomachs that can digest grass. Most grazing livestock are ruminants including cows, sheep, and goats along with several other species.

  • sustainable aviation fuel

  • A wetland ecosystem regularly flooded by tides and containing salt-tolerant plants, such as grasses and herbs.

  • Intertidal coastal wetlands with salt-tolerant plants.

  • An ecosystem characterized by low-density tree cover that allows for a grass subcanopy.

  • Very large or small numbers are formatted in scientific notation. A positive exponent multiplies the number by powers of ten; a negative exponent divides the number by powers of ten.

  • Seasonal coefficient of performance

  • Sustainable Development Goals

  • Average units of heat energy released for every unit of electrical energy consumed, used to measure heat pump efficiency.

  • A single pane window (glass and frame) added to an existing single-glazed window, converting the unit into double glazing, with each pane independently operable.

  • A practice in which multiple utility companies own and operate high-voltage power lines, sharing both costs and benefits.

  • A window consisting of one glass pane without any additional insulating layers.

  • Small-scale family farmers and other food producers, often with limited resources, usually in the tropics. The average size of a smallholder farm is two hectares (about five acres).

  • soil organic carbon

  • The process of using direct, real-world observations to verify, validate, and/or improve data and models about social systems, often using in-person observations in the field.

  • Carbon stored in soils, including both organic (from decomposing plants and microbes) and inorganic (from carbonate-containing minerals).

  • Carbon stored in soils in organic forms (from decomposing plants and microbes). Soil organic carbon makes up roughly half of soil organic matter by weight.

  • Biologically derived matter in soils, including living, dead, and decayed plant and microbial tissues. Soil organic matter is roughly half carbon on a dry-weight basis.

  • Reducing global warming by increasing how much of the sun's radiation is reflected back to space and/or decreasing how much of the Earth's radiative heat is trapped in the atmosphere. 

  • A material's ability to reflect solar radiation incident on its surface, often reported as a fraction or percentage.

  • soil organic matter

  • A substance that takes up another liquid or gas substance, either by absorbtion or adsorption.

  • sulfur oxides

  • sulfur dioxide

  • The rate at which a climate solution physically affects the atmosphere after being deployed. At Project Drawdown, we use three categories: emergency brake (fastest impact), gradual, or delayed (slowest impact).

  • Climate regions between latitudes 23.4° to 35° above and below the equator characterized by warm summers and mild winters.

  • A polluting gas produced primarily from burning fossil fuels and industrial processes that directly harms the environment and human health.

  • A group of gases containing sulfur and oxygen that predominantly come from burning fossil fuels. They contribute to air pollution, acid rain, and respiratory health issues.

  • Processes, people, and resources involved in producing and delivering a product from supplier to end customer, including material acquisition.

  • Sport utility vehicle

  • A mixture of hydrogen, carbon monoxide, and other gases, used to produce chemicals like ammonia and methanol, or as a synthetic fuel made from non-fossil feedstocks, including biomass and waste.

  • metric ton

  • metric tons

  • Technology developers, including founders, designers, inventors, R&D staff, and creators seeking to overcome technical or practical challenges.

  • Climate regions between 35° to 50° above and below the equator characterized by moderate mean annual temperatures and distinct seasons, with warm summers and cold winters.

  • A measure of energy equivalent to the energy delivered by one trillion watts of power over one hour.

  • trifluoroacetic acid

  • trifluoroacetic acid

  • A measurement indicating the ability of a material to release heat after it has been absorbed.

  • A measure of how well a material prevents heat flow, often called R-value or RSI-value for insulation. A higher R-value means better thermal performance.

  • A measure of the rate of heat flow or heat transfer through a material or building component. A lower U-value means better thermal performance.

  • Individuals with an established audience for their work, including public figures, experts, journalists, and educators.

  • Charges for disposal of materials paid to facility operators. Fees can be charged per ton of waste disposed or based on economic indicators such as the Consumer Price Index.

  • A solar PV systems with panels that move automatically to follow the sun’s path, maximizing energy capture and improving efficiency over fixed systems.

  • A window consisting of three panes of glass separated by two insulating inert gas-filled layers, providing more heat flow resistance than single or double glazing.

  • Low-latitude (23.4°S to 23.4°N) climate regions near the Equator characterized by year-round high temperatures and distinct wet and dry seasons.

  • Terawatt, equal to 1,000 gigawatts

  • terawatt-hour

  • United Nations

  • United Nations Environment Programme

  • U.S. Composting Council

  • Self-propelled machine for transporting passengers or freight on roads.

  • A measure of one vehicle traveling a distance of one kilometer.

  • Aerobic decomposition of organic waste by earthworms and microorganisms.

  • vehicle kilometer

  • volatile organic compound

  • Gases made of organic, carbon-based molecules that are readily released into the air from other solid or liquid materials. Some VOCs are greenhouse gases or can harm human health.

  • watt (a measure of power or energy transfer.)

  • Watts per square meter Kelvin

  • A thin, flat slice of silicon cut from an ingot and processed to create individual solar cells that convert sunlight into electricity.

  • Landscape waste, storm debris, wood processing residues, and recovered post-consumer wood.

  • A framework for waste management that ranks options by their sustainability: 1) prevent (do not purchase unnecessary waste), 2) reduce, 3) reuse, 4) recycle, 5) recover, 6) dispose.

  • A measure of power equal to one joule per second.

  • World Conservation Monitoring Centre

  • Using strategies such as insulation, air sealing, ventilation, and moisture control to upgrade a building’s exterior structure, making indoors more comfortable and energy efficient.

  • Aerobic decomposition of organic waste in long, narrow rows called windrows. Windrows are generally twice as long as they are wide.

  • A subset of forest ecosystems that may have sparser canopy cover,  smaller-stature trees, and/or trees characterized by basal branching rather than a single main stem.

  • extruded polystyrene

  • The rotation of the nacelle (the enclosed housing at the top of a wind turbine tower that contains the main mechanical and electrical components of the turbine) so that the rotor blades are always facing directly into the wind.

  • year-over-year

  • year

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