Coastal ‘Blue Carbon’: An Important Tool for Combating Climate Change

Coastal Wetlands: A Key Component of Sustainable Development Goals

Editor’s note: This brief was updated on Oct 1, 2021, to clarify the data on carbon dioxide equivalent sequestered and stored by coastal wetlands in the lower 48 U.S. states in 2019.

Introduction

Coastal wetlands, such as salt marshes, mangrove forests, and seagrass meadows, are highly productive and threatened ecosystems that provide numerous benefits to both people and nature. These habitats play a crucial role in helping communities adapt to climate-related threats, sequestering carbon from the water and atmosphere, and mitigating the effects of climate change. However, over the past 50 years, coastal wetlands have lost more than a third of their area.

Coastal Wetlands as Carbon Sinks

Coastal wetlands are considered one of the world’s most important natural “carbon sinks” because they can store far greater amounts of carbon than they release. Despite covering less than 5% of global land area and less than 2% of the ocean, they store approximately 50% of all carbon buried in ocean sediments. The wet, low-oxygen conditions of these ecosystems slow down the decay of organic material, allowing carbon to be locked in the soils for thousands of years.

However, when coastal ecosystems degrade, they release vast amounts of greenhouse gases, including carbon dioxide, methane, and nitrous oxide. The destruction of coastal wetlands worldwide emits an estimated 450 million metric tons of carbon dioxide each year, contributing to climate change.

Role in Achieving Sustainable Development Goals

The United Nations Framework Convention on Climate Change recognizes the importance of protecting and restoring coastal wetlands in achieving climate mitigation and adaptation goals. Coastal wetlands are the only marine ecosystem for which the Intergovernmental Panel on Climate Change has developed methodologies for measuring carbon dynamics. Efforts are also underway to quantify the role of other marine ecosystems, such as kelp forests, in capturing and sequestering carbon.

Blue Carbon Habitat Fast Facts

Carbon sequestration is just one benefit of healthy coastal habitats. They also provide coastal protection, absorb floodwaters, stabilize shorelines, reduce ocean acidification, support fisheries, and contribute to the cultural heritage of coastal Indigenous peoples. Here are some fast facts about the ecosystem services provided by different types of coastal wetlands:

Salt Marshes

• Absorb up to 1.5 million gallons of floodwater per acre.
• Reduce the release of pollutants into coastal waterways.
• Provide essential food and habitat for U.S. fisheries species.
• Sequester approximately 1,940 pounds of carbon per acre per year.

Seagrasses

• Provide nursery and feeding grounds for 20% of the world’s largest fisheries.
• Offer erosion control and other benefits with an estimated global value of nearly $29,000 per hectare per year.
• Sequester approximately 1,230 pounds of carbon per acre per year.
• Store an estimated 10% of all organic carbon sequestered in the ocean annually.

Mangroves

• Provide important habitat for economically valuable species.
• Boost coastal resilience to storms and protect millions of people worldwide.
• Provide $65 billion annually in global flood protection benefits.
• Sequester an estimated 2,016 pounds of carbon per acre per year.

The Urgency to Act on Blue Carbon

Despite the essential role of coastal wetlands in mitigating climate change, these habitats are under threat. They have lost an estimated 35% of their global cover since 1970 due to human-driven factors such as land conversion, coastal development, pollution, and sea-level rise. Recognizing the potential of protected and restored coastal habitats, many countries and U.S. states are incorporating blue carbon ecosystems into their environmental conservation policies and plans.

International Actions

Parties to the Paris Agreement can include action plans for protecting and restoring natural areas in their nationally determined contributions (NDCs). By quantifying carbon stocks and advancing restoration efforts, countries can meet greenhouse gas and climate adaptation goals.

Case Study: Seychelles

Seychelles is committed to protecting its seagrass and mangrove habitats as part of its NDC. The country is collaborating with organizations like The Pew Charitable Trusts to map seagrass beds and estimate carbon storage. This project serves as a model for other countries interested in including seagrass protections in their climate response policies.

United States Actions

The U.S. Environmental Protection Agency (EPA) includes coastal wetlands in its annual inventory of greenhouse gas emissions and sinks. Coastal wetlands in the lower 48 states sequestered 4.8 million metric tons of carbon dioxide equivalent in 2019. By incorporating blue carbon objectives into their NDCs, the U.S. can demonstrate international leadership and advance nature-based solutions for resilient coastal communities.

State-Level Actions: Case Study Oregon

Oregon is developing strategies to enhance carbon storage in its natural and working lands. The state has conducted a blue carbon inventory and is exploring strategies for maintaining and enhancing carbon storage in its estuaries. Restoring forested tidal wetlands can help Oregon meet its carbon sequestration objectives.

Conclusion

Coastal wetlands are vital ecosystems that provide numerous benefits to people and nature. Protecting and restoring these habitats is crucial for achieving sustainable development goals and addressing climate change. By incorporating blue carbon objectives into national and state policies, countries can harness the power of coastal wetlands to secure ecological and economic benefits for generations to come.

Endnotes

1. C.M. Duarte, J.J. Middelburg, and N. Caraco, “Major Role of Marine Vegetation on the Oceanic Carbon Cycle,” Biogeosciences 2, no. 1 (2005): 1-8.
2. S. Crooks et al., Coastal Blue Carbon Opportunity Assessment for the Snohomish Estuary: The Climate Benefits of Estuary Restoration (Environmental Science Associates, Western Washington University, EarthCorps,and Restore America’s Estuaries, 2014).
3. W.R. Moomaw et al., “Wetlands in a Changing
   

   SDGs, Targets, and Indicators

   SDG 13: Climate Action

   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters.
   • Target 13.2: Integrate climate change measures into national policies, strategies, and planning.
   • Indicator: The article discusses the importance of coastal wetlands in mitigating the effects of climate change and adapting to a changing climate. It highlights the role of wetlands in sequestering carbon and reducing greenhouse gas emissions.

   SDG 14: Life Below Water

   • Target 14.2: Sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts.
   • Target 14.5: By 2020, conserve at least 10% of coastal and marine areas, consistent with national and international law and based on the best available scientific information.
   • Indicator: The article emphasizes the importance of protecting and restoring coastal wetlands, including salt marshes, mangroves, and seagrass meadows, as vital blue carbon ecosystems. It also mentions the need to measure carbon dynamics in these ecosystems.

   SDG 15: Life on Land

   • Target 15.1: By 2020, ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems and their services.
   • Target 15.5: Take urgent and significant action to reduce the degradation of natural habitats, halt the loss of biodiversity, and protect and prevent the extinction of threatened species.
   • Indicator: The article highlights the need for conservation and restoration of coastal wetlands to prevent their degradation and loss. It emphasizes the role of these ecosystems in providing various benefits, including carbon sequestration, storm buffering, flood absorption, and habitat for fish and marine invertebrates.

   Table: SDGs, Targets, and Indicators

   SDGs	Targets	Indicators
   SDG 13: Climate Action	Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters.	The article discusses the importance of coastal wetlands in mitigating the effects of climate change and adapting to a changing climate. It highlights the role of wetlands in sequestering carbon and reducing greenhouse gas emissions.
   SDG 14: Life Below Water	Target 14.2: Sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts.	The article emphasizes the importance of protecting and restoring coastal wetlands, including salt marshes, mangroves, and seagrass meadows, as vital blue carbon ecosystems. It also mentions the need to measure carbon dynamics in these ecosystems.
   	Target 14.5: By 2020, conserve at least 10% of coastal and marine areas, consistent with national and international law and based on the best available scientific information.	The article highlights the need for conservation and restoration of coastal wetlands to prevent their degradation and loss. It emphasizes the role of these ecosystems in providing various benefits, including carbon sequestration, storm buffering, flood absorption, and habitat for fish and marine invertebrates.
   SDG 15: Life on Land	Target 15.1: By 2020, ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems and their services.	The article emphasizes the need for conservation and restoration of coastal wetlands, which are important terrestrial ecosystems. It highlights their role in carbon sequestration, storm buffering, flood absorption, and habitat provision.
   	Target 15.5: Take urgent and significant action to reduce the degradation of natural habitats, halt the loss of biodiversity, and protect and prevent the extinction of threatened species.	The article emphasizes the importance of protecting and restoring coastal wetlands to prevent their degradation and loss. It highlights their role in supporting biodiversity and providing habitat for fish and marine invertebrates.

   Behold! This splendid article springs forth from the wellspring of knowledge, shaped by a wondrous proprietary AI technology that delved into a vast ocean of data, illuminating the path towards the Sustainable Development Goals. Remember that all rights are reserved by SDG Investors LLC, empowering us to champion progress together.

   Source: pewtrusts.org

    

   

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