This year, the 197 Parties to the Paris Agreement are updating their domestic climate commitments, known as Nationally Determined Contributions (NDCs), to reduce global emissions and climate change impacts. Science tells us that countries need to step up the ambition within these NDCs, and within each subsequent revision every 5 years going forward, in order to reduce greenhouse gas emissions and bring the world on track to meet the goals of the Paris Agreement.
Recognition is growing across governments that nature-based solutions, which the International Union for Conservation of Nature defines as “actions to protect, sustainably manage, and restore natural or modified ecosystems,” can be a bigger part of the solution to climate change. The degree to which different nature-based solutions mitigate and build resilience to climate change varies but, nonetheless, policymakers are becoming increasingly aware that they are an underutilized tool.
For example, some countries could protect and restore coastal wetlands, such as mangrove, seagrass and saltmarsh habitats, a move that could safeguard the range of benefits these habitats provide to people and nature. Coastal wetlands are often referred to as “triple win” ecosystems for tackling climate change because they can help mitigate emissions and support frontline communities in adapting and becoming more resilient to the impacts of a warming world, such as rising sea levels and increasingly severe storms.
In fact, these ecosystems sequester and store such large amounts of carbon in their soils for long periods of time that policymakers, nongovernmental organizations, and other experts often use the terms “coastal wetlands” and “blue carbon” interchangeably. Countries can draw on the Intergovernmental Panel on Climate Change’s (IPCC) internationally recognized methodologies to measure this carbon sequestration and storage and commit to protecting and enhancing this value within the mitigation component of their NDC.
As the only marine nature-based solution recognized by the IPCC for the measurable contribution they can make toward mitigation commitments, coastal wetlands are assuming further significance as governments and advocacy groups consider how best to situate additional ocean and coastal protections within climate commitments.
To assist policymakers in applying the IPCC methodologies and navigating the variety of entry-points and justifications for protecting coastal wetlands within their NDC, Pew was pleased to have recently collaborated with international experts in the development of technical guidance.
While the IPCC guidance for coastal wetlands has built upon the recognition within the Paris Agreement to preserve and enhance carbon sinks, the contributions of additional marine ecosystems to the goals of the agreement are currently less clearly defined for policymakers. To help address that disparity, the United Nations Framework Convention on Climate Change (UNFCCC) will convene an “oceans dialogue” at its next meeting.
Many people—and almost all experts—already acknowledge the role our ocean has played in shielding the planet from a more extreme form of climate change, for example, by absorbing approximately 30 percent of human-caused greenhouse gas emissions and over 90 percent of the excess heat resulting from anthropogenic warming. Numerous studies have also shown how healthy ocean ecosystems—including coral reefs—protect coasts and coastal communities by enhancing resilience to the impact of severe storms and flooding.
However, the science supporting the carbon benefits of protecting marine species and habitats beyond coastal wetlands, and the degree to which these can be measured, managed, and monitored, is still developing. Additional research is needed to understand their mitigation potential, the measurable contribution they can make to reducing emissions—the primary goal of the Paris Agreement.
But even as scientists further explore this mitigation potential, evidence clearly shows that ocean protections beyond coastal wetlands can safeguard nature and people, and play a potentially significant role in helping countries meet the adaptation and resilience components of their NDCs.
The ocean dialogue will be vital to increasing understanding of precisely how marine nature-based solutions advance the goals of the Paris Agreement. A critical first step is to build on what’s already known by setting robust, ambitious protections for coastal wetlands.
Courtney Durham is a senior associate and Thomas Hickey is a senior officer with Pew’s Protecting Coastal Wetlands and Coral Reefs project.