Drops of Change: Wetlands “Bogged Down” by Climate Change
This post is part of a monthly series called “Drops of Change” by the North American Youth Parliament for Water (NAYPW), a chapter of the World Youth Parliament for Water (WYPW). For more information on the NAYPW, you can explore their website or contact NAYPW at outreachnaypw@gmail.com.
Written by Zoe Rosenblum, M.S. Oregon State University
Did you know that February 2nd is World Wetlands Day? This year marks the 50th anniversary of the Ramsar Convention, the global treaty for wetland conservation.
Wetlands have a complex relationship with climate change—they are simultaneously vulnerable to and resilient against its impacts. Sea-level rise threatens to flood wetlands, yet wetlands also protect coastal communities by storing floodwaters. Given the many benefits that wetlands provide, and the imminent threat of climate change, it is critical that we learn how to protect them.
Globally, wetlands cover more than 12 million square kilometers—an area about the size of Greenland—and are found on every continent except Antarctica. Wetlands provide numerous benefits to the environment and society, such as supporting biodiversity, protecting communities from flooding, improving water quality, and facilitating economic activities such as fisheries. However, despite their importance to many human and ecosystem processes, the importance of wetlands was not always well understood.
Figure 1. Wetlands provide habitat for birds, fish, macroinvertebrates, and mammals. (Photo by author from Murrells Inlet, South Carolina, USA.)
Wetland Loss
Despite their many benefits, wetland habitat is lost at an alarming rate. About 87% of wetlands have been lost globally since the 1700s. The Millennium Ecosystem Assessment identified the underlying causes of wetland degradation to be growth of the economy and the human population, with the direct drivers being intensification of agriculture, water abstraction, and coastal development. Historically, many wetlands were drained for agricultural land. A significant portion of Europe’s wetlands have been converted to agriculture. Since 1975, an estimated 60% of mangroves, a type of wetland, in Thailand were converted to shrimp farms. Shrimp aquaculture accounts for approximately 38% of total mangrove loss. However, well-managed wetland development can preserve their many benefits.
Wetlands and climate change
Vulnerability
Wetlands are vulnerable to climate change. Sea-level rise threatens to flood out coastal wetlands. As the sea-level rises, wetland plants may “migrate” inland over time (Figure 2). However, this wetland migration is often restricted by built infrastructure, such as housing developments, dikes and tide gates. In the presence of these obstacles, wetlands are flooded as the sea-level rises.
Figure 2. Tidal wetlands can cope with climate change by migrating inward. Top figure represents a wetland. Middle figure shows wetland plants moving upland in response to sea level rise. Bottom figure demonstrates that wetlands will be flooded out when they are blocked by built infrastructure such as dikes. (Designed by author, based on diagram by Harold Burrell of the Virginia Institute of Marine Science.)
Resilience
Wetlands also protect communities from many consequences of climate change, such as flooding and erosion. Wetlands act as a buffer for communities by absorbing storm surge and dissipating wave energy. The roots of wetland plants promote downward infiltration of water, in contrast to hardened surfaces, such as paved roads or compacted land, that water rushes across as run-off. In coastal wetlands, plants also absorb the impact of waves, minimizing erosion to the land beyond them.
In addition to protecting coastal communities in these observable ways, wetlands also mitigate other impacts of climate change. Wetlands sequester carbon, which means they help to reduce atmospheric greenhouse gases. A recent report co-authored by AGWA and Wetlands International highlights the key role of wetlands in the global carbon cycle. Wetlands also regulate the local climate since open-water evaporation and the evapotranspiration from wetland plants create a cooling effect. Furthermore, wetlands provide storage for stormwater and thus enhance groundwater recharge by providing a place where water can slowly infiltrate into the soil.
Building wetland resilience
To preserve the important functions of wetlands, we must take action. One option is to create protected land for wetland migration. In the northwestern United States, Tillamook Estuary in Oregon is leading the way for climate adaptation by mapping out priority areas to protect for marsh migration. Subsequent action requires thoughtful planning and collaboration because landownership can be a significant obstacle. By prioritizing public land and undeveloped areas, Tillamook Estuary largely avoided this obstacle. Another option is to remove dikes and other drainage systems in order to restore wetland hydrology. Plans for building wetland resilience must be location-specific to ensure that the needs of the community and the environment are met.
Barriers to wetland protection
These proposed actions to protect wetland habitat require thoughtful collaboration. Land use and land ownership present challenges. Removing dikes and floodgates has serious implications for agriculture, as does the protection of the marsh landward migration zones. Public land and undeveloped areas are given a higher protection priority than private and developed land. Implementation of the recommended solutions requires careful planning and prioritization of sites, as well as stakeholder involvement.
Protect wetlands to build resilience against climate change
Wetlands help to protect communities from the impacts of climate change. However, climate change and development will continue to threaten the world’s wetlands. Careful planning is needed to protect wetlands and human livelihoods. Successful wetland restoration and protection can build resilience in the face of climate change
For more information, check out these organizations and resources:
Wetlands International – global non-profit organization for wetland conservation and restoration
Ramsar – international treaty for wetland conservation
Sustainable Wetlands Adaptation and Mitigation Program – global wetland map
Society of Wetland Scientists – professional organization for scientists and managers