Wetlands and sea-level rise
Wetlands are diverse ecosystems that play crucial roles in environmental health and human society, ranging from providing habitats for wildlife to supporting recreational activities. They can be found in various locations worldwide, including coastal and inland areas, and are characterized by specific hydrological conditions, soils, and vegetation adapted to wet environments. However, the classification of wetlands is complex, as definitions can vary widely based on geographic, ecological, and regulatory factors.
The impact of climate change, particularly sea-level rise, poses a significant threat to coastal wetlands. This phenomenon can lead to the alteration, destruction, or creation of wetlands, especially as glaciers melt in the Arctic regions. As sea levels rise, coastal wetlands face increased flooding risks and changes in water chemistry, which can disrupt the delicate balance of flora and fauna and affect surrounding human settlements. Moreover, the ecological functions of wetlands, such as nutrient removal and carbon sequestration, may be compromised, with potential negative implications for biodiversity and local economies, particularly in regions reliant on tourism. Understanding the dynamics of wetlands in the context of climate change is essential for effective conservation and management strategies.
Subject Terms
Wetlands and sea-level rise
Definition
Wetlands are found from the equatorial region to the arctic regions of Canada. Even in the deserts, wetlands are found near oases. Wetlands are important to society as they provide sanctuary for fish and wildlife, water resources for streams and aquifers, and, in most cases, serve to mitigate the severity of flooding. Wetlands also provide support for fishing, hunting, and other recreational and educational activities such as bird watching, photography, painting, tourism, and research. They provide humans and wildlife with food sources and function as sources of energy and sinks for greenhouse gases (GHGs), sequestering carbon through the formation of peat, a precursor to the formation of coal.
Wetlands can be harbingers for disease-causing insects and may limit some human activities, such as construction and farming. Some wetlands can also contribute to flooding in some cases, as they reduce the rate at which water is removed from the surface. Wetlands are great sources of methane gas, as plants account for about 20 percent of the methane found in wetlands. Wetlands are sometimes referred to as ecotones, transition zones between open bodies of water and land, and sometimes are described as the kidneys of the landscape or as biological supermarkets because of the roles they play.
Because of the varied nature of wetlands, it is often difficult to say what a wetland is and is not. Wetlands have different meanings to different people, depending on their background, exposure, knowledge, and political stand. There is no universal definition of what a wetland is, even within the United States. The main reason wetlands are difficult to define is that they are found in widely varied locations, have different climates, soils, landscapes, water quantity and quality, flora, fauna, and other characteristics, including human disturbances such as dikes, draining, pollution, and so on. The definition of wetland depends on the specific purpose for defining it, such as research studies, general habitat classification, natural resource inventories, or environmental regulations.
All wetland definitions fall into two categories: regulatory definitions and nonregulatory definitions. Because there are myriad, variable definitions and changes in definitions, there is some confusion among legislative and regulatory bodies. This confusion has caused several isolated wetlands to be destroyed, as these wetlands were not connected to navigable waters and may not have seemed to qualify for protection.
Three criteria are necessary to define an area as a wetland: hydrology, hydric soil, and hydrophytes (vegetation adapted to wet conditions). Wetlands are areas that are typically wet most of the time or where the groundwater is very close to the surface. Hydrology is the main factor for identifying wetlands, because not all wetlands exhibit hydric soil conditions. Water quantity and quality determine soil characteristics and which plants and wildlife communities can inhabit the area. The soil, plants, and wildlife affect water quantity and quality.
Wetlands can be broadly divided into two major types: coastal wetlands and inland wetlands. Coastal wetlands are found along the oceans and seas, whereas inland wetlands are found along rivers and streams, near lakes, in low-lying land depressions, or where the groundwater meets the surface. Because of these conditions, the major types of wetlands that have been recognized are bogs, swamps, marshes, fens, potholes, and player lakes.
Significance for Climate Change
Any climate change could modify, create, or eliminate several types of wetlands. With an increase in global warming and sea-level rise, most of the coastal wetlands may be altered, destroyed, or eliminated. However, with the demise of coastal wetlands, new wetlands would be created in places such as Canada and Siberia’s arctic regions as glaciers melt. Change in the climate would affect the effectiveness of wetlands to remove nutrients from flow-through systems such as lakes or riparian wetlands. Aquatic life-forms would be lost as a result of prolonged nutrient loading to such wetlands. Wetland values would be altered, as the hydrology regime was altered in those wetlands. Climate change that would involve a sea-level rise would be detrimental to coastal regions and human life.
Many of the world’s largest cities, located near coastal areas, have wetlands buffering the effect of ocean waves or flooding. Any meaningful sea-level rise would cause serious problems to these wetlands, changing the water chemistry and thus the flora and fauna. It would also affect those coastal cities by increasing the risk, incidence, and severity of flooding. Global warming would lead to destruction of some coastal wetlands and the creation of new wetlands, mainly in the Northern Hemisphere. Tourism may suffer in places where tourism helps the economy, such as the Florida Everglades, with shifts in locations of wetlands. Southeast Asian wetlands may be decimated with a rise in sea level resulting from climate change.
The use of wetlands to reduce GHGs may not be beneficial across the board, as it has been found that developmental strategy may be better for than emission reduction of GHGs. Specific regions would need to assess their wetlands according to their and economic persuasions, noting that wetlands play significant roles in relation to carbon and GHGs such as methane. They can be carbon storage sinks, sequestering several metric tons of organic carbon and helping offset carbon emissions elsewhere.
Bibliography
Bullock, A., and A. Acreman. “The Role of Wetlands in the Hydrological Cycle.” Hydrology and Earth System Sciences 7, no. 3 (2003): 358-389.
McFadden, L., R. Nicholas, and E. Penning-Rowsell, eds. Managing Coastal Vulnerability. San Diego, Calif.: Elsevier Press, 2007.
Mitsch, W. J., and J. G. Gosselink. Wetlands. Edison, N.J.: John Wiley & Sons, 2000.
Musmanni, Gabriela Diaz. "Five Ways Wetlands Are Crutical to Climate Change Adaptation." Global Center on Adaptation, 2 Feb. 2022, gca.org/5-ways-wetlands-are-crucial-to-climate-change-adaptation/. Accessed 20 Dec. 2024.
Tiner, R. A. Wetlands Indicators: A Guide to Wetland Identification, Delineation, Classification, and Mapping. Boca Raton, Fla.: CRC Press, 1999.
Woods Hole Coastal and Marine Science Center. "Learn How Wetlands Can Naturally Help with Climate Change." US Geological Society, 12 May 2023, www.usgs.gov/centers/whcmsc/news/learn-how-wetlands-can-naturally-help-climate-change-impacts. Accessed 20 Dec. 2024.