Impact of sea level rise on ecosystem services values and adaptation measures

Abstract

Sea level rise, one of the most obvious and direct effects of climate change in coastal areas, has become an important and urgent problem. Rising sea level has brought about coastline retreat, coastal erosion, storm surge strengthening, pollutant release, habitat change, and wetlands migration. In addition, it has caused changes in the ecosystem service value of coastal areas. Five processes of coastal ecosystems that may be affected by sea level rise are inundation, erosion, overwash, saturation, and accretion. Wetlands migration is simulated by the Sea Level Affecting Marshes Model and benefit transfer method in Hillsborough County, US, where the sea level is assumed to rise 1 m from 2010 to 2100. According to the calculation results, ecosystem services values for every 10 years are evaluated using the benefit transfer method. The results showed that dry land areas will decrease by 3037 hm2, while wetlands will increase by 3037 hm2 with sea level rise. Areas of estuarine open water, beaches, salt marshes, and regularly flooded marshes will increase by 394.29%, 380.62%, 141.93%, and 121.41%, respectively. The areas of irregularly flooded marshes, tidal fresh marshes, tidal flats, estuarine beaches, and inland shores will decrease by 95.52%, 91.31%, 59.29%, 37.59%, and 21.44%, respectively. Mangroves, inland open waters, swamps, inland fresh marshes, and cypress swamps will be less affected, and will decrease by 6.67%, 4.05%, 2.35%, 0.90%, and 0.10%, respectively. Increasing the total wetland area contributes to reducing the total ecosystem service value due to the large loss of beaches and freshwater wetlands. The values of art, entertainment, water regulation, climate regulation, spirit and culture will decrease, while the values of water supply, habitat protection, disturbance regulation, and waste disposal will increase. Extensive efforts have been devoted to adaptation planning and impact analysis in the face of rising sea levels. Protection, accommodation, and retreat are the main adaptation measures that have been adopted by both state and local governments in the U.S. The analysis results showed that different measures have very different impacts on ecosystem services values. According to the comprehensive application of these measures, planners develop adaptive strategies to cope with rising sea levels. Due to global differences in sea level rise, local topography, seawater erosion degree, and the existing measures, it is difficult to judge whether the impact of sea level rise will have beneficial or detrimental effects on an ecosystem. The case study of Hillsborough County needs more discussion, such as the uncertainty of sea level rise and scenario simulation, the change and valuing of ecosystem service value per unit area for different types of wetlands, and quantitative analysis for impacts of adaptation measures on ecosystem services. In addition, the application of SLAMM in Chinese research should also be considered.