[H-CG22] Adaptation to climate change and its social implementation

[HCG22-P05] A systematic review of economic valuation of coastal environments and ecosystems: differences between domestic and foreign studies

*Hiroya Abe¹ (1.National Institute for Environmental Studies)

Keywords:coastal area, coastal ecosystem, economic valuation, climate change, future projection, adaptation measures

Coastal environments and ecosystems are closely related to our lives and are known to have high economic value. However, many areas worldwide have reported a decrease in beaches and tidal flats and the degradation of coastal ecosystems due to climate change and coastal development. When utilizing or conserving the environment and ecosystems, it is essential to understand their value properly. However, it is assumed that there needs to be more examples of economic valuation and even fewer papers showing possible future changes. The objectives of this study are: 1) to clarify the differences in the number of papers and evaluation methods by nation/region and environment/ecosystem, 2) to organize the scenarios on which future projections are based, and 3) to compare the differences in research trends between Japan and other countries for the economic evaluation of coastal environments and ecosystems. We targeted beach and tidal flats as coastal environments, salt marshes, coral reefs, seagrass beds, seaweed beds, and mangrove forests as coastal ecosystems. A systematic review of scientific articles was used to identify research trends. The databases used to search for papers were Web of Science for English papers and J-Stage for Japanese papers. The search period for the papers was from 1980 to 2023. The search terms for English-language papers are as follows: ("economic valu*" OR "monetary valu*"), ("beach*" OR "dune*"), ("tidal flat*" OR "mudflat*"), ("salt marsh*" OR "tidal marsh*" OR "coastal wetland*"), ("coral reef *" OR "coral communit*"), ("seagrass*"), ("seaweed *" OR "macroalga*"), ("mangrove*"). The details of the search keywords in Japanese are omitted, but similar keywords were used to search. After removing duplicate papers and limiting them to those that could be downloaded, we screened them to ensure that they covered the coastal zone, that quantitative economic evaluation had been conducted, and that they covered the actual site. The full review organized the paper's publication year, the country/region covered, the environment/ecosystem, the method of economic evaluation, whether there are future projections, and whether there are adaptation measures. The English-language article database yielded 340 articles, indicating that the number of research cases varies widely by country/region and environment/ecosystem concerning the economic valuation of coastal areas. By country, the United States had the most significant number of papers (n=40), followed by Australia, China, Indonesia, and Thailand, which were the top five countries. The number of papers tended to be higher in Southeast and South Asia. Concerning environment and ecosystem, although about 20% of the cases could not determine which category they fell into, studies on mangroves were the most common (more than 20%), followed by beaches, coral reefs, salt marsh, and seagrass beds. On the other hand, there were only a few reports on seaweed beds and tidal flats. Coral reefs accounted for more than half of the English-language papers focusing on Japan as a field (n=4). The Japanese-language article database yielded 25 cases targeting coastal areas in Japan. Of these, 16 papers were on beaches and shorelines, and one was on seagrass beds. Ten environmental change scenarios were considered, including future projections covering beaches and shorelines. Since it was not possible to organize specific amounts in this study, evaluating the differences in value for different environments and ecosystems is a future task. The review of this study showed that the case for economic valuation of coastal areas is highly skewed by country/region and by type of environment/ecosystem. The main issues to be addressed in the future are to assess the impacts on the environment and ecosystems widely and to accumulate examples in each region that will enable quantitative evaluation of the effects of adaptation measures.