Coastline migration and restoring recommendations in China 

Coastal areas are important and functional regions due to their location and abundant natural resources that support human life and certain industries, while these areas are also ecologically vulnerable and have experienced dramatic changes due to both human activities and natural factors. In this article, remote sensing and geographic information system technology are utilized to extract and analyze the spatiotemporal changes in China’s coastline from 1980 to 2018. Additionally, the study introduces the Ecosystem Service Values (ESVs) evaluation method to quantitatively assess the impact of coastline changes on coastal ESVs. Results indicate that from 1980 to 2018, the length of China's mainland coastline increased by 10.2%, characterized by a significant increase in artificial and a sharp decrease in natural coastlines. Aquaculture ponds were the type of coastline with the most increase, followed by construction land and ports. Bedrock coastline was the type of coastline with the most reduction, followed by sandy and muddy coastlines. Over the past four decades, the changes in coastline have led to a decrease of $6.83 billion in ESV in China's coastal zone. Therefore, protecting and restoring China's natural coastline should be highly prioritized. Local authorities should evaluate the ecological environment of specific coastal zones in a timely and effective manner using big data and decision-making tools, and provide feedback to guide the adjustment and implementation of relevant national/regional policies.