The value of China's coastal wetlands and seawalls for storm protection

Abstract

China has relied on seawalls for storm protection along its coasts for decades. In contrast, the storm protection functions of coastal wetlands are often ignored by decision makers in China. We examined 127 historical storms with consequent economic loss to China from 1989 to 2016 and estimated the value of coastal wetlands with controlling for seawalls for storm protection. A regression model with the natural log of damage per unit gross domestic product in the storm swath as the dependent variable and explanatory variables including the length of existing seawalls in the storm swath and the natural logs of wind speed, storm duration and wetland area in the storm swath was highly significant and explained 59.2% of the variation in relative damages. Results show that a gain of 1 km 2 of wetlands corresponds to an average CNY 83.90 million (median = CNY 11.87 million) decrease in storm damage from specific storms. Coastal wetlands are gifts of nature and self-maintaining so they have zero construction and maintenance costs. They also provide many other valuable ecosystem services that hard seawalls do not.