Evaluation Of Typhoon Mitigation Factors In China's Coastal Zone Based On Environmental Economic Model

The coastal zone is an area with a high density of population and economic activities and is also an area with the most frequent typhoon disasters.The coastal areas of China have been hit by typhoons all the year round,which have caused a huge loss of lives and properties to coastal provinces.Coastal wetlands and its vegetation are natural barriers against typhoon attacks.Coastal wetlands and its vegetation play an important role in typhoon protection service by reducing typhoon wind speed,reducing typhoon wave height,reducing flood water level and flow velocity during typhoon,and hence reducing economic losses caused by typhoon.However,with the over-exploitation and utilization of coastal wetlands by human beings,the area of coastal wetlands in China has been dramatically decreased.Seawalls are an important man-made infrastructure for resisting typhoon attacks in coastal areas around the world.For decades,China mainly relies on seawalls to against typhoon attacks in coastal areas,but there is little known on the value of seawalls in preventing typhoons.China has the second largest area of paddy fields in the world.As the largest constructed wetland,paddy fields not only provide food for human society,but also provide other ecosystem services.However,there are few studies on whether paddy fields have the same typhoon protection value as natural wetlands.This paper is based on the data of 138 typhoons hitting China's coastal areas from 1989 to 2018 with direct economic losses.The comprehensive use of environmental economics,statistics,econometrics,and geography,with the help of Arc GIS and EViews software,enables us to establish the environmental economic model to evaluate the typhoon protection value of coastal wetlands,seawalls and paddy fields,respectively and further based on the results of the environmental economic models to quantify the typhoon protection value of coastal wetlands,seawalls and paddy fields.The main findings are summarized as follows:(1)According to the Marine Disaster Bulletin,the typhoon events that caused direct economic losses from 1989 to 2018 were considered and the variations in the spatial and temporal scales of economic losses caused by typhoons were studied in details.Regarding the spatial scale,among the coastal provinces in China,Guangdong province and Fujian province have suffered from the most typhoon attacks and the most total direct economic losses in the past 30 years.Nearly 90% of typhoons landed at the southern coastal provinces.Regarding the temporal scale,the period 1989-2018 was divided into three 10 years.It was found that the number of deaths and missing persons,the number of house collapses and the direct economic losses caused by typhoon data are all decreased gradually with the time goes on.However,the number of typhoons that caused direct economic losses gradually increased over time,and their intensity gradually increased as well.(2)The paper established an environmental economic model for the evaluation of coastal wetlands,seawalls and paddy fields.It is demonstrates that coastal wetlands,seawalls and paddy fields play a significant positive role in typhoon protection and can reduce economic losses caused by typhoons.Based on the results of the environmental economic model,the marginal value of typhoon protection of coastal wetlands,seawalls and paddy fields was evaluated.The marginal value of typhoon protection for coastal wetlands ranged from 48,900 RMB per square kilometer to3,459.42 million RMB per square kilometer,with an average value of 120.64 million RMB per square kilometer,the median value is 14.6 million RMB per square kilometer.The marginal value of typhoon protection for the seawalls ranged from20,000 RMB per kilometer to 125.05 million RMB per kilometer,with an average value of 9.75 million RMB per kilometer,the median value is 4.61 million RMB per kilometer.The marginal value of typhoon protection for paddy fields ranged from 382 RMB per square kilometer to 58.62 million RMB per square kilometer,with an average value of 937,800 RMB per square kilometer,the median value is 133,000 RMB per square kilometer.(3)The paper presented an environmental economic model for a comprehensive evaluation of typhoon mitigation factors: coastal wetlands,seawalls and paddy fields at the same time.The coefficient of coastal wetlands and paddy fields were still negative and significant,and the coefficient of seawalls was negative but not significant,confirming that in the comprehensive evaluation model,the existence of coastal wetlands and paddy fields can still reduce the economic losses caused by typhoon.This study evaluated the typhoon protection value of coastal wetlands,seawalls and paddy fields from the perspective of an environmental and economic model based on the whole China scale and long time series.This paper quantified the marginal value of typhoon protection services for coastal wetlands and seawalls,and based on the environmental economic model,finds that paddy fields,as constructed wetlands,can reduce the economic losses caused by typhoon.The research results of this paper can provide decision support for managing typhoon protection measures in coastal areas for hybrid or alternative measures with more economic and ecological benefits.