Study for Evaluation of Socio-economic Impact by Sea Level Rise Based on the Unit Values of Land Use in Kumamoto Plain, Kyushu Island, Japan

Abstract

A rapid sea level rise (SLR) caused by global warming has been predicted by many researchers recently. The rise may have a great impact on human life in coastal regions all over the world. For the reason, a detailed preliminary assessments of the impact is required in order to implement measures to counteract SLR among many governments. SLR will change environmental conditions especially in coastal regions all over the world. The change will induce natural disasters such as various types of floods, land use, vegetation, geomorphological conditions, hydrological circumstances.But the unit value method, that enables us to evaluate the total loss by them easily, was developed based on the idea of the property density, which was calculated by combination with land use information and data of socio-economic properties.In this study, Kumamoto plain was selected as a typical coastal plain in Japan and was also the most suitable area for evaluating affected properties in combination with the unit value method and the ground elevation map.Socio-economic properties includes price of real estate (yen/m2), productivity (yen/m2/year), working population (persons/km2), residential population (persons/km2), household article (yen/m2), and stock (yen/m2). Their density forms each unit value every land use.The following estimation was an extreme case study based on the premise that there is no countermeasure against the future SLR in the Kumamoto plain. If 1 meter SLR occur in future, we can estimate the followings: approximately 10km2 of land is drowned and its value, app. four hundreds of billions yen is lost, app. twenty billions yen of building is inundated, app. 1 billion eight hundreds millions yen per year of productivity is lost, app. ten thousands persons of resident, app. one thousand persons of worker, app. sixteen, billions yen of household article, app. one billions yen of depreciative property and app. one hundred million yen of stock have to be withdrawn inland.This study was carried out for establishing a simple evaluation method of impact by SLR in foreign countries where there is little data. And we could succeed to combine unit value and land use, and gave value of added productivity to land use which is the minimum unit of geographical phenomena.Near future, we may also apply the unit value method for evaluating the loss of various natural disasters easily and rapidly.