The Risk Assessment Of The Impact Of Climate Change On Desertification In Hexi Corridor

Climate change is an important driving and shaping force of landscape. Under the background of global climate change, all kinds of ecological system are in progressive development. Desertification has become a major obstacle of sustainable development in the world, and a no-continuous desertification arc in North China is a grim situation. However, over the past 30 years, the relationship between climate change and desertification, the impacts and risks of climate change on desertification have not been studied clearly. Faced to the desertification risk prediction blank of climate change over the next 30 years the, the lack of related policies on desertification and climate change requires for basic research.Therefore, with the support of 3S technology, in this study area of Hexi corridor of Gansu Province, aiming at knowing the key impact problems of climate change on desertification evolution, this paper reconstructs the desertification spatio-temporal process of Gansu Hexi area in the past 30 years. We try to construct an evaluation method for the dynamic simulation and risk of desertification. Then, based on the scenario data of climate change, desertification risk caused by climate change in the future 30 years is estimated. The main conclusions of this paper are:1) During the year of 1980-2010, judging from the spatial distribution and excluding Gobi and saline alkali soil, degree of desertification distribution location in Gansu Hexi cooridor has no significant change. Statistics on different desertification land area found that over the past 30 years, the desertification area in Hexi corridor of Gansu province decreased. The year of 1980-1990, desertification land reversion is small,280km2/10a; the year of 1990-2000, desertification land reversion is 2628km2/10a. Seen from the area rate change of different grade of desertification land, non-desertification land increased significantly in the 2000s, the mild desertification land area in the state of steady increase, moderate desertification in a relatively large reversal rate in the 1990s and it delays after the moderate severe desertification reversion time. In the process of different levels of desertification land area change, while the total area of different desertification land types reduces, the desertification land internal change in different levels is complex.2) The main two factors effects of climate change on desertification risk are temperature and precipitation. In the analysis of correlation of NDVI and annual accumulated temperature and annual precipitation in the past thirty years found that, the correlation between NDVI and accumulated temperature is not very significant. In the area of human activities shows a slight correlation. In the past thirty years, the correlation of NDVI and precipitation in Hexi area also shows a low correlation relationship; but in the ten year scale, in comparison of the correlation effects, three years have a significant correlation between multiple regions. Over the past thirty years, the annual precipitation contributes more than the annual accumulated temperature, which is consistent with the analysis of the NDVI and the annual precipitation and annual accumulated temperature relationship.3) Over the next thirty years, under different climate change scenarios, the spatial distribution features of desertification risk in Hexi corridor were different: RCP2.6 and RCP4.5 showed high similarity, RCP6.0 is under the minimize desertification risk and RCP8.5 is under the biggest desertification risk.