Research On The Evolution Characteristics Of Extreme High Temperature Events And Population Exposure In The “Belt And Road” Region

Global warming has led to an increase in extreme heat events,which in turn has far-reaching impacts on human societies and ecosystems.As the population and economy continue to grow,the damage caused by extreme weather events will increase dramatically along the Belt and Road,which accounts for about 70% of the global population.Addressing climate change is a common challenge for all countries along the Belt and Road today and in the future.In the process of promoting the "Belt and Road" initiative,it is necessary to fully consider the impact of climate change in various aspects such as economy,trade,humanities,transportation and energy,and to effectively deal with various disaster risks.The analysis and clarification of the characteristics and impacts of climate change and extreme events in the "Belt and Road" region is the most fundamental prerequisite for scientific response to climate change and effective disaster risk management in the construction of the "Belt and Road".This paper is based on the ERA-Interim summer daily maximum temperatures,the climate scenario data of the Coupled Model Intercomparison Project Phase 6(CMIP6),and the Shared Socioeconomic Pathways(SSPs).(SSPs),an improved intensity-area-duration(IAD)extreme event identification method is used to identify extreme temperature events in the "Belt and Road" region for the historical period(1979-2018)and the future(2021-2100)using population gridded data under Shared Socio-economic Pathways(SSPs).The characteristics of extreme heat events and population exposure in the "Belt and Road" region during the historical period(1979-2018)and in the future(2021-2100)were studied using an improved intensity-area-duration(IAD)method.The main findings are as follows.1.In 1979-2018,the frequency,intensity and duration of extreme summer heat events in the "Belt and Road" region show an increasing trend,with significant increases in eastern China,western Russia,and Central and Eastern Europe;extreme summer heat events occur in the northern part of the study area,such as Kazakhstan,Xinjiang,and central Russia.The frequency and intensity of extreme summer heat events in the "Belt and Road" region under all scenarios from 2021 to 2100 show an overall increasing trend,and increase with The frequency and intensity of extreme summer heat events in the "Belt and Road" region in all scenarios from 2021 to 2100 show an overall increasing trend and increase with the increase of radiative forcing.Compared with the base period,the frequency of extreme heat events significantly increases in the late 21 st century in regions such as southeastern Saudi Arabia,Thailand,and southern Iran;the intensity changes significantly in some regions such as Southeast Asia and northern Russia,with an increase of more than 30%.The duration increased by more than 300% in regions such as the Arabian Peninsula,Iran,and Central Asia of Afghanistan.2.The average and maximum temperatures in the "Belt and Road" region are expected to increase during 2021-2100,and the temperature increases continuously with increasing radiative forcing.The spatial pattern of temperature increase is basically similar in all SSPs-RCPs scenarios,and the temperature increase is larger in the northern part of the study area.The peak of population occurs around 2050.Spatially,under the SSP3,the population increases significantly in most regions,with up to 2 million people/year in parts of India.Most of the remaining paths show decreasing trends.3.There is an overall increasing trend of impact area and population exposure from 1979-2018 to2021-2100.The high value areas are mainly distributed in eastern China,mainland India,and countries around the Black Sea;the high value areas of exposed population under different future scenarios will keep expanding with the increase of radiation forcing.The regions of eastern China,Russia,and India will become the hotspot areas for research.4.The contributions of climate,population,and other factors are comparable in the influencing factors of population exposure change in 1979-2018,but the contribution of climate factors increases significantly in the last decade.the contributions of climate,population,climate,and other factors in2021-2100 are comparable in the low and medium emission scenarios in the near to medium term,and climate factors enhance at the end.The contribution of climate factors increases significantly and dominates in the high emission scenario.