Spatio-Temporal Variation,Detection And Attribution Of Global Land Surface Air Temperature

Global warming has brought serious impacts on human life,the ecological environment,and the social economy.Under the influence of global warming,the land surface air temperature,which is closely related to human life,is also changing.It is of great significance to correctly understand global surface temperature change and the impact of human activities on it.Nevertheless,the latest Sixth Assessment Report of the Intergovernmental Panel on Climate Change(IPCC)lacks updated assessments and attribution conclusions for global land surface air temperature change.Therefore,this paper combines the latest observations data(CRUTEM5)and the Coupled Model Intercomparison Project Phase 6(CMIP6)to study the changes in global land surface air temperature since the Industrial Revolution and uses the optimal fingerprinting method to detect and attribute the changes,and finally predicts the possible changes in the future based on the attribution results.The main conclusions are as follows.First,since the 1850s,the global land surface air temperature has generally shown a warming trend.In the last ten years(2011-2020),it has warmed by about 1.5°C compared with 1851-1900.This decade is the fastest land warming.Higher latitudes in the Northern Hemisphere are warming faster.Second,the CMIP6 multi-model ALL forcing simulations can better simulate the overall spatial pattern of global land surface air temperature warming,while simulations that do not include anthropogenic greenhouse gas forcing cannot reproduce the historical change characteristics.Specifically,in the individual aerosol or natural external forcing,the global land surface air temperature has generally cooled or largely unchanged.Third,this study proposes a new framework for optimal fingerprinting analysis by "optimizing the regression configuration to improve the reliability of detection and attribution results",and finds that the best option for quantifying the influence of anthropogenic greenhouse gases and aerosols on global land surface air temperature warming is all-forcing,aerosol-only,and natural-only simulations.Fourth,the optimal fingerprinting analysis based on the above configuration shows that,since industrialization,anthropogenic greenhouse gases have caused the global land mean surface air temperature increase of 1.4 to 2.3°C,and offset by aerosol cooling of 0.2 to 1.2°C,the total effect of the two could explain the observed warming.Fifth,the future projected results of the attribution-constrained show that,relative to 1851-1900,global land mean surface air temperature will warm to 2.35°C by the end of this century under the SSP1-2.6 scenario,while if under the SSP5-8.5 scenario with permissive greenhouse gas emissions is adopted,the warming will reach 5.86?.The above conclusions provide the latest and complete scientific evidence for scientific understanding of global land surface air temperature changes,the contribution of anthropogenic activities to historical changes,and possible future climate change.It has important reference value for global warming monitoring and climate governance.