Will the summer sea ice in the Arctic reach a tipping point?

作     者：Ola M.Johannessen Elena V.Shalina Ola M.Johannessen;Elena V.Shalina

作者机构：Nansen Scientific SocietyBergenNorway Nansen International Environmental and Remote Sensing CentreSt PetersburgRussia 

出 版 物：《Atmospheric and Oceanic Science Letters》 (大气和海洋科学快报（英文版）)

年 卷 期：2023年第16卷第3期

页      面：58-62页

核心收录：

学科分类：07[理学] 0707[理学-海洋科学] 0705[理学-地理学] 070501[理学-自然地理学] 

基　　金：funding support from the Nansen Scientific Society 

主　　题：Sea ice Arctic Climate change Tipping point 

摘      要：The Arctic sea-ice cover has decreased in extent,area,and thickness over the last six *** global climate models project that the summer sea-ice extent(SIE)will decline to less than 1 million(mill.)km^(2) in this century,ranging from 2030 to the end of the century,indicating large ***,some models,using the same emission scenarios as required by the Paris Agreement to keep the global temperature below 2°C,indicate that the SIE could be about 2 ***^(2) in 2100 but with a large uncertainty of±1.5 ***^(2).Here,the authors take another approach by exploring the direct relationship between the SIE and atmospheric CO_(2) concentration for the summer-fall *** authors correlate the SIE and In(CO_(2)/CO_(2)r)during the period 1979-2022,where CO_(2)r is the reference value in *** these transient regression equations with an R2 between 0.78 and 0.87,the authors calculate the value that the CO_(2) concentration needs to reach for zero *** results are that,for July,the CO_(2) concentration needs to reach 691±16.5 ppm,for August 604±16.5 ppm,for September 563±17.5 ppm,and for October 620±21 *** values of CO_(2)for an ice-free Arctic are much higher than the targets of the Paris Agreement,which are 450 ppm in 2060 and 425 ppm in 2100,under the IPCC SSP1-2.6 *** these targets can be reached or even almost reached,the no tipping pointhypothesis for the summer SIE may be valid.