Understanding the response of the Earth system to varying concentrations of carbon dioxide(CO_(2))is critical for projecting possible future climate change and for providing insight into mitigation and adaptation stra...Understanding the response of the Earth system to varying concentrations of carbon dioxide(CO_(2))is critical for projecting possible future climate change and for providing insight into mitigation and adaptation strategies in the near future.In this study,we generate a dataset by conducting an experiment involving carbon dioxide removal(CDR)—a potential way to suppress global warming—using the Chinese Academy of Sciences Earth System Model version 2.0(CASESM2.0).A preliminary evaluation is provided.The model is integrated from 200–340 years as a 1%yr^(−1) CO_(2) concentration increase experiment,and then to~478 years as a carbon dioxide removal experiment until CO_(2) returns to its original value.Finally,another 80 years is integrated in which CO_(2) is kept constant.Changes in the 2-m temperature,precipitation,sea surface temperature,ocean temperature,Atlantic meridional overturning circulation(AMOC),and sea surface height are all analyzed.In the ramp-up period,the global mean 2-m temperature and precipitation both increase while the AMOC weakens.Values of all the above variables change in the opposite direction in the ramp-down period,with a delayed peak relative to the CO_(2) peak.After CO_(2) returns to its original value,the global mean 2-m temperature is still~1 K higher than in the original state,and precipitation is~0.07 mm d^(–1) higher.At the end of the simulation,there is a~0.5°C increase in ocean temperature and a 1 Sv weakening of the AMOC.Our model simulation produces similar results to those of comparable experiments previously reported in the literature.展开更多
Tropical rainfall is important for regional climate around the globe.In a warming climate forced by rising CO_(2),the tropical rainfall will increase over the equatorial Pacific where sea surface warming is locally en...Tropical rainfall is important for regional climate around the globe.In a warming climate forced by rising CO_(2),the tropical rainfall will increase over the equatorial Pacific where sea surface warming is locally enhanced.Here,we analyze an idealized CO_(2) removal experiment from the Carbon Dioxide Removal Model Intercomparison Project(CDRMIP)and show that the tropical rainfall change features a stronger pattern during CO_(2) ramp-down than ramp-up,even under the same global mean temperature increase,such as the 2℃ goal of the Paris Agreement.The tropical rainfall during CO_(2) ramp-down increases over the equatorial Pacific with a southward extension,and decreases over the Pacific intertropical convergence zone and South Pacific convergence zone.The asymmetric rainfall changes between CO_(2) ramp-down and ramp-up result from time-varying contributions of the fast and slow oceanic responses to CO_(2) forcing,defined as the responses to abrupt CO_(2) forcing in the first 10 years and thereafter,respectively,in the abrupt-4xCO_(2) experiment.The fast response follows the CO_(2) evolution,but the slow response does not peak until 60 years after the CO_(2) peak.The slow response features a stronger El Niño-like pattern,as the ocean dynamical thermostat effect is suppressed under stronger subsurface warming.The delayed and stronger slow response leads to stronger tropical rainfall changes during CO_(2) ramp-down.Our results indicate that returning the global mean temperature increase to below a certain goal,such as 2℃,by removing CO_(2),may fail to restore tropical convection distribution,with potentially devastating effects on climate worldwide.展开更多
基金jointly supported by the National Key Research and Development Program of China (Grant No. 2022YFC3105000)the Youth Innovation Promotion Association of CAS (2022074)+3 种基金the National Natural Science Foundation of China (Grant Nos. 42005123, 42275173 and 41706028)the National Key Research and Development Program of China(2022YFE0106500)the 7th Youth Talent Support Project of Ningxia Hui Autonomous Region Association for Science and TechnologyNational Key Scientific and Technological Infrastructure project ‘‘Earth System Science Numerical Simulator Facility’’(EarthLab) for supporting the simulations in this study
文摘Understanding the response of the Earth system to varying concentrations of carbon dioxide(CO_(2))is critical for projecting possible future climate change and for providing insight into mitigation and adaptation strategies in the near future.In this study,we generate a dataset by conducting an experiment involving carbon dioxide removal(CDR)—a potential way to suppress global warming—using the Chinese Academy of Sciences Earth System Model version 2.0(CASESM2.0).A preliminary evaluation is provided.The model is integrated from 200–340 years as a 1%yr^(−1) CO_(2) concentration increase experiment,and then to~478 years as a carbon dioxide removal experiment until CO_(2) returns to its original value.Finally,another 80 years is integrated in which CO_(2) is kept constant.Changes in the 2-m temperature,precipitation,sea surface temperature,ocean temperature,Atlantic meridional overturning circulation(AMOC),and sea surface height are all analyzed.In the ramp-up period,the global mean 2-m temperature and precipitation both increase while the AMOC weakens.Values of all the above variables change in the opposite direction in the ramp-down period,with a delayed peak relative to the CO_(2) peak.After CO_(2) returns to its original value,the global mean 2-m temperature is still~1 K higher than in the original state,and precipitation is~0.07 mm d^(–1) higher.At the end of the simulation,there is a~0.5°C increase in ocean temperature and a 1 Sv weakening of the AMOC.Our model simulation produces similar results to those of comparable experiments previously reported in the literature.
基金supported by the National Key Research&Development Program of China(2019YFA0606703)the National Natural Science Foundation of China(41975116 and 42105027)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202025)the China Postdoctoral Science Foundation(BX20200329 and 2020M680646)the Special Research Assistant Project of Chinese Academy of Sciences。
文摘Tropical rainfall is important for regional climate around the globe.In a warming climate forced by rising CO_(2),the tropical rainfall will increase over the equatorial Pacific where sea surface warming is locally enhanced.Here,we analyze an idealized CO_(2) removal experiment from the Carbon Dioxide Removal Model Intercomparison Project(CDRMIP)and show that the tropical rainfall change features a stronger pattern during CO_(2) ramp-down than ramp-up,even under the same global mean temperature increase,such as the 2℃ goal of the Paris Agreement.The tropical rainfall during CO_(2) ramp-down increases over the equatorial Pacific with a southward extension,and decreases over the Pacific intertropical convergence zone and South Pacific convergence zone.The asymmetric rainfall changes between CO_(2) ramp-down and ramp-up result from time-varying contributions of the fast and slow oceanic responses to CO_(2) forcing,defined as the responses to abrupt CO_(2) forcing in the first 10 years and thereafter,respectively,in the abrupt-4xCO_(2) experiment.The fast response follows the CO_(2) evolution,but the slow response does not peak until 60 years after the CO_(2) peak.The slow response features a stronger El Niño-like pattern,as the ocean dynamical thermostat effect is suppressed under stronger subsurface warming.The delayed and stronger slow response leads to stronger tropical rainfall changes during CO_(2) ramp-down.Our results indicate that returning the global mean temperature increase to below a certain goal,such as 2℃,by removing CO_(2),may fail to restore tropical convection distribution,with potentially devastating effects on climate worldwide.
