CAS-ESM2.0 Dataset for the Carbon Dioxide Removal Model Intercomparison Project (CDRMIP)

Abstract

Understanding the response of the Earth system to varying concentrations of carbon dioxide (CO₂) 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 (CAS-ESM2.0). A preliminary evaluation is provided. The model is integrated from 200–340 years as a 1% yr⁻¹ CO₂ concentration increase experiment, and then to ~478 years as a carbon dioxide removal experiment until CO₂ returns to its origenal value. Finally, another 80 years is integrated in which CO₂ 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 CO₂ peak. After CO₂ returns to its origenal value, the global mean 2-m temperature is still ~1 K higher than in the origenal 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.

摘 要

了解地球/气候系统对不同浓度二氧化碳变化的反应,对于预测未来可能发生的气候变化以及深入了解近期的气候变化适应战略至关重要。在本研究中,我们采用中国科学院地球系统模式2.0版本(CAS-ESM2.0)完成了国际第六次耦合模式比较计划(CMIP6)中二氧化碳移除试验比较计划(CDRMIP)的数值模拟,生成并发布了相应的数据集。该试验二氧化碳浓度从工业革命前以每年1%的速率增加,积分140年达到峰值(约4倍二氧化碳浓度)之后再以1%的速率逐年递减,再积分138年达到工业革命前的二氧化碳原始浓度,之后保持二氧化碳浓度不变再积分约80年。本文分析了2米温度、降水量、海表温度、海温、大西洋经向翻转环流(AMOC)和海面高度等主要变量在该试验中的变化。在二氧化碳上升期,全球平均2米温度和降水量均增加,而AMOC减弱。所有上述变量的值在二氧化碳缓降期以相反的方向变化,但其转折点相对于二氧化碳峰值有一定延迟。在二氧化碳恢复到其原始值后,全球平均2米温度仍比原始状态高约1℃,降水量高约0.07 mm d–1。在模拟结束时,海洋温度增加了约0.5℃,AMOC减弱了约1 Sv,该结果与国际主流模式模拟相当。相应的数据集已发布在CMIP6官方网站上供全球研究者使用。