在低排放和高排放场景下,大气pCO对强烈的AMOC减弱的反应
Amber A Boot1, Anna S von der Heydt1,2, Henk A Dijkstra1,2
1Department of Physics, Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Princetonplein 5, Utrecht, 3584CC The Netherlands.
概括
由于气候变化,大西洋南部翻转循环 (AMOC) 的减弱可能会增加大气中的CO2. 本研究量化了不同排放场景下的二氧化碳反应,揭示了对碳循环和气候系统的局部影响.
科学领域:
- 地球系统科学 地球系统科学
- 气候建模气候模型
- 碳循环研究 碳循环研究
背景情况:
- 人为温室气体排放导致全球变暖,增加了地球系统临界点的风险.
- 大西洋南部翻转循环 (AMOC) 的崩或显著减弱可能会对气候产生重大影响.
- 对于AMOC变化对海洋和陆地碳循环的影响,以及随之而来的大气二氧化碳的影响,涉及不确定性.
研究的目的:
- 在不同的排放场景下 (SSP1-2.6和SSP5-8.5) 调查大气二氧化碳对AMOC减弱的反应.
- 利用社区地球系统模型v2 (CESM2) 模拟这些气候和碳循环相互作用.
- 分析二氧化碳反应的驱动因素,区分海洋和陆地贡献.
主要方法:
- 模拟了北大西洋的淡水流异常,以诱导AMOC减弱.
- 用于地球系统建模的社区地球系统模型v2 (CESM2).
- 从2015年到2100年,分析了低 (SSP1-2.6) 和高 (SSP5-8.5) 排放路径下的大气pCO2变化.
主要成果:
- 显著的AMOC减弱导致了积极的大气pCO2反应 (0.451.3 ppm每Sv下降).
- 对于SSP1-2.6来说,海洋和陆地碳循环都对pCO2增加做出了贡献;对于SSP5-8.5,只有海洋是主要的驱动因素.
- 气候和碳循环反应的空间模式在所有排放场景中都是相似的,这表明到2100年,它们与累积的二氧化碳水平无关.
结论:
- 减弱AMOC可以导致大气二氧化碳的可测量的增加,其贡献因排放情况而异.
- 尽管全球pCO2变化可能很小,但对碳循环和气候系统的局部影响可能是严重的.
- 这些局部变化对生态系统和人类社会构成重大风险,强调了解AMOC动态的重要性.
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