韩国首尔国立大学Jong-Seong Kug团队研究了二氧化碳减排下厄尔尼诺周期的突变。2025年6月16日出版的《美国科学院院刊》发表了这项成果。

从大气中去除二氧化碳正在成为缓解全球变暖的可行策略，但气候系统对二氧化碳减少的反应仍然不确定。厄尔尼诺行为最不确定的方面之一是响应二氧化碳强迫的周期性变化。在这项研究中，课题组表明，一旦二氧化碳减排开始，气候模型一直预测厄尔尼诺周期会突然缩短。 

除了缓慢的平均状态变化的贡献外，这一现象还被证明是由热带辐合带（ITCZ）的南移以及随之而来的厄尔尼诺现象空间格局的缩小所驱动的，这增强了海洋热量补给/排放过程的有效性，从而缩短了其周期性。这表明，厄尔尼诺周期性的突然转变是由涉及ITCZ动力学和厄尔尼诺空间结构的级联反应引起的。这些发现突显了全球能源平衡在塑造厄尔尼诺特征方面的关键作用。

附：英文原文

Title: Abrupt shift of El Nio periodicity under CO2 mitigation

Author: Iwakiri, Tomoki, Kug, Jong-Seong, Jin, Fei-Fei, Zhao, Sen, An, Soon-Il, Kim, Geon-Il, Park, Dongkyu

Issue&Volume: 2025-6-16

Abstract: Removing CO2 from the atmosphere is emerging as a viable strategy to mitigate global warming, yet the responses of the climate system to CO2 reduction remain uncertain. One of the most uncertain aspects of El Nio behavior is the change in periodicity in response to CO2 forcing [O. Alizadeh, Earth-Sci. Rev. 235, 104246 (2022)]. In this study, we show that climate models consistently project an abrupt shortening of El Nio periodicity once CO2 reductions commence in ramp-up and ramp-down CO2 experiments. Besides the contribution of slow mean state changes, this phenomenon is shown to be driven by a southward shift of the Intertropical Convergence Zone (ITCZ) [J.-S. Kug, et al., Nat. Clim. Chang. 12, 47–53 (2022)] and the consequent narrowing of El Nio’s spatial pattern, which enhances the effectiveness of ocean heat recharge/discharge processes, thereby shortening its periodicity. This suggests that the abrupt shift in El Nio periodicity results from a cascading reaction involving ITCZ dynamics and El Nio’s spatial configuration. These findings highlight the critical role of the global energy balance in shaping El Nio characteristics.

DOI: 10.1073/pnas.2426048122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2426048122