近日，美国科罗拉多大学波德分校Jeremy M. Klavans团队揭示人类排放驱动了最近北太平洋气候变化的趋势。2025年8月13日出版的《自然》杂志发表了这项成果。

太平洋年代际振荡（PDO）——驱动北太平洋及周边大陆变化的主要气候变率模式——现在被认为是由气候系统内部过程产生的。根据这一范式，PDO的特征不规则振荡源于北太平洋和热带太平洋海洋和大气相互作用的一系列机制。最近海洋-大气耦合系统的变化，如2015年的厄尔尼诺现象，应已经将PDO转变为正相位。然而，三十多年来，PDO一直处于持续下降的趋势，使附近地区受到一系列稳定的气候影响。

研究组表明，二十世纪PDO指数的主要几十年变化，包括持续数十年的负面趋势，主要是由人类排放的气溶胶和温室气体驱动的，而不是内部过程。这种人为影响以前未被发现，因为当前这一代气候模式系统地低估了强迫气候变率的幅度。一种新的归因技术在统计上纠正了这一错误，表明观测到的PDO影响——包括美国西部持续多年的干旱——可以在很大程度上归因于人类活动，通过外部强迫PDO变化。这些结果表明，研究人员需要重新思考区域气候多年代际变化的归因和预估。

附：英文原文

Title: Human emissions drive recent trends in North Pacific climate variations

Author: Klavans, Jeremy M., DiNezio, Pedro N., Clement, Amy C., Deser, Clara, Shanahan, Timothy M., Cane, Mark A.

Issue&Volume: 2025-08-13

Abstract: The Pacific decadal oscillation (PDO)—the leading pattern of climate variability driving changes over the North Pacific and surrounding continents—is now thought to be generated by processes internal to the climate system1,2. According to this paradigm, the characteristic, irregular oscillations of the PDO arise from a collection of mechanisms involving ocean and atmosphere interactions in the North and tropical Pacific3,4,5. Recent variations in the coupled ocean–atmosphere system, such as the 2015 El Nio, ought to have shifted the PDO into its positive phase6. Yet, the PDO has been locked in a consistent downward trend for more than three decades, remanding nearby regions to a steady set of climate impacts. Here we show that the main multidecadal variations in the PDO index during the twentieth century, including the ongoing, decades-long negative trend, were largely driven by human emissions of aerosols and greenhouse gases rather than internal processes. This anthropogenic influence was previously undetected because the current generation of climate models systematically underestimate the amplitude of forced climate variability. A new attribution technique that statistically corrects for this error suggests that observed PDO impacts—including the ongoing multidecadal drought in the western United States—can be largely attributed to human activity through externally forced changes in the PDO. These results indicate that we need to rethink the attribution and projection of multidecadal changes in regional climate.

DOI: 10.1038/s41586-025-09368-2

Source: https://www.nature.com/articles/s41586-025-09368-2