近日，美国哥伦比亚大学Sean Cohen团队报道了二氧化碳上升导致平流层冷却和辐射强迫的放大。这一研究成果于2026年5月11日发表在《自然—地球科学》杂志上。

平流层响应于二氧化碳浓度升高而发生的冷却，是人类活动影响气候的一个指纹特征。然而，控制这一冷却幅度及垂直结构的机制此前尚不明确。

研究组利用光谱学和辐射传输的理想化模型，解释了平流层温度对二氧化碳浓度的敏感性。结果发现，平流层冷却主要由二氧化碳主要吸收带中质量吸收系数的分布驱动，并受到光谱其他区域水汽和臭氧的长波冷却调节。

这些光谱机制解释了为什么平流层上部的冷却幅度大于下部，为什么二氧化碳浓度每增加一倍会在整个平流层深度范围内引起大约0到8开尔文的冷却，以及为什么平流层冷却会使二氧化碳在大气层顶的辐射强迫增加约50%。这一理论表明，平流层冷却并非温室气体光学厚度增加所带来的必然结果，而是该气体独特光谱特性的产物。

附：英文原文

Title: Stratospheric cooling and amplification of radiative forcing with rising carbon dioxide

Author: Cohen, Sean, Pincus, Robert, Polvani, Lorenzo M.

Issue&Volume: 2026-05-11

Abstract: The cooling of the stratosphere in response to increasing carbon dioxide concentration is a fingerprint of human effects on climate. However, the mechanisms that control the magnitude and vertical structure of this cooling have not been clear. Here we use idealized models of spectroscopy and radiative transfer to explain the sensitivity of stratospheric temperature to carbon dioxide concentration. We find that stratospheric cooling is mainly driven by the distribution of mass absorption coefficients in the primary carbon dioxide band and modulated by the longwave cooling of water vapour and ozone in other parts of the spectrum. These spectral mechanisms explain why the stratosphere cools more aloft than it does below, why each doubling of carbon dioxide yields roughly 0 to 8 degrees Kelvin of cooling across the depth of the stratosphere and why stratospheric cooling increases the top of atmosphere radiative forcing of carbon dioxide by about 50%. This theory implies that stratospheric cooling is not a fundamental consequence of increasing the optical thickness of a greenhouse gas but rather the unique result of the spectroscopy of that gas.

DOI: 10.1038/s41561-026-01965-8

Source: https://www.nature.com/articles/s41561-026-01965-8