Human influence on climate detectable in the late 19th century

作者：Benjamin D. Santer, Susan Solomon, David W. J. Thompson, Qiang Fu, Yaowei Li · 发表于：Proceedings of the National Academy of Sciences · 年份：2025 · DOI：10.1073/pnas.2500829122 · 被引用次数：10 · 研究领域：Atmospheric and Environmental Gas Dynamics、Climate variability and models、Atmospheric Ozone and Climate

The physics of the heat-trapping properties of CO[Formula: see text] were established in the mid-19th century, as fossil fuel burning rapidly increased atmospheric CO[Formula: see text] levels. To date, however, research has not probed when climate change could have been detected if scientists in the 19th century had the current models and observing network. We consider this question in a thought experiment with state-of-the-art climate models. We assume that the capability to make accurate measurements of atmospheric temperature changes existed in 1860, and then apply a standard "fingerprint" method to determine the time at which a human-caused climate change signal was first detectable. Pronounced cooling of the mid- to upper stratosphere, mainly driven by anthropogenic increases in carbon dioxide, would have been identifiable with high confidence by approximately 1885, before the advent of gas-powered cars. These results arise from the favorable signal-to-noise characteristics of the mid- to upper stratosphere, where the signal of human-caused cooling is large and the pattern of this cooling differs markedly from patterns of intrinsic variability. Even if our monitoring capability in 1860 had not been global, and high-quality stratospheric temperature measurements existed for Northern Hemisphere mid-latitudes only, it still would have been feasible to detect human-caused stratospheric cooling by 1894, only 34 y after the assumed start of climate monitoring. Our study provi...