New research provides clear evidence of a human “fingerprint” on climate change and shows that specific signals from human activities have altered the temperature structure of Earth’s atmosphere.
Differences between tropospheric and lower stratospheric temperature trends have long been recognized as a fingerprint of human effects on climate. This fingerprint, however, neglected information from the mid to upper stratosphere, 25 to 50 kilometers above the Earth’s surface.
“Including this information improves the detectability of a human fingerprint by a factor of five. Enhanced detectability occurs because the mid to upper stratosphere has a large cooling signal from human-caused CO2 increases, small noise levels of natural internal variability, and differing signal and noise patterns,” according to the journal article, “Exceptional stratospheric contribution to human fingerprints on atmospheric temperature,” published in the Proceedings of the National Academy of Sciences (PNAS). Noise in the troposphere can include day-to-day weather, interannual variability arising from El Niños and La Niñas, and longer-term natural fluctuations in climate. In the upper stratosphere, the noise of variability is smaller, and the human-caused climate change signal is larger, so the signal can be much more easily distinguished.
Read more at: Woods Hole Oceanographic Institute
https://www.whoi.edu/press-room/news-release/atmospheric-research-provides-clear-evidence-of-human-caused-climate-change-signal-associated-with-co2-increases/