According to new research reported in the Proceedings of the National Academy of Sciences, water vapor changes in the stratosphere contribute to warmer temperatures and play an important role in the evolution of climate.
High-level water vapor influences weather and climate, according to a new study. Image credit: NASA.
Prof Andrew Dessler of Texas A&M University and his colleagues found that increased surface temperatures, such as from the addition of carbon dioxide to the atmosphere, leads to increased humidity in the stratosphere. Because stratospheric water vapor is a greenhouse gas, this leads to additional warming. This cycle is frequently called a climate feedback.
“We find that this stratospheric water vapor feedback is probably responsible for 5-10 percent of the total warming you get from adding carbon dioxide to the climate. While it’s not really surprising that this process is going on, we were surprised at how important the process is for our climate system,” Prof Dessler said.
“Climate models already include this process, but unevenly. Some models predict large increases in stratospheric humidity, while others don’t.”
Dr Sean Davis from the University of Colorado at Boulder, co-author of the study, added: “it’s clear to us that, if models want to make accurate predictions of climate change, they should get stratospheric water vapor right.”
“A better understanding of the stratospheric water vapor feedback could help explain some of the spread among predictions of future climate change from different models.”
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Bibliographic information: Dessler AE et al. Stratospheric water vapor feedback. PNAS, published online September 30, 2013; doi: 10.1073/pnas.1310344110
