title: Upper-tropospheric moistening in response to anthropogenic warming.
abstract: Water vapor in the upper troposphere strongly regulates the strength of water-vapor feedback, which is the primary process for amplifying the response of the climate system to external radiative forcings. Monitoring changes in upper-tropospheric water vapor and scrutinizing the causes of such changes are therefore of great importance for establishing the credibility of model projections of past and future climates. Here, we use coupled ocean-atmosphere model simulations under different climate-forcing scenarios to investigate satellite-observed changes in global-mean upper-tropospheric water vapor. Our analysis demonstrates that the upper-tropospheric moistening observed over the period 1979-2005 cannot be explained by natural causes and results principally from an anthropogenic warming of the climate. By attributing the observed increase directly to human activities, this study verifies the presence of the largest known feedback mechanism for amplifying anthropogenic climate change.
authors: Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149;
authors: Eui-Seok
authors: ES
authors: Chung
authors: Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149; b.soden@miami.edu.
authors: Brian
authors: B
authors: Soden
authors: School of Earth and Environmental Sciences, Seoul National University, Seoul 151-747, Korea; and.
authors: B J
authors: BJ
authors: Sohn
authors: National Climatic Data Center, National Oceanic and Atmospheric Administration, Asheville, NC 28801.
authors: Lei
authors: L
authors: Shi
mesh_terms: D001272:Atmosphere / Q000032:analysis*; D057231:Climate Change; D004784:Environmental Monitoring; D057232:Global Warming; D017752:Greenhouse Effect; D006801:Humans; D008962:Models, Theoretical; D013227:Steam / Q000009:adverse effects / Q000032:analysis*; D013997:Time Factors
chemical_list: D013227:Steam
keywords: attribution; detection; long-term monitoring