quaith writes "Nature reports that a team led by researchers at the National Oceanic and Atmospheric Administration describe how a mysterious 10% drop in water vapor in the stratosphere since 2000 could have offset the expected warming due to greenhouse gases. The calculated offset is roughly 25%. The team's model also suggests that an increase in water vapor might have boosted earlier warming by about 30% in the 1980s and 1990s. This drop in atmospheric water vapor is now on the list of possible culprits causing average global temperatures to flatten out over the past decade, despite increasing greenhouse-gas emissions."
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