evidence: "Carbon dioxide and other non-condensable greenhouse gases act as control knobs for the climate," said Andrew Dessler, a professor of Atmospheric Sciences at Texas A&M University in College Station. "As humans add carbon dioxide to the atmosphere, small changes in climate are amplified by changes in water vapor. This makes carbon dioxide a much more potent greenhouse gas than it would be on a planet without water vapor." Increases in atmospheric water vapor also amplify the global water cycle. They contribute to making wet regions wetter and dry regions drier. The more water vapor that air contains, the more energy it holds. This energy fuels intense storms, particularly over land. This results in more extreme weather events.