The decade of 2000-2009 ended up being the warmest on record. The 1990s were previously the warmest decade on record. With such data and continued trends of warming, many fear global warming will only continue to worsen. One aspect of global warming few think of, water vapor, may actually have surprisingly helped slow warming this past decade.
Researchers have discovered through satellite and balloon data that water vapor in the stratosphere has declined. The layer in which the vapor has decreased is about 10 miles above the surface of the earth. The overall findings can be found in the journal Science.
The data found that after the year 2000, water vapor actually decreased in this area. Because of this, the researchers have concluded that warming in the 2000s has not been as great as it would have been otherwise. Susan Solomon, of the National Oceanic and Atmospheric Administration, worked on the project and has stated that the reason for the decrease in water vapor was unknown.
The researchers did state, however, that water vapor did increase between 1980 and 2000, which most likely led to increased impacts of warming in the 1990s.
In their study the researchers stated: “Stratospheric water vapor concentrations decreased by about 10 percent after the year 2000. This acted to slow the rate of increase in global surface temperature over 2000-2009 by about 25 percent compared to that which would have occurred due only to carbon dioxide and other greenhouse gases.”
