While water vapor has always been considered one of the primary greenhouse gases, a new report says that scientists have underestimated the role it plays in determining global temperature changes:
The research, led by one of the world’s top climate scientists, suggests that almost one-third of the global warming recorded during the 1990s was due to an increase in water vapour in the high atmosphere, not human emissions of greenhouse gases. A subsequent decline in water vapour after 2000 could explain a recent slowdown in global temperature rise, the scientists add . . . .
The new research, led by Susan Solomon, at the US National Oceanic and Atmospheric Administration, who co-chaired the 2007 IPCC report on the science of global warming, is published today in the journal Science, one of the most respected in the world . . . .
The new study analysed water vapour in the stratosphere, about 10 miles up, where it acts as a potent greenhouse gas and traps heat at the Earth’s surface.
Satellite measurements were used to show that water vapour levels in the stratosphere have dropped about 10% since 2000. When the scientists fed this change into a climate model, they found it could have reduced, by about 25% over the last decade, the amount of warming expected to be caused by carbon dioxide and other greenhouse gases.
They conclude: “The decline in stratospheric water vapour after 2000 should be expected to have significantly contributed to the flattening of the global warming trend in the last decade.”
Based on this new research we can expect Congress to amend the climate change bill to require dehumidifiers be added to all SUVs.