This report on the link between climate and changes in the earth's surface "specific humidity" should be self-explanatory.
The amount of moisture in the air near the surface - the stuff that makes hot weather unbearable - increased 2.2 percent in just under three decades. And computer models show that the only explanation is man-made global warming, according to a study published in Thursday's journal Nature.
"This humidity change is an important contribution to heat stress in humans as a result of global warming," said Nathan Gillett of the University of East Anglia in Britain, a co-author of the study.
Gillett studied changes in specific humidity, which is a measurement of total moisture in the air, between 1973-2002. Increases in humidity can be dangerous to people because it makes the body less efficient at cooling itself, said University of Miami health and climate researcher Laurence Kalkstein. He was not connected with the research.
Humidity increased over most of the globe, said study co-author Katharine Willett, a climate researcher at Yale University. However, a few regions, including the U.S. West, South Africa and parts of Australia were drier.
If anyone is able to find a link to the abstract or full article in Nature, please post a comment.