Global warming is real and is affecting the western and southwestern regions of the United States, climate change experts said during a conference that was co-sponsored by The University of Arizona's law school.
Jonathan Overpeck, geosciences professor and director of the Institute for Environment and Society at the UA, said more climate change is a sure bet and natural variability could make it worse with a megadrought that could persist for decades.
He also said climate scientists have reached a consensus that there is "little doubt" that humans are causing the warming.
Global climate models indicate that the Southwest will get drier, with more droughts and, paradoxically, more floods. These changes will dry the soils and landscape and cause associated hydrological changes.
"The scary thing is that what has been projected is actually happening," Overpeck said during the conference, "Adaptation to Climate Change in the Desert Southwest: Impacts and Opportunities," which was held in Tucson on Thursday and Friday.
Overpeck's comments kicked off the conference, which was held at the Westward Look Resort. The conference was sponsored by the Climate Assessment for the Southwest, the Program on Economics, Law, and the Environment, the Institute for Environment and Society and the James E. Rogers College of Law.
Nearly 300 scientists, scholars and national and community leaders convened at the conference to take a hard look at climate change, which is considered of the Southwest's most pressing challenges.
Drought settled upon the region in the latter part of the 1990s and was particularly severe in 2002 and 2004 when the dry conditions crept deep into Mexico and into Canada, Overpeck said.
Those conditions are unlike any seen in the 20th century, he added. If a multi-decade drought settles on the region, offering no significant rainfall to replenish water supplies for years on end, infrastructure can be overwhelmed.
Overpeck emphasized: "We should be adapting to make ourselves resilient to this kind of catastrophe."