Excellent brief summary of research on climate change in the desert southwest, published in the journal Science. This story predicting nearly a century of drought has vital meaning for us all. At stake are the population and agriculture of the entire desert southwest, and those who depend on this resource.
Currently, the majority of water in the Southwest is used in agriculture, but the urban population of the region is growing and so the water needs of people are growing as well, he explained.
“So, in a case where there is a reduced water supply, there will have to be some reallocation between the users,” Seager said. “The water available is already fully allocated.”
Researchers studied 19 computer models of the climate, using data dating back to 1860 and projecting into the future, to the year 2100. The same models were used in preparing the reports of the Intergovernmental Panel on Climate Change.
The consensus of the models was that climate in the southwestern United States and parts of northern Mexico began a transition to drier conditions late in the 20th century and is continuing the trend in this century, as climate change alters the movement of storms and moisture in the atmosphere. The models show the drying trend continuing all the way to 2100 — for more than 90 years.
Jonathan T. Overpeck, director of the Institute for the Study of Planet Earth at the University of Arizona, said the finding “agrees with what is already happening in the Southwest, and will be further complicated by the already declining spring snowpack due to warming.”
“These are scary results, but scary in part because they are results of well thought-out scientific work by a large number of strong scientists,” said Overpeck, who was not part of the research team.
The bleak future predicted for the southwest is not unfamiliar to the territory. Ancient civilizations of surprising sophistication flourished between AD 850 and 1250, and then disbursed when the land could no longer sustain large populations. Today, agricultural products grown in Arizona and California with Colorado River water provide food far beyond the region's boundaries. As we pave prime agricultural land and turn fields into business parks around the nation, we should remember the long-term risks of drought and crop failure in the places where our food comes from.