Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California have recently found that California is warming up, but the main cause seems to be land use. The largest temperature increases were in the urban areas of the San Francisco Bay Area and Southern California. Lower increases were noted in non urban areas. There was cooling In a narrow band in the North East section of the state (which is basically wilderness). In addition, the minimum temperatures (nighttime) increased more than the maximum (daytime) temperatures. This work has been published in Climate Research 33:159-169. These results seem to be consistent with those of Prof. John Christy of the University of Alabama in Huntsville, who found warming in California's Central Valley (J. Climate, 19, 548-563) that was mainly due to land use. Chisty also found that nighttime temperatures increased more than daytime which he attributed to the effects of land use. Indeed Christy stated that:
It suggests that to “do something” about warming in central California means removing agricultural and urban development rather than reducing greenhouse gas emissions.
We may conclude that Governor Schwarzenegger and the legislature need to do more than just mandating a reduction in greenhouse gases if we are going to cool the golden state. We need to start by bulldozing the heavily populated urban areas and plant native grasses and oak trees in their place. Perhaps Los Angeles could be selected as a pilot project?