SACRAMENTO, Calif. (AP) - Twenty of the nation's top scientists have sent a letter to California's governor urging him to place a moratorium on the controversial practice of hydraulic fracturing, or "fracking.''
They say the practice increases pollution and runs counter to Gov. Jerry Brown's efforts to cut the state's emissions.
In the letter, the group argues that Brown can't say he wants to reduce global warming while also expanding fossil fuel development in California.
Brown has come under increasing criticism from opponents of fracking, which injects water, sand and chemicals into the ground to fracture underground rock formations and release fossil fuels.
The letter's signatories include Anne Ehrlich and Paul Ehrlich of Stanford University, Alastair Iles of the University of California, Berkeley, and Shaye Wolf of the Center for Biological Diversity.