The Arizona Legislature is considering pulling the state out of a regional coalition of states to limit greenhouse gas emissions. At the hearing last week on House Bill 2467, Arizona's leading climate expert (and my old classmate) Jonathan Overpeck warned that Phoenix temperatures could routinely reach 130 F later this century, the Colorado River flows are likely to drop by 20% by 2050, and Arizona will warm and dry up faster than any other state. He spoke against the bill. [right, Glen Canyon Dam and Lake Powell. Predictions are that there is 30% chance the lake could go dry by 2050]