A bipartisan group of mayors from across the country unanimously approved a resolution Monday that calls on cities to use natural solutions to fight the effects of climate change.Participants at the U.S. Conference of Mayors in Dallas voted on the resolution, which encourages cities to use nature to “protect freshwater supplies, defend the nation’s coastlines, maintain a healthy tree and green space cover and protect air quality,” sometimes by joining with nonprofit organizations. The resolution was backed by Democratic mayors from GOP-dominated states: Austin Mayor Lee Leffingwell, Houston Mayor Annise Parker and Phoenix Mayor Greg Stanton. It passed easily even though conservatives and others remain deeply divided over how to deal with climate change. Though science shows that human industrial activity is contributing to global warming, some conservatives remain skeptical.“What’s so significant is that there was a unanimous vote on an issue that can be so divisive,” said Laura Huffman, director of the Nature Conservancy in Texas. “When you peel away the high-level arguments and deal with the ground-level issues, everyone just rolls up their sleeves and gets to work.”Mayors are looking for alternatives to traditional infrastructure projects, alternatives that are cost-effective and provide amenities. For example, Huffman said, Philadelphia Mayor Michael Nutter is combining traditional pipes with open spaces as he revamps the city’s storm-water collection system. These open spaces collect water much like pipes do and provide more parks. “We’re seeing that all over the country,” Huffman said.