Sealevel rise and increasingly ferocious storms – both driven by climate change – are eroding thousands of miles of Mexico’s coastline facing the Gulf and the Pacific Ocean. Around this country of nearly 130 million people, drought is draining reservoirs dry and creating severe water shortages. Deadly heat is straining people and crops and aging infrastructure is struggling to keep up. But the leading presidential candidate, Claudia Sheinbaum, an environmental scientist and a co-author of the 2007 Nobel Prize-winning Intergovernmental Panel on Climate Change report, is not making climate a cen…