Desert-dominated Arizona has warmed 1.1°C in the past century. Its biggest city faces problems of extreme heat and a dwindling water supply due to climate change. Snowfall in the Sierra Nevada mountains will be down by two-thirds depriving the city of water. By 2100, under a business-as-usual scenario, San Francisco’s temperature will rise more than 4°C. A 1.2-meter sea-level rise will flood large parts of the city. Despite global efforts, CO2 emissions are still rising year after year. To hit global targets, emissions need to fall 45% by 2030. Watch the video to learn about which other US cities will be hit hard by climate change.