The southwestern United States is in the grips of a historic drought — and now, one of the country’s biggest reservoirs, Lake Mead, has seen its water levels plummet. It’s the result of a two-decades-long dry spell fuelled by climate change. John Fleck, a professor of water policy and governance at the University of New Mexico, talks about the importance of Lake Mead; and Peter Fiske, director of the National Alliance for Water Innovation and the Water-Energy Resilience Institute, explains why desalination could solve the growing water crisis.