Water supplies and security will be one of the most pressing issues as the world faces the challenge of climate change. If average global temperatures rise by only a few degrees most of the world’s glaciers will all but disappear, leading to floods and severe water shortages for millions of people. “Hot Cities” goes to Lima in Peru, one of the driest cities in the world but a city which relies heavily on the water from three rivers fed by glacial melt. As the city swells in size the demands on the water supply are increasing. But already Lima is working on a survival strategy based on re-cycling projects and “fog-catching” – literally catching fog in large thin-meshed nets and using the “captured” moisture to irrigate plants..