California just recently came out of a terrifying drought, which underscores the very real problems that will face water systems going forward. Simply put, many of the places where we live have water systems heavily affected by climate change. And for Cape Town, South Africa’s largest city with nearly four million residents, it’s close to becoming an outright crisis. Simply put, there is, potentially, a day on the calendar (“Day Zero”) when Cape Town, which is already rationing its water, will officially run out. And there may not be many realistic long-term solutions, if the drought keeps up, but here are the essential details of this crisis: Cape Town residents are currently living on only 13 gallons of water a day: The water ration, already a quarter of what your average American uses in a day, was just cut by nearly half. For contrast, thirteen gallons is enough water for a six minute…