Simply put, Day Zero is the day when the water runs out, the taps are dry, and city officials have to recon with how much violence zero water will inspire. Day Zero has already happened in places like Syria and Iran but at a city level, not for a whole country.

The latest city to flirt with this calamity is Cape Town, South Africa, where officials expect day zero to happen in April absent a sudden miracle. A story in the New York Times by Norimitsu Onishi and Somni Sengupta provides the chilling details. The report includes this:

“When Day Zero comes, they’ll have to call in the army,” said Phaldie Ranqueste, who was filling his white S.U.V. with big containers of water at a natural spring where people waited in a long, anxious line.

But in many ways that’s beside the point. Cape Town is a much-awarded city by conservation groups for instance,

Just a couple of years ago, the situation could not have looked more different here. In 2014, the dams stood full after years of good rain. The following year, C40, a collection of cities focused on climate change worldwide, awarded Cape Town its “adaptation implementation” prize for its management of water.

The big takeaway is that conditions changed much faster than humans could adapt through constructing new reservoirs and desalination plants or finding new sources of ground water. Climate change is like that and it is only beginning as one city manager put it,

Climate models show that Cape Town is destined to face a drier future, with rains becoming more unpredictable in the coming decades. “The drier years are expected to be drier than they were, and the wetter years will not be as wet,” Mr. Piotr Wolski said.

Wolski is a hydrologist at the University of Cape Town and he studies Cape Town’s precarious water situation.

It’s the same story in other countries. I recently posted that as many as 33 countries could face sever water restrictions by mid-century. Southern California came close to day zero two years ago and when the rains came there wasn’t adequate storage for all of it. Will California be as fortunate next time?

Cities elsewhere have faced serious water shortages. Millions of Brazilians have endured rationing because of prolonged droughts. Brasília, the capital, declared a state of emergency a year ago. Experts say the water shortages in Brazil, which have affected more than 800 municipalities across the country, stem from climate change, the rapid expansion of agriculture, bad infrastructure and poor planning.

My take

The hardest part of a situation like climate change is the feeling of helplessness you get from inaction. Coming up with solutions to water shortage is not hard but we’ve spent too much time and effort in denial about the global situation than in applying solutions that already exist. Cape Town shows that frittering away the time can be deadly.

In the short run fixing the water problems like those cropping up around the world involves creating new sources of fresh water including creating more dams and reservoirs to store water when the rains come and building desalination plants that run on renewable electricity. But none of these solutions is quick or cheap though they are certainly better than the alternative of day zero.

The long-term solution requires some planning and engagement of even those who dismiss climate change as a hoax. Long term we need to reduce the amount of carbon already in the atmosphere because there’s already too much there. Simply reducing emissions won’t do the trick.

There are solutions for water problems as well as carbon and they are laid out in “The Age of Sustainability” but to implement them we first have to admit the problem.