Cape Town, South Africa, has been in the news a lot lately, due to its water crisis, labeled “Day Zero.”
But what exactly does the term mean? How did a water crisis like this came about, how bad is it, and is it a portent of the future for other cities? Are major cities expected to be in this predicament—and what can we do about it? Are there any lessons the whole experience may hold for those of us living in other parts of the world?
To answer these questions and more, the Bulletin’s Dan Drollette interviewed scientist and water conservation specialist Peter Gleick, who received a MacArthur “genius” Fellowship for his work on the consequences of climate change for water resources, and the risks of conflicts over water. Gleick helped to define basic water needs and the human right to water—work that has been used by the United Nations and in human rights court cases. He has pioneered and advanced the concepts of the “soft path for water” and “peak water,” and founded the Pacific Institute.
(Editor’s note: This interview has been condensed and edited for clarity.)
Dan Drollette: Cape Town is facing what is called Day Zero, which I guess is the date when they’re supposed to pretty much run out of water. What exactly is going on down there? What are your impressions?
Peter Gleick: For the first time, a major city is on the verge of literally turning off its municipal water supply system because of a lack of water. Whether or not it actually happens depends on whether they’re able to implement programs that reduce enough demand, and whether it starts to rain. But it’s really the closest I can recall of a city ever coming to turning off the taps. I can’t remember a previous time that’s happened.
It’s unprecedented, and I think it’s a little bit scary.
Dan Drollette: It has never happened before, at least for a major city on this kind of scale? Is that right?
Peter Gleick: We’ve seen extreme water shortage or flooding in the past, and cities design their water systems for those kinds of extremes. But I’ve never heard of a city literally turning off the taps because there was insufficient supply to run the municipal water system.
Dan Drollette: What do you think happened here? As I mentioned while we were arranging this interview, this story really struck home for me, because I was part of a group of science journalists who traveled to South Africa about a dozen years ago —post-apartheid — where our sponsoring organization took us to all these different townships. And it was obvious that the organizers were really proud of the fact that in the years since apartheid ended, the new government had managed to provide water to all these communities that had never been served before. They made it a point to show all the progress they’d made in supplying water.
What do you think happened there?
Is it a case of human nature, of people taking it for granted that the water will always be there—just like air—and no one needs to worry about it?
Peter Gleick: First of all, South Africa does have a lot to be proud of in the water area. They’ve been a world leader since apartheid ended, in addressing previously unmet needs for water and sanitation. There’s still enormous disparities in water availability and use there, but they have top notch water planners and managers.
The problem here is a problem that could face any big city, and that is a combination of population growth and absolute limits on new supply. They’re running into what I call peak water constraints, and the new reality of climate change. Previously, water planners and managers had assumed that the climate was variable but stable, that there would be wet years and dry years but that it wouldn’t be changing over time in the long run.
That’s no longer true. We know that humans are causing climate change, and we know that some of the worst impacts will be manifested in changes in the hydrologic cycle and changes in water availability and demand.
Dan Drollette: Is there one item that stands out head and shoulders above the rest, or are all these factors pretty much equally at fault?
Peter Gleick: It’s hard to say that any particular water crisis is X percent one or the other of any of those factors. We know that all of those factors are in play here. We know that Cape Town is at the limits of getting any new supply—that there is no more water. They’re overtapping their rivers. They’re overpumping groundwater. We know that population continues to grow and demands for water continue to grow. We know that climate change is happening. We know the current drought is showing the influence of higher temperatures—which increases demand for water and the loss of water from soils and reservoirs—which in turn worsens the severity of the drought that they’re experiencing.
I’m not arguing that climate change caused the current drought. No one is arguing that, so far as I know. But it certainly now appears that climate change is influencing and worsening the current drought. All of these things have come into play.
Dan Drollette: Climate change didn’t cause the draught, but it exacerbates the problem?
Peter Gleick: Yes, that’s right. We know that temperatures are higher. We know that higher temperatures increase the demand for water at the same time that they increase the loss of water from the reservoirs that serve Cape Town. We also know worldwide that climate change is influencing extreme events. I think that’s going to turn out to be evident here.
Dan Drollette: It’s ironic that just a few months ago the Bulletin was doing stories about extreme events in the other direction—Hurricane Harvey, for example. It was hard to simply envision the sheer volume of water involved that was dumped on Texas.
Peter Gleick: That’s right.
Dan Drollette: You mentioned “peak water.” What’s the best way to explain that concept to those of us who have not come across it before? Is it like the idea of peak oil—that hypothetical point when the global production of oil reaches its maximum, and then production gradually declines?
Peter Gleick: I wrote a paper for the Proceedings of the National Academy of Sciences a few years ago with a colleague that defines peak water. The simplest way to think about it is that even though water is a renewable resource, there are limits to how much we can take and use. When you take the entire flow of a river—as we do on the Colorado River, or the Yangtze River, or the Yellow River in China—then you can’t have anymore. We might want more water out of the Colorado River, but we can’t have it; it’s just not there. That’s a peak constraint. In addition, we’re overdrafting many non-renewable water resources as well, such as groundwater. When we pump groundwater faster than nature recharges it, it’s like peak oil. You’re using up a stock.
As much as a third of all the groundwater that’s pumped worldwide now comes from non-renewable groundwater resources. That’s a peak limit as well. More and more regions of the world—including places like Cape Town—are reaching what I call peak water.
Dan Drollette: What would be a good example here in the States of drawing too much water from a non-renewable resource? The Ogallala Aquifer?
Peter Gleick: The Ogallala Aquifer, yeah.
Dan Drollette: What would be a good way to describe the situation there? They’re constantly removing water from this underground source, and within a few decades they’ll probably be out?
Peter Gleick: Here’s the way it works. We don’t literally run out. What we run out of is the economic ability to pump from ever deeper and deeper levels. Groundwater levels drop when you use them faster than nature recharges them. It really is like oil in that sense. The Ogallala Aquifer, which underlies Texas, Oklahoma, Nebraska, Kansas, and several other states, is a fossil aquifer. It was laid down over thousands or tens of thousands of years, but we’re pumping it out in decades, especially in the southern part of the aquifer. It is becoming harder and harder, and more and more expensive, to pump—to the point where some farmers who depend on it can no longer afford to pump groundwater. That’s a very good example of a peak limit.
We see that in many parts of the world: the Middle East, Northern China, parts of Indian, in parts of the Central Valley of California. That places a limit on how much water we can use.
Dan Drollette: Is there one place in the United States that you would identify as being most likely to face a Day Zero of its own in the near future?
Peter Gleick: I think it’s possible that we will see more Day Zeros around the world. I think it’s likely. I don’t expect to see a major city in the United States have to turn off its taps because of scarcity—not even in the southwestern US, which is the most water scarce part of the country.
We have the economic and technical ability to shift water from one user to another, to implement conservation programs that reduce demand—to do the things that Cape Town is doing now—but to do them more effectively. So, I’m a little less worried about the United States running into a Day Zero situation, at least in the near future.
I am more worried about places like Jakarta, or Tehran, or places in the developing world where they don’t have alternatives, where they don’t have the economic ability to use treated wastewater or to desalinate water, and where they don’t have the management ability to implement smart and effective conservation programs.
Dan Drollette: Speaking of conservation, a few years ago officials in Boston were talking about having to greatly increase the number of reservoirs in Massachusetts in order to supply the city’s demand for more drinking water. They also proposed to divert or siphon off much of the contents of New England’s largest river, among other things. Then the engineers discovered that they could just plug a lot of leaks and upgrade all the pipes and whatnot in their water supply system, which reduced the city’s water consumption by something like 40 percent since the 1980s.
Peter Gleick: That’s exactly right. The cheapest source of new water is not actually new water; it’s spending money on conservation and efficiency programs that let us save water we’re already using. A gallon of water that we save with a conservation program is a gallon of water we don’t have to find in another overtapped river, or to build another dam, or to pump another groundwater aquifer.
The smartest thing we can do is make our water use more efficient, to grow more food with less water, to flush our toilets and wash our clothes with less water, to keep the benefits of our water use while reducing the volume of water required to satisfy those benefits.
Dan Drollette: Which brings up another point. Didn’t California somehow manage to reduce its water consumption dramatically in that recent drought?
Peter Gleick: In the third or the fourth year of our drought—which lasted five years and may have now come back—the state imposed a mandatory reduction in urban water use of 25 percent. There was some variation; some water agencies had to conserve a little more, some that had already done a lot could conserve a little less, but the statewide target was a 25 percent reduction. We met that target with really no pain at all.
Dan Drollette: How did they accomplish that?
Peter Gleick: Through a mix of programs, such as ones that offered people money to remove lawns and replace them with “xeriscaped,” or drought-resistant, gardens. Utilities offered rebates on efficient toilets and washing machines. There were restrictions on the timing and the amount of outdoor landscaping. There were changes in rate structures that encouraged people to save money by saving water.
And there were also some penalties. For people that did not cut their water use, there were some penalties imposed on high water users. It was a big mix of policies that were put in place by the utilities to save urban water.
Dan Drollette: It sounds like progress can be made; targets and goals can be met.
Peter Gleick: Yes, I’m an optimist. I believe that in the long run we’re moving toward a sustainable future for water, what I call the soft path for water.
I wrote a piece about it for the journal Science, “Water for the next administration.” It involves all of these things: alternative sources of supply like using treated wastewater and capturing more stormwater; improving the way we use water and becoming more efficient; smart economic policies and better management. It involves accepting the reality of climate change and integrating the risks of climate change into the way we plan and manage our water systems.
And we have to recognize that there are different ways of motivating different kinds of people. Climate change is a real issue. Humans are responsible for it. That’s the scientific reality. But there are some communities who respond better to positive incentives and better communications around what the advantages of implementing certain policies are than to particular words about the risks that we face.
I’m a fan of communicating in the best way possible with different communities, but I also don’t think we need to hide our heads in the sand. Climate change is real. Let’s deal with it. Let’s accept it. We could have a debate about the right way to respond, but we shouldn’t be denying the reality that faces us.
Dan Drollette: A recent article in the New York Times noted that in the $1.5 trillion proposal that the Trump Administration issued to rebuild the nation’s infrastructure, there’s nothing about planning for the effects of climate change.
It quoted a researcher from Arizona State University, Michael Kuby, as saying: “The impact of not considering climate change when planning infrastructure means you end up building the wrong thing, in the wrong place, to the wrong standards.”
Peter Gleick: Yes, I agree with that, although there are two points I’d like to make.
One is that I would not call it a $1.5 trillion infrastructure plan because it turns out there’s almost no new federal money in it. It’s sort of a fraud in that regard.
But it’s also true that it says nothing about climate change. If you don’t integrate climate change into your infrastructure investments, that could be a very expensive failure.
Dan Drollette: It sounds like there’s a whole lot of lessons that this experience in Cape Town can offer for the rest of us in other parts of the world.
Which reminds me of one other question I wanted to ask: Do you think that there are other major cities that are in this predicament? Or is it pretty much isolated to Cape Town?
Peter Gleick: No, I would argue there’s nothing special about Cape Town. I think there are many parts of the world that are increasingly likely to face their own Zero Days if we don’t improve the way we deal with water.
I would also point out—and this is pretty important—that even if Cape Town avoids Day Zero, and they’re able to ensure that their population continues to receive water, there are hundreds of millions of people worldwide who every day, all the time, don’t have access to safe water and sanitation.
If Cape Town solves its problem, we shouldn’t forget these other populations who are already at risk of serious water problems.They don’t necessarily live in modern sophisticated cities.
They face a Day Zero every day.