When Will We Run Out of Water?

Illustration for article titled When Will We Run Out of Water?
Illustration: Elena Scotti (Photos: Getty Images)
Giz AsksGiz AsksIn this Gizmodo series, we ask questions about everything and get answers from a variety of experts.

Even people who believe in climate change are climate change deniers: you might know, intellectually, that our world is coming to an end, but it is hard to truly register this fact, the same way one both does and does not believe that they will one day die. There are counterexamples—you might be one of them; Ethan Hawke in First Reformed is another—but most of us are still sort of asleep, no matter how many grim longform articles we might read. One development that will likely make things real: the end of the Earth’s drinkable water supply. The question is not if, but when—and it is this question we’re posting for this week’s Giz Asks, with the help of a number of….

Megan Konar

Assistant Professor, Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, whose research focuses on hydrology, environmental science, and economics

The planet as a whole is not going to run out of water. However, certain locations may face water scarcity—when their built water supplies are unable to meet their water demands intermittently or for long durations.

Household water uses (e.g. for drinking, cooking, bathing) are not in jeopardy in most places. However, agricultural water use will need to adapt to increasing demands from other water users and shifting climate patterns. Agriculture is by far the largest user (in both withdrawal and consumptive terms) around the world. Currently, much agricultural production around the world relies on the unsustainable use of groundwater aquifers. These crops will likely need to be grown somewhere else when these groundwater reserves are no longer economically accessible.

This means that supply chains of all kinds—but particularly of water-intensive goods—will need to reorganize to account for water risk. Water risk encompasses long term depletion of local water resources and water hazards (e.g. drought, flood) that impact production throughout the supply chain. Water risk may also impact the ability to transport goods in a supply chain, such as flooding or drought that disrupts river navigation.

Water resources engineers, managers, and policy makers face a conundrum. Water insecurity and hazards are expected to increase in the future, which makes it increasingly important to develop infrastructure to manage these risks. However, there is uncertainty regarding the future nature and costs of these water risks. This uncertainty contributes to underinvestment in critical infrastructure.


Peter Gleick

Water and climate scientist, Cofounder of the Pacific Institute, a MacArthur Fellow, member of the US National Academy of Sciences, and recent winner of the Carl Sagan Prize for the Popularization of Science

I’ve learned over the years to try to answer the question that should have been asked, if the question that was asked isn’t quite right.

That’s the case here: we (the world, the US, or even local communities) will never “run out of water” in a literal sense. Water is a renewable resource. It circulates through stocks (like lakes and groundwater and the ocean) and flows (like rainfall and rivers and evaporation) and there’s as much water on the planet today as there was billions of years ago. But we do, indeed, have a water “crisis” or many different crises related to pressures from growing populations, increases in demands for water, “peak water” limits on supplies, the contamination of water with human and industrial wastes, ecological destruction, and especially unsustainable or misuse of the water we have. And we do hear more and more worrisome stories in the media about cities or communities or vulnerable populations that are running out of water—by which we really mean that they are experiencing more and more impacts of droughts and shortages as demands for water run up against the limits of renewable supplies.

We suck some rivers—like the Colorado, Yellow River in China, or Nile—completely dry of their renewable flows so that they no longer reach the sea except during unusually wet years. We overdraft groundwater, pumping out water faster than nature recharges it, leading to falling water levels, wells going dry, and land subsiding and compacting in places like Jakarta, the Central Valley of California, and large regions in India and southern Asia. And now that humans are rapidly changing the climate, we are faced with rising temperatures and demands for water, changes in rain and snow patterns, and worsening extremes of both floods and droughts. We’re increasingly living with old water infrastructure and antiquated institutions created in the 19th and 20th century, in a 21st century world of changing climate.

In short, our water system is out of balance. We are not living within the natural constraints of our most precious renewable resource and more communities and ecosystems will face growing water scarcity, shortage, contamination, and disruption if we fail to move to a more sustainable approach.

The good news is there is a path to a positive future for water, the soft path for water, that can support the needs of humans and the natural environment within the limits of our resources. The soft path requires that we work to provide basic safe water and sanitation for all (an objective of the Sustainable Development Goals); continue to expand water supply by finding non-traditional sources of water such as advanced water treatment and reuse, more effective stormwater capture, and desalination (as we’re starting to see in places like Singapore, California, Israel, and elsewhere); greatly improve the efficiency and productivity of current water use so that we grow more food and produce more goods and services but with far less water (as we see with modern precision irrigation systems, more efficient water-using appliances and industries, and efforts to recapture and prevent leaks); explicitly protect natural ecosystems and guarantee water for the environment (like efforts to rewater the lower Colorado River, or guarantee minimum ecological flows for wetlands and fisheries); acknowledge that access to water and sanitation is a human right, but also develop smart economic tools to help price, manage, and use water efficiently; and finally improve our institutions to manage water sustainably. There is no silver bullet to fix our water problems, but there are many innovative and successful strategies to stop us from “running out of water” and continue to better satisfy all human and ecological needs within the limits of the planet’s natural resources.

Mark W. LeChevallier

Vice President and Chief Environmental Officer for American Water, the largest publicly traded U.S. water and wastewater utility company

We won’t run out of water. What characterizes the earth is that it’s blue, because of the oceans. 97% of the water on earth is in the oceans; 2% is in ice; only about 1% is available for—that isn’t in the ocean or trapped in the ice caps. And even of that, majority of that is underground, and some of that is tied up in minerals, so it’s really only a fraction of a percent of what we use today as water—surface water from lakes and rivers, or groundwater from wells. What our experience of water is is only a fraction of what’s available. For the most part, water doesn’t get consumed. You can break water down to hyrdrogen and oxygen, but for the most part water is recycled—it’s not like you use it once and it’s gone.

So we—the global we—are not going to run out of water. Individually, water is a local issue. I may not have water where I’m at, it doesn’t matter we have oceans of it, I still don’t have any, so that’s a problem. We’re certainly seeing that in certain large cities around the globe, so that is becoming a bigger crisis. Climate change is really about water change—in some place it’s going to get wetter, and we’ll have more floods; in some places it’s going to get dryer, and we’ll have droughts, and so that’s a problem.

That said, I might have water, but I might not have clean water, I may not have drinkable water. And so being able to purify the water is the second part of this. And there are technologies—we have technologies to treat seawater to make it drinkable. But that becomes a question of: can I afford it?

We transport oil from across the globe—from Saudi Arabia to our car—but we pay three dollars a gallon for that. We could do that with water, but—you think a bottle of water is expensive now, it will be even that much more expensive. So there are solutions and technologies, but the question is can we provide clean, safe drinking water at affordable price to people around the globe? And that may be difficult in some areas. Transporting water—water’s heavy, it’s over eight pounds a gallon, so moving it is expensive, is costly. Which is really, when you think about the bottle of water, when you get water from Fiji, an island in the Pacific, the cost of moving all that water, transporting it, is really the major portion of that. Water’s free. And that may not be a very sustainable thing to do given that the energy used in transporting that water creates greenhouse gases that drives climate change and just makes the water cycle more severe. So you kind of need to look at this in a holistic manner.

There are technologies that can provide water—that can evaporate the moisture in the air, condense that and provide drinking water. It’s not very much, but probably enough that you wont die of dehydration, but you’re not going to be able to wash your lawn or water your car with that. So the final part of that is well how much water do you need? Do you need just enough to survive, or do you need to have the kind of quality of life that we’ve come to expect?

I think the bottom line is that—people have to change their attitude about water and realize it’s a precious resource. We just celebrated the fifth anniversary of the ice bucket challenge—we did that because water is inconsequential, but if that’s all the water you had to survive on, you wouldn’t be pouring it over your head, so it’s kind of changing the attitudes. Maybe valuing water differently than we do today is the ultimate answer.


Stephanie Tatge

Ecosystems Services Analyst at The Freshwater Trust

There’s a saying out there in resource management that goes something like “You can’t manage what you can’t measure.” Following this logic, we might not know when we are going to run out of water, because we don’t know how much water we are currently using. As a society, we need to track our water use more closely. For instance, in California, TFT tries to develop automated systems which monitor and quantify freshwater quantity and quality based on changes in land use, weather, human processes, restoration projects, etc.

Google, Apple, Amazon, Uber: companies like these have come to embody innovation, efficiency, and success. How often is freshwater conservation characterized in the same terms? Sadly, freshwater conservation is frequently seen as a losing battle, waged by well-meaning, but ultimately ineffective idealists. It doesn’t have to be this way; in fact, it can’t be this way if we are to maintain our economy, let alone our health or the planet’s.

TFT draws lessons from the world’s most tech-savvy, high-impact organizations to make real gains for the environment. Quantified Conservation is an approach which moves beyond a procedure based past to an outcome-based future. It’s about ensuring every action translates to a positive outcome for the environment, and leveraging the best practices used by businesses and social sector organizations to restore the state of our natural resources.


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“When Will We Run Out of Water?”

I know this isn’t the answer this question is looking for, but, in the most literal sense, approximately one to two billion years from now, as the Sun gets older and more luminous, slowly turning Earth into Venus.

One billion years from now, about 27% of the modern ocean will have been subducted into the mantle. If this process were allowed to continue uninterrupted, it would reach an equilibrium state where 65% of the current surface reservoir would remain at the surface. Once the solar luminosity is 10% higher than its current value, the average global surface temperature will rise to 320 K (47 °C; 116 °F). The atmosphere will become a “moist greenhouse” leading to a runaway evaporation of the oceans. At this point, models of the Earth’s future environment demonstrate that the stratosphere would contain increasing levels of water. These water molecules will be broken down through photodissociation by solar UV, allowing hydrogen to escape the atmosphere. The net result would be a loss of the world’s seawater by about 1.1 billion years from the present. This will be a simple dramatic step in annihilating all life on Earth.


The loss of the oceans could be delayed until 2 billion years in the future if the atmospheric pressure were to decline. A lower atmospheric pressure would reduce the greenhouse effect, thereby lowering the surface temperature. This could occur if natural processes were to remove the nitrogen from the atmosphere. Studies of organic sediments has shown that at least 100 kilopascals (0.99 atm) of nitrogen has been removed from the atmosphere over the past four billion years; enough to effectively double the current atmospheric pressure if it were to be released. This rate of removal would be sufficient to counter the effects of increasing solar luminosity for the next two billion years.