The world has a groundwater problem. Can we solve it?

Summary

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Podcast Summary: Short Wave — The World Has a Groundwater Problem. Can We Solve It?

Date: March 24, 2026
Hosts: Emily Kwong, Burleigh McCoy
Guests: Hayes Kelman (Kansas farmer), Deborah Perrone (UC Santa Barbara), Mohammad Shamsadoha ("Shams", University College London), Filippo Menga (University of Bergamo)

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Overview

This Short Wave episode, part of a water-themed series, examines the global crisis of groundwater depletion. Hosts Emily Kwong and Burleigh McCoy explore what aquifers are, why they matter, how scientists track their health, and what can be done to stop their decline. The episode features perspectives from farmers, engineers, and political geographers, offering a nuanced look into the intertwined science, data challenges, and social impacts of groundwater use.

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Key Discussion Points & Insights

What Are Aquifers and Why Do They Matter?

• Aquifer Defined: "An aquifer is just an underground layer of rock or materials that holds water." (Burleigh McCoy, 00:31)
• Vital Resource: Groundwater from aquifers supplies about half the water people use globally. (Deborah Perrone, 00:52)
• Not a Bathtub: “It's more like water between rocks that gets to the surface through wells and springs.” (Deborah Perrone, 00:44)

The Ogallala Aquifer: A Farmer's Perspective

• Hayes Kelman’s Reality:
  • Noticed well levels dropping significantly during high school. “I started watching how certain wells were just dropping off significantly, how we were removing a sprinkler from... a certain area of land because we didn't have enough water.” (Hayes Kelman, 01:32)
  • The Ogallala, or High Plains Aquifer, spans eight states and is rapidly losing water.
• Impact: Farmers can’t reliably plan harvests because water availability now depends on unpredictable rainfall. (Burleigh McCoy, 02:11)

The Global State of Aquifers

• Massive Data Collection: Researchers analyzed close to 1,700 aquifers, covering about three-quarters of all land tapped for groundwater. (Burleigh McCoy, 04:24, 04:39)
• Findings:
  • About one-third of aquifers studied are losing water, sometimes at catastrophic rates. “Groundwater levels are going down.” (Deborah Perrone, 04:55)
  • Some are drying up entirely, risking drinking water, wetland habitats, and even causing land subsidence—“draining an aquifer can cause the land to actually sink.” (Deborah Perrone, 05:03)
  • On average, declines exceed four inches per year; in some, it’s over 20 inches per year. (Burleigh McCoy, 05:45)
• Domino Effect: When aquifers deplete, other local sources dry up too, creating cascading shortages in water supply. (Deborah Perrone, 06:19)
  • “You’re getting hit twice, you’re getting hit with supply…and then you’re also getting hit with demand.” (Deborah Perrone, 06:19)

The Challenge of Shared Resources

• Aquifers Cross Borders: Multiple countries often access the same underground water, complicating management and negotiation efforts. (Burleigh McCoy, 07:05)
• Supply vs. Demand: Although the world could have enough water, it's about how it’s used.
  • “Water withdrawals over time grow much faster than global population. So it has to do with our lifestyle.” (Filippo Menga, paraphrased by Shams, 07:47)

Data Problems: Tracking the Invisible

• Inconsistent Monitoring: Well data is hard to compare—some are checked daily, others monthly, each aquifer has varying numbers of monitoring wells. (Burleigh McCoy, 08:51)
• Reluctant Governments: “If a government doesn't want to do that or doesn't want to share their data, that's kind of it.” (Deborah Perrone, 08:36)
• The Data is Messy: “One of the hardest parts...was actually reconciling all the different data and trying to make sure that they're comparable across space and time.” (Deborah Perrone, 08:36)

Scientific Tools: Satellites and Gravity

• Alternative: Satellite Sensing: Scientists use paired satellites (like NASA’s GRACE mission) to detect gravitational changes—an indirect measure of water movement. (Shams, 09:11)
  • “...by measuring the distance between the two satellites, you can actually make out how much gravitational field on Earth's surface is changing.” (Shams, 09:11)
• Limitations: Satellites show changes, not absolute water availability, nor local specifics important to farmers. (Burleigh McCoy, 10:07)

Living With Less: The Farmer’s Dilemma

• Hayes Kelman: Working with hydrologists to determine sustainable usage—“they've figured out what amount of water we can pull from the aquifer to become stable because it does have a recharge rate.” (Hayes Kelman, 10:26)
• Economic Complications: Switching to less water-intensive crops (like milo) is hard if there’s no market for them. Water-saving could hurt the wider agricultural economy, affecting livestock and meatpacking, and entire local economies. (Burleigh McCoy, 10:50-11:20; Hayes Kelman, 11:20)
  • “Our economies are based around agriculture, and irrigation is a massive part of that agriculture.” (Hayes Kelman, 11:20)

International Solutions & Hopeful Trends

• Shared Management Example: The 2010 Guarani Aquifer agreement between Argentina, Brazil, Paraguay, and Uruguay aimed to share data and avoid harm but lacked enforceable quotas and has seen slow implementation. (Burleigh McCoy, 11:59)
  • Agreement’s goal: “...ensure multiple, reasonable, sustainable and equitable use of its water resources.” (Treaty, quoted in episode, 12:24)
• Signs of Improvement: In 16% of studied aquifers, water levels are increasing again, often where proactive water management (like reduced extraction) was put into practice. (Deborah Perrone, 12:39)
  • “So it’s not all doom and gloom. And I’m actually cautiously optimistic.” (Deborah Perrone, 12:57)
  • “It is possible, yeah, to turn the tides on our declining aquifers.” (Deborah Perrone, 13:06)

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Notable Quotes & Memorable Moments

• Emily Kwong (Wondering Aloud): “Wow. Thank you, aquifers, for keeping us all alive.” (00:55)
• On Data Complexity: “The data is a complete mess.” (Deborah Perrone, 08:36)
• On the Future: “Everything we do is for our kids and for the future.” (Hayes Kelman, 10:47)
• On Water Management: “Everyone knows we need to use less water, but figuring out how is going to take a lot of time and a lot of agreement.” (Burleigh McCoy, 11:40)
• Cautious Optimism: “So it’s not all doom and gloom. And I’m actually cautiously optimistic.” (Deborah Perrone, 12:57)

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Key Timestamps

• 00:31–01:54 — What is an aquifer? Hayes Kelman on witnessing water decline.
• 04:24–05:59 — Global aquifer study results; the downward trend and its consequences.
• 06:19–07:26 — Why droughts are “a double hit” and basics of shared aquifers.
• 08:36–09:02 — The messiness of aquifer data and the difficulties in global monitoring.
• 09:11–10:07 — Satellites and invisible groundwater: what we can (and can’t) know.
• 10:26–11:20 — Local water management, economic dilemmas for farmers.
• 11:59–12:34 — The Guarani Aquifer agreement: a rare instance of international cooperation.
• 12:39–13:10 — Evidence of positive trends and reasons for hope.

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Final Takeaway

The episode highlights groundwater’s vital but endangered role, the global scope of the crisis, and the immense scientific and political challenges in fixing it. Solutions require collective action, honest data sharing, and lifestyle changes—offering hope, but no easy answers.

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Transcript

[Commercial Announcer]

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[Emily Kwong]

You're listening to Short Wave from NPR. Hey, shortwavers. Emily Kwong here continuing our water series where we dive into all things H2O. With me is producer and fellow mermaid Burleigh McCoy. Hi, Burley.

[Burleigh McCoy]

Hi, Emily. So I'm here with part two, aquifers. And don't worry, it's okay if you missed part one. So an aquifer is just an underground layer of rock or materials that holds water.

[Emily Kwong]

Oh, so it's not like a bathtub.

[Burleigh McCoy]

It's not.

[Deborah Perrone]

It's more like water between rocks that

[Burleigh McCoy]

gets to the surface through wells and springs. And that groundwater is responsible for about

[Deborah Perrone]

half of the water people use globally.

[Emily Kwong]

Wow. Thank you, Aquifers, for keeping us all alive.

[Burleigh McCoy]

Seriously. And for this episode, I called up someone who has a very close relationship with his local aquifer.

[Hayes Kelman]

Earliest memory of farming probably would be sleeping on the floor of a combine while my dad drove. Drove the combine through the field and harvested corn or wheat.

[Burleigh McCoy]

This is Hayes Kelman. He's a fifth generation farmer in western Kansas. And he loves it. Getting his hands in the soil, watching a crop grow from seed to harvest. But around. Around the time he was in high school, he noticed something about the water they used to irrigate the family farm.

[Hayes Kelman]

I started watching how certain wells were just dropping off significantly, how we were removing a sprinkler from a. From a certain area of land because we didn't have enough water.

[Burleigh McCoy]

So his farm sits above the Ogallala, or High Plains Aquifer, which is a huge aquifer. It spans eight states. And it's losing water like a lot of other aquifers around the world.

[Deborah Perrone]

Sometimes it's because of cities, but a lot of the time it's because of farms using a lot of water.

[Emily Kwong]

Right. Watering crops. So what does that mean for farmers like Hayes who rely on aquifers for their livelihood?

[Deborah Perrone]

Yeah, he says they're growing the same crops, but it's kind of up to chance what he'll harvest based on how much or how little rain they get.

[Emily Kwong]

So he can't plan on a certain yield, which makes the business side of farming really hard.

[Burleigh McCoy]

It's true. And it's getting worse for Hays and a lot of other farmers all over the world. But understanding the issue on a global scale, that is a beautiful beast of a project. And it's one that scientists hadn't tackled until a couple of years ago.

[Emily Kwong]

So today on the show, the state of the world's groundwater and what it means for life on the surface.

[Burleigh McCoy]

Plus how farmers like Hayes are rethinking

[Deborah Perrone]

how they use their water.

[Emily Kwong]

You're listening to shortwave, the science podcast from N.

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[Emily Kwong]

Okay, Burley. So aquifers are clearly very important to life on earth. Groundwater is responsible, you said, for half of the water people use globally. Do we know how many aquifers there are in the world?

[Burleigh McCoy]

So definitely hundreds, maybe thousands. It turns out that's a tough number for scientists to estimate because aquifers are underground ground.

[Emily Kwong]

Yeah. So if that's the case, how do scientists get a sense of the state of the world's aquifers?

[Deborah Perrone]

Yeah.

[Burleigh McCoy]

So a couple researchers spent years gathering all of the aquifer data they could find on close to 1700 aquifers around the world. And they compiled it into one scientific paper that was published in 2024.

[Emily Kwong]

1700 aquifers. That's a lot.

[Deborah Perrone]

It was.

[Burleigh McCoy]

And they estimated that that's three fourths of all the land being tapped for groundwater.

[Deborah Perrone]

And the data basically comes from monitoring

[Burleigh McCoy]

wells that people monitor the water of.

[Deborah Perrone]

And the study team found that in about a third of the aquifer systems

[Burleigh McCoy]

they looked at, groundwater levels are going down. Wow.

[Emily Kwong]

Are they drying up entirely? And what does that mean for life on Earth?

[Deborah Perrone]

Yeah, that can definitely happen. It's a huge issue if that's where your drinking water comes from. Plus, less water in an aquifer can mean the loss of wetland habitat. And in Some places, draining an aquifer can cause the land to actually sink. It's called subsidence. And over time, it also means that you can't recharge that aquifer.

[Burleigh McCoy]

So fill the aquifer back up.

[Emily Kwong]

Yeah. If we don't recharge our aquifers, fill them back up with water, I imagine it can really alter the landscape.

[Burleigh McCoy]

Yeah. If the aquifer is by a coast and it gets really low, salt water can flow in and then contaminate the freshwater in that aquifer.

[Emily Kwong]

So in the places where scientists saw water in decline in these aquifers, how much water are we talking?

[Burleigh McCoy]

So on average, more than about 4 inches per year. Which imagine if you have a well, that can eventually be catastrophic. And so a third of those aquifers are losing more than about 20 inches per year.

[Deborah Perrone]

Deborah Perrone is a water resource engineer at the University of California, Santa Barbara, who worked on the study. And she says the places with the most rapid declines tended to be in dry regions around the world with lots of cultivated land. So in India, the U.S. china, Mexico, Saudi Arabia. In lots of places, when you have

declines in precipitation, you're getting hit twice, you're getting hit with supply because you no longer have that recharge, you no longer have the ability to replenish your aquifer. And then you're also getting hit with demand because now people don't have other sources of water. They can't do rain fed irrigation. Their rivers probably have lower flows, their reservoirs have less water in them, so now they're turning to groundwater.

[Emily Kwong]

So there really is a domino effect here in places where the aquifer is depleting the most. Are people just they're going to run out of water entirely?

[Burleigh McCoy]

That is one possibility. And we had an episode yesterday that was all about day zero, the predicted day. A place runs out of water.

[Deborah Perrone]

Yeah.

[Burleigh McCoy]

And the solution seems simple, right, Emily? Use less. But there are a lot of reasons why that's really difficult. One big issue is that many aquifers span borders. So multiple countries have to agree on how much water they can use. And in a lot of places, people across borders already don't get along or they can't agree on water usage.

[Deborah Perrone]

Yeah.

[Emily Kwong]

And our planet, I mean, it has more than 8 billion people at this point. This is an uncomfortable question to ask, but does our planet have enough water for all of us?

[Burleigh McCoy]

Yeah.

[Deborah Perrone]

I talked to Filippo Menga about this. He's a political geographer at the University of Bergamo in Italy, and he says the problem isn't the amount of people.

[Mohammad Shamsadoha]

Water withdrawals over time grow much faster than global population. So it has to do with our lifestyle.

[Emily Kwong]

So there is enough water, but not if certain groups of people are using

[Burleigh McCoy]

a lot of it.

[Emily Kwong]

Right.

[Burleigh McCoy]

And it's a good and a bad thing. It means we're using way more water than we need, especially in richer countries. But it also means we can theoretically use less. True, but that requires good data and countries reporting honestly how much water they are pulling.

[Emily Kwong]

Oh, that sounds like a research nightmare.

[Burleigh McCoy]

Yeah.

[Deborah Perrone]

This is why Deborah and her team had such a painstaking time saying something about aquifers globally. Because the best way to really measure an aquifer's level is by drilling a well and measuring it on the ground. And if a government doesn't want to do that or doesn't want to share their data, that's kind of it.

The data is a complete mess. Yes. And one of the hardest parts of this project was actually reconciling all the different data and trying to make sure that they're comparable across space and time.

[Burleigh McCoy]

So some people might monitor a well every day, while others do it every month. One aquifer may have 20 monitoring wells, while another only has five. And water levels can be different at each one.

[Emily Kwong]

Is there no other way to look at aquifer levels besides monitoring these wells?

[Burleigh McCoy]

There are actually these satellites that can tell scientists something about groundwater.

[Mohammad Shamsadoha]

It's a pair of satellites that move around the Earth's orbit in kind of every 90 minutes. And by measuring the distance between the two satellites, you can actually make out how much gravitational field on Earth's surface is changing.

[Burleigh McCoy]

So this is Mohammad Shamsadoha. He goes by Shams, and he's a groundwater scientist at University College London.

[Mohammad Shamsadoha]

And he says by knowing the distance, geodesist can turn that into a field of gravitational anomaly on the Earth's surface. And the only reason the Earth's gravity will change within a matter of, let's say, a month is because of movement of water from one place to another, from one season to another.

[Emily Kwong]

So they're using changes in the gravitational field on the Earth's surface as kind of an indicator of water movement. Can they see if there's more or less water in an area?

[Burleigh McCoy]

They can, but only by the amount that it's changed by, not. Not the total amount that's there. And it also can't tell you about water changes in fine detail, like monitoring a single well can. So like for Hayes, the farmer we heard from earlier, he's consulting local experts that study his specific area, the hydrologists

[Hayes Kelman]

and geologists, they've figured out what amount of water we can pull from the aquifer to become stable because it does have a recharge rate.

[Deborah Perrone]

And so those experts will tell him how much he needs to reduce his water use over time so that the aquifer can recharge enough to be a renewable resource. And he says he's ready to make those changes.

[Hayes Kelman]

Everything we do is for our kids and for the future.

[Burleigh McCoy]

But he admits it's going to be hard. His farm used to sell a lot of something called Milo. That's a grain that uses less water, but now no one is buying it and it's just sitting there. So he still needs to grow the more water intensive wheat and corn to make a living.

[Emily Kwong]

Those are the products people want more.

[Burleigh McCoy]

Exactly. And he points out that if people stop growing as much corn, for example, cattle farmers are going to feel it because they feed that to their cows. And the meatpacking plants are affected because cattle numbers then drop. So he wonders, how does that affect

[Hayes Kelman]

the town that I grew up in? Our economies are based around agriculture, and irrigation is a massive part of that agriculture.

[Emily Kwong]

Yeah. Everything flows from water. And he knows something needs to change, but it's going to have, again, a domino effect on all these other places and people who he cares about.

[Burleigh McCoy]

Yeah. And that was kind of the general feeling I got from all of this reporting, Emily. Everyone knows we need to use less water, but figuring out how is going to take a lot of time and a lot of agreement. Yeah.

[Emily Kwong]

Are there examples of people actually doing this, like coming to an agreement about how to share groundwater?

[Burleigh McCoy]

Yeah, one kind of famous one was an agreement in 2010 between Argentina, Brazil, Paraguay and Uruguay on how to utilize water from the Guarani aquifer. It didn't give specific quotas, but instead promised that countries would share data, avoid causing harm to each other by pulling too much water, and to quote, ensure multiple, reasonable, sustainable and equitable use of its water resources.

[Emily Kwong]

Nice.

[Burleigh McCoy]

But even with all of that, implementation has been slow, and there's not super clear evidence whether changes are letting this aquifer recharge. Okay.

[Deborah Perrone]

Yeah. Tough news. At the same time, Emily, that paper I mentioned earlier.

[Burleigh McCoy]

Yeah.

[Deborah Perrone]

Deborah's team did discover areas where aquifers that had been losing water in the 80s and 90s were now gaining water in 16% of the aquifer systems they looked at. Yeah. And some of these were in places where people were active in their water management, like using less and less, letting the aquifer recharge.

So it's not all doom and gloom. And I'm actually cautiously optimistic.

[Emily Kwong]

So we can do it. We can live with aquifers and not deplete them entirely.

[Deborah Perrone]

It is possible, yeah, to turn the

[Burleigh McCoy]

tides on our declining aquifers.

[Emily Kwong]

Burley McCoy, thank you for bringing us this reporting and indeed, this whole series about water.

[Burleigh McCoy]

Thanks, Emily.

[Emily Kwong]

If you like this episode, please share it with a friend. And check out yesterday's episode on the Idea of Day Zero and When Cities Run out of Water. We'll link it in our show notes. This episode was produced by Rachel Carlson and edited by our showrunner, Rebecca Ramirez. It was fact checked by Arun Nair and Angela Zhang. Jimmy Keeley was the audio engineer. Thank you so much for listening to Short Wave from npr. See you tomorrow.

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