Episodes

  • What's up with recycled wastewater's PR problem?

    What's up with recycled wastewater's PR problem?
    Mar 27 2026
    Would you drink recycled wastewater? It could be a solution to the global water crisis. But not everyone is ready to jump onboard. They say it’s not technology that’s keeping more cities from recycling their wastewater, but psychology. Experts call this resistance “the yuck factor.” We chat with water journalist Peter Annin about some history behind water recycling – and why more cities could adopt the solution soon.


    This is part of a whole series on the world’s dwindling water supply. Check out the rest of the water series:
    Part 1: When the wells run dry
    Part 2: The world’s groundwater problem
    Part 3: Freshwater’s growing salt problem


    Email us your questions about water, the wider environment – or anything else to do with science at shortwave@npr.org. We may turn it into an episode in the future!


    Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.


    Listen to Short Wave on Spotify and Apple Podcasts.


    This episode was produced by Rachel Carlson. It was edited by Rebecca Ramirez. Aru Nair checked the facts. The audio engineer was Jimmy Keeley.

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    14 mins
  • The world’s freshwater is getting saltier. Why?

    The world’s freshwater is getting saltier. Why?
    Mar 25 2026
    Around the world, the planet’s freshwater is getting saltier. And it’s because of people. For decades, salting roads, fertilizer run-off and evaporation driven by human-caused climate change have upped the salinity of lakes, rivers and groundwater. All that salt is detrimental to a lot of aquatic life and can be problematic for drinking water, too. But there’s still time to reverse course. In fact, many people have already started to change their ways. Today, producer Berly McCoy is on the case to see what solutions exist.

    This is part of a whole series on the world’s dwindling water supply. Check out part one and part two of this water series!

    Email us your questions about water, the wider environment – or anything else to do with science at shortwave@npr.org. We may turn it into an episode in the future!

    Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.


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

    The world has a groundwater problem. Can we solve it?
    Mar 24 2026
    Groundwater is responsible for about half of the water people use globally. It’s drying up. Hayes Kelman started noticing the family farm in western Kansas was slowly getting less water around the time he was in high school. Now, as an adult and co-owner of Kelman farms, he is acutely aware that there’s a problem: the aquifer he uses to water his crops is being drained faster than it can be refilled. If something doesn’t change, someday it will run out of water.

    Today, producer Berly McCoy dives into the state of the world’s groundwater and asks: What happens when people pull too much? And can the damage be reversed?

    Check out part 1 of our water series, Day Zero: When the wells run dry.

    Interested in more water science? Email us your question at shortwave@npr.org.

    Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

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    13 mins
  • Day Zero: When the wells run dry

    Day Zero: When the wells run dry
    Mar 23 2026
    In honor of World Water Day, Short Wave is exploring the ways water touches our lives. From increasing water shortages around the world, to how it’s affecting agriculture and aquifers. We’re starting with “day zero”: the day a city or place runs out of water. Cape Town, Mexico City, Chennai in India are just a few places that have come close to day zero events. Today, we talk to experts and hear from someone who lived in Cape Town during the crisis about why we’re overdue for rethinking our relationship to water.

    Interested in more science behind current events? Email us your question at shortwave@npr.org.

    Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

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    12 mins
  • How did these flowers evolve to survive a megadrought?

    How did these flowers evolve to survive a megadrought?
    Mar 20 2026
    A multi-year megadrought in the Western U.S. has claimed untold populations of wild plants. Amid the conditions, some have survived. Scientists have produced a stunningly complete picture about how populations of one particular flower – the scarlet monkeyflower – made it through.

    In a new study published in the journal Science, a team of scientists spent decades studying and sampling select populations of scarlet monkeyflowers in California and Oregon. Through genetic sequencing, the team discovered that the populations that did best went through genetic changes in a short time period. This is known as rapid evolution.

    The team found that three of the populations that recovered the BEST adapted their stomata to open less, so they could conserve more water. Stomata act like a plant’s pores, managing gas exchange and water loss. This allowed the scarlet monkeyflowers to hunker down in the drought and survive.

    Interested in more stories about rapid evolution? Email us your question at shortwave@npr.org.

    Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

    Listen to Short Wave on Spotify and Apple Podcasts.

    This episode was produced by Jeffrey Pierre, Rachel Carlson and Hannah Chinn. It was edited by Christopher Intagliata and Rebecca Ramirez. Aru Nair checked the facts. The audio engineers were Becky Brown and Robert Rodriguez.

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    8 mins
  • A dietitian and doctor review RFK Jr's new food pyramid

    A dietitian and doctor review RFK Jr's new food pyramid
    Mar 18 2026
    The new food pyramid was released earlier this year. It emphasizes protein, full-fat dairy and what Health and Human Services Secretary Robert F. Kennedy Jr. calls “healthy fats.” These guidelines influence the standards for school lunches, food labeling and programs like SNAP. Today on the show, Short Wave co-host Emily Kwong chats with registered dietitian nutritionist Shana Spence, and Dr. Sarah Kim, a diabetes specialist, about the new guidelines. Plus, NPR’s Reflect America fellow Kadin Mills unpacks how the new food pyramid could change school lunch trays.

    Check out more of Kadin’s coverage about the changes in dietary guidelines.

    Interested in more health science? Email us your question at shortwave@npr.org.

    Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

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    13 mins
  • ‘Black rain’ in Iran and the environmental cost of war

    ‘Black rain’ in Iran and the environmental cost of war
    Mar 17 2026
    US-Israeli airstrikes on oil depots culminated in ‘black rain’ in Iran early last week – a phenomenon usually caused by large amounts of soot, carbon and other pollutants in the air. Usually, rain leaves the atmosphere cleaner than it was before. But in this case, the rain left Tehran’s residents with sore throats and burning eyes. Oily, sooty residue was all over the city. So, we talked to an environmental pollution expert to find out: What’s in this ‘black rain’, what are its potential short- and long-term environmental and health effects, and what could recovery look like?

    Interested in more science behind current events? Email us your question at shortwave@npr.org.

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    13 mins
  • This is your brain on pleasure (even the guilty kind)

    This is your brain on pleasure (even the guilty kind)
    Mar 16 2026
    It’s likely you have at least one “guilty pleasure.” Maybe it’s romance novels. Or reality TV… Playing video games… or getting swept into obscure corners of TikTok. Neuroscientists say the pleasure response helps us survive as a species. So why do we feel embarrassed by some of the things we love the most? Even if you don't have these negative emotions, experiencing – and studying – pleasure is not as straightforward as it might seem. For a long time, neuroscientists thought the concept of "pleasure" referred to a singular system in the brain. But as research into the subject grew, scientists realized that pleasure is really a cycle of "wanting" and "liking" – each with separate neural mechanisms. Today on the show, producer Rachel Carlson explores this cycle with researchers, who weigh in on the science of pleasure. Even the kind that makes us feel guilty.

    Read more of Rachel’s story on guilty pleasures.

    Interested in more brain science? Email us your question at shortwave@npr.org.

    Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.

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    14 mins