Short Wave

Day Zero: When the wells run dry

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 [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 [http://plus.npr.org/shortwave]. To manage podcast ad preferences, review the links below: See pcm.adswizz.com [https://pcm.adswizz.com] for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

How did these flowers evolve to survive a megadrought?

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 [https://www.science.org/doi/10.1126/science.adu0995], 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 [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 [http://plus.npr.org/shortwave]. Listen to Short Wave on Spotify [https://n.pr/3HOQKeK] and Apple Podcasts [https://n.pr/3WA9vqh]. 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. To manage podcast ad preferences, review the links below: See pcm.adswizz.com [https://pcm.adswizz.com] for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

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

The new food pyramid [https://realfood.gov/] 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 [https://www.thenutritiontea.com/about], and Dr. Sarah Kim [https://profiles.ucsf.edu/sarah.kim], a diabetes specialist, about the new guidelines. Plus, NPR’s Reflect America fellow Kadin Mills [https://www.npr.org/people/g-s1-90680/kadin-mills] unpacks how the new food pyramid could change school lunch trays.  Check out more of Kadin’s coverage [https://www.npr.org/2026/02/05/nx-s1-5691598/school-lunch-food-pyramid-usda-dietary-guidelines] about the changes in dietary guidelines. Interested in more health science? Email us your question at shortwave@npr.org [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 [http://plus.npr.org/shortwave]. To manage podcast ad preferences, review the links below: See pcm.adswizz.com [https://pcm.adswizz.com] for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

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

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 [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 [http://plus.npr.org/shortwave]. To manage podcast ad preferences, review the links below: See pcm.adswizz.com [https://pcm.adswizz.com] for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]

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

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 [https://www.npr.org/2024/02/08/1229783535/ultimate-world-cruise-tiktok-reality-show]. 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 [https://www.npr.org/people/1112796909/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 [https://www.npr.org/sections/shots-health-news/2024/06/15/nx-s1-5006168/guilty-pleasure-meaning-brain-science] on guilty pleasures.  Interested in more brain science? Email us your question at shortwave@npr.org [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 [http://plus.npr.org/shortwave]. To manage podcast ad preferences, review the links below: See pcm.adswizz.com [https://pcm.adswizz.com] for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. Learn more about sponsor message choices: podcastchoices.com/adchoices [https://podcastchoices.com/adchoices] NPR Privacy Policy [https://www.npr.org/about-npr/179878450/privacy-policy]