Snowflakes. These intricate, whimsical crystals are a staple of magical wintry scenes, but how big can they really get? Well, according to the Guinness World Record keepers, the "largest snowflake" ever recorded was a whopping 15 inches in diameter. It was spotted near Missoula, Montana in 1887. But Kenneth Libbrecht, a physicist at Caltech, has long been skeptical of that record. So he set out to find what makes a snowflake a snowflake and whether that 1887 record is scientifically possible. You can read more about what he discovered here. (encore)

Want to share the snowflakes you've spotted this winter? Email us a photo at shortwave@npr.org.

Farmland is being abandoned across Europe as it's difficult to make a living. Some ecologist fear that some plant and species will lose ground but some hope that other species may fill in the gaps.

New research shows artificial light can upend underwater communities around coral reefs just like they do on land.

Former President Jimmy Carter's work on energy efficiency and renewable energy were criticized, but it laid the groundwork for the country to address climate change now.

Moo Deng and Haggis are joined by another slick, round supreme on the scene — a new pygmy hippo born at Metro Richmond Zoo in Virginia. Fans can vote on the two options for her name through Saturday.

(Image credit: Metro Richmond Zoo)

The region drained by the Amazon River, including the Amazon Rainforest, is in the second year of a punishing drought. That has lead to the lowest water levels in more than 100 years for the Amazon and its major tributaries. Millions of people and an array of wildlife depend on those quickly disappearing waters. In a story we first brought you in October, we travel to the region to see the effects.

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The death of an Olympic snowboarding athlete is a reminder that even the most skilled and experienced athletes are not immune to the threat of avalanches, and that knowledge is key to staying safe.

(Image credit: Millo Moravski)

Norway is the largest exporter of salmon in the world. And while some of those fish are wild-caught, many are raised in "fish farms"- large cylindrical pens made of nylon in the open water. Sometimes these farmed fish escape, mixing with the local population and causing ecological issues. In a story we first brought you in October, we see farmed fish in a Norwegian fjord and hear about potential solutions to the problem.

(Image credit: Rob Schmitz)

In the early 20th century, a blight fungus wiped out most of the 4 billion American chestnut trees on the eastern seaboard. The loss was ecologically devastating. Short Wave host Emily Kwong dives deep into how scientists are trying to resurrect the American chestnut tree — and recent controversy over a plan to plant genetically modified chestnuts in the wild.

Want to hear about more efforts to recover endangered or lost species? Let us know by emailing shortwave@npr.org!

NPR's Juana Summers talks with Martin Cheek, a conservation botanist for the Royal Botanic Gardens, about new plant and fungus species he and his colleagues discovered this year.

It's looking like 2024 will be the hottest year since record-keeping began, unseating 2023 for the top spot. Climate change is playing a role, and scientists say it was even hotter than expected.

(Image credit: Patrick T. Fallon)

Vehicle dealers are pushing back on rules that would increase the number of electric trucks sold in New Jersey. It could be a preview of a brewing fight over state rules about cars.

(Image credit: Spencer Platt)

One of modern history's worst natural disasters, the tsunami left about 230,000 dead across a dozen countries.

(Image credit: Sakchai Lalit)

About the size of Rhode Island, the iceberg known as A23a got stuck in an ocean vortex this summer, spinning in place for months. Now, it's free, and heading back into open Antarctic waters.

(Image credit: NOAA)

The Biden administration has approved California's plan to require new vehicles sold in the state by 2035 to have zero-emissions. President-elect Trump has said he would role back the rules.

Old mines leave behind a a pressing problem: Huge holes that make the landscape look like a chunk of swiss cheese. But in Germany, some scientists and city planners are turning these into lakes.

The largest one will be the biggest artificial lake in Germany when it's done, with a shoreline of 26 kilometers or about 16 miles all around.

But it's not as easy as simply filling the holes with water. It takes a LOT of research to get this science right.

Interested in more environmental stories? Email us at shortwave@npr.org. We'd love to hear from you!

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(Image credit: Willa Rubin)

Granholm's statement came as the Energy Department released a long-awaited study that found U.S. LNG shipments drive up domestic wholesale prices and frequently displace renewable energy sources.

(Image credit: Rafiq Maqbool)

Instead of regulating harmful agricultural runoff, Iowa -- the nation's biggest corn-producing state -- backs a voluntary, industry-friendly program. But it's not as effective as advertised.

A decade of effort to win more water from the Colorado River is finally paying for the Navajo Nation. The Infrastructure Act is funding new irrigated farms now that the desert tribe can legally pull water from the river.

Amidst exceptionally dangerous wildfire conditions, a blaze broke out late Monday in Malibu, California. Firefighters say difficult conditions are expected through Wednesday.