Climate

In recent weeks, extreme heat waves have broiled the United States, China and Europe. But scientists are warning of another hazardous form of heat: chronic heat. In places like Miami and Phoenix, temperatures can soar for months at a time without reaching heat wave levels, potentially contributing to health issues such as kidney disfunction, sleep apnea and depression. But too little research has focused on how these impacts may compound over months of exposure, University of Miami climate and health researcher Mayra Cruz and colleagues report in the June Environmental Research Climate.

“It’s the family that lives with conditions that are just a little bit too hot all the time and no air conditioning,” says Victoria Turner, an urban planner at UCLA who was not involved in the study. “The mother is pregnant in hot conditions, their children go to bed without air conditioning and go to schools without air conditioning, and then that’s changing their developmental physiology.” More

A cool house without air conditioning may soon be possible.

Scientists in Singapore have developed a new type of paint that reflects sunlight and cools surfaces by slowly evaporating water. Unlike other commercially available cooling paints, which are designed to repel water to protect the underlying material, the new one even works in hot, humid places, offering a low-energy way to stay cool, researchers report June 5 in Science.

“The key is passive cooling,” which requires no energy input, says material scientist Li Hong In other words, it works without using electricity or mechanical systems. Right now, radiative cooling is the most common type of passive cooling used in materials, including certain paints. It works by reflecting sunlight and radiating heat from a surface such as walls or roofs, into the sky. But in humid places like Singapore, water vapor in the air traps heat near the surface, which prevents it from escaping into the atmosphere and keeps the surfaces warm.In response, Hong and two other material scientists from Nanyang Technological University developed a cement-based paint that combines three cooling strategies: radiative cooling, evaporative cooling, which our skin uses, and solar reflection. In the study, the scientists painted three small houses: one with regular white paint, one with commercial cooling paint that uses only radiative cooling and one with their new formula. After two years of sun and rain in Singapore, the first two paints had turned yellow. But “our paint was still white,” says coauthor Jipeng Fei. Unlike other colors, white helps materials maintain their high reflectivity and cooling performance. More

This year may already be on track to be the second hottest on record, after 2024. Floods and tornadoes are wracking wide swathes of the United States. And more wild weather is expected to be on the horizon.

But the federal government’s ability — and long-standing charge — to warn the nation about the future impacts of climate change is in jeopardy. On April 28, the Trump administration abruptly dismissed the hundreds of U.S. scientists working on the sixth National Climate Assessment, a congressionally mandated interagency report. The latest report was expected to be released in 2028, but now its future is in doubt. And that could greatly hobble the nation’s ability to prepare for future climate-related extreme events. More

Warming temperatures may cause methane emissions from wetlands to rise — by helping methane-producing bacteria thrive. Higher temperatures favor the activity of wetland soil microbes that produce the potent greenhouse gas, at the expense of other microbes that can consume it, researchers report April 23 in Science Advances.

The scientists, led by microbiologist Jaehyun Lee of the Korea Institute of Science and Technology in Seoul, conducted a summer field study in coastal wetlands near the Chesapeake Bay, analyzing soil conditions in a set of marshy plots with differing environmental conditions. The findings may offer clues to a puzzling and worrisome spike in wetland emissions of methane over the last decade. More

Earth’s landmasses are holding onto a lot less water than they used to — and this loss is not just due to melting ice sheets. Terrestrial water storage, which includes water in underground aquifers, lakes, rivers and the tiny pore spaces within soil, declined by trillions of metric tons in the early 21st century, researchers report in the March 28 Science.

This sharp decrease in freshwater stores is driven by rising temperatures on land and in the oceans, which in turn are linked to an increased global incidence of drought. And given the projected warming of the planet, this trend isn’t likely to change any time soon, say geophysicist Ki-Weon Seo of Seoul National University and colleagues. More

Beneath the great, white expanse of the Antarctic Ice Sheet, a mysterious realm of streams and lakes lies out of sight. Much about this hidden water world remains poorly understood. But a new study suggests that if scientists continue to overlook it, they might greatly underestimate global sea level rise.

Factoring this subglacial water into computer simulations could boost projections of sea level rise over the next two centuries by about two meters, researchers report April 7 in Nature Communications. For context, scientists estimate that climate warming has raised sea levels by about 0.2 meters over the last century. More

The Arabian Desert, today the largest expanse of windswept sand dunes on Earth, experienced recurring periods of humidity millions of years ago, researchers report April 9 in Nature. The study may explain how mammals at that time survived the trek across what is now a vast and barren landscape.

The findings come from mineral formations deep inside caves beneath the Arabian Peninsula. These speleothems — stalagmites and stalactites, formed by dripping rainwater — provide evidence that the region underwent repeated humid periods stretching back nearly 8 million years. The scientists used uranium dating to precisely determine the ages of speleothem samples, offering one of the oldest climate records for the region. More