Overnight Science News Digest: Supercharged heat waves used

Extreme heat and humanity

On Tuesday, shortly before wildfires swept through parts of south-east England, the Daily Mail published a comment piece by a writer called Stephen Robinson. “Why can’t the Met Office just tell us the weather, instead of spreading alarm and scolding us with doom-laden lectures?” he raged, accusing the UK’s leading centre of climate and meteorological research of being “woke” and “alarmist”. […]

The comment piece is one example of how the rightwing press is now seeking to undermine climate action by framing it as another ripple in the culture wars. The writer portrayed the Met Office’s (utterly sensible) warnings about the extreme heatwave as “cod medical advice” and “nanny-knows-best” statements. Elsewhere, the Daily Express published an article on Monday by James Whale, who claimed that the reason we should all ignore the “climate-fanatic panic” was because “planets move and we have been getting closer to the sun for thousands of years”.


Heat waves are becoming supercharged as the climate changes – lasting longer, becoming more frequent and getting just plain hotter. One question a lot of people are asking is: “When will it get too hot for normal daily activity as we know it, even for young, healthy adults?”

The answer goes beyond the temperature you see on the thermometer. It’s also about humidity. Our research shows the combination of the two can get dangerous faster than scientists previously believed.


The record-setting heat that blasted much of Europe this week had immediate and obvious effects on public health. More than 2,000 people died from heat-related causes, like heat stroke or dehydration, in Spain and Portugal alone, and the London Ambulance Service was fielding 400 calls an hour during the hottest periods.

But as scientists have begun to discover, heat waves harm mental health, too. From increases in suicides to spikes in aggressive behavior, research is just starting to reveal how and why extreme heat can impair mental health, especially in those with underlying psychiatric conditions.

On days that drastically exceed normal highs, emergency room visits across the U.S. for substance use, anxiety, schizophrenia and other mental illnesses increase by as much as 8 percent, according to a study in JAMA Psychiatry published earlier this year. Hot weather can also stir aggressive behavior, a link scientists have long noted. Laboratory studies show that heat increases irritability and hostility, which could explain, in part, why violent crime tends to rise in summertime.


The dizzyingly quick shift from an abstract threat to an era of tumbling temperature records, megadroughts, and pervasive fires has many people wondering: is climate change unfolding faster than scientists had expected? Are these extreme events more extreme than studies had predicted they would be, given the levels of greenhouse gases now in the atmosphere?

As it happens, those are two distinct questions, with different and nuanced answers.

For the most part, the computer models used to simulate how the planet responds to rising greenhouse gas concentrations in the atmosphere aren’t wildly off the mark, especially considering that they aren’t geared for predicting regional temperature extremes. But the recent pileup of very hot heat waves does have some scientists wondering whether models could be underestimating the frequency and intensity of such events, whether some factors are playing more significant roles than represented in certain models, and what it all may mean for our climate conditions in the coming decades.

Extreme heat and birds


It’s bad enough that Earth could be losing thousands of species each year. Now, two independent studies of birds have concluded the ones most likely to disappear are those that serve unique—and possibly irreplaceable—functions in their ecosystems. Consider the toucan: Its iconic beak lets it eat and disperse seeds and fruit too large for other birds in South American rainforests. Yet these striking creatures, as well as vultures, ibises, and others with distinctive physical traits, are likely to be the first to go extinct, homogenizing the avian world, according to one study. A second paper predicts communities will grow more alike as species flock to cooler regions in the face of climate change.

“That’s alarming because we know that diversity of sizes and shapes and behaviors is a signature of a healthy community,” says Scott Edwards, an evolutionary biologist at Harvard University who was not involved with the work. “This is laying out the grim world we are going to be facing.”

He and others hope the papers will spur conservationists to think more broadly about what biodiversity means. “The impacts of human actions can actually be worse than what we might think just based on species tallies alone,” says Jedediah Brodie, an ecologist at the University of Montana, Missoula. “We haven’t focused on what kinds of functions we might be losing,” adds Marta Jarzyna, a macroecologist at Ohio State University.

I recently shared the disturbing story about how some desert birds are going to be roasted into local extinction within five years, thanks to accelerating climate change (more here). It almost goes without saying that birds and mammals (including humans) who experience heat waves can die en masse. But how is global warming (global cooking?) affecting those birds that actually manage to avoid being roasted to death?

In general, birds are quite vulnerable to climate warming because they are small, they have a high metabolism, and most of them are active during the daytime. Although adult birds have a variety of behavioral and physiological strategies to reduce their chances of heat stroke and death, their hatchlings and nestlings have far fewer options because they are stuck in a nest where they are totally dependent upon others for life-sustaining care, they are experiencing rapid growth (rapid cell divisions) and their bodies are still developing. Thus, the effects of extreme heat are likely to be exaggerated in young birds and the resulting damages may persist into adulthood.

A team of scientists at Monash University investigated and found that animals exposed to hot and dry climate conditions can indeed suffer long-term health consequences (ref). 

Large farm vehicles crushing soil health


If you start talking with Thomas Keller or Dani Or about farm machinery, sooner or later the conversation will turn to dinosaurs. Why would two experts in the biology and structure of soils segue from tractors and combines to extinct behemoths? Because today’s farm vehicles, they explain in a recent paper, have become nearly as heavy as the largest animals that ever stomped the Earth—and the sheer weight is crushing one of the world’s most precious resources: fertile soil.


Researchers used a supercomputer to analyse thousands of images of craters on Mars to find one that matched the properties of an unusual rock.

Don’t forget to wear a mask!

The secret to efficiently heating some buildings might lurk beneath our feet, in the heat that humans have inadvertently stored underground.

Just as cities warm the surrounding air, giving rise to urban heat islands, so too does human infrastructure warm the underlying earth (SN: 3/27/09). Now, an analysis of groundwater well sites across Europe and parts of North America and Australia reveals that roughly a couple thousand of those locations possess excess underground heat that could be recycled to warm buildings for a year, researchers report July 8 in Nature Communications.


The pandemic was, and remains, a global human tragedy. But for ecologists, it has also been an unparalleled opportunity to learn more about how people affect the natural world by documenting what happened when we abruptly stepped back from it.

A growing body of literature paints a complex portrait of the slowdown of human activity that has become known as the “anthropause.” Some species clearly benefited from our absence, consistent with early media narratives that nature, without people bumbling about, was finally healing. But other species struggled without human protection or resources.

“Human beings are playing this dual role,” said Amanda Bates, an ocean conservation scientist at the University of Victoria in Canada. We are, she said, acting as “threats to wildlife but also being custodians for our environment.”

The research has actionable lessons for conservation, scientists say, suggesting that even modest changes in human behavior can have outsize benefits for other species. Those shifts could be especially important to consider as the human world roars back to life and summer travel surges, potentially generating an “anthropulse” of intense activity.