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Two women use manual fans during a heatwave.

Heat exposure can lead to heart strain well before a person’s core temperature rises.Credit: Cristina Quicler/AFP via Getty

Even moderate heat strains the heart

A person can experience cardiovascular strain — a progressive increase in heart rate — in air temperatures as low as 34 ℃, before their internal temperature starts to rise. Researchers spotted the warning sign in 51 healthy volunteers who engaged in light physical activity in humid conditions inside an environmental chamber. For older people or those with a heart condition, the effect can be lethal. “If all of a sudden you notice your heart rate going up quickly and progressively, then that might mean that your core temperature will start to rise,” says exercise physiology researcher and study co-author Rachel Cottle. “That’s when you need to take precautionary measures.”

Nature | 4 min read

Reference: Journal of Applied Physiology paper

Sweden axes development-research funding

International-development researchers in Sweden are in turmoil after the country’s government decided to cut all further public funding for the field with immediate effect. The sudden move could derail collaborations that have taken decades to build, scientists say. The government cited the need to prioritize aid to Ukraine. Scientists have countered that this is confusing humanitarian needs with development research. More than 600 researchers have now signed an open letter calling for a reversal of the move.

Nature | 5 min read

AI could help to forecast extreme weather

Two algorithms have demonstrated the potential for artificial intelligence (AI) to make faster and more accurate weather forecasts.

• Pangu-Weather, trained on 39 years of weather data, can retrospectively predict global temperature, pressure and wind speed a week in advance. It’s 10,000 times faster and no less accurate than making predictions on the basis of an understanding of physics.

• NowcastNet combines deep-learning methods with physics equations to give local predictions of heavy rain up to three hours in advance. The meteorologists who tested NowcastNet judged it to be better in most cases than four leading ‘nowcasting’ systems.

AI could help make better weather prediction cheaper and more widely available, and could one day attempt other complex predictions, such as the spread of wildfire smoke. Human oversight will be key, note atmospheric scientists Imme Ebert-Uphoff and Kyle Hilburn in the Nature News & Views article: the systems can struggle with extreme events, which are more likely to occur in a changing climate.

The Daily Beast | 8 min read & Nature News & Views article | 7 min read (Nature paywall)

References: Nature paper 1 & paper 2

Features & opinion

Hunger and famine are not accidents

Human actions, not natural disasters or crop failures, are the primary cause of hunger and famine. On top of the disruptions caused by violent conflict, there is evidence that sellers are pushing up their profits on food and energy, which buyers can’t do without. These are pivotal reasons that the world is not on track to end hunger and malnutrition by 2030 — a promise that is one of the 17 United Nations Sustainable Development Goals (SDGs). In September, world leaders will gather in New York City to come up with a rescue plan for the SDGs. As part of a series of articles about how scientists can help, a Nature editorial calls on researchers to continue to uncover evidence about what is exacerbating hunger and how it can be eliminated.

Nature | 5 min read

A circular economy for rare-earth elements

The market for valuable rare-earth elements is “a ‘zero sum’ game, in which one nation’s or company’s gain is another’s loss”, write a group of environmental management and resource economics researchers. They propose rethinking the industry to meet the soaring demands of clean-energy technologies, without damaging the environment. Policies and programmes need to encourage recycling, recovery and tracing of rare-earth elements, and the supply chain needs to be reworked to build “win–win alliances and a global circular economy”, they write.

Nature | 11 min read

A primer on how to fight sexism in science

Putting women off careers in science, technology, engineering and mathematics (STEM) means shutting out much-needed scientific talent, argues experimental physicist Athene Donald, a leading authority on gender-equity issues, in her new book Not Just for the Boys. It’s an enjoyable and useful primer that draws evidence from history, neuroscience and social science, writes space scientist Karly Pitman in her review. The solutions are “often obvious”, Donald says — but their need is frequently underestimated beyond the affected group. To help rectify this, Donald offers a helpful table listing practical steps individuals can take.

Nature | 6 min read

Where I work

Fernando Calderón-Gutiérrez, an underwater cave ecologist, dives and studies the organisms in the coastal caves of Mexico.

Fernando Calderón Gutiérrez is a marine biologist at Texas A&M University in San Antonio.Credit: Natalie L Gibb for Nature

Cave ecologist Fernando Calderón Gutiérrez is studying the resilience of cave-adapted species in the face of climate change and other stressors. In this photo taken in Belize during a plankton-collecting dive, it’s clear that this unique environment — which he fell in love with while watching a film about cave diving in secondary school — also comes with risks. “You can see that I always carry duplicate lights and navigation tools, and bring extra air tanks,” he says. (Nature | 3 min read)

Quote of the day

“The idea that the end point of the evolution of intelligence is human intelligence and that it is embodied in the organization of the cortex makes no sense from a biological point of view.”

Neurobiologist Giorgio Vallortigara responds to the debate about whether Tyrannosaurus rex and other theropod dinosaurs might have been as smart as modern primates — or whether the way their brains were organized would have prevented them from ever evolving to a human level of intelligence. (Scientific American | 7 min read)

Reference: Journal of Comparative Neurology paper 1 & paper 2