Hello Nature readers, would you like to get this Briefing in your inbox free every day? Sign up here

Elevated view of an Indian farmer crossing a dry pond bed.

An Indian farmer walks across the bed of a pond that has dried during a water crisisSanjay Kanojia/AFP via Getty Images

More than 1 billion face unbearable heat

Models of population growth and warming indicate that climate change is pushing much of humanity out of the comfortable ‘climate niche’ we have enjoyed for the past 6,000 years. If no substantial action is taken to cut greenhouse-gas emissions, places home to one-third of the global population will experience temperatures similar to the Sahara’s within 50 years. Even under optimistic scenarios, the homelands of more than 1 billion people will become unbearably hot by 2070 — with catastrophic consequences for human migration and food production. “I’ve previously studied climate tipping points, which are usually considered apocalyptic. But this hit home harder. This puts the threat in very human terms,” says climate scientist Tim Lenton.

The Guardian | 6 min read

Source: PNAS paper

Microbe blocks malaria in mosquitoes

A microbe discovered in mosquitoes on the shores of Lake Victoria in Kenya seems to prevent the insect from harbouring the malaria parasite. The microsporidian symbiont, Microsporidia MB, occurs naturally in the insect and doesn’t seem to harm them. It’s not exactly clear how the microbe prevents malaria in the mozzies. Researchers hope that infecting more mosquitoes with Microsporidia MB could someday limit malaria transmission to humans.

BBC | 4 min read

Reference: Nature paper

COVID-19 coronavirus outbreak

Profile of a killer

The new coronavirus, SARS-CoV-2, has an array of adaptations that make it much more lethal than the coronaviruses humanity has met so far. Unlike close relatives, SARS-CoV-2 can readily attack human cells at multiple points, with the lungs and the throat being the main targets. Once inside the body, the virus makes use of a diverse arsenal of dangerous molecules. And genetic evidence suggests that it has been hiding in nature possibly for decades. But there are many crucial unknowns about this virus, including how exactly it kills, whether it will evolve into something more — or less — lethal and what it can reveal about the next outbreak from the coronavirus family.

Nature | 14 min read

A family of killers. Chart showing evolution of SARS-CoV-2.

Source: M. F. Boni et al. Preprint at bioRxiv https://doi.org/10.1101/2020.03.30.015008 (2020).

Modelling the pandemic’s financial fallout

Physicist-turned-economist Arthur Turrell tells Nature how Bank of England researchers are fusing economics and epidemiology to study the complex effects of the pandemic. Two of the most pressing topics: the interaction between the macroeconomy and the progression of the disease, and how people’s economic choices might change the risk that they come into contact with the virus.

Nature | 5 min read

AI separates preprint wheat from chaff

An artificial-intelligence (AI) tool called Scite.ai aims to reveal whether COVID-19 studies stand up to subsequent research — especially preprints that haven’t undergone peer review. Unlike conventional citation-metrics tools, Scite.ai tells users how often a paper has been supported or contradicted by the studies that cite it, as well as how many times it has simply been mentioned. The tool is limited to open-access papers, but it has managed to analyse more than 16 million full-text scientific articles so far.

Nature | 6 min read

Notable quotable

“Human connection is important. But without food, shelter and safety, there can be little hope for sustaining good mental health during or after this crisis.”

Meditation apps are not enough to stem the coming tide of despair, argues community-health psychologist Rochelle Burgess. (Nature | 5 min read)

Coronavirus research highlights: 1-minute reads

How China stopped the outbreak

Drastic social distancing in Shanghai and Wuhan was enough to bring the epidemic under control in the two cities. Modelling work suggests that, in Shanghai, school closures alone would not have stopped the epidemic — but they did lower the number of new infections per day at the epidemic’s peak, which relieved stress on hospitals. Another study shows that quick detection and isolation of infected people were the most effective steps for containing COVID-19 in China. But even with those efforts in place, the number of cases would have soared if officials hadn’t restricted travel and social interactions.

Reference: Science paper & Nature paper

Portraits of a viral enzyme could aid the hunt for drugs

Molecular snapshots of a key SARS-CoV-2 enzyme in action provide clues to how drugs, including the experimental therapy remdesivir, attack the virus. Two teams looked at the action and structure of a viral enzyme called an RNA-dependent RNA polymerase.

Reference: bioRxiv preprint & Science paper

Get more of Nature’s continuously updated selection of the must-read papers and preprints on COVID-19.

Features & opinion

How to give a computer common sense

Computer scientists have built a system that can make simple guesses — for example, what happens after “Gary stacks kindling and logs and drops some matches”. Machine-learning techniques, such as neural networks, can make statistical guesses after absorbing large amounts of data, but they are notoriously lacking common sense. Other attempts relied on knowledge bases containing millions of rules and sentences handpicked by humans. COMET combines the two approaches, using a knowledge base to train a neural network. Lead researcher Yejin Choi says she was surprised that no one had tried this approach before. “It’s almost as if nobody bothered because they were so sure this would never work.” COMET’s guesses are still statistics-based, but at least they’re often right.

Quanta | 14 min read

Image of the week

Animated brain scan sequence of a microscopic nematode

This brain scan of a microscopic C. elegans nematode was created as part of a study into how its nervous system changes as its body grows and its behaviours mature. Reference: bioRxiv preprintWitvliet et al., 2020

Quote of the day

“Remember when ATLAS tried to reduce the number of meetings? They formed a committee. That [committee] could not find a time to meet, due to conflicting meetings… so it cancelled its own meeting… and declared success!”

Particle physicist Daniel Whiteson recalls how one research group at CERN tackled meeting overload. (Twitter)