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

A woodlouse with a yellow head and black body is peering at the camera.

Arthropods, such as this Cubaris sp. ‘Rubber Ducky’ isopod, are the most diverse group on Earth, with an estimated seven million species. Around 30% of these species live underground. (Suriyapong Koktong/Getty)

Soil is home to more than half of all life

About 59% of all species on Earth live in soil, estimate researchers who reviewed global biodiversity data. This would make the ground the planet’s single most biodiverse habitat. The figure doubles an earlier estimate and could be even higher because so little is known about soil, the researchers suggest. It is home to 99% of Enchytraeidae worms, 90% of fungi, 86% of plants and more than 50% of bacteria — but only 3% of mammals live in it.

The Guardian | 4 min read

Reference: PNAS paper

Graphical overview of the share of species living in soil.

(Illustrations by Michael Dandley)

Disappearing clouds exacerbate warming

Ships have drastically cut their sulfur pollution following regulations introduced in 2020, which has improved air quality worldwide, but has also unintentionally exacerbated global warming. Sulfur particles create ‘ship track’ clouds, which are reflective and help to cool Earth’s climate — and under the new rules, there are now fewer of these clouds. This natural geoengineering experiment shows that planetary cooling by deliberately brightening clouds, for example using salt particles, could be possible, says atmospheric scientist and study author Michael Diamond.

Science | 6 min read

Reference: Atmospheric Chemistry and Physic paper

The ‘unknome’: a map of mystery genes

Researchers have catalogued the human ‘unknome’, the one-fifth of human genes whose purpose remains mysterious. Many of them could have important functions. Out of 260 of these mystery genes, at least 60 seem to be essential to life. In experiments with fruit flies, which share many genes with humans, removing any one of these essential mystery genes caused the insects to die. Other genes seem to have important roles in reproduction, growth, movement and stress resilience. The scientists hope their database will help researchers to fight back against academia’s bias towards studies in well-understood areas.

Wired | 7 min read

Reference: PLoS Biology paper

Features & opinion

A US drug policy harms patients worldwide

The US Food and Drug Administration (FDA) offers accelerated approval for some much-needed drugs, particularly cancer therapies. The process prioritizes speed over certainty, granting approval on the basis of evidence that doesn’t necessarily prove efficacy. Companies are required to complete follow-up studies to confirm a treatment’s benefits. Withdrawal of drugs that fail to prove their worth can take time, and some continue to be recommended even after they have been withdrawn. Some people continue to take drugs that have been proven ineffective, especially outside the United States, where the nuances of the FDA approval system are not always clearly communicated.

Nature | 11 min read

Rules to keep AI in check

Countries are clamouring for legal guard rails around artificial intelligence (AI). The technology is a constantly moving target, and what exactly needs restricting isn’t clear. The European Union’s highly precautionary laws, which are expected to pass this year, would ban uses judged to be unacceptably high risk, including in predictive policing and real-time facial recognition. The United States has so far been hands-off, with “nothing substantive and binding”, says policy researcher Ryan Calo. China has issued the most AI legislation so far in a bid to balance innovation with retaining its tight control over corporations and free speech.

Nature | 15 min read

How clean energy can fuel the future

As with other Sustainable Development Goals (SDGs), the world is falling short in meeting the targets of SDG 7: to expand renewable energy and provide affordable access to it. One reason for the slow progress is the myth that clean energy gets in the way of economic development. Research suggests that the picture is more complex. Energy is a linchpin for most of the SDGs, including those focused on climate, health, food, poverty and education. “The lesson is that it might be easier, not harder, to address these challenges together,” argues a Nature editorial.

Nature | 5 min read

Quote of the day

“How come it’s our problem? It’s your mess. You should be able to help yourself.”

If wealthy countries really believe in recycling, they shouldn’t push the process’s burden and risks onto others, says Yuyun Ismawati, co-founder of a Jakarta-based environmental research and advocacy group. Indonesia is one of countries that is cracking down on imports of contaminated and unrecyclable plastic waste. (Undark | 9 min read)