Amid the many warnings around growing hunger in many parts of the world, scientist Deepak Ray published an eye-opening study. Looking at 10 major crops, he and his collaborators estimated that by 2030 only about 29% of the global harvests will be consumed as food in the countries where they were produced. That’s down from 51% in the 1960s. In his summary of the study Ray explains that because of global demographic changes and policies, these crops are increasingly being used in processed ingredients such as animal feed and biofuels and being sold on global markets.

The Biden administration just announced that another round of rapid home COVID-19 tests is now available free of charge. UMass Chan Medical School researchers Nathaniel Hafer and Apurv Soni unpack the perennial question: How accurate are these antigen tests? They explain the latest research, including their own on how over-the-counter rapid tests perform in real-world settings, and also explain why taking two tests 24 to 36 hours apart is critical for detecting infections.

In recent years studies have shown that trees have great potential to soak up the rising levels of carbon dioxide in the atmosphere, but two new studies temper those hopes. Ecologist William Anderegg, who was involved in both studies, explains that the effects of stressors exacerbated by climate change, such as drought, fires and pests, are happening faster than many scientists expected. “We’re also seeing evidence that the benefits trees get from higher levels of carbon dioxide in a warming world may be more limited than people realize,” he writes.

Also in this week’s science news:

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Harvesting soybeans in Mato Grosso, Brazil. Brazil exports soybeans and uses them domestically to make animal feed and biodiesel. Paulo Fridman/Corbis via Getty Images

A shrinking fraction of the world’s major crops goes to feed the hungry, with more used for nonfood purposes

Deepak Ray, University of Minnesota

A new study finds that by 2030, less than one-third of the world’s major crop harvests will go directly to feed people.

Once in short supply, rapid antigen tests are now available throughout the U.S. Boy_Anupong/Moment via Getty Images

Just how accurate are rapid antigen tests? Two testing experts explain the latest data

Nathaniel Hafer, UMass Chan Medical School; Apurv Soni, UMass Chan Medical School

With the relaxation of mask-wearing mandates, there’s even more need to know how much over-the-counter tests help.

When trees burn, all the carbon they have stored goes back into the atmosphere. Patrick T. Fallon/AFP via Getty Images

Trees aren’t a climate change cure-all – 2 new studies on the life and death of trees in a warming world show why

William R.L. Anderegg, University of Utah

More carbon dioxide in the air doesn’t necessarily mean more growth for trees, and the increasing risk of wildfires and drought has major consequences, as an interactive map shows.