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Body temperatures seem to have fallen since the 1800s.Credit: Getty

Normal body temperatures have dropped by around half a degree since 1860 — at least in the United States. Researchers looked at hundreds of thousands of thermometer measurements taken since 1860 and found that average body temperature dropped by 0.03 °C per decade. Not everyone is convinced — there are a lot of unknown variables in how temperatures were measured — but others aren’t surprised, considering how much life has changed in 200 years. “If you looked at the great majority of people back in the nineteenth century, I’m sure literally all of them had a chronic inflammatory condition,” says infectious-disease epidemiologist Julie Parsonnet.

Nature | 4 min read

Reference: eLife paper

China actively encourages its scientists to study abroad and then bring their expertise home. But contrary to the common perception that such experience furthers careers, a study finds that returnees take longer than their peers who remained in China to obtain the prestigious Changjiang scholarship. Of 1,500 Chinese nationals awarded the Changjiang in the sciences between 1999 and 2015, those with PhDs from foreign universities were about 2.3 years further along their career path when they got the scholarship, compared with those who stayed home.

Nature | 5 min read

Reference: Science and Public Policy paper

The debate over the proposed Thirty Meter Telescope (TMT) on Mauna Kea is profoundly changing how astronomy is done in Hawaii — with implications for how science progresses everywhere. While Native Hawaiians and others grapple with the ethics of placing yet another giant installation on the sacred mountain, the clock is running out on funding for the potentially transformative telescope.

Nature | 5 min read

Features & opinion

Anti-CRISPR proteins serve as the rocks to CRISPR’s molecular scissors, stopping the gene-editing tool in its tracks. Anti-CRISPRs offer scientists a tantalizing tool for keeping gene editing in check — from fine-tuning gene therapies to serving as a countermeasure against a bioweapon. They also raise questions about how the arms race between bacteria and phages caused CRISPRs and anti-CRISPRs to evolve in the first place.

Nature | 10 min read

The late ecologist Donella Meadows’s approach for bringing a wildly different world into being, systems thinking, helped to create a global movement. Now the technique is seen as crucial to meet big global challenges such as the United Nations’ Sustainable Development Goals. A Nature Editorial urges researchers to use systems thinking to imagine a world with no hunger and then change the food system to make it happen.

Nature | 4 min read

An extremely rare species of tree that has survived since the dinosaurs has been saved from bushfires in Australia. The last-remaining grove of wild Wollemia nobilis trees was protected by specialist firefighters, who dropped water and fire retardant from the air and set up an irrigation system to soak the ground. The location of the grove in Wollemi National Park is kept secret to protect it from tourists.

The Sydney Morning Herald | 4 min read