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The Karlsruhe Tritium Neutrino (KATRIN) experiment monitors the nuclear decay of the hydrogen isotope tritium.Credit: Michael Zacher

An experiment in Germany has made the best measurement yet of the maximum mass of neutrinos. The lightest of all the known subatomic particles are so devilishly difficult to measure that physicists have only been able to estimate an upper limit on their mass. The first results from the Karlsruhe Tritium Neutrino (KATRIN) experiment in southwestern Germany find that neutrinos weigh at most 1.1 electronvolts — a two-fold improvement over previous upper-bound measurements of 2 electronvolts.

Last month, researchers used astronomical data to indirectly estimate a mass of 0.086 electronvolts at most.

Nature | 3 min read

Reference: arXiv preprint

Presidential science adviser Kelvin Droegemeier has outlined his plan to strengthen national policies on research security. The move follows months of outcry over whether the US government is unfairly targeting foreign-born researchers over purported security breaches. Droegemeier is planning a listening tour of US universities, which will inform government-wide requirements for what information researchers need to disclose to receive federal research grants.

Nature | 4 min read

Palaeogeneticist Ed Green has turned the skills that he honed sequencing the first complete Neanderthal genome to solving crimes. His technique for sequencing DNA from strands of hair that don’t have their cell-bearing root gives law-enforcement agencies a new way of identifying victims and suspects. “Criminals think of wearing gloves or wiping down blood,” says genetic-services company executive Justin Loe, “but fewer think to shave their head.”

The New York Times | 8 min read

Weather observers are on the front lines of climate change as temperature records are broken from California’s Death Valley to Antarctica. “I felt a mixture of elation but also sadness,” says Katie Martyr, who in July measured the hottest temperature ever officially recorded in Britain in her role as a horticulturalist at the Cambridge University Botanic Garden. “To have a temperature like that — there are consequences globally if this is to continue.”

Nature | 5 min read

Why Nature joined the Covering Climate Now initiative

FEATURES & OPINION

Groups that track climate-related funding estimate that more than half a trillion dollars is being spent each year to help deal with the effects of climate change — but it’s not enough, it’s not all going to where it’s needed most and almost as much cash is going to subsidize fossil fuels. Economic analysts say we need firm commitments from wealthy nations, promises to the low-income communities that will suffer most, and nothing short of a total transformation in how we think about the carbon impact of every dollar spent.

Nature | 12 min read

The processes underlying climate change are complex and intricately intertwined. To plot a course to our best possible future, scientists have devised computer simulations known as integrated assessment models. But some say that tackling climate change will require a radical reinvention of industrial society that the models are not equipped to address. Climate scientists Kevin Anderson and Jessica Jewell present opposing views on the suitability of these simulations.

Nature News & Views Forum | 8 min read

Environmental lawyer Farhana Yamin was a lead author for three reports by the Intergovernmental Panel on Climate Change and an adviser in United Nations climate negotiations for almost 30 years. This April, she was arrested for supergluing her hands to the pavement outside Shell’s London headquarters. She explains what drove her to civil disobedience and gives advice to others contemplating the same.“What we need is not system change or personal change — it’s both,” says Yamin. “Not street circus or government and industrial overhaul, but both. Not reform through revolution or the ballot box. Both.”

Nature | 9 min read

IMAGE OF THE WEEK

Credit: Contains modified Copernicus Sentinel data [2015-2019], processed by Pierre Markuse

These satellite images show rapid deforestation of a 48-kilometre-wide area in the Brazilian state of Rondônia over the past four years, as patches of rainforest are cleared by burning and converted to roads or agricultural plots. Rondônia has become one of the places in the Amazon affected most by deforestation — it was once home to more than 200,000 square kilometres of rainforest, but an estimated 67,000 square kilometres had been cleared by 2003.

See more of the most spectacular images of the month, as selected by Nature’s photo team.