Science

In the past two decades, the US President’s Emergency Plan for AIDS Relief (PEPFAR) has prevented millions of deaths and new HIV infections through the provision and support of HIV testing, treatment, and prevention programs in more than 50 countries worldwide (1). Although HIV remains incurable, treatment with antiretroviral therapy (ART) leads to sustained viral suppression, which halts both immune system destruction and HIV transmission (2–4). With ART delivery at its core, PEPFAR has been enormously successful in improving both individual and public health: At the end of 2024, more than 20 million people were receiving life-saving ART through PEPFAR, and between 2010 and 2023, new HIV infections were reduced by an estimated 52% in PEPFAR-supported countries (1). However, in January, th...

AI could automate some government paperwork, but it comes with serious risksBrett Hondow / Alamy Many countries are exploring how artificial intelligence might help with everything from processing taxes to determining welfare benefits. But a survey shows citizens are not as enthusiastic as their governments – and this can create real risks for democracy. “Focusing only on short-term efficiency gains and shiny technology risks triggering public backlash and contributing to a long-term decline in democratic trust and legitimacy,” says Alexander Wuttke at the Ludwig Maximilian University of Munich in Germany. Wuttke and his colleagues asked around 1200 people in the UK to share their feelings about government actions where either a human or an AI handled the task. Th...

Dozens of storm-chasing meteorologists have undertaken the largest-ever study of extreme hail across the US Great Plains. New Scientist environment reporter James Dinneen hitched a ride inside a fortified truck called the Hail Hunter to get an inside view of the campaign during one of the most extreme hailstorms to affect the Texas panhandle on 5 June. The project, known as ICECHIP, collected more than 10,000 hailstones over 42 days, as well as huge volumes of data on virtually every aspect of the storms that produced them. The largest stone they collected was 149 millimetres in diameter, about the size of a large grapefruit. Such hailstones can be extraordinarily destructive. Every year, extreme hailstorms in the US cause ...

Each year, the Climate School Office of Undergraduate Programs celebrates graduating students with the Departmental Honors Award for their outstanding academic achievement in the Sustainable Development program. This year, four students were selected: Rachel Brzezicki, Harrison Gerson, Esha Karam and Yoon Kim. As recipients of Departmental Honors, all students maintained a 3.7 GPA in their major courses and received at least a B+ in two semesters of the senior thesis seminar. For this spotlight, we caught up with Brzezicki, Gerson and Karam about their time at Columbia and post-graduation plans. Sustainable Development Class of 2025 Award winners. From left to right: Emine Taha (Gaffin Award), Harrison Gerson (Departmental Honors, Gaffin Award), Rachel Brzezicki (Departmental Honors)...

The universe follows the arrow of timeWavebreakmedia Ltd DW1802_1 / Alamy Where does time really come from? I am often asked this question after acquaintances or friends of friends learn that I am a physics reporter. There is not a set answer – but to better understand it, it helps to look at the arrow of time. Dating back to the 1920s, this concept stems from the laws of physics that describe energy, heat and entropy. Entropy is the big one, as time seems to move from low- to high-entropy states – this is the direction in which the “arrow of time” flies. Entropy gets a bad reputation for being about disorder, but the more precise way to think about it is to count how many ways something large – a macrostate – can be assembled from smaller constituent parts, or mi...