New Scientist

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Virtual event A scientist’s guide to a rational life The modern world is full of contradictions that we must navigate as best we can. But what should we believe? And in what and whom should we trust? In this talk, Jim Al-Khalili offers advice on how we can borrow the best bits of the scientific method and apply them to our lives. Join us at 6pm BST on 16 September or watch on demand later. Tickets available now. newscientist.com/events Podcast Weekly “Freedom day” arrived in England this month, as the country dropped most covid-19 restrictions. The team discuss why hundreds of experts are calling the move an “unethical experiment”. They also chat about the launch of Blue Origin’s New Shepard spacecraft and Jeff Bezos’s plans to build a “road to space”. Plus the news that tomatoes…

a road ill-travelled

DURING the coronavirus pandemic, we have all become amateur epidemiologists, readily discussing R numbers, herd immunity and test sensitivity in everyday conversation. Now, with the virus still nowhere near eliminated, we would do well to concern ourselves with the principles of viral evolution too. It is a widespread misconception that viruses tend to evolve to become less deadly. To really grasp what a virus is likely to do, we must look at the opportunities it has to evolve and the selection pressures that could force it to change. In these respects, the UK has stumbled into a dangerous realm (see page 8). Its high infection numbers provide ample chance for evolutionary experimentation, while high-but-not-yet-high-enough levels of vaccination could prove a strong driver for new “escape variants” that can better evade the immune…

uk covid-19 cases fall

ONE swallow doesn’t make a summer, but the recent sustained fall in covid-19 cases in the UK may represent a turning point. However, experts warn there are many other explanations for the decline that cannot be ruled out. As New Scientist went to press, the number of people in the UK testing positive for covid-19 had fallen for seven consecutive days, the longest sustained fall since daily cases started being recorded. According to official UK government figures, 23,511 new cases were reported on 27 July, down from 46,558 on 20 July. There are various possibilities for the fall, says Kit Yates at the University of Bath, UK, who keeps track of the numbers for the Independent SAGE group. “One is that genuinely infections are coming down because we’ve peaked and hit the…

the variant race is upon us

BACK in March, an eventual end to the coronavirus pandemic appeared to be in sight. The number of covid-19 cases were plummeting in the UK and the US as vaccination levels rose. It seemed the same might gradually happen in country after country around the world. But then India was hit by a devastating second wave, due largely to a new variant now known as delta. After delta spread to many other countries, case numbers soared once again, including in the UK and US. The question is, will this keep happening? Will more dangerous variants keep evolving, causing fresh waves of infections around the world despite vaccine roll‑outs? The answer is almost certainly yes. “Variants will continue to arise, there’s no doubt,” says Ravi Gupta at the University of Cambridge. The SARS-CoV-2 coronavirus…

is an exit wave a real thing?

The current wave of cases in the UK as restrictions are relaxed is being described as an exit wave. This term implies it will be the last wave the country will see, but many experts think there will be more. “The idea that that’s the end of it – unfortunately not,” says Aris Katzourakis at the University of Oxford. “We may be undergoing this harm for no long-term pay-off.” In fact, there could be more waves even without new variants emerging. “If there’s waning immunity or if contact rates go up, then we will see future waves as well,” says Graham Medley at the London School of Hygiene & Tropical Medicine. “It is a bit of a euphemism to call it an exit wave.” It has also been suggested that a big exit…

is the climate becoming too extreme to predict?

RECORD-BREAKING climate events, such as Canada’s highest temperature on record being exceeded by almost 5°C last month, will be increasingly likely in the coming decades, suggests new research. It comes as the ability of climate models to predict such extremes has been called into question following intense weather events around the world. Erich Fischer at ETH Zurich, Switzerland, and his colleagues ran computer models to simulate the average maximum temperature of the hottest week of the year in parts of North America and Europe to see if they could yield temperatures that broke records by large margins. They could: some emissions scenarios smashed records by more than 1°C by 2030, not the 0.1°C or 0.2°C usually predicted. The researchers conclude that the likelihood of such record-breaking events is largely down to the…