What the scientists are saying…
Europe’s giant flightless bird
When early humans first arrived in Europe from Africa, they may have been confronted by giant birds, three times as heavy as a modern-day ostrich. Researchers excavating a cave on the Crimean peninsula discovered a 40cm-long femur (thigh bone) last summer that they have now established belonged to a previously undiscovered species of flightless bird that was 3.5m tall and weighed about 450kg. “We think of [giant birds] in Madagascar, New Zealand and Australia, but this is very solid evidence that they were also in the European region,” said Dr Helen James of the Smithsonian National Museum of Natural History in Washington, who wasn’t involved in the study. Based on similarities to other animal remains found near by (including sabre-toothed cats and giant cheetahs), the scientists estimate that
Pachystruthio dmanisensis lived between 1.5 and two million years ago, about the time that our ancestor Homo erectus started migrating to Europe. Writing in the Journal of Vertebrate Paleontology, they suggest that these early humans could have hunted the birds for their meat, though there is as yet no evidence for this.
Antarctic sea ice disappearing
The amount of sea ice around Antarctica suddenly went into “precipitous” decline in 2014, having previously risen steadily for three decades, says The Times. An analysis of satellite data revealed that between 2014 and 2017, the floating ice around Antarctica decreased from 12.8 million square kilometres to 10.7 million square kilometres – a loss equivalent to the size of Mexico, and about the same amount as has disappeared from the Arctic over the past 34 years. Before this reversal, sea ice cover in Antarctica had been steadily getting more extensive, a trend that puzzled climate scientists, given the warming pressures across the planet as a whole. “Those of us in the climate community who study sea ice expected that eventually cover would start to decrease,” said Dr Claire Parkinson, a Nasa climate scientist and the author of the new report. “What is surprising is how fast it has occurred.” While loss of sea ice doesn’t raise sea levels, it is still a serious worry. Animals rely on it for migration and hunting, and its loss is liable to accelerate global warming, as solar energy that would have been reflected by the ice is instead absorbed by the dark ocean, driving up sea temperatures.
Taking brain pills a waste of time
“Memory supplements” have become big business: in the US, a quarter of people over 50 are thought to take them, often believing that they help ward off dementia. But according to a new report, these people are wasting their money. Researchers from the Global Council on Brain Health looked at evidence across a range of supplements, including those containing B vitamins, vitamin D, omega-3 fatty acids, caffeine, coenzyme Q10 and ginkgo biloba. Few, they found, had been tested for their impact on brain health, and where tests had taken place, there was little clear evidence that they improve brain function or prevent dementia. The researchers said that if people are concerned about maintaining their brain health, there are far better ways, including eating healthily, taking exercise and getting enough sleep.
Vapour trails warm the planet
Aviation is, of course, a major emitter of CO2, but in terms of the industry’s impact on climate change, carbon is only the half of it: according to a new study, far more atmospheric warming is caused by the cloud-like vapour trails – or “contrails” – that planes leave in their wake when flying at high altitude. These are created when vaporised water condenses or freezes around sooty exhaust particles to create cirrus-type clouds. These can persist for hours, but are too thin to reflect warmth. Instead, ice crystals within them trap heat, warming the planet. Researchers from the Institute of Atmospheric Physics in Germany estimate that aircraft vapour trails typically have twice the warming impact of CO2 emissions. And as air traffic increases, the problem will only get worse. In a paper published in Atmospheric Chemistry and Physics, they argue that the industry cannot solely focus on aircraft fuel efficiency; they must also acknowledge and address the currently overlooked problem of contrails.