What the scientists are saying…
The polar switch disaster
Towards the end of the Stone Age, Neanderthals disappeared in Europe; there was a creative explosion of cave art; and in Australia, every mammal bigger than a kangaroo disappeared. Now, scientists think all these things can be linked to one cataclysmic event, says The Times. Around 42,000 years ago, the poles flipped, and magnetic north became south. During the reversal, the ozone layer was destroyed, electrical storms ravaged tropical areas, and Arctic air engulfed North America. “It would have been an incredibly scary time,” says Professor Chris Turney, of New South Wales University. Known as the Laschamp event, the reversal was identified in the 1960s, but it’s only now that, by analysing carbon isotopes in fossilised kauri trees in New Zealand, scientists have worked out its exact timing and scale. It seems that over several hundred years, the magnetic field that envelops Earth gradually weakened, until it was only 6% of current levels – leaving Earth vulnerable to extreme bursts of radiation. In this period, lightning strikes would have sparked devastating wildfires, UV light would have streamed in, and temperatures would have risen. The theory is that Neanderthals and Australia’s megafauna were unable to adapt to these extreme changes; but early humans sheltered in caves.
Next year’s flu could be a killer
Scientists have warned that the world should be braced for a dramatic resurgence of flu next winter. This year, seasonal flu levels were far lower than normal, largely owing to social distancing and measures designed to combat the coronavirus. While this has helped health services cope with the current crisis, there are fears that it will also result in reduced immunity levels to flu – resulting in an extreme outbreak in the coming season. “We have effectively missed out on flu this winter, so levels of immunity are less than are typical,” Professor John Edmunds, of the London School of Hygiene & Tropical Medicine, told The Daily Telegraph. “In fact, it is not impossible that we will have an out-of-season epidemic, perhaps in the autumn rather than winter [assuming distancing measures have been relaxed].” Typically, flu kills between 10,000 and 30,000 people a year in Britain; but in the past year, flu deaths have hardly registered. As well as reducing immunity levels, this year’s low flu levels will make it more difficult to predict the next strain, and so create a vaccine for it.
Asteroid theory “confirmed”
The long-held theory that dinosaurs were wiped out by an asteroid that slammed into what is now the Gulf of Mexico, 66 million years ago, has been confirmed, scientists say. An international team studied rock core samples from thousands of feet below the seabed in the Chicxulub crater, and found high levels of asteroid dust within them. “We are now at the level of coincidence that geologically doesn’t happen without causation,” said Professor Sean Gulick, a researcher at the University of Texas at Austin. The team found that levels of iridium – an element that is present only in low concentrations on Earth – were 30 times higher than average in the Cretaceous/ Tertiary boundary, the layer of sedimentary rock laid down in the period the dinosaurs disappeared. When the asteroid struck the planet, the impact kicked up so much dust into the atmosphere, the Sun was obliterated, and 75% of plant and animal life died. Scientists now estimate that the dust circulated for only around 20 years. You could make an argument that it all happened within a couple of decades, said Gulick, “which is basically how long it takes for everything to starve to death”.