If the poles flip, compasses will south – and it could have significant effects on Earth’s power grid, although any ‘flip’ is not likely to happen immediately.
An ‘anomaly’ in South Africa might hold the key to predicting the next flip, according to researchers from the University of Rochester – a place where compasses point south, deep under the ground.
Professor John Tarduno of the University of Rochester says, ‘There’s a patch of reversed polarity beneath southern Africa at the core-mantle boundary where the liquid iron outer core meets the slightly stiffer part of the Earth’s interior.
‘In this area, the polarity of the field is opposite to the average global magnetic field. If we were able to use a compass deep under southern Africa, we would see that in this unusual patch north actually points south.
‘We speculate that these reversed core patches grow rapidly and then wane more slowly. Occasionally one patch may grow large enough to dominate the magnetic field of the Southern Hemisphere – and the poles reverse.
‘The conventional idea of reversals is that they can start anywhere in the core. Our conceptual model suggests there may be special places at the core-mantle boundary that promote reversals.
But before you head for the doomsday bunkers, it’s probably not going to happen right away – with scientists predicting a ‘flip’ sometime in the next 2,000 years.
NASA has poured cold water on the idea that magnetic field reversals could lead to an apocalypse, saying in 2012 that, ‘The science shows that magnetic pole reversal is – in terms of geologic time scales – a common occurrence that happens gradually over millennia. While the conditions that cause polarity reversals are not entirely predictable – the north pole’s movement could subtly change direction, for instance – there is nothing in the millions of years of geologic record to suggest that any of the doomsday scenarios connected to a pole reversal should be taken seriously.’
Researchers reconstructed 6,000 years of vegetation and fire history around two geoglyphs – and found that humans had altered bamboo forests for millennia, building clearings around the geoglyphs.
Dr. Watling said: ‘Despite the huge number and density of geoglyph sites in the region, we can be certain that Acre’s forests were never cleared as extensively, or for as long, as they have been in recent years.
‘Our evidence that Amazonian forests have been managed by indigenous peoples long before European Contact should not be cited as justification for the destructive, unsustainable land-use practiced today. It should instead serve to highlight the ingenuity of past subsistence regimes that did not lead to forest degradation, and the importance of indigenous knowledge for finding more sustainable land-use alternatives’.