The ozone layer is a protective shield in the Earth's stratosphere which absorbs some of the ultraviolet radiation reaching us from the sun. Without the layer, it would be nearly impossible for anything to survive on the planet.
Dubai - Scientists say the hole is due to the unusually low temperatures in the atmosphere above the North Pole; it is not expected to pose any danger to humans unless it moves further south.
Published: Thu 9 Apr 2020, 1:03 AM
A hole has opened up in the ozone layer above the Arctic, and looks set to be the biggest on record for the region.
Scientists say the hole is due to the unusually low temperatures in the atmosphere above the North Pole.
The ozone layer is a protective shield in the Earth's stratosphere which absorbs some of the ultraviolet radiation reaching us from the sun. Without the layer, it would be nearly impossible for anything to survive on the planet.
The new hole, which has been followed from space and the ground over the past few days, is not expected to pose any danger to humans unless it moves further south.
If it extends further south over populated areas, such as southern Greenland, there would be the risk of sunburn for people.
Maps of the Arctic Hemisphere from Nasa's Ozone Watch, created with satellite data, illustrate the hole growing in size from late last year until now.
However, experts believe current trends mean that the hole will disappear altogether in a few weeks.
The European Space Agency-backed Copernicus Atmosphere Monitoring Service (CAMS) has been tracking the 'unusual ozone hole' since it first formed.
A hole over Antarctica in the southern hemisphere forms annually but a hole over the Arctic is a rare occurrence, according to CAMS.
Plummeting temperatures in the northern polar regions caused an uncommon stable polar vortex, and the presence of ozone-destroying chemicals such as chlorine and bromine in the atmosphere - from human activities - caused the hole to form.
"From my point of view, this is the first time you can speak about a real ozone hole in the Arctic," Martin Dameris, an atmospheric scientist at the German Aerospace Center, told Nature.
"Our forecasts suggest that temperatures have now started to increase in the polar vortex," added Vincent-Henri Peuch, Director of CAMS.
"This means that ozone depletion will slow down and eventually stop, as polar air will mix with ozone-rich air from lower latitudes," he said. "It is very important to maintain international efforts for monitoring the annual ozone hole events and the ozone layer over time."
In Antarctica, the thickness of the ozone alters according to the season.
The bitterly cold winters lead to high-altitude clouds combining with ozone-damaging chlorofluorocarbons (CFCs), that have been in the atmosphere for decades, to thin out the layer.
In the North Pole region, the weather is typically warmer and doesn't cause high-altitude clouds.
In 2020, uncommonly cold temperatures and forceful winds formed a "polar vortex" in the Arctic, creating the frigid conditions that have led to a vast ozone depletion, about three times the size of Greenland.
Last month, weather balloons were sent up by Arctic researchers and reported a 90 per cent drop in ozone at the layer's core.
Scientists are keeping tabs on what happens next but it is expected that the new ozone layer depletion in the Arctic will be greater than smaller holes recorded in 1997 and 2011.
Levels of ozone over the Arctic are very depleted - the last time it was this bad was during the spring of 2011 - and this year looks set to be worse, CAMS said.
"While we are used to ozone holes developing over the Antarctic every year during the Austral spring, the conditions needed for such strong ozone depletion are not normally found in the Northern Hemisphere," the CAMS team wrote.
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