The Antarctic ozone hole is the smallest since it was discovered

James Marshall
October 22, 2019

Unusual weather patterns in the upper atmosphere over Antarctica have caused a drastic reduction in ozone depletion, leaving the ozone with the smallest hole seen since its discovery in 1982, according to NASA and the National Oceanic and Atmospheric Administration. The chemical reactions are encouraged by polar stratospheric cloud formation, but in recent years, warmer stratospheric air has helped limit these reactions and curtailed the growth of the ozone hole. As a result the hole has been shrinking, and this year it's gotten to its smallest size yet recorded, at around 10 million square kilometers or 3.9 million square miles.

Similar climate patterns produced unusually small ozone holes during the autumns 1988 and 2002. "It's not a sign that atmospheric ozone is suddenly on a fast track to recovery", said Paul Newman, a scientist at NASA's Goddard Space Flight Center in a recent statement.

The ozone layer is important because it acts like a sunscreen, blocking potentially harmful ultraviolet energy from reaching our planet's surface.

The 1987 Montreal Protocol was enacted after scientists disturbingly found a hole in the ozone over Antarctica and Australia in 1985.

Every 365 days, an ozone hole kinds throughout the Southern Hemisphere's leisurely winter as the sun's rays start chemical reactions between the ozone molecules and man-made chemically active styles of chlorine and bromine.

Scientists first noticed the ozone layer was weakening in the 1970s; they quickly fingered a class of chemicals called chlorofluorocarbons, or CFCs, commonly used in refrigerants and aerosol cans, as responsible. This helped forestall the lack of a substantial quantity of ozone.

© Robert Schwarz/University of Minnesota A timelapse of weather balloons used to measure ozone.

The weather methods that minimized ozone depletion in September, identified as "sudden stratospheric warming" events, were strangely strong this 365 days. About 12 miles above Earth's floor, temperatures throughout September have been 29 levels larger than common, NASA reported, "which was the warmest in the 40-year historical record for September by a wide margin".

Instead, the Antarctic polar vortex was knocked off balance and slowed significantly, from an average wind speed of 161 miles per hour (260 km/h) to just 67 miles per hour (107 km/h). This additionally helped enhance ozone ranges there. But the polar vortex, the annual swell of cold air, has been "unusually wonky" this year, leading to an effect known as a stratospheric warming.

Curiously, native weather swap is rarely anticipated to trigger extra frequent sudden stratospheric warming events over the South Pole, and as a replace it could well probably probably possibly well give a boost to, not weaken, the polar vortex overall. Although we're making progress in cutting down on the use of ozone-depleting chemicals, the milestone doesn't mean we've solved the problem, the agencies cautioned. "If the warming hadn't happened, we would likely be looking at a much more typical ozone hole", said Strahan. Former U.N. Secretary-General Kofi Annan said it was "p$3 erhaps the single most successful global agreement to date" and it has been widely regarded as successful, with the ozone continuing to recover each year.

Since 2000, atmospheric ranges of CFCs salvage been slowly declining, but they're unexcited sufficiently phenomenal to trigger annual ozone holes at the North and South poles.

Other reports by Click Lancashire

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