Just when we thought it was getting smaller, the hole in the ozone layer has reached record proportions.
Between 21 and 30 September, the average area of the hole reached 27.5 million square kilometres, according to scientists monitoring ozone levels over the South Pole using NASA鈥檚 Aura satellite and balloon-borne instruments. This marks an increase of roughly 3.9 million square kilometres from last year.
The blip is due to colder-than-average stratospheric temperatures in the preceding months, explains atmospheric scientist Paul Newman at NASA鈥檚 Goddard Space Flight Center in Greenbelt, Maryland. Although human production of substances that damage the ozone layer has dropped, the gases are still at peak levels in the stratosphere, and lower temperatures enhance the reactions that produce ozone-depleting chlorine and bromine. We won鈥檛 see the effects of the drop until about 2024 because the gases have such a long lifetime, says Newman.
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鈥淭he good news is that human activity isn鈥檛 making the hole any worse,鈥� says Newman. 鈥淏ut we are vulnerable to changes in the weather and that鈥檚 bad news for people living in the southern hemisphere.鈥�
