News24

Antarctic ozone hole shrinks

2012-10-25 09:36

Washington - The seasonal hole in the ozone layer above the Antarctic this year was the second smallest in two decades, but still covered an area roughly the size of North America, US experts said.

The average size of the Earth's protective shield was 17.9 million square kilometres, according to satellite measurements by the National Oceanic and Atmospheric Administration and US space agency Nasa.

"It happened to be a bit warmer this year high in the atmosphere above Antarctica, and that meant we didn't see quite as much ozone depletion as we saw last year, when it was colder," said Jim Butler of NOAA's Earth System Research Laboratory in the Colorado city of Boulder.

The Antarctic ozone hole, which forms in September and October, reached its largest size for the season - 21.2 million square kilometres, roughly the combined area of the United States, Mexico and Canada - on September 22, NOAA said.

In comparison, the largest ozone hole recorded to date was one of 29.7 million square kilometres in the year 2000.

The ozone layer - which helps protect the Earth from potentially dangerous ultraviolet rays that can cause skin cancer and cataracts - began developing holes on an annual basis starting in the 1980s due to chlorofluorocarbons, or CFCs.

CFCs, once commonly used in refrigerators and aerosol cans, now are almost non-existent thanks to an international treaty signed on 16 September 1987, amid global concern over widening holes in the ozone layer.

Still, it could take another decade before scientists detect early signs that the ozone over the Antarctic is returning, NOAA said.

The ozone layer above Antarctica likely will not return to its early 1980s state until about 2060, according to Nasa scientist Paul Newman.

Comments
  • phae.rayden - 2012-10-25 10:30

    And to all of you that refuse to accept our massive contribution towards causing global warming, this is what happens when we take responsibility and control our destructive behaviour. Ready to take responsibility yet???

      ernst.j.joubert - 2012-10-25 10:36

      Well said!

      petrus.ngwenya.3 - 2012-10-25 11:50

      You may be set in your ways, but I am adaptable, and a good portion of the rest of the human race is also. I am part of nature, and therefore any changes to my environment as a result of me is the same as any other animal changing it's environment. Are you expecting me to do my family in, or to make them suffer to recitfy a mistake made by someone else?

      petrus.ngwenya.3 - 2012-10-25 12:03

      Not yet. First of all, magically, it is shrinking. Secondly, I am pretty far from the south pole. Thirdly, the concept here is "Climate CHANGE". In other words, when one door closes, another opens. The end is nigh, the end is nigh... NOT! I can adapt, sorry to hear about you, fossils.

      stirrer.stirrer - 2012-10-25 12:20

      @phae.rayden - One explanation by scientists why the Antarctic is cooling while the Arctic is melting, is exactly the hole in the ozone layer. Ozone is also a greenhouse gas, so they are using the hole to explain what they otherwise cannot. So - is the hole bad, or good? Quite a dilemma here...

      brian.exmachina - 2012-10-25 12:46

      @petrus "First of all, magically, it is shrinking." It's not shrinking magically, it's shrinking due to the strict controls placed on CFC's since the 1980's. "Secondly, I am pretty far from the south pole" The hole is not static and changes shape. It influences much more than just the South pole. "Thirdly, the concept here is "Climate CHANGE". In other words, when one door closes, another opens. The end is nigh, the end is nigh... NOT!" Um, no, the concept here is the hole in the ozone layer that causes increased harmful radiation to reach the earth, causing cancer and eye problems. It is not directly related to climate change, but well done on displaying your ignorance nonetheless.

      petrus.ngwenya.3 - 2012-10-25 13:04

      @Brian If it was shrinking due to controls put in place in the 80's then why hasn't it declined consistently over the last years? Yes, it does affect more than just the South pole. But does it affect me? Are you seriously telling me, that the high frequency (easily absorbed) radiation at the south pole reaches South Africa?

      brian.exmachina - 2012-10-25 16:41

      @petrus "If it was shrinking due to controls put in place in the 80's then why hasn't it declined consistently over the last years?" Because there are many contributing factors that affect the thickness of ozone, including the amount of radiation the earth receives. UV radiation in the stratosphere interacts with CFC's to produce chlorine and bromine which depletes ozone. This isn't limited to the South pole, just most measurable and devastating there. I'm sure you can logically follow that some years more ozone will be depleted and some years less, leading to a bigger hole some years and smaller others; but that overall the hole will recover as time progresses. "Yes, it does affect more than just the South pole. But does it affect me?" Yes, you are at a greater risk of skin cancer and cataracts because of this. As already explained ozone depletion isn't limited to the South pole, just most evident there. Last year the ozone hole stretched onto parts of South America, for example. http://www.earthweek.com/2011/ew111014/ew111014c.html "Are you seriously telling me, that the high frequency (easily absorbed) radiation at the south pole reaches South Africa?" Easily absorbed by what? Oh, that's right, it's easily absorbed by the earth's protective layer of ozone... oh wait... snap.

      andreviljoenjoubert - 2012-10-26 09:25

      Man! the only animal who pays to live on planet earth! Makes you think.

  • JNaMolefe - 2012-10-25 14:00

    Facebooker, read this!! Quite important for you to realise .... we need to save our earth from global warming!!!!

  • pages:
  • 1