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OzoneHole

Page history last edited by ar.fisk@... 11 years, 7 months ago

p136

Exosphere: On the downside, Teresa remembered one awful autumn where she and Jason came home almost daily to find pathetic creatures dying on the lawn. Or worse, hopping about in panic because they could no longer see.

 

Blind robins. Some threshold had been reached and within weeks they were all dead.


Status: Unlikely

Like climate change from rising levels of carbon dioxide, the effects of depleted ozone on Earth's fauna and flora form a backdrop and driving force to intiatives such as the eco-arks.

 

Reality

Being stable and non-toxic, chloro-fluorocarbons (CFCs) were, for a long time, popular for use as refrigerants and fire-retardants. However, concerns about the effect CFCs might have on the ozone layer were being expressed as early as the mid-seventies. In 1985, a region of depleted ozone dubbed 'the Ozone Hole' was detected over the south pole. A similar, smaller hole was also detected over the North pole.

 

In 1987, the Montreal accord banning the use of fluorocarbons came into effect and was universally observed. Nevertheless, due to the persistent nature of CFCs, levels have only started dropping in recent times

 

As noted by the IPCC in 2005, the situation is currently stable. The hole has now been present for at least twenty five years. No reduction in the ozone hole has been noted as yet, and none is expected until 2015 at least. However, it isn't getting any bigger and, at the current time, no particularly adverse effects on wildlife have been recorded.

 

The greenhouse effect and ozone depletion have a number of weak interactions. The blanketing effect of greenhouse gases means that the stratosphere doesn't receive as much heat from underneath, so it cools. This tends to foster ozone depleting mechanisms. On the other hand, decreased ozone has a overall cooling effect on the troposphere.

 

References

 

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