The ozone layer, shielding Earth from damaging ultraviolet rays has thinned to a low unprecedented over the Arctic in spring by harmful chemicals and a cold winter, the United Nations weather agency said Tuesday.
The fragile ozone layer Earth in the Arctic region has suffered a loss of about 40 per cent since the beginning of the winter until late March, exceeding the previous seasonal loss of about 30%, said the World Meteorological Organization.
Agency based in Geneva blamé loss on an accumulation of chemical ozone-eating once widely used as a coolant and products flame in a variety of devices and the very cold temperatures in the stratosphere, the second major layer of Earth's atmospherejust above the troposphere.
Arctic ozone conditions vary more than ozone seasonal "hole" that forms high in the stratosphere, near the South Pole each winter and spring, and temperatures are always warmer than over the Antarctic.
These above the Sweden, polar stratospheric clouds play an important role in the destruction of the ozone layer. (Reuters)Because of the evolution of conditions weather and with temperatures some winters Arctic did experience almost no loss of ozone, while to other conditions stratospheric exceptionally cold are sometimes lead to the depletion of the ozone substantial, A scientific say.
Of the ground, but more more in the stratosphere that normal de in the Arctic. Officials of the United Nations said the latest losses - unprecedented, but entirely unexpected step - have been detected in observations of the soil and balloons and satellites over the Arctic.
Specialists of the atmosphere which are concerned about global warming focus on Arctic because it is a region where the effects are expected to be felt first.
Ozone scientists have said that the significant Arctic ozone depletion is possible in the case of a stratospheric Arctic winter cold and stable. Losses of ozone to produce on the regions polar, when the temperature descends below-78 ° C, when the cloud to form in the stratosphere.
Average temperatures in January range from-40 0 C, while average temperatures in the range of 10 c to-10 July.
"The Arctic stratosphere continues to be vulnerable to the destruction of ozone-depleting substances activities related to human, ozone layer," said the Secretary General of the WMO, Michel Jarraud. "The degree of loss of ozone experienced in winter especially depends on weather conditions."
Loss comes despite the Treaty of ozone of United Nations, known as the Montreal Protocol of 1987, which resulted in the reduction of chemical substances harmful to ozone, such as chlorofluorocarbons, halons, and others, which have been used in the manufacture refrigeratorsair conditioners, fire extinguishers and even hairspray.
Ozone 196-nation Treaty encourages industries to use less harmful to the ozone replacement chemicals, the atmospheric layer that contributes to the protection against the most harmful rays of the Sun.
But, because these compounds have atmospheric long lifetimes, it takes decades for their concentrations of collapse to levels from before 1980, as it has been agreed in the Montreal Protocol.
Project staff of the United Nations, outside the polar regions ozone layer will recover to levels from before 1980 between 2030 and 2040.
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