Ozone layer over Earth thinner than ever, UN warns

Ozone layer over Earth thinner than ever, UN warns
Ozone layer over Earth thinner than ever, UN warns

The thickness of the ozone layer over the Arctic has decreased to record levels due to atmospheric chemicals and frost in the stratosphere. About this, reports "Interfax", said in the report of the UN World Meteorological Organization.

It is reported that the amount of ozone in the Arctic has decreased by 40% since the beginning of winter. Previously, the largest recorded damage to the ozone layer was about 30% for the entire winter.

According to scientists, the main reason for the depletion of the ozone layer in 2011 was the effects of ozone-depleting chemicals and the unusually cold winter in the stratosphere. At the same time, in the troposphere, that is, in the lower layer of the atmosphere, extremely low temperatures were not observed, but the disappearance of ozone was influenced by a significant decrease in air temperature in the stratosphere.

Depletion of stratospheric ozone occurs over the polar regions when temperatures drop below -78 ° C, the scientists said. At such low temperatures, clouds form in the stratosphere. Cloud particles undergo chemical reactions that convert neutral field gases (eg, hydrogen chloride) into active ozone-depleting gases. The result is the rapid destruction of ozone by exposure to sunlight.

By the way, the ozone hole hanging over Antarctica is a phenomenon that repeats itself every year precisely because of the low temperatures of the stratospheric air. In the Arctic, however, meteorological conditions fluctuate to a much greater extent from one year to the next, and the temperature of the stratospheric air is always higher than over Antarctica. As a result, almost no ozone loss occurs in the Arctic in some winter periods, while the low stratospheric temperatures that persist in the Arctic after the end of the polar night can lead to a significant loss of ozone, experts explain.

It will take several decades for the concentration of ozone-depleting chemicals to fall to the level of the 1980s. Thanks to the Montreal Protocol, the recovery of the ozone layer outside the polar regions to pre-1980 levels is projected to occur around 2030-2040. But recovery of the ozone layer in the spring season over Antarctica is expected around 2045-2060, and in the Arctic, the ozone layer will recover probably one to two decades earlier.

The stratosphere is the second main layer of the atmosphere, located above the troposphere and below the mesosphere. The stratosphere begins at an altitude of about 10 km and extends to an altitude of about 50 km. About 90% of the ozone in the atmosphere is in the stratosphere and the remaining 10% in the troposphere. Ozone in the stratosphere is called the ozone layer, which absorbs ultraviolet radiation and protects life on Earth from the sun's harmful ultraviolet radiation. Ozone in the troposphere, especially near the Earth's surface, is undesirable because it is a corrosive gas that damages vegetation and can disrupt lung function and cause respiratory inflammation in humans and animals.

Observations carried out from satellites and meteorological balloons show that ozone losses occur in the atmosphere at altitudes of 15-23 km above the earth's surface with a minimum ozone concentration at an altitude of about 19-20 km. This coincides with a temperature range below -78 ° C. More than 2/3 of ozone has been destroyed in this region of the atmosphere so far.

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