The hole in Earth’s ozone layer is healing

Ozone hole healing animation Katie Mossman/NASA Goddard Space Flight Center

Efforts to repair the hole in Earth’s ozone layer over Antarctica appear to be paying off, according to a New, NASA says this is the first study to directly look at ozone-destroying chemicals in the atmosphere.

Earth's ozone layer protects the Earth's surface from some of the sun's more harmful rays, which can cause cancer and cataracts in humans and damage plant life. In the mid-1980s, researchers discovered a huge hole in the ozone layer over Antarctica and determined that it was caused primarily by human-produced chemicals chlorofluorocarbons (CFCs).

Previous satellite observations have observed changes in the size of the ozone hole, noting that it can grow from year to year. But the new study is the first to directly measure changes in atmospheric chlorine levels over Antarctica, a major byproduct of ozone depletion, according to a NASA statement. Research shows that ozone depletion due to chlorine decreased by 20% between 2005 and 2016. [Earth's Atmosphere: Composition, Climate, and Weather]

The new study looked at ozone data collected between 2005 and 2016 by the Microwave Limb Sounder (MLS) on the Aura satellite. The instrument does not detect chlorine atoms directly, but instead detects hydrochloric acid, which is formed when chlorine atoms react with methane and then combine with hydrogen. During the Southern Hemisphere's summer, when Antarctica is bathed in sunlight, CFCs break down and produce chlorine, which then breaks down ozone atoms. But during the winter (early July to mid-September), chlorine can easily combine with methane "once all ozone is destroyed" in its vicinity, according to the statement.

"Around mid-October, all chlorine compounds are conveniently converted into a gas, so by measuring hydrochloric acid," we have a good idea of ??the total amount of chlorine measurements," study lead author Susan Strahan, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. Daily Observation of the Ozone Hole. A view of the Earth's atmosphere from space (NASA)

During this time, the temperature in Antarctica is always very low, so the rate of ozone destruction depends mainly on the amount of chlorine we want. When measuring ozone loss

Because previous studies relied on measurements of the physical size of the ozone hole, the authors of the new study say their study is the first to directly show that ozone depletion is decreasing due to chlorofluorocarbons. A direct result of the reduction in chlorine content in carbon dioxide, Strahan said, the 20% reduction in ozone depletion is very close to what our model predicts. "This gives us confidence," she said. showed that by mid-September, the decrease in ozone depletion was due to falling chlorine levels from CFCs. "But we have not yet seen a significant shrinkage of the ozone hole, because this is mainly controlled by the temperature after mid-September, which varies greatly from year to year.

The study was published in " Geophysical Research Letters.

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