Shrinking Ozone Hole, Climate Change Are Causing Atmospheric "Tug of War"

Shrinking Ozone Hole, Climate Change Are Causing Atmospheric "Tug of War"Shrinking Ozone Hole, Climate Change Are Causing Atmospheric "Tug of War"

The notorious Antarctic “ozone hole” sparked worldwide concern after its discovery in the 1980s, and for good reason — declining ozone allows harmful ultraviolet radiation to reach the Earth’s surface, a major threat to public health. But the ozone hole had another effect on the planet: It caused major atmospheric changes in the Southern Hemisphere. With less ozone trapping solar radiation higher in the atmosphere, the stratosphere began to cool. The jet stream shifted toward the South Pole. The warm, wet tropics expanded, and the dry zone below the tropics shifted southward, as well. Weather patterns in certain parts of the Southern Hemisphere began to change. Thanks to the Montreal Protocol, an international agreement to phase out ozone-depleting chlorofluorocarbons, the ozone hole is now in recovery. The treaty has been regarded as one of the most successful cooperative environmental efforts in history. As it turns out, it’s had a noticeable effect on the Southern Hemisphere’s atmosphere. Since about the year 2000, there’s been a pause in the shifting of the jet stream and the other changes caused by the declining ozone. These are the findings in a study published yesterday in Nature. Led by Antara Banerjee of NOAA’s Earth System Research Laboratory, the researchers analyzed historical data from the Southern Hemisphere and revealed that past trends in the shifting atmosphere had been on hold for two decades. Then they used climate models to test whether the pause is the result of the recovering ozone layer or some other factor, like greenhouse ...
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