Global Warming

Ozone Hole Over Antarctica Caused Southern Africa Warming

The infamous hole in the ozone layer above Antarctica may have caused warming in southern Africa over the past two decades, researchers say.

However, as the hole in the ozone layer continues to shrink due to international policies that limit the chemicals that eat away at the ozone, temperatures may cool down in southern Africa, the study researchers also said.

Ozone is a cousin to the oxygen molecules people breathe, consisting of three atoms of oxygen instead of the regular oxygen molecule's two. This gas is concentrated in a layer about 12 to 19 miles (20 to 30 kilometres) above Earth's surface. This ozone layer absorbs most of the ultraviolet light from the sun, helping to defend people against sunburns and skin cancer.

Now, researchers have found that the ozone hole may be linked to warming in southern Africa.

Previously, scientists found that surface air temperatures in southern Africa had risen significantly over the past two decades, mostly in the early summer. Investigators had suggested this heating was due to the global warming caused by human-linked greenhouse-gas emissions changing climate around the planet. However, climate models hinted that global-warming effects from greenhouse gases should not differ between seasons in southern Africa, but instead be uniform throughout the year.

Scientists recently found that the ozone hole might help boost global warming slightly. By letting more energy penetrate deeper into the atmosphere, the ozone hole apparently shifted wind patterns over Antarctica. This shift pushed clouds closer to the South Pole, affecting how much of the sun's radiation the clouds reflect and, in turn, slightly warming the planet.

Effects on southern Africa

To see if the ozone hole might also explain the warming in southern Africa, scientists compared climate data on southern Africa from before the development of the ozone hole with the climate data from after the ozone hole had developed. They found that the ozone hole would have altered Southern Hemisphere wind patterns. These changes, in turn, would have intensified the Angola Low, a low-pressure system in the atmosphere mostly located over Angola, situated on the west coast of southern Africa. This, in turn, would have led warm air from near the equator to flow into southern Africa.