Ozone depletion contributes to climate change
The ozone hole leaves a lasting impression on southern climate, The Conversation, Sharon Robinson Professor at University of Wollongong, 8 November 2014, Many people think of sunburn and skin cancer when they hear about the ozone hole. But more ultraviolet (UV) radiation isn’t the only problem.
The ozone hole has also led to dramatic changes in Southern Hemisphere weather patterns. These in turn are altering natural ecosystems and food production. These climate changes are likely having a similar if not greater impact than more UV radiation.
We discuss some of these changes in a paper published today in Global Change Biology.
This week the parties to the Montreal Protocol will meet in Paris, to consider the latest report from the United Nations Environment Programme Environmental Effects Assessment Panel. This report summarises the impact of both ozone loss and the associated increase in ultraviolet radiation on the environment and human health.
The Montreal Protocol continues to be effective at phasing out ozone depleting chemicals and has decreased levels of these greenhouse gases in the atmosphere. But while the Montreal Protocol is a success story, the Southern Hemisphere still faces the threat of climate change from rising greenhouse gases. There is still much to do.
Changing the weather
In recent years, climate scientists have shown that the ozone hole has had a profound impact on weather systems throughout the Southern Hemisphere, especially during summer.
The ozone hole has pulled the polar jet stream further south, increasing its strength. These winds isolate Antarctica and help to keep most of it cold as the rest of the world warms. This has prevented sea ice melt and rising sea-levels. By changing atmospheric circulation, the ozone hole modifies wind, rain and snowfall patterns across the Southern Hemisphere. The changing pattern and strength of winds has caused shifts in the regions that get plenty of rain or snowfall, and those that stay dry. …….
A world avoided
The Montreal Protocol (1987) is a major success story. As a result of this international agreement, the ozone hole is likely to recover by the middle of this century.
Ultraviolet (UV-B) radiation damage to all living organisms, including humans, has been minimised since the region where major ozone depletion occurred is over the sparsely-populated Antarctic. Even there the impacts on terrestrial life are thought to be small, probably less than a 6% loss in productivity in plants.
By controlling the release of ozone depleting chemicals the Montreal Protocol has made a large contribution to reducing greenhouse gases.
The world is cooler now than it would have been without the Montreal Protocol’s controls on emissions of ozone depleting chemicals. This is because many of the chemicals that break down ozone are also potent greenhouse gases (such as chlorofluorocarbons — CFCs).
Climate change in the Southern Hemisphere can be attributed to ozone depletion, as well as increasing greenhouse gases. Decades after the ozone hole was identified and action was taken, we are still discovering how profound its implications are both in terms of the “world avoided”, and unanticipated climate change.
Prompt action was taken in 1987 but the lag time for recovery is still long (see also here)………
Sharon Robinson and Dr. David Erickson, Oak Ridge National Laboratory, USA present this work in the scientific journal Global Change Biology. They are both members of the UNEP-EEAP. ttp://theconversation.com/the-ozone-hole-leaves-a-lasting-impression-on-southern-climate-34043
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