A full recovery of the stratospheric ozone hole could modify climate change in the Southern Hemisphere and even amplify Antarctic warming, according to scientists from the University of Colorado at Boulder, the National Oceanic and Atmospheric Administration and NASA.
While Earth’s average surface temperatures have been increasing, the interior of Antarctica has exhibited a unique cooling trend during the austral summer and fall caused by ozone depletion, said Judith Perlwitz of the Cooperative Institute for Research in Environmental Sciences, a joint institute of CU-Boulder and NOAA. “If the successful control of ozone-depleting substances allows for a full recovery of the ozone hole over Antarctica, we may finally see the interior of Antarctica begin to warm with the rest of the world,” Perlwitz said.
Perlwitz is lead author of a new study on the subject to be published April 26 in Geophysical Research Letters. Co-authors include Steven Pawson and Eric Nielson of NASA’s Goddard Space Flight Center in Greenbelt, Md., and Ryan Fogt and William Neff of NOAA’s Earth System Research Laboratory in Boulder. The study was supported by NASA’s Modeling and Analysis Program.
The authors used a NASA supercomputer model that included interactions between the climate and stratospheric ozone chemistry to examine how changes in the ozone hole influence climate and weather near Earth’s surface, said Perlwitz.
The study authors calculated that when stratospheric ozone levels return to near pre-1969 levels by the end of the 21st century, large-scale atmospheric circulation patterns now shielding the Antarctic interior from warmer air masses to the north will begin to break down during the austral summer. The circulation patterns are collectively known as a positive phase of the Southern Annular Mode, or SAM.
The scientists found that as ozone levels recover, the lower stratosphere over the polar region will absorb more harmful ultraviolet radiation from the sun. This could cause air temperatures roughly 6 to 12 miles above Earth’s surface to rise by as much as 16 degrees Fahrenheit, reducing the strong north-south temperature gradient that currently favors the positive phase of SAM, said the research team.
The supercomputer modeling effort also indicated that ozone hole recovery would weaken the intense westerly winds that currently whip around Antarctica and block air masses from crossing into the continent’s interior. As a result, Antarctica would no longer be isolated from the warming patterns affecting the rest of the world.
NASA’s Pawson said ozone recovery over Antarctica would essentially reverse summertime climate and atmospheric circulation changes that have been caused by the presence of the ozone hole. “It appears that ozone-induced climate change occurred quickly, over 20 to 30 years, in response to the rapid onset of the ozone hole,” he said. “These seasonal changes will decay more slowly than they built up, since it takes longer to cleanse the stratosphere of ozone-depleting gases than it took for them to build up.”
The seasonal shift in large-scale circulation patterns could have repercussions for Australia and South America as well. Other studies have shown that the positive phase of SAM is associated with cooler temperatures over much of Australia and increased rainfall over Australia’s southeast coastline.
During late spring and early summer, the positive phase of SAM also is associated with drier conditions in South America’s productive agricultural areas like Argentina, Brazil, Uruguay and Paraguay, said Perlwitz. If ozone recovery induces a shift away from a positive SAM, Australia could experience warmer and drier conditions while South America could get wetter, she said.
But just how influential a full stratospheric ozone recovery will be on Southern Hemisphere climate largely depends on the future rate of greenhouse gas emissions, according to the GRL authors. Projected increases in human-emitted greenhouse gases like carbon dioxide will be the main driver for strengthening the positive phase of SAM.
“In running our model simulations, we assumed that greenhouse gases like carbon dioxide would double over the next 40 years and then slowly level off,” said Perlwitz. “If human activities cause more rapid increases in greenhouse gases, or if we continue to produce these gases for a longer period of time, then the positive SAM may dominate year-round and dwarf any climatic effects caused by ozone recovery.”
could anyone explain this is a simpler way? i am having trouble understanding
thankyou
How about the experts telling everyone that if we don’t stop the use of florocarbons, we will destroy our life as we know it becuause of ozone deterioration. Now it looks like in a few years we will be told to “go green, use freon in our cars and refrigerators and the old stuff in our hairspray. You know your shouldn’t try to mess with “Mother nature!”
johnk
The statistical correlation between annual atmospheric CO2 (Mauna Loa) and the annual value of global population (Census Bureau) since at least 1959 is a stunning, almost perfect 99.85%. This means that the sum total of all human activities (not people, per se, of course) is the proximate cause of the ever increasing CO2 (not to mention methane and CFCs). If these are greenhouse gases, and there seems to be little serious debate on that, then our “global footprints” are increasing, even as we try to mitigate them. Even if CO2 is not THE cause of the warming, it must certainly add to whatever the cause may be. Too many people on the planet, and growing…
Must read the actual paper, but I think these people may have confused the so-called ozone hole with the polar vortex. The latter is a seasonal wind-driven climatic feature that, when completely formed, isolates the ozone within it from the rest of the atmosphere. The polar vortex, and its areal extent, have nothing to do with stratospheric chlorine monoxide from CFCs and the temporary loss of ozone it is supposed to have caused. Repairing the ozone hole by eliminating CFCs should not have an effect on the polar vortex. If the polar vortex were to be eliminated the ozone hole would disappear, not the reverse. Chicken and the egg?
Why not say “Yes†to Solar, Wind, and Hydro Power and “No†to fossil fuels! But when? And who will lead us?
This perspective is deeply appreciated; but it is evidently not shared by most of the leaders in my not-so-great generation of elders. Our behavior speaks louder than any words. Our behavior indicates with remarkable clarity that Earth and its environs are not nearly as important as the growth of, and profits derived from, the artificially designed, manmade construction called the global economy.
Your perspective appears to suggest that “It’s the ECOLOGY, STUPID!â€; whereas the great majority of our leaders would say that “It’s the ECONOMY, STUPID!†Too many leaders think only of economic growth and profits. Earth’s ecology is an afterthought.
Perhaps time is short to make the necessary changes; and, indeed, time is not on our side.
The singer, Madonna, reports to all of us in her latest song that we have just “four minutes to save the world.â€
We need to go far fast in a new direction. But, where do we find the leaders to take us in the direction we need to go? Most of our leaders appear to be engaged in idolatry of the global political economy, come what may for our children, biodiversity, a limited resource base, frangible ecosystem services and the Earth as a fit place for human habitation by coming generations.
Sincerely,
Steve
Steven Earl Salmony
AWAREness Campaign on The Human Population,
established 2001
http://sustainabilitysoutheast.org/
Here’s my question about this study. What they’re saying is that the hole int he ozone is letting in deadly radiation but it’s keeping the upper atmosphere cool, and if we close the hole then we keep out the deadly radiation then the souther hemisphere might start to warm up, right?
Ouch. Which should we prefer?