Susan Solomon, Ph.D., of the University of Colorado, Boulder, presented a review of the past and present state of ozone depletion at the August 29, 2011, 242nd National Meeting and Exposition of the American Chemical Society (ACS).
Dr. Solomon is responsible for the expedition to the Antarctic that provided some of the clinching evidence that underpinned a global ban on CFCs and certain other ozone-depleting gases. She has worked with NOAA, NASA, and is the winner of several prizes for her scientific work. She claims her inspiration to be a scientist came from watching The Undersea World of Jacques Cousteau.
Dr. Solomon notes that while some ozone depleting substances have been abandoned the ozone is still disappearing. She attributes the loss to the longevity of the gases that originally caused the problem and verifies that last winter’s loss of 40% of the ozone over the Arctic still occur due to the extremely long lifetimes of ozone-destroying substances released years ago before the ban.
The ozone layer is necessary to filter a part of ultraviolet radiation from sunlight. It took 56 years for man to realize the damage that some chemicals had done to the ozone layer and to reduce or eliminate the use of those chemicals.
The effects of gases and aerosols on the ozone layer is tied to climate change according to Dr. Solomon.
The discovery of the Antarctic ozone hole shocked the scientific world when it was discovered in 1985, and research provided the underpinning for a landmark global agreement to mitigate the emissions of ozone-depleting chlorofluorocarbons and bromocarbons that were responsible. The ozone hole was linked to chemical processes occurring on surfaces of particulate matter in the cold Antarctic stratosphere, underscoring the effectiveness of surfaces in driving chemical phenomena in planetary atmospheres. However it is remarkable that key scientific questions remain today regarding exactly which types of cold liquid and solid icy surfaces contribute to the observed ozone losses, demonstrating the complexity of the chemistry, and the importance of continuing research. Both the understanding of ozone depletion and the enduring challenge of detailed surface chemistry will be reviewed in this talk. Chemical phenomena involving stratospheric surfaces are also important for some proposed schemes for deliberate engineering that may be able to cool the Earth’s climate. But the understanding of key aspects of the particle physics and chemistry relevant to these phenomena also poses major challenges, and there have been surprises in evaluating how much human addition of precursor gases would form surfaces that might engineer a controlled and quantifiable change in our climate. Finally, the suite of greenhouse gases and aerosols that are contributing to anthropogenic climate change will be reviewed, with a view towards comparing and contrasting the major chemical phenomena and challenges relevant to each.
The research was reviewed at the Eureka Alert web site on August 29, 2011.