Analysis of several different satellite records and surface monitoring instruments indicates that the ozone layer is no longer declining, according to a study by scientists working with the Center for Integrating Statistical and Environmental Science (CISES) at the University of Chicago.
In some parts of the world, the ozone layer has increased a small amount in the past few years, although it still well below normal levels.
The results will be published Aug. 31 in the Journal of Geophysical Research and follow 18 years after an international agreement, the Montreal Protocol, was established to limit the production of chemicals determined to be harmful to the atmosphere.
The work, funded by the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration and the Environmental Protection Agency, is a collaboration between atmospheric scientists and statisticians through CISES. "The work of this team of scientists and statisticians is widely recognized as some of the most authoritative in the statistical analysis of stratospheric ozone," said Michael Stein, director of CISES at the University of Chicago.
"These early signs indicate one of the strongest success stories of international cooperation in the face of an environmental threat," said retired Navy Vice Adm. Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator.
For the past few years, studies have focused on ozone declining in the topmost layer of the atmosphere where there is naturally very little ozone. However, this study addresses the total ozone column layer that has significant impact on how much ultraviolet radiation is coming through the atmosphere, said Betsy Weatherhead of the University of Colorado.
"Our work focuses on the thickness of the ozone layer and is therefore relevant to the amount of harmful ultraviolet (UV) radiation reaching the surface of the Earth," said Weatherhead, a co-author on the paper.
The Montreal Convention worked. We will never know if the Kyoto Convention could work just as well because Australia and the US refused to ratify Kyoto.