Last Updated:
February 28, 2007

GCRIO Program Overview

Library 
Our extensive collection of documents.

Privacy Policy

Archives of the
Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999

FROM VOLUME 5, NUMBER 6, JUNE 1992

NEWS...
NORTHERN HEMISPHERE OZONE

Item #d92jun100

Major results are in from the U.S. and European studies on stratospheric ozone conducted over the past winter using aircraft, satellite, ground-based and balloon measurements.

Researchers from the U.S. National Aeronautics and Space Administration reported in late April that Arctic ozone loss reached about 10 percent this winter. In February 1992, they had warned that the presence of cold temperatures in the weeks ahead, together with increasing levels of sunlight, could lead to even more serious depletion. This conclusion was based on the discovery over the Arctic of unexpectedly high levels of chlorine monoxide (ClO), resulting from anthropogenic emissions. (See GLOBAL CLIMATE CHANGE DIGEST News, Mar. 1992.) In the presence of sunlight and particles that form at low temperatures, ClO is considered a key ingredient in ozone destruction. Because of an early warming in the Arctic stratosphere this winter, temperatures cold enough for ozone destruction were present only about half as long (39 days) as usual. However, the potential for more serious losses in future years still exists, as predicted earlier.

For the Northern Hemisphere, satellite measurements of the total amount of ozone hit a record low in January and February, and were 10-15 percent below normal in February. Particles from the eruption of Mount Pinatubo are thought to have had a measurable but not major effect on ozone loss. Results of the U.S. study are discussed in Sci. News, p. 308, May 9, 1992; Science, p. 734, May 8; Eos, p. 210, May 12; Intl. Environ. Rptr., p. 245, May 6.

Results of the European Arctic Stratospheric Experiment, involving scientists from 17 countries, show that ozone over much of Europe (including some cities) thinned by a record 10-20 percent last winter. Contributing to the loss was the presence of an extremely large high-pressure system over Europe and the North Atlantic during December and January, but anthropogenic chemicals are considered a major ingredient as well. Researchers expect to untangle these factors and the influence of Mount Pinatubo particles over the next few months. (See Nature, p. 552, Apr. 16, 1992; New Scientist, p. 5, Apr. 11.)