John Bluck

NASA Ames Research Center, Moffett Field, CA (Phone: 650/604-5026 or 604-9000)


Lynn Chandler

NASA Goddard Space Flight Center, Greenbelt, MD (Phone: 301-614-5562)


There was a 60 percent loss of ozone at 60,000 ft. in the Arctic sky near the North Pole last winter, one of the coldest on record, according to NASA and a team of international scientists who completed the biggest field study of its kind to date in the region. The ozone loss is one of the worst measured at that altitude in the Arctic, researchers said.

This finding raises the question of whether or not climate change may delay recovery of the Earth’s life-shielding ozone layer, investigators said.

“Last winter’s results have heightened concerns that ozone levels over the north polar region may continue to decline despite the benefits of international agreements to stop production and release of ozone-destroying chemicals,” said Dr. Hanjürg Jost of NASA’s Ames Research Center, located in California’s Silicon Valley.

More than 350 researchers from the United States, Europe, Canada, Russia and Japan took part in the combined NASA/European Union-sponsored field campaign, according to project manager Mike Craig of NASA Ames. Researchers measured ozone, other atmospheric gases, particle amounts and air motions in the Arctic stratosphere, the atmospheric layer between roughly eight and 50 km altitude. From November 1999 to March 2000, investigators used spacecraft; aircraft; large, small and long-duration balloons; and ground-based instruments to gather data. The aircraft and large balloon launch teams were based in Kiruna, Sweden.

More than a decade ago scientists determined that ozone depletion is caused mostly by man-made chlorine and bromine compounds. Manufacturers made the chlorine compounds, chlorofluorocarbons or CFCs, for use as refrigerants, aerosol sprays, solvents and foam-blowing agents. Fire fighters used bromine-containing halons to put out fires. Manufacture of chlorofluorocarbons ceased in 1996 in developed countries under the terms of the Montreal Protocol and its amendments.

Cooling of the stratosphere will likely increase ozone loss during Arctic winters in the coming decades, even as chlorine and bromine levels decrease as a result of the Montreal Protocol, according to scientists. The buildup of greenhouse gases, such as carbon dioxide, tends to trap more heat near the Earth’s surface, while at the same time colder than normal temperatures are experienced in the stratosphere, where the ozone breakdown occurs, scientists explained.

Researchers used a National Oceanic and Atmospheric Administration ozone instrument aboard NASA’s high altitude ER-2 aircraft to measure ozone losses in the lower stratosphere. Data from the ER-2 show ozone in the Arctic decreasing by about 60 percent between January and mid-March, according to ER-2 co-project scientist Paul A. Newman of NASA’s Goddard Space Flight Center, Greenbelt, MD.

These measurements are comparable to the large ozone losses in the lower stratosphere observed during several winters in the mid-1990s. Total ozone losses throughout the depth of the atmosphere were slightly reduced because ozone losses were smaller above 66,000 feet (20 km). Spacecraft observations by NASA’s Total Ozone Mapping Spectrometer-Earth Probe clearly showed an area of low ozone over the polar region during February and March. The average total polar ozone for the first two weeks of March was 16 percent lower than scientists observed during the same time period in the early 1980s.

The campaign included the NASA-sponsored Stratospheric Aerosols and Gas Experiment (SAGE III) Ozone Loss and Validation Experiment (SOLVE), and European Union-sponsored Third European Stratospheric Experiment on Ozone (THESEO-2000).

More information (including a list of participating institutions) can be found at:


(THESEO 2000) —