On Sept. 3, a mapping spectrometer on a NASA satellite measured the ozone hole to cover 11 million square miles, or three times the size of the United States. That bested the old record of 10.5 million square miles set in September 1998.
NASA said the hole could still grow larger in late September or October, when ozone holes are typically at their largest.
The ozone layer, usually found between six and 18 miles above the earth's surface, absorbs harmful ultraviolet radiation from the sun. It's made up of molecules of oxygen.
NASA, which has been measuring ozone holes since the early 1970s, said the size of the whole was surprising, but that fluctuations are common.
"Variations in the size of the ozone hole and of ozone depletion accompanying it from one year to the next are not unexpected," said Dr. Jack Kaye, director of the Office of Earth Sciences, in a statement. "At this point we can only wait to see how the ozone hole will evolve in the coming few months and see how the year's hole compares in all respects to those of previous years."
The space administration attributed the record size to two factors: a strong air current over Antarctica that keeps the hole centered on the icy continent and "early-spring conditions."
"These observations reinforce concerns about the frailty of Earth's ozone layer," said Dr. Michael J. Kurylo, manager of NASA's Upper Atmosphere Research Program.
Global warming theory hypothesizes that the build-up of gases like carbon dioxide eats away at the ozone layer. As the layer thins, stronger sun rays reach the earth's surface and heat the earth, raising temperatures.
Higher global temperatures could lead to melting ice caps, higher sea levels, changing weather patterns and the depletion of habitats for animals and plants.
But global warming theory is not universally accepted. Some scientists feel that greenhouse gasses aren't to blame for increases in the earth's temperature, and some researchers dispute that a warmer earth is necessarily harmful.
Several recent reports have given credence to aspects of global warming theory, however.
In late August, visitors to the North Pole reported that the thick ice that covers the Arctic Ocean at the pole had melted, leaving a mile-wide stretch of water at the top of the world.
A few days later, using computer models projecting world temperatures over the next century, the World Wide Fund for Nature reported that by the year 2100, up to one-third of the world's species of plants and animals could be driven from their habitats by rising temperatres.
The group called for a global effort to reduce greenhouse emissions.
In a possible step toward CO2 reductions, another round of negotiations on implementing the Kyoto Protocola 1997 amendment to a standing United Nations environmental treatyis scheduled for September in Lyon, France.
The protocol would require industrial countries to reduce man-made heat-trapping gasesmainly carbon dioxideto below 1990 levels. For the United States, that would mean a 7 percent reduction below what they were a decade ago.
In the declaration, the member states resolved, "To make every effort to ensure the entry into force of the Kyoto Protocol, preferably by the tenth anniversary of the United Nations Conference on Environment and Development in 2002, and to embark on the required reduction in emissions of greenhouse gases."
The Clinton administration has angered some environmentalists by pushing for the United States to get credit under Kyoto for carbon emissions that are supposedly absorbed by the nation's forests, a process known as "carbon sink." The move could reduce the overall reductions the treaty requires the U.S. to make.
The U.S. has signed the protocol but the Senate has yet to ratify it.
By JARRETT MURPHY