Warm air ‘keeping ozone hole small’

This image provided by NASA was compiled by the Ozone Monitoring Instrument on NASA's Aura satellite from Sept. 21-30, 2006 the average area of the ozone hole was the largest ever observed, at 10.6 million square miles government scientists said Thursday Oct. 19, 2006. This image, from Sept. 24, the Antarctic ozone hole was equal to the record single-day largest area of 11.4 million square miles, reached on Sept. 9, 2000. The so-called hole is a region where there is severe depletion of the layer of ozone _ a form of oxygen _ in the upper atmosphere that protects life on Earth by blocking the sun's ultraviolet rays. The blue and purple colors are where there is the least ozone, and the greens, yellows, and reds are where there is more ozone.

This image provided by NASA was compiled by the Ozone Monitoring Instrument on NASA's Aura satellite from Sept. 21-30, 2006 the average area of the ozone hole was the largest ever observed, at 10.6 million square miles government scientists said Thursday Oct. 19, 2006. This image, from Sept. 24, the Antarctic ozone hole was equal to the record single-day largest area of 11.4 million square miles, reached on Sept. 9, 2000. The so-called hole is a region where there is severe depletion of the layer of ozone _ a form of oxygen _ in the upper atmosphere that protects life on Earth by blocking the sun's ultraviolet rays. The blue and purple colors are where there is the least ozone, and the greens, yellows, and reds are where there is more ozone.

Published Oct 25, 2013

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Washington - Warm air at high altitudes this September and October helped shrink the man-made ozone hole near the South Pole ever so slightly, scientists say.

The hole is an area in the atmosphere with low ozone concentrations. It is normally is at its biggest this time of year. Nasa says on average it covered 8.1 million square miles this season. That's six percent smaller than the average since 1990.

The ozone hole is of concern because high-altitude ozone shields Earth from ultraviolet radiation.

Nasa chief atmospheric scientist Paul A. Newman says the main reason for this year's result is local weather. The upper air has been almost 2 degrees warmer than normal in the globe's southernmost region. That has led to fewer polar stratospheric clouds. These clouds are where chlorine and bromine, which come from man-made products, nibble away at ozone.

“It's just like watching the Pac-Man eating cookies, where cookies are ozone. The chlorine atoms are the Pac-Man,” Newman said.

James Butler, director of the global monitoring division at the National Oceanic and Atmospheric Administration's Earth System Research Lab, said that the new figures are “sort of encouraging news.”

“It's not getting worse,” Butler said. “That's a good sign.”

Butler said it stopped getting worse around the late 1990s. But he added, “We can't say yet that it's a recovery.”

Newman and Butler said they can't tell if the ozone hole changes are related to man-made global warming.

While warm upper air helped keep the ozone hole small, the surface of the Southern Hemisphere was also warm last month, with the second-highest average temperature on record for September, NOAA announced. Records go back to 1880.

For the entire globe, last month tied 2003 for the fourth hottest September on record, with an average temperature 1.15 degrees higher than the average for the 20th century. September was the 343rd consecutive month that global temperatures have been higher than 20th century average.

This year, after nine months, is on track to be the sixth warmest on record globally, 1.22 degrees hotter than normal.

For the United States, this was the sixth warmest September on record, 2.5 degrees higher than the 20th century average. It was the hottest since 2005. But the nation's average temperature over the first nine months of the year is only the 28th highest on record. - Sapa-AP

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