Air Date: Week of October 16, 1992

Steve reports on the latest data on the Antarctic ozone hole, which has opened every southern spring for the last decade and a half. This year's hole is 20 percent bigger than last year and is passing for the first time over large human settlements.

Transcript

ANNOUNCER: . . . the rest of New South Wales, but the good news is they should start to move out over the next 24 to 48 hours. Ultraviolet radiation reached 2 point 4 today, back to a moderate reading on the scale. Air pollution as tracked by the State Pollution Control . . . ( fade under )

CURWOOD: The ultraviolet radiation rating has become as much a part of the daily weather report in Sydney, Australia, this year as temperature, wind and rain. That's because Australians, and others deep in the Southern Hemisphere, are worried about increasing levels of cancer-causing UV radiation getting in through the ever-thinning ozone layer. Ozone-destroying chemicals produced around the world tend to concentrate over the cold regions, especially the South Pole. For more than a decade now, a large hole in the earth's protective ozone layer has opened up over the region each southern spring. Recently, NASA and other monitors reported that the Antarctic ozone hole this year has grown by 20 percent, to a record size. Jim Anderson is an atmospheric chemist at Harvard University, who has worked with NASA on ozone depletion. He says this means that for the first time, the ozone hole is passing over sizeable human populations.

ANDERSON: We now have a region that's 12 to 13 percent of the entire area of the Southern Hemisphere, and so as it moves over Australia, Argentina and Chile it leaves a very large gap overhead through which ultraviolet radiation can penetrate.

CURWOOD: This year's Southern Hemisphere ozone depletion also began earlier than the usual mid-September; it's proceeded more quickly and it's expected to last longer than the 4 to 6 weeks seen in the past. Exactly why the South Pole's ozone hole has grown so dramatically remains a mystery. Volcanic eruptions may be adding to the problems caused by CFC's. And the depletion of ozone may be feeding back on itself. What scientists do know is that each year the news seems to be worse than the year before. Again, Jim Anderson.

ANDERSON: We don't want to overreact to this problem. We don't want to scare people, we don't want to invert economic priorities, but at the same time we don't want to underestimate the severity, which we have done now for twenty years.