ANDRIA HALL, CNN ANCHOR: Environmentalists have long been talking and warning about the ozone layer.</s>BILL HEMMER, CNN ANCHOR: That they have. Now, NASA says that the ozone hole is bigger than it's ever been. Also signs of the ozone may soon be on the mend. More, now, from Natalie Pawelski on this story.</s>NATALIE PAWELSKI, CNN CORRESPONDENT (voice-over): NASA announces the largest ozone hole ever measured: more than 11 million square miles, three times the size of the United States. Scientists blame ozone-destroying chemicals in the stratosphere and a high-level air current called the polar vortex.</s>PAUL NEWMAN, NASA: It circulates all the way around Antarctica. And this polar vortex is a little bit bigger this year. The polar vortex acts to contain the ozone hole, and so the fact that it's a little bit bigger creates a bigger ozone hole.</s>PAWELSKI: The hole, actually an area of severe thinning in Earth's protective ozone layer, opens up over the South Pole each Antarctic winter, allowing more of the Sun's harmful ultraviolet rays to reach Earth. That can translate into higher rates of skin cancer and cataracts. But, despite this year's record ozone hole, researchers say levels of ozone-destroying chemicals in the atmosphere are beginning to stabilize. Diplomacy gets the credit. Back in 1987, dozens of countries agreed to phase out chloroflourocarbons and other chemicals blamed for depleting the ozone layer.</s>NEWMAN: We've stopped the pollution that's causing the problem. Now nature will heal itself, but it's going to take a long time to happen.</s>PAWELSKI: If the chemical crackdown stays in place, researchers say, the ozone layer could repair itself by the end of the century. Natalie Pawelski, CNN.
NASA: Ozone Layer Hole Is Bigger than Ever