July 29, 2003

Excellent News for Ozone Man

No, the ozone layer is not becoming thicker. But at least it is now becoming thinner at a slower rate.

Ozone Layer Is Improving, According to Monitors: Scientists monitoring the highest levels of the atmosphere say they have detected a slowing in the rate of destruction of Earth's protective veil of ozone, the first sign that the phasing out of chemicals that harm the ozone layer is having a restorative effect. The ozone layer blocks ultraviolet radiation from the sun that can cause skin cancer and harm ecosystems. It has deteriorated for decades, especially in Antarctica, under an assault from synthetic chemicals.

The phasing out of the most important class of these chemicals %u2014 chlorofluorcarbons, or CFC's %u2014 began in 1989 with enactment of the Montreal Protocol, an international treaty. But the destructive substances take decades to decay, resulting in the long lag before any beneficial effects could be measured.

The findings, from satellite measurements, are to be published in an edition of the American Geophysical Union's Journal of Geophysical Research. They were released publicly yesterday by that private scientific group and the authors.

The study's lead author, Dr. Michael J. Newchurch, an atmospheric chemist at the University of Alabama at Huntsville, cautioned that the effects had been found only in the uppermost stratosphere, where less than 20 percent of the ozone layer is situated.

Dr. Newchurch also emphasized that what had been detected was just a notable slowing of the rate of ozone loss, not a reversal. It will be at least four or five decades before the ozone layer rebuilds to the levels seen before the damage started, he said.

Still, Dr. Newchurch and several independent experts said the findings were a significant turning point in the fight to heal damage to the atmosphere caused by humans...

Posted by DeLong at July 29, 2003 10:05 PM | TrackBack


Now for the unpopular parallel:

The Montreal Protocol promised to fix an international ecological problem and it carried fairly low economic costs on individual national terms. The Kyoto treaty on the other hand merely promised to slow down an international ecological problem by very small precentages. Its costs were going to be much larger for some nations.

There are potential lessons. For starters cost benefit matters. Hopefully technology can improve the cost benefit structure of greenhouse gas remediation enough to make it easier to reach agreement. The Montreal Protocol gives some reason for hope. Of course everybody here already understands all of this...

Posted by: Stan on July 30, 2003 06:54 AM
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