Transcript of interview with Paul Newman, February 20, 2009, GSFC
Ozone depletion is caused by chlorofluorocarbons and bromine compounds that actually deplete stratospheric ozone -- the good ozone that protects us from solar ultraviolet radiation. So it's a direct human health issue. Less ozone means more UV at the surface, more UV means more cases of skin cancer, cataracts, etc.
So we decided that scientists made projections of very large losses. Policy makers acted on those predictions. We can go back and rewind and ask ourselves, now, 'Well, did scientists actually make good predictions, back in the 1970s? Were they about on the mark, were they too low, were they too high, what were those predictions?' And we can use that to compare now, where we would have been, if we'd done nothing.
The predictions at present are that by 2065 the ozone layer in the mid-latitudes of the United States, will be back to about what it was in 1980. So there was a few percent depletion by 2065 -- it will be back to a more normal level. If we'd never regulated CFCs, you wouldn't have been able to go outside for much time at all.
If you let chlorofluorocarbons increase by 3 percent each year starting in 1974, by the year 2065, virtually two-thirds of the ozone layer has been destroyed. Over Antarctica you have almost a permanent low ozone conditions. UV levels at the surface are extremely high, over Antarctica, in mid-summer. In the United States, ozone levels again would have gone down by about two-thirds. As a measure, the UV index, which in the U.S., is typically, in middle U.S. is something like a UV index of 9 or 10, it would have tripled by the year 2065, it would have been somewhere around 30 in most of the United States.
UV radiation is used to sterilize things. By 2065, you're probably starting to approach those levels of UV radiation.
We know that more UV means more skin cancer, means more cataracts, eye problems, it means the suppression of immune systems, it has impacts on crops. But typically people increase, you know when they do laboratory tests, they only increase UV by about 50%. We're talking about UV changes of 300% or more depending on what particular wavelengths we're looking at. So it's hard for us to say exactly what it means for life at the surface. But it would have been, we're pretty sure, it's a very severe impact.
So the impact by 2065 would have been extremely severe. So the answer is that the regulation was in fact a very smart thing to do, as opposed to have done nothing.