Dr. Steve Hipskind, Chief, NASA’s Earth Science Division
- Friday, 28 March 2008
NTB: The Earth Science Division has done extensive research into the problem of ozone depletion over the South Pole. What’s causing this depletion, and how does it factor into the overall climate change equation?
Dr. Hipskind: That’s kind of a classic example of the value of NASA’s science capability to really understand these major global problems. We did some of the pioneering work with partners from around the country and, in fact, around the world, back in the late 1980s. NASA had developed these airborne platforms, which were really the only systems capable of making direct measurements into the ozone hole in the southern hemisphere. Those field campaigns that were done, both in the Antarctic in 1987 and then in the Arctic over a series of campaigns in the late 1980s to early 1990s, demonstrated very conclusively that the ozone loss in the polar stratosphere was linked to manmade chlorine. That’s a huge success story in that scientific evidence was used to make international environmental policy – the Montreal Protocol – and the evidence is very clear that the Montreal Protocol is doing its job. The amount of chlorine getting into the stratosphere has definitely been declining.
NTB: Will the ozone layer come back? Will the hole fill itself if we continue along this path?
Dr. Hipskind: Yes. That’s very much the expectation. The Montreal Protocol is doing what was intended. These compounds have decades-long lifetimes, so the expectation is that once we shut the major production of the CFCs off in the late 1990s, it would be several decades before it completely recovered and returned to “normal,” i.e. pre-1980s levels. And the evidence is that that is, indeed, occurring.
There is not a particularly direct relationship between the stratospheric ozone loss and climate change, although it does seem that with global warming there’s a tendency that while the lower atmosphere warms, the upper atmosphere – the stratosphere – tends to cool. And it’s those cold temperatures that are part of the ozone loss equation. So with global warming the tendency is for the ozone recovery to be slowed down.
NTB: It seems like the world has been experiencing a rash of weird natural phenomena over the last few years – earthquakes, volcanoes, tornadoes, tsunamis, hurricanes. It even snowed in Baghdad this year, which no one had ever seen before. Is global warming causing all of this, or are there other explanations? Is it a much more complicated equation, or is it purely global warming?
Dr. Hipskind: Well, that’s certainly the focus of a lot of attention and research right now. I mean, there’s a large current controversy over whether global warming is the root of the increased hurricane activity. That’s certainly an area where NASA has a lot of capability to help understand the question. One of the things that we are hopefully getting geared up to do in the next couple of years is to begin to use these large, unpiloted aircraft to really get some better detailed information on the genesis and the amplification of these hurricanes. But that is a major area of controversy right now, so the jury is still out on how much of these strange phenomena are attributable to global warming. Clearly, it occurs to me that there’s an increase of these odd events, as you said.
NTB: It just seems strange. Maybe it’s nature, or maybe it’s caused by us.
Dr. Hipskind: Yes. We certainly don’t have too many tornadoes at this time of year [January] like we just had in the last couple of weeks.
NTB: Particularly when you get one that goes through New York City. I don’t think anyone has ever seen that happen before. Do you think we’ll ever have the technology to, if not control weather patterns, at least alter them, or lessen their severity?
Dr. Hipskind: That’s certainly another controversial issue. There was a lot of research in this country and other countries in the 1960s and 1970s into trying to do weather modification. The research was abandoned in the early 1970s because it was felt that there really was no…that the efforts to do weather modification were completely inconclusive. It didn’t seem like it was possible to actually influence the weather.
I think the best thing that we can hope for is to continue on the road that we’re on, to deploy monitoring satellites so that we are better able to track weather systems. Whether we’ll ever be able to modify them is very debatable.