The MacNeil/Lehrer Report; Evidence That Our Climate May Be Changing

ROBERT MacNEIL: Good evening. For the second year in a row, it`s been a very rough winter in the Northern Hemisphere. This week, unusually heavy snowstorms blanketed Italy, France, Switzerland and Scotland, and at least fifteen deaths are reported there. In this country, at least 129 deaths have been attributed to storms which struck the eastern half of the country recently. Does all this extreme weather mean that our climate is actually changing? Some scientists believe that a new ice age is on the way. Others argue that, on the contrary, our world is warming up. Tonight, the evidence that our climate may be changing, and what, if anything, we could do about it. Jim?

JIM LEHRER: There probably wouldn`t be all this concern about what the weather`s doing now if it wasn`t for last year`s. National Geographic called 1977, "the year the weather went wild." If you live out West, you remember it as the year of the drought, no rain, no snow, no nothing but dry cold air. Midwesterners and those up here in the East think back a year to bitter cold, colder than anything since 1918 in some areas, and monstrous snowstorms. National Guardsmen were called out to dig people, cars and places out of snowdrifts. National fuel shortages caused schools and many industrial plants to close. There was severe unemployment in some areas. It`s remembrances of these things past that cause all of us non- expert weather watchers to ask the experts what`s going on. Robin?

MacNEIL: Two successive winters of severe weather, of course, don`t make an ice age, but there is a body of scientists who believe we are heading in that direction. They claim that ice ages occur in cycles, and that we`re due for one now. If their estimates prove correct, colder temperatures would move south, and sheets of ice could gradually grow to cover more and more of the surface of the earth, until perhaps the entire Northern Hemisphere was under a layer of ice. One of the scientists who believes things are moving toward an ice age is Dr. Robert Jastrow, founder and director of the Goddard Institute for Space Studies at NASA, professor of geology at Dartmouth and Columbia University. He`s also the author of a new book, Until the Sun Dies, a frightening prospect.

Dr. ROBERT JASTROW: It won`t happen for a while yet.

MacNEIL: Dr. Jastrow, why do you believe we are headed for a new ice age?

JASTROW: The facts suggest, in both the long term and the short term, that we`re overdue on this cycle. And those facts are, first of all, that for three hundred thousand years in the past, the world has been colder than it is today, ninety-seven per cent of the time. Only three per cent of the time has it been as warm as it is now. The second point is, that the world has never been free of ice for more than ten thousand years in that long interval ... relatively free, that is.

MacNEIL: Free of ice in the populated areas.

JASTROW: That`s right. We climbed out of our last ice age, when the ice covered Connecticut, and so on, about eleven thousand years ago, so we`re a thousand years overdue. Another indication is that right now and of course, we don`t know when this ice age will return; we only know it will return soon, just as we know the earthquake will occur on the San Andreas fault soon -- but when? Around the 1940s, the temperature of the world, which had been climbing steadily since the seventeenth and eighteenth centuries turned downward. It has now declined three-tenths to four-tenths of a degree centigrade. And one last thing is, the nine banded armadillo used to be in Texas, went up to Kansas and Nebraska when it was warm, and started moving southward again.

MacNEIL: All right. Can we look at these things in a little more detail here? First of all, the three hundred thousand year cycle...

JASTROW: This graph, which actually shows ice volume rather than temperature, indicates when the world has been icy or free of ice. And you see that the horizontal line at the top, which represents today`s condition, is exceeded in only a few places and times. That means that almost always the world has been colder than now. Only in those few rare instances has it been as warm as it is today.

MacNEIL: And so these blobs in here would represent the very big ice ages.

JASTROW: They are the big ice ages. They`re cyclic, as you said, but the period is rather complicated, so they don`t look very uniform to the eye.

MacNEIL: And these would be little ice ages, or the beginnings or ends of ice ages ... these little bits in here.

JASTROW: Well, the very last thing that turns upward is what happened eleven thousand years ago. The little ice age that hit Europe in the seventeenth century is too small to be seen on this graph.

MacNEIL: I see. So that these little bits up here are the only times that the world has been as warm as it is now.

JASTROW: That`s right. The last thirty years have been a period of warmth we haven`t seen, literally, for six thousand years, and we`re not likely to see it again for a long time.

MacNEIL: All right. Now what about the temperature changes you talked about?

JASTROW: This graph, compiled by Mitchell, and brought up to date by Kukla shows the temperature in the Northern Hemisphere over the last hundred-odd years. At the beginning you see that steady climb out of the depths of the little ice age, until about 1945 or so, when the temperature turned down. The trend downward is continuing right to the present day, according to Kukla. We don`t know what will happen next year, but on the present trends, it`s going to be very cold at the end of the century.

MacNEIL: And these are temperatures averaged up for a whole year. From where?

JASTROW: From the Northern Hemisphere and from the globe, but this one is the Northern Hemisphere.

MacNEIL: All right. Can we look at one particular place, like New York, which you have here ?

JASTROW: We got the records from the weather bureau for the Central Park station since about 1860. They show a lot of variation, four or five degrees, from year to year. You can see the blizzard of `88 as a little valley at the left. You can see the warm winter of `73 as the big peak at the right. You can see the cold winters of the last year or two. That`s not climate, however; those fluctuations always occur.

MacNEIL: Those are New York, Central Park temperatures averaged for a whole year, are they?

JASTROW: That`s correct, each one of them averaged for a year. We did the averaging in our own lab, our own computer at the Institute, and we`re sure of these numbers. And now, if you put a trend line on these, you see a steady rise up to the 1940s or 50s, in this case, and then the beginning of the decline, which showed up in Mitchell`s data also, for the world.

MacNEIL: O.K. If things are going the way you say, getting colder and towards a new ice age, what`s the main cause of it?

JASTROW: The cause of the big change is the varying distance of the earth from the sun, produced by the perturbations of the planet Jupiter, mainly, on our planet. The small changes, like the little ice age that occurred in the seventeenth century and caused widespread famine in Europe, have a cause which is unknown, although there is suggestive evidence that it is related in some way to sunspot activity and changes in solar energy output.

MacNEIL: O.K. We`ll come back. Jim?

LEHRER: All right. That`s one theory about what`s going on, but there`s another which says just the opposite, that the earth is actually getting warmer, not colder. Its believers say that our industrial society and its burning of fossil fuels, oil and coal particularly, have caused a build-up of carbon dioxide in the atmosphere. It`s acting kind of like a greenhouse up there. The sun`s heat comes through, but then it`s trapped above the earth`s surface and can`t get back out because of the greenhouse or carbon dioxide. Thus, we have the heating up of the earth. One of the holders of this theory is Gordon- MacDonald, a geophysicist and professor of environmental policy at Dartmouth College. He`s currently a visiting scholar at the Mitre Corporation, a non-profit research. center located outside of Washington. So, no ice age is coming, is that right, Mr. MacDonald?

GORDON MacDONALD: Bob Jastrow talked about the natural fluctuations in climate. I think that basically the picture he drew is correct, except he left out one important factor, that is, man. Man has been doing lots of things that are going to change climate in very significant ways. For example, he`s burning oil, gas, coal, putting the carbon dioxide into the atmosphere. He`s also clearing forests, turning lands that were once covered with biologically active material into areas that are no longer biologically active. That means that the carbon that was once fixed in those forests is now released into the atmosphere. These two effects plus a very important effect, that is, natural gas coming from deep within the earth, coming into the atmosphere and being oxidized, all lead to the greenhouse that you described.

LEHRER: How do you know the greenhouse is up there?

MacDONALD: We know because we can measure how much carbon dioxide is there. It`s quite clear that the amount of carbon dioxide has increased over the last twenty years or so, and you can extrapolate back into 1880, and basically you have something like a fifteen per cent increase in this essential constituent of the atmosphere.

LEHRER: All right. Theories aside, has the earth actually gotten warmer in the last few years? It`s gotten colder, hasn`t it?

MacDONALD: Certainly through about1970 the cooling effect that Bob described...that is between about 1945, 1950 to 1970...you had a worldwide cooling. Over the last six to seven years, as I look at the data, the cooling has slowed down, and the temperatures have remained more or less constant in the Northern Hemisphere, and, indeed, in the Southern Hemisphere there`s some evidence that the Southern Hemisphere is beginning to warm up.

LEHRER: All right. Is this something to worry about?

MacDONALD: Very definitely. It`s not only the fact that a major climatic change can bring about changes in where you can produce food, how people live, and so forth, but there are other consequences. For example, if there is a warming, the warming is going to be much more pronounced at the Poles than it is at the equator. this implies that you could get very major melting of the Antarctic ice cap, particularly the western part of the Antarctic, and a consequent rise in sea level which, if the melting did indeed take place as a result of doubling the carbon dioxide content, would flood New York City, put Florida under water. You know, a few things like that.

LEHRER: You and brother Jastrow have given us two very good alternatives. We can either die by flood or die by ice. Is that what we`re really talking about?

MacDONALD: Yes, I think that`s really in the cards, either way. I certainly agree with Bob Jastrow that the last fifty years have been very unusual years in terms of the whole history of climate. They have been warm.

LEHRER: One final question. If your theory is right and Jastrow is wrong, then how do you explain the cold winters of `77 and `78?

MacDONALD: How do you explain the warm summers? You have to balance one effect against the other, and if you look at the average temperature, particularly over the Southern Hemisphere, but also in the Northern Hemisphere, it hasn`t been all that cold. You just freeze on occasional days.

LEHRER: All right. Thank you very much. Robin?

MacNEIL: Yet another group of scientists is studying the impact of climate change, whatever it is, at the National Center for Atmospheric Research at Boulder, Colorado. Stephen Schneider is deputy leader of their climate sensitivity group, and the author of a book called, The Genesis Strategy. Mr. Schneider, is the nine-banded armadillo right in heading south again, as Dr. Jastrow suggests, or could he just as well stay where he is?

STEPHEN SCHNEIDER:I now have the unenviable job of trying to both agree with Bob Jastrow and Gordon MacDonald and still tell you whether it`s warming or cooling. I think that the lesson that one can say about studying climate is that certain predictions in climate are really playing in a fool`s paradise. Anybody who`s tried to look at a trend in climate, and anyone who`s looked at a trend in the stock market, knows the great dangers we have about trying to extrapolate forward. Now, I agree with the evidence that Bob Jastrow cited, suggesting that in the long run, over a period of thousands of years, that we are, if left to natural devices, without interference from man as Gordon MacDonald suggested, heading toward an ice age. But in the very short run, that cooling trend, for example, that Bob pointed out, was only on the order of a few tenths of a degree. Yet, if we talk about the little ice age, which he mentioned earlier, that was a cooling which we believe was on the order of 12 degrees, yet we recovered from that cooling about the bottom of 1850 and went up to the warmest period in the thousand years or so, in the middle of this century. I think the short-term trends are virtually impossible, with present knowledge, to predict. I think the very long-term trend, would, if left to our own devices, as said, be toward an ice age. But the relative rates of human pollution are so much faster than the causative mechanisms we believe responsible for ice ages, that I think, in the short run, all bets are off, and we have to ask, what are the relative effects of man at the same time. And that`s why I believe it`s a fool`s paradise to try to predict specifically what`s in the future.

MacNEIL: So, in a sense, you`re saying that both gentlemen are right; that the longer trend of the earth going away from the sun and therefore the trend being the earth getting colder is happening, but at the same time, man is heating up the earth through the process Dr. MacDonald describes, and the two are neutralizing each other.

SCHNEIDER:I don`t know that they`re neutralizing yet. What man is doing is probably not strong enough today to dominate even the inter-annual variations in the climate; that is, the difference in the extreme winter from this year to next year or last year. But, yet, if our trends continue, due to large population growth and demand for affluence, the use of energy and the clearing of farm lands, then we become a competitive factor as early as the end of the century. And since it takes society on the order of a generation to change its strategy of how much energy it uses, the decisions have to be based now, when the theories are, in fact, very incomplete. I think there really is a message though. Even if we`re not sure if it`s warming or cooling, both can be bad. The main way climate affects people is through food supply, and our crops are tuned to the present climate. So, if we warm or cool, and we change the locations of where it rains, then in the short run at least, when we have very short food supply and demand around the world -- you know, there`s supposedly a wheat crop, but it really is not very much and it`s only in the U.S. -- if we get changes at all, then we get caught. In the long run, it could be better or worse for some. So, the message is, not to live too close to the vest. And to ask another question. Not just what will happen to the climate -- that`s the tough, technological question we looked at -- but where are the vulnerabilities in society? What difference does it make if climate changes, warming or cooling? This is an interdisciplinary question, one that we academics are hard-pressed to deal with. We`re very cramped into components of meteorologist or geologist. We have to ask, how does it hurt us, and how can we make ourselves less vulnerable.

MacNEIL: Can I ask one more question? The changes that man is bringing about have been mainly accidental. They are not designed to change the climate. To what extent can we change the climate by design?

SCHNEIDER: As far as climate is concerned, that`s true. We have deliberately intervened with cloud seeding to try to modify clouds. If you extrapolate that mentality, and many have, we don`t have to go far into the future to propose climate control. The problem is, with ignorance of both the full causes of natural change, and the relative inadvertent accidental effects of man`s activities, to intervene could easily be a cure worse than the disease. It would be like having a cold and breaking into a drug store and taking the first pill on the shelf you could find and assuming you`d be better. I think we`d do better to make ourselves less vulnerable to climate changes of any kind than to attempt climate control in the state of ignorance that we`re in now.

MacNEIL: O.K. Thank you. Jim?

LEHRER: Man-made efforts to change the weather do have many ramifications, and one of them is international. It`s something that particularly concerns Senator Claiborne Pell, Democrat from Rhode Island, a member of the Senate Foreign Relations Committee, and the prime congressional mover behind laws governing how, when and where weather is modified. Senator, what is the danger, in real terms, of individuals or nations trying to modify the weather, in you opinion?

CLAIBORNE PELL: Very real indeed. Not through any desire to spread evil or do harm to other nations, but merely a by-product of an action conducted for their own good. For example, if the Soviet Union decided to take the rivers that presently go into the Arctic Ocean and instead turn them around and have them go into the Black Sea and the Caspian Sea, that would be a huge advantage to the Soviet Union because it would make those sort of tundras and dry areas much more fertile. But the effect of that would be that the rivers would no longer be going to the Arctic Ocean, which would increase the amount of salt water, which would in turn mean that the ice cap there would decrease because salt water is less likely to freeze than fresh water. And as this happened, it would raise the level of waters around the world a certain amount, which, since living on the shore of New England, as a Rhode Islander on the shores of the Atlantic, would not be too pleasant. And more important, if the ice cap was smaller, there would be less heat reflected and you`d find that the earth would get warmer. So you would have both a low element of flood and of heat.

LEHRER: Do you agree with Dr. Schneider, that man shouldn`t intentionally tinker with the weather?

PELL: No. I think man should be permitted to tinker with it as long as it`s aboveboard, as long as the results are reasonably known through experimentation in the past. What I don`t think is correct, is for it to be done without proper notice to all the requisite authorities and approval and clearance. In my own thinking, what is very much needed now is a treaty.

LEHRER: You`ve drafted a treaty...

PELL: I`ve drafted a treaty-- I`m holding hearings on it, actually later on this month--which would require any nation that is going to take an action that would hurt another nation or the global commons -- that`s a term for the oceans or the Arctic or Antarctic Ocean -- would have to let UNEP, that`s the United Nations Environmental Program, Nairobi, be aware of it and know about it ... be on record for it. That would give a chance for public opinion around the world to amass a crescendo of protest if it was going to be obviously harmful to the world community.

LEHRER: But how would you know? In terms of this uncertainty that we`ve been talking about thus far, how would anybody really know what the bad effects of anything would be?

PELL: Well, one thing we know now. For example, in Germany, the factories are spewing forth their pollution, and that pollution ends up in Sweden and in Norway. That`s an effect right now. And I think that if a lot more factories were to be built by Germany, that that would be a matter that should be made apprised to UNEP.

LEHRER: But how would an international body take into effect the differences of opinion demonstrated here tonight? Let`s say that somebody proposed clearing a forest in South America, and somebody with the MacDonald theory comes along and says, "hey, don`t let those folks do that because that could warm the temperature more," to follow the greenhouse theory. You`d have to buy the whole theory in order to enforce that, would you not?

PELL: Absolutely. These things would have to be resolved first. I won`t get into the question of who`s right in these cases; I`m not a scientist. But we do know certain things as a matter of fact. We do know that if you turn the rivers around...and in the Soviet Union that would have an effect. We know what we did many, many years ago when we diverted rivers from watering Mexico, as they had, to watering our own people. We know that had a bad effect in Mexico. And probably, looking back on it in retrospect, we should have put the Mexicans on notice, and maybe given them some form of compensation. It`s this kind of action that we know about that I`m talking about.

LEHRER: Thank you, Senator. Robin?

MacNEIL: Let`s just go back: over the ground a little bit here to discuss some disagreements. Back to you Dr. Jastrow. You heard the comments from Drs. Schneider and MacDonald on this. How much longer before we really know what`s going on?

JASTROW: It will take several years or a decade or more to really understand, if we`re lucky, the causes of weather, before we can begin to tamper, with confidence, with the natural weather. But I think what people are looking to scientists. for is something related, but a little different. We as people, would like to know whether we can switch from imported oil to coal right now, for example, of which we have a lot and which can be used without this terrible damage to the strength of the dollar. And there, some facts are in order, which I would like to quote in about twenty seconds. And they are, that the theorists estimate, reliably, according to my colleagues, that the thirteen per cent increase in carbon dioxide which has occurred since the beginning of the industrial revolution, has warmed the earth`s temperature or surface by about three- tenths of a degree centigrade. If we continue on at our present rate, that thirteen per cent will go to thirty per cent and the temperature of the earth will go up another three-tenths of a degree centigrade between now and the year 2000. On the other hand, the natural cooling trend, if continued, will bring the earth`s temperature down by three-tenths to five- tenths of a degree. So, the answer, it seems to me, is that we can safely burn coal between now and the end of the century without being worried about a catastrophe.

MacNEIL: Let`s put that to Dr. MacDonald. Do you agree with that?

MacDONALD: Not at all. I think one has to look not only at the average temperature, but what happens in different parts of the globe, and particularly what happens in the polar regions. The models that have been computed are imperfect, but nonetheless there`s general agreement that the warming would be amplified in the polar regions and this could lead to partial melting of the ice caps, particularly the sea ice, and bring about rather major changes in sea level, other changes in the over-all balance of waters, where the water is distributed, and could really perturb life as we know it in very, very major ways.

MacNEIL: Are we, Dr. Schneider, acquiring knowledge fast enough that we only need ten years, as Dr. Jastrow suggests, really to understand what changes the climate?

SCHNEIDER: In my judgment, as one who builds the kind of mathematical models that try to answer these questions, is that we can`t at all count on the fact the scientists will have reasonable certainty as to our climatic future before the atmosphere itself performs the experiment, for example, of telling us whether the C02 greenhouse effect is true, or whether we should really have the right to extrapolate that cooling trend, which, by the way, many of my colleagues deny even exists. There`s quite a battle among climatologists, because there aren`t enough thermometers.

MacNEIL: O.K. Let`s go back a moment. How will the atmosphere perform the experiment? How will we know that the atmosphere has performed the experiment?

SCHNEIDER: Over the next twenty years we`ll be taking the earth`s temperature with as many thermometers as we can. Hopefully the satellites will help us a great deal. NASA has provided a major contribution to us there. And we`ll find out the extent to which the earth is warming and cooling. The real problem is, I think that we insult the environment, by that I mean C02 increases, at a much faster rate than we understand them. And whether we can safely burn coal ... here I would disagree with Bob Jastrow, but our disagreement may be as much one of values as one of facts. And I think we have to get straight, in any scientific discussion what are facts and what are values. The facts are, will it get warmer or cooler. I contend that that`s a point of major debate among competent opposites in the scientific community, and probably will continue to be over the next twenty years. The time frame with which, if present theories are true, serious, large, global effects could occur. Therefore, the values are, do we want to take the chance. And whether we want to take the chance is a public policy decision that people have to make in full recognition that we`re playing on a global scale, with ignorance. Yet, we`re proceeding.

MacNEIL: Let`s pursue that a bit with Jim. Jim?

LEHRER: Yes. And let`s go right back to you, Senator Pell. You heard what Mr. Schneider just laid out: the pursuing of a global international policy in a state of ignorance. Is that how you feel about it at this point, in terms of the weather?

PELL: I don`t think we`ve got any policy now. Before we can develop a policy, we must set up a system of brakes, and this is what I`m suggesting, so that we will at least not go into areas that can be harmful. I`ve already got through the United Nations my no-weapons mass destruction of the sea-bed floor international treaty, also a treaty saying that environmental modification will not be used as a means of warfare. These are what I call brakes. And what I`m now advocating and this would be the third, probably the last one I would push through -would be a treaty that would prevent certain actions that are obviously harmful.

LEHRER: But Senator, that`s my point. Just based on what we`ve heard tonight, who would make the decision as to what is obviously harmful? All these gentlemen concede that there`s still an awful lot of information they don`t have, and it might be years before we have it. In political terms, who makes that decision for the world?

PELL:UNEP, United Nations Environmental Program would make the decision, and I wouldn`t talk too much about weather because we don`t know. I think we`ve seen that both scientists have different views on that, but we do know what happens if you take the rivers away from a country.

LEHRER: And I know we`re out of time. Robin?

MacNEIL: Thank you both in Washington, and thank you both here. Good night, Jim. That`s all for tonight. We`ll be back tomorrow night. I`m Robert MacNeil. Good night.