Transcript - Global Warming Briefing

June 13, 1997        Global Warming - Program Agenda - click here

BURNETT 		Okay, if there are no questions, we'll move along. The first questions that should be raised about any global warming policy is what is the science behind the theory, and we have two good scientists here to answer that question, or at least address it. First is Norman J. Macdonald. He's a certified consulting meteorologist. This was awarded to him by the American Meteorological Society in 1995. He works for Accuweather. Mr. Macdonald has worked in radio and TV for over 31 years, has published more than 30 publications and scientific journals. Before going to work for Accuweather, Mr. Macdonald worked at the University of Colorado's high altitude observatory for four years, at the air force research laboratories in Cambridge for five years, and he spent 10 years in the meteorology department at Massachusetts Institute of Technology. Please welcome, to speak about the observational evidence of global warming, Norman J. Macdonald.

NORMAN J. MACDONALD 		Thank you very much. You know, I got a kick out of the fact that you haven't asked many questions and that means one of two things. Either we didn't get through to you, or you just weren't interested, one or the other. I hope that you'll have some questions with me.

First of all, let's start off with what it is that causes the global warming. It's primarily produced by what we call loosely the greenhouse effect. Well, it sounds like a bad term, but it isn't. Thank God for the greenhouse, because if we didn't have a greenhouse effect in this atmosphere, the temperature at the planet surface right now here in Washington, D.C., would be 0 degrees Fahrenheit.

What happens is that the visible radiation from the sun, we can see the short wave radiation, as we call it, comes right through the atmosphere when there are no clouds or when it's not reflected, heats the earth up; the earth in turn sends the heat back out to space in the infrared which we can't see very well. Now, fortunately, the atmosphere is composed of certain gases, chemical compositions, so that it absorbs a lot of this radiation going back out. It acts like a blanket. You go to sleep at night, you put a blanket on yourself. It's a very similar analogy.

The primary absorbers of infrared radiation -- I'm kind of over-simplifying this thing, it's very complicated, but basically it's as follows: the big trappers of infrared radiation, the thing that keeps us warm -- not the sun, it's the earth's atmosphere acting as a blanket. It's water in its different stages -- liquid, gaseous, and even ice particles. About 90-92 percent of the radiation is trapped by the water in its various states, but mostly water vapor. That's one reason why in our humid night here in Washington, for example, the temperature won't drop off at all. It stays warm. But if you've got a dry night with low dewpoints, humidity with low dewpoints, I guess you've heard that from enough of the meteorologists, I presume, that's when it cools off because the earth's heat can go right out to space. Radiational cooling they call it.

Carbon Dioxide and methane and other small trace gases absorb the other 5-8 or 9 percent, depending on the calculation. Carbon dioxide is about 5 percent, water vapor 90. Now, that's the basic physics behind it. Now, the observations that nobody is arguing with, over the past 40 years carbon dioxide in the northern and southern hemisphere has increased by a factor of about 50 percent. Now it's increasing even more rapidly, is a good observation that it will probably be doubling if it continues at the rate that it is now by the year 2025.

What's the source? Fairly obvious; industry for one thing, automobiles, motorcycles -- not bicycles -- and strangely enough, us, people. I ran some calculations before I came down here, and human beings on the planet Earth in one year exhale 10-to-the-17th cubic centimeters of carbon dioxide into the atmosphere, period. Now, that's not as much as we put in by the other processes, but we're making our contribution, too. So don't just blame the industrial people, blame people, too. Maybe we can do something else besides exhale carbon dioxide. I'll let the future generation think about that.

Now, what are the carbon sinks? Where does this stuff go? Why doesn't it just accumulate all the time? Well, the obvious answer is trees and plant life, but the biggest absorber of carbon dioxide is not plant life, not trees, not the Amazon Forest, but oceans. Most of it goes into the oceans.

Now, since the carbon dioxide is going up, the temperatures on the planet should be going up. Well, the problem we have with measuring temperatures, especially going very far back in time, is that 75 percent of the planet is water. Not too many people live out there. Consequently, we're stuck with observations that are made on the surface of the earth. And most of us live near cities, and cities we know are consistently warmer, an urban heat island effect, produced supposedly by the carbon dioxide and other combustion products, but in my opinion, it's just as likely to be the sensible heat that comes from opening doors in the wintertime, heating houses, and in the summertime with the big air conditioning systems pumping heat out in the atmosphere all the time. Also, the big silent areas, we have never been able to get really good measurements on, out of the oceans, into the Antarctic and Arctic, back to the beginning of time -- not the beginning of time, please. Back to the 1800s.

But the climatologists have really worked hard on this, and diddling around with the data in various fashions, and trying to get the biases out of it, and they've come up with the IPCC report, which the last one I saw was 1994, and it's about 1-1.5 degree increase in temperature Fahrenheit since the turn of the century. A 1-1.5 degrees average surface temperatures over both the northern and southern hemisphere.

The question is what's caused that increase in temperature. I don't think the big argument is whether or not that's been the case; it has. Well, of course, the carbon dioxide theories would say well, it's been carbon dioxide. Curiously enough, in the graph which, if some of you got this, you'll see it inside here, if you look at the graph of these temperatures in the IPCC report, you'll see that one of the biggest increases occurred from the late teens, about 1917 to the early '40s. That was before the big carbon dioxide increase started, which was after World War II.

There has been an increase since the 1970s in the surface observation. But is it necessarily due to carbon dioxide? It might not be. It might be due to changes in the external heat source, the primary one, our nearest star, the sun. The sun has spots on it from time to time. It's not a quiet sun. The sun spot cycle is well known. You'd think that when the spots, these dark regions that appear on the sun as you can actually see sometimes yourself on a hazy day on a sunspot maximum, you'd think that would make the sun cooler. It doesn't. In between the sunspots, pillage areas, very, very hot. So when there's lots of sunspots, the sun is putting out more energy for unit time in the visible part of the spectrum than it does when it's quiet.

Now, way back in the 1600s and early 1700s there weren't very many sunspots at all, so called vonder minimum. Now, not enough of you are old enough here to be my age to have remembered Hans Brinker and the Silver Skates, and maybe you read it, I don't know, but they used to skate on the dikes in Holland, and Dickens stories are always filled with snowstorms in England. Well, in those days it was a mini-ice age, they called it, in Europe. That's when there weren't any sunspots. But since around 1800 and the late 1700s the sunspots have increased, and they've increased rapidly in the 19th Century.

Sally Baliunas at Smithsonian Astrophysical Observatory has done some serious work on this, and she's convinced that part of that warming has been due to the fact that the sun has been putting out more energy. I'm not going to argue with Sally.

Now, as I mentioned, the increase in temperatures at surface temperatures since the 1970s is fairly obvious, but the thing that's happened since 1979 is that we've had satellites measuring the earth's temperature. They're not measuring the same temperature that the thermometers are measuring. They're measuring the temperature from the surface, up to about 6,000 feet, vertically integrating it. But that should be a good measure of the total heat in the lower part of the troposphere, as we call it. And the beauty of these things is they're up there 24 hours a day, seven days a week, and if they don't feel like going out to look at the thermometer, they still get the observations. And it's over the silent areas, they've got us covered in the Antarctic and the Arctic, and the observations have been taken now since 1979. If I could have my first overhead.

What you're seeing on the central bar line is the normal for that period of time. This is the data for 1979, January through March of 1997 of this year. And the arcs that you see that are above that one line, those are the three- month periods. This is every three months, in other words, the first quarter, January-February-March -- for that entire sample. There were just about as many temperatures above normal -- this is both the northern and southern hemisphere, this is for the whole planet, satellites, the lower bar graphs are the times when the temperature was below normal.

If you see any trend in that, then you've got better eyes than I do. It just about balances off. So there's no observational evidence from the satellites that there is any kind of increase in the global temperatures since 1979, and yet the carbon dioxide has been going up very rapidly.

Now, the argument is that the warming is really there but it's masked, and it's masked in the following fashion. The aerosols, that's a byproduct of a combustion process. It's a sulphur compound -- and I don't understand the chemistry on this. I'm not smart on everything by any means, and these sulphur particles, reacted on by sunlight and formed little teeny aerosols, little articulate matter. That brightens the sky a little bit and reflects more sunlight. Also that allows water droplets to coalesce on these little hydroscopic nuclei, more clouds, brighter clouds, reflecting the heat back out to space, increasing the planet's albedo, as we call it, reflectivity. Visible light doesn't get in as much, so it doesn't warm up. Masking of the global warming.

Well, 85 percent of the aerosols are generated in the northern hemisphere, and they live about three to five days. There is very little, if any, transport into the southern hemisphere. Southern hemisphere temperatures shouldn't be masked. You should see them going up. We don't. Satellite temperatures don't see them going up.

There are some other arguments, too, about the southern hemisphere with ozone is basking it and so on and so forth, but that's only a small part of it.

With all of this evidence that the temperatures aren't going up yet, or if they are, it may be caused by the sun. Why are we concerned about global warming? It's primarily because of the models. Dr. Balling is going to talk more about that later on.

Basically what the models tell us is these are climatic models that take and say okay, here's the climate today. We're going to increase the carbon dioxide. That's going to increase the temperature, and that's going to change the weather, change the climate. The models are predicting anywhere from 2-5 degrees Centigrade, and I think maybe Bob is a little bit more up to date on this and he can correct me on this if I'm wrong. They're predicting 2-5 degrees in the next hundred years or so.

Now, what's wrong with the warming up? I mean, it means the growing season is going to last longer and so on and so forth. What's wrong with that? Well, in the process, most of them, or in fact, all of them say two things. First, the average temperature and the average precipitation will make a geographical shift. Areas where the farming is great right now won't be so good 100 years from now and vice versa. Places where it's drought now, it will be floods. That's one.

Second, and this is most important -- not only will there be a geographical shift produced by this global warming of the average precipitation and temperatures, but the variations will go up. In other words, extreme events will occur more often as associated with this thing.

Now, that's the model put out for it, and I'm not commenting on the models. I'll leave that to Dr. Balling. My comment is as follows: that's at variance of what we see today in the world we live in. Think about it. In the summertime when the average temperature is warm, higher than it is in the wintertime, day to day variations in the weather are noticeable by their absence. Maybe a thunderstorm one day and it drops the temperature in Washington 3 degrees, from 96 to 93. In the wintertime when the temperature lowers, the variance goes up. But it's not just the temperatures in Washington or Baltimore or New York or Boston or anyplace. It's geographically the same. San Juan, Puerto Rico, where the average temperature is higher than it is in Washington, D.C. 12 months of the year -- well, maybe not in the summertime -- the variance day to day, month to month, season to season, year to year variation, and the weather in San Juan is significantly less than it is further north in the middle latitudes. I suspect that holds all the way up. So what we see today is when the temperature goes up, the variance goes down, the models are predicting the opposite. Maybe they're right, I don't know.

Just one more point, and that is we have -- one of the reasons that the global warming is supposed to produce more extreme events is, for example, hurricanes. If the ocean warms up, and it makes sense that if the atmosphere warms up, the ocean would warm up as well, then since one of the preconditions for hurricanes is that you have to have very warm surface water temperatures, you don't see hurricanes form in the Bering Sea, for example, they are in the tropics. So if the oceans warm up, this means we're going to get more hurricanes, and therefore if we get more hurricanes, we have a better chance of getting bigger ones.

Now, what I'd like to do is to show in the next overhead the North Atlantic and Caribbean hurricanes that we've seen since 1886, I believe it is, on the left and on the right. That's the actual number. And as you can see, on the left, back at 1886, I think, and it goes on up to 1996, there's 110 y ears of record, and you can see that the number of hurricanes really hasn't shown any significant increase.

Now, I admit that when you get to the 20s there, you'll see there aren't any years since then that we haven't had at least one hurricane. One of the reasons for that, I think, is the fact that our observational techniques have improved substantially. We have more ships out there than we did at the turn of the century, we've got the satellites, we've got the weather hunters, we've got more people and so on and so forth. But look back there at the turn of the century. If we had the same observational techniques now when we had those two years that there were 10 of them, I think it was 1950 -- and I can see from here there were 11 hurricanes, and these are hurricanes and not tropical storms. That's over 75 miles an hour or more. Back at the turn of the century, if we had our observational techniques that we have today, I bet you we would have had more hurricanes then than we've had at any time in the 19th Century.

So I guess that's just one. We've looked at tornadoes. Eighty-five percent of the tornadoes on the planet occur in this country. So the statistics in this country are a pretty good sample of the entire planet. And if you look at the total number of tornadoes, that's also in this report, since about 1975, the total number of tornadoes has gone up through the 1980s into the early 1990s, total number. But when you break it down to the class 2, 3, 4, and 5, the big damaging tornadoes, there has been a decrease in the big ones. And the reason that the total number has gone up, and this isn't my opinion, this is the opinion of the people out in the Midwest, the severe storms laboratory, that it is due to the fact that people are much more aware of tornadoes today than they were a few years ago, and they're out taking pictures with cameras, and the National Weather Service has done a great job in alerting people, be conscious of tornadoes. And I think that's one reason why we've seen the small ones, the little ones have increased. The big ones, the ones that damage have decreased in number.

So why is it that we keep thinking, and I think a lot of people are saying to themselves now wait a minute, Norman. I know the weather is getting worse. Every time I turn around there's some big flood here or there's some big drought here, or there's a cyclone hitting India, or this is happening and that's happening, and I say, and I'm old enough to be able to say this because I have experienced this, that not only have our communication systems improved markedly during my time on this earth, but so has the number of people. And we've got a lot of people living in places that nobody ever lived in before, information is coming to us much faster than it used to. We're much better at taking weather data. People are more weather conscious.

So I think one of the perceptions we have of the fact that the variance, as the models are predicting, will also occur. See, if there's masking of the warming, you should still see that variance going up, and we don't. I don't think we do, anyway. The reason that we think it's there is primarily because of the fact that there are a lot more people in our communication systems, much more sophisticated than they are today.

One final comment and that's on the Red River and the floods, which has been in the press lately, and I'm not an expert on hydrology so I'm going to be very careful here. But one of the peculiar things about the Red River, and I don't think I've read this, is that it flows to the north. It's the only major river in this country that flows to the north, which means every year the thawing starts at the headwaters. The Mississippi runs the other way, and the thawing starts further south from the headwaters. Get that picture in your mind. In Russia, all the rivers in Siberia, most of them anyway, flow to the north. They have floods every year. They have floods because the thawing starts at the headwaters, moves down, forms ice jams, and they get natural flooding.

I don't know whether the Red River was -- part of the flooding was caused by that, but I suspect it was. The ice jams downstream enhanced it and made it worse. There's another problem we have, too, when we see how much damage there is from hurricanes and the like along the Gulf Coast and these other places. We're building in places we never used to build before. We putting dikes up in rivers that we never did before. Flood control projects that started in the '30s when the floods were just as bad and the droughts were even worse than they have been now, sometimes they've done more harm than good.

So in summary, the theoretical argument is not an invalid one, that is, an increase in carbon dioxide could cause the planet's temperatures to go up. I don't know enough about the models -- I know some of the people who have done the models. I don't know how they get around the problem of chaos. I don't know how they really arrive at some of these conclusions. But I don't see any evidence that when temperatures go up, that the variance necessarily has to go up, which is what they're saying.

We have no evidence of the increase in extreme events going on at the present time in this climate. The theory isn't a bad one, but I think the observational evidence doesn't support it, and that's what science is all about. Theories are fine; facts support them. Thank you.

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