Carl Sagan from his Keynote Speech at the Emerging Issues Forum in Cornell University in Feb of 1990 Carl Sagan from his Keynote Speech at the Emerging Issues Forum in Cornell University in Feb of 1990

Carl Sagan’s Keynote Speech at the 5th Emerging Issues Forum (1990)43 min read

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If you have not watched this amazing video of Carl Sagan from his Keynote Speech at the 5th Emerging Issues Forum in Feb of 1990 (1 hour 5 min) where he talks about climate change, then do it NOW! Sadly, his powerful and amazingly prophetic words are still very, very relevant today.

I also have another of his speeches posted on my blog: Carl Sagan and His Famous ‘Pale Blue Dot’ Speech. In that post I have many more links there for Carl Sagan and Cosmos too if you want to learn more.

I. Video

Here are the 2 major sections of the video in case you want to skip around a bit:

  1. Introduction (00:00:00)
  2. Carl Sagan’s Main Speech (00:06:10)
Carl Sagan from his Keynote Speech at the 5th Emerging Issues Forum in Feb of 1990

In the next section, I will transcribe his entire speech for posterity. I will break up the text into paragraphs as well as add headers and images that may be of use to understanding his speech. To start, I will not transcribe Carl Sagan’s introduction which goes until 6 min 10 secs, although I may attempt to do that at a later time.

II. Video Transcript

A. Introduction 

Governor Hunt, Mr Park, thank you very much for your extremely generous introduction. My friends, I am very happy to be here with you. I think the idea of a state organizing a concentrated look on the critical issues of our day involving leaders and ordinary people state wide is extremely important and I would like to see this emulated in the other 49 states and maybe 159 other countries. In general, I think its an excellent idea.

In choosing the issue of global change I think is extremely important because here is an issue where the risk is very high. The issue is removed from everyday life. The solutions cannot take place in the course of a year or two. It involves the scientific issues which are distant from the familiar everyday acquaintance of many people. And for this constellation of reasons it poses difficult public policy issues.

My own involvement with the issue of global warming did not begin on this – well, I certainly began on this lovely world – but my interest in global warming began in the study of a different world – Venus, our nearest planetary neighbor. It’s been my great good fortune to have not only witnessed but also to have participated in the historic first preliminary reconnaissance of the solar system in which we live. Beginning in 1962 when the United States launched the first successful interplanetary vehicle Mariner 2 we humans, mainly Americans and Soviets, have sent spacecraft to visit all of the planets known to the ancients, to our ancestors, and many other worlds besides. 

B. Life is Rare

We have examined many dozens of other worlds. A few of them in great detail having landed on their surfaces and most flying by at great speed but with instruments of enormous capability taking the data as we speed past. An enormous amount of important and interesting information has been acquired. The perspective that we get about those other worlds illuminates a wide range of science. 

Viking 2 Lander from NASA
Viking 2 Lander from NASA

One of the issues that I have been most focused on, concerned about, is the issue of life elsewhere and it is certainly a fair summary to say that in these dozens of worlds, while we  have many cases of prebiological organic matter, the stirrings and intimations of life, if you wish. Nevertheless, there is nothing, not the least hint of anything alive on those other worlds. I spent over a year, in the manner of speaking, on the planet Mars. In 1976-1977 after the Viking spacecraft – 2 of them landed on Mars – and we had an armory of instrumentation to look for life and there was nothing, not a mouse, not a footprint, not a microbe, not even an organic molecule. 

The lesson is that you can have dozens of worlds, some of them breathtaking in splendor and beauty without life on any of them. Life is something rare and precious. There is something extraordinary about the planet that we are privileged to live on, and in this peculiarly self-congratulatory way about we ourselves. Life is rare. That’s the lesson from exploring space.

And the lesson from exploring time if you look back at the geological record at the history of mass extinctions is that there is no guaranteed tenure for any species no matter how self confident on this planet. Sixty-five million years ago an event occurred which not only wiped out the dinosaurs, but wiped out most of the species of life on Earth. This can happen to anyone. These explorations in space and time are a reminder or a warning to us that we cannot be guaranteed of our continued happy existence. It’s important to understand our world and, I argue, others as well. 

C. A Lesson from the Planet Venus

Venus - Maat Mons (from NASA)
Venus – Maat Mons (from NASA)

When we look at Venus we find a world of roughly the same size, mass, density as ours, but a stunning difference – 2 stunning differences. One is that there is a massive atmosphere about 90 times the surface pressure of the air right here down on Earth. And the other is that the surface temperature is stunningly hot. The surface of Venus is at 900 degrees Fahrenheit – hot enough to melt tin or lead, hotter the hottest household oven. And it is not because Venus is a little closer to the sun because the clouds of Venus are brighter than the Earth is and Venus reflects  so much more light back to space relative to the Earth that it ought to be cooler, not warmer than the Earth. 

Why is Venus at 900 degrees fahrenheit? Because of the greenhouse effect. That massive atmosphere is made of mostly of carbon dioxide and a large amount of carbon dioxide can trap the heat and warm a planet. Warm it to certain, certainly very uncomfortable levels. This is, I claim, a kind of providential warning to us. I am not for a moment suggesting that there was one a species of Venusians who refused to drive fuel efficient automobiles and this is what happened to their planet. The story is in fact more interesting than that, but I won’t go into it here. 

But the lesson here is not only that the greenhouse effect can exist but that a large greenhouse effect can be exceptionally dangerous. So, for anyone who views our exquisite planet and hears the warnings of scientists and says all this greenhouse stuff is just some theory I ask them to reflect on the fate of the planet Venus, our nearest planetary neighbor.

D. A Lesson From the Planet Mars 

Mars Landscape (from NASA)
Mars Landscape (from NASA)

By the way, while I am not going to be talking about it, or at least not much today. Mars is an example of what happens when you don’t have an ozone layer. The reason, we think, that we can find only not only no trace of life, but not even an organic molecule on the surface of Mars is that Mars has a planet wide ozone hole so to say. Negligible ozone, ultraviolet light from the sun strikes the surface unimpeded. The surface becomes rich in fabulously oxidizing molecules and they simply gobble up any organic matter that happens to be there. Mars is also a salutory warning to us, we, who are pushing and pull, and tugging on a planetary environment which we still insufficiently understand. 

E. When is the Right Time to Act?


Well, many of you have attended the sessions today. I was privileged to be able to listen to a few of the extraordinarily interesting papers presented. You know something of the evidence for Greenhouse warming. The predicted consequences, the disasters for agriculture, the rise in sea level. I will say a little bit about the evidence later. 

But, I want to ask you to think about the following general very practical political issue. What happens when a group of scientists makes some prediction of impending disaster. Keep doing such and such they say and the following catastrophe will result. And changing the catastrophe, averting it, mitigating it is going to be expensive. It might require changing the way we think, in which case it is politically expensive. Or it might involve changing the way we do business, in which case it is fiscally expensive. One way or another it’s expensive. 

At what point do policy makers have to take this seriously. This is an issue that is extremely current today. And I’d like to just spend a few minutes on two examples from the rich cultural history of our species. Of policy makers and predictions of disaster and I will reach to ancient Greece. Both of these stories can be found in the classic Greek literature. The first in Herodotus. The second in Aeschylus’ play Agamemnon. They both are at least in part based on historical events. 

1. Croesis, King of Lydia

The Happiness of King Croesus
The Happiness of King Croesus
a. The Tale

The first case that I want to tell you about is Croesis, King of Lydia. Apollo was the god of the sun, but in addition to being in charge of sunlight, he had another specialty and that was being in charge of prophecy. Not just generalized prophecy, but systematic prophecy in human institutions called oracles, the most famous of which was the Oracle at Delphi. And the way it would work you would go to Delphi as a supplicant. You would being some gifts for the priestess who was called the Pithia and you would say what your concern is and then from the Pithia, usually in a kind of trance, back would come the advice from the gods, or at least from Apollo.

Now, Croesis was immensely rich. There is still a phrase ‘rich as Croesis‘. It’s almost current just a little, a little obsolete. One of the reasons was that he was so rich was that he was one of the boys who invented money. The first metal coins in human history, as far as we know, were coined in Lydia in Croesis’ reign. Lydia is in Anatolia, contemporary Turkey. 

Well, we can speculate on the reason, but Croesis’ ambitions were not contained within the boundaries of his small nation. He had grander objectives and so he thought: wouldn’t it be a good idea to conquer Persia. Persia was the superpower of the 7th century BC. The Persian emperor, Cyrus, had forged a mighty empire by combining 2 different peoples – the Persians and the ?Meaties?.

So, Croesis had some degree of trepidation because of the power of the Persian empire. So, naturally he sent emissaries to the oracle at Delphi. And, the question put by his  emissaries on Croesis’ behalf was ‘What will happen if Croesis makes war on Persia?’ and without hesitation the Pithia, the priestess answered ‘ He will destroy a mighty empire.”. The gods are with us thought Croesis! Time to invade! So, he assembled a vast mercenary army, invaded persia, and was promptly and humiliatingly defeated.

Not only was Lydian power destroyed forever, but he, Croesis, was forced to spend the rest of his life a a sort of pathetic minor functionary in the Persian court. A hanger-on ex-king. It’s a little bit like – this isn’t a perfect analogy – but it’s a little like the Emperor Hirohito living out his days as a consultant on the beltway in Washington DC.

Well, the injustice really got to him. After all Croesis had played by the rules. He had asked for advice from the Pithia. She gave it to him. He acted on it and look what happened. She had done him wrong. So, after mulling this over for some years he sent another emissary to Delphi. This one bearing much less opulent gifts as was appropriate to his now diminished station and he asked: “How could you do this to me?”.

And here, from Herodotus’ history is the answer from the god “The prophecy given by Apollo ran that if Croesis made war upon person he would destroy a might empire. Now, in the face of that, said the priestess, if he had been well advised he should have sent and inquired again if it was his own empire or that of Cyrus that was spoken of, but Croesis did not  understand what was said nor did he ask questions again, so he has no one to blame but himself.

So much for Croesis.

b. The Lesson 

Now, if the Delphic Oracle was just a kind of an institutionalized scam to fleece credulous kings then of course it would need excuses to explain way the inevitable mistakes disguised ambiguities are the stock and trade of oracles. 

Nevertheless, the lesson of the Pithia is germane. Even of oracles we must ask intelligent questions. Even, or especially when the tell us what we want to hear. The policy makers must not blindly accept. They have to understand. They have to ask questions. They must not let their own ambitions stand in the way of understanding. The conversion of prophecy to policy must be done with care and it seems to me that this advice is fully applicable to the modern oracles: the scientists, and think tanks, and universities.

Sometimes the policy makers ask them and the prophecy comes back. More often these days the oracles voluntarily submit even to those who never ask them and then the policy makers have to figure out what do I do now. And since the modern oracles are deeply  immersed in science and technology its very important for the policy makers and the people who determine who the policy makers are to understand science and technology. 

3. Cassandra, Princess of Troy

Cassandra, Princess of Troy
Cassandra, Princess of Troy
a. The Tale

So, this is on the one hand. Now, I want to tell you a on-the-other-hand story also from classical Greece. This is also about Apollo and also about oracles. This is the story of Cassandra, Princess of Troy. The event occurs just before the Trojan war begins. You know, the one that Homer wrote about. 

She was the smartests and the most beautiful of the daughters of King Priam. And Apollo, who like all of the Greek gods was constantly on the prowl for attractive humans, fell in love with her, at least that is the way the story is described. 

Oddly, this almost  never happens in Greek myth, she resisted his advances. She was smart. She was beautiful. She was happy. Who needed Apollo? So, he tried to bribe her, but what could he giver her? She as already a princess. She had everything that she wanted. Apollo thought of something she didn’t have. He promised her the gift of prophecy. The offer was irresistible. She agreed. Quid pro quo, Apollo did whatever that gods do create seers, oracles, and prophets out of mere mortals.

And, then after he had done that, scandalously, Cassandra reneged. She changed her mind. She refused the overtures of a god. Apollo was not amused, but he could not withdraw the gift of prophecy, but whatever you can want to say about Greek gods they keep their promises, so instead he condemned her to an ingenious and cruel fate – that no one would believe her prophecies.

So, Cassandra predicts the invasion by the Greeks headed by Agamemnon. Nobody pays attention. She predicts the fall of Troy. Nobody pays attention. She predicts to the Greeks the death of Agamemnon. They pay no attention. She predicts her own death. Nobody pays any attention to that. 

Instead they make fun of her. They call her the Lady of Many Sorrows. Today it would be something like Prophet of Gloom and Doom – just a  minor translational difference, same sentiment. “I prophesied to my countrymen” she says “all their disasters” but  they ignored her prophecies. They were destroyed. Agamemnon was destroyed and soon so was she. 

b. The Lesson

Well, this resistance to dire prediction is very human. You can certainly see it today. I mean, if we are faced with some very heavy ominous prediction – things you never saw happen are going to happen and it’s going to be expensive to mitigate it we have a natural tendency, to reject, to ignore the prophecy. And, after all there is no prophets, not even the scientific community, who are right all of the time and you can find competent scientists who have made predictions – supersonic transports will destroy the ozone layer, for example – that are just wrong, and so it is very easy to dismiss. 

Also, if the factors precipitating the anticipated catastrophe are long standing then the prediction is a kind of a rebuke to us. How did we permit this peril to develop? Why didn’t we see it before hand? Why didn’t we take political steps to prevent it? So, these are uncomfortable ruminations that through our own inattention or inaction that some catastrophe is coming. Put it out of our mind or find a reason to reject it. 

This temptation to minimize, to dismiss, is something that psychiatrists know very well about. They have a technical name for it. It is called denial. The rock group Dire Straights – I am sure many of you know their repertoire – has a line in one of their songs that goes “denial ain’t just a river in Egypt”. 


So, these 2 cases, I claim, are the opposite poles of policy response to prediction of disaster. Croesis representing the pole of credulous uncritical acceptance propelled a little bit by greed or other character flaws. And Cassandra representing –  I mean the response to her – representing the pole of stolid, immobile rejection of the possibility of danger.

Well, today we have a set of such prophecies and for all of the average person understands it just as well could have emanated from the Delphic Oracle for all of the fundamental understanding of the underpinnings there is, so it gets to be a kind of a challenge – a battle between two arguments from authority. 

There’s one bunch they’re sort of nice looking. They say it’s worrisome. There’s this other bunch that is sort of  nice looking and they say it’s not worrisome. What’ll I choose. Well, I choose the one that is the most comfortable. I think we are much closer to the danger of Cassandra than of the danger of Croesis. 

F. About Climate Change Evidence


Now, let me give a very brief statement of why I take greenhouse warming so seriously. Those of you who have attended the sessions this morning and this afternoon have heard a much more detailed expert summary of these reasons. 

1. Greenhouse Effect 

First of all, there is no question that “Is such a thing as a greenhouse effect exists?”. I talked about Venus. This benign planet looking exactly as it does here, but with no greenhouse effect would be 20 degrees centigrade – that is what 36 fahrenheit – below the freezing point of water. With no greenhouse effect this planet would be frozen solid. The oceans would be 3 kilometers of ice. A little greenhouse effect is a good thing. We owe our lives to the greenhouse effect. No greenhouse effect and we would never have come into being. 

The principal greenhouse gasses are water vapor and carbon dioxide. Now, there are some minor constituents: methane, oxides of nitrogen, and chlorofluorocarbons which go by the brand name freons and they are an especially interesting aspect of this because they are wholly man made. 

You see, astronauts, many of them in Earth orbit seeing to the naken unaided eye this beautiful vista can make out as perhaps is hard to do in this picture the very thin blue aura that surrounds the bright hemisphere – the illuminated hemisphere of the Earth. That’s just a thin atmosphere seen at dawn. This phrase ‘the ocean of air’ is a kind of a misnomer. Oceans suggest massive, impervious, but instead that thin line that you can barely make out in this picture is very fragile, vulnerable of the depredations of human beings. 

Our technology and our numbers have both reached a state where inadvertently we can pose a danger to the global environment especially through the atmosphere. The abundance of greenhouse gasses is increasing. Greenhouse gasses act as a kind of a blanket holding the heat in. There is no question that all of the gasses I just mentioned are steadily increasing in abundance.

2. Global Temperature Trends

In addition, it seems very clear that the average temperature of the Earth has been increasing through the 20th century. It’s a noisy record. There are  hot years and cold years always, so the curve of temperature versus time has a jagged aspect to it, but the slow increase with time is becoming increasing clear: and one indication of that is the that the 5 hottest years of the 20th century were in the decade of the 1980’s. That is also the decade that had the highest abundance of all of those greenhouse gasses. 

In addition, there is most interesting evidence from an Antarctic ice core taken by a Soviet team in which the past temperature history of the Earth for tens of thousands of years and the past abundance of carbon dioxide in the atmosphere can both be measured in the little bubbles of air that are trapped in the ice laminated between successive snow falls. And, we find that when the carbon dioxide is higher that the temperatures are higher. When the carbon dioxide is lower the temperature’s are lower. They is a virtually a one-to-one correlation.

Now, nobody pretends we understand everything about the global climate. There are feedbacks, some of which warm the Earth a little bit and the tendency would be to further increase the temperature – so called positive feedback. And others in which warm the Earth a little and the situation is self correcting like a thermostat and it cools the Earth a little. And, there is a push and pull, a tug, between these competing feedbacks. Doubtlessly we have not identified all of them. The present consensus, I believe, is that the bad kind of feedback, the ones that makes the worse, the so called positive feedbacks dominate. 

I would think that it was be an astonishing coincidence if the balance of all of these feedbacks just exactly corrected the problem we are generating through human technology, a sort of a deus ex machina to go back to the Greek analogies. In the Greek plays when the playwright got himself into a plot pickle, he couldn’t figure out how to solve it, then there was an actor on wires representing a god who flew into the set and put everything right called the deus ex machina – the god of the machine – the machine being the device that plopped him down on the stage. It is asking a lot believe that the problem is going to fix itself.

3. Global Effects of Climate Change

If we look at the prognostications, the three dimensional general circulation computer models of which there are some six independent models working right now mainly in the United States and one in the UK., they all predict temperature increases of a few degrees centigrade between now the middle of the next century and the difference between them is only a factor of 2 in temperature rise. None of the models predict that the Earth climate is going to get cooler. None of them predict that its going to be tens or hundreds of degrees increase. 

The agreement, considering the state of our knowledge, is quite good. If you then look at the output of these computer models which purport to give a sense of how the temperature is changed on region basis as you go through time you begin to see some very worrisome things. Yes, there are some places that get cooler and some places that get warmer, but the overall trend is warmer and by the middle of 21st century there is no winner. Every place has gotten warmer.

To give you and idea of how much warmer – a few degrees centigrade doesn’t sound like so much. Let me point out that a one degree temperature change in this case decrease following a massive volcanic explosion is enough to produce widespread suffering and famine worldwide as happened following the Tamboura explosion, volcanic explosion, in 1815 and other cases which are still more serious. Several degrees is a very major temperature increase. 

Some of these predictions make, prognosticate, that the American midwest will be converted into something approaching scrub desert by the second half the 20th century, and likewise the Soviet Ukraine and so on. But the American midwest is the breadbasket of the world. If the grain and cereal food stuffs from those places are unavailable there is – we are in serious trouble.

In addition to the volume expansion of seawater and the melting of glacier and polar ice, sea levels rise and again there is an uncertainty. Average  prediction for the middle of next century is a meter – 3 feet – that might be as little as 1 and it might be as much as many meters. And then take a look at the low lying coastlines around the world and ask what happens when the sea levels rise. Ok, the Dutch, they are very good at building dikes and levies they’ll build more dikes and levies. That’s not going to destroy Holland, but take a look at Bangladesh where 1-3 meter temperature rise will flood an area which is inhabited by tens of millions of people. Where are those guys going to go? Environmental refugees. It’s a new prospect. 

For these reasons I take very seriously the prediction of greenhouse warming. 

4. The Double Standard for Argument 

Now, there are policy makers who would like to respond as follows and you have perhaps seen this sort of opinion in the pages of, naturally the editorial page of the Wall Street Journal. It’s the first place to expect a complaint about having to change anything. 

‘It’s too uncertain’ they say. This is serious stuff. There are a few scientists with computer models and who can be sure that they know what they are talking about and you want us to turn everything upside down because some scientist say that things are going to get a few degrees warmer. It’s a few degrees warmer on the stage than it is in the audience. You don’t see any catastrophe up here do you? 

I’d like to pose the following question: Imagine this kinda thinking back in the height of the Cold War. You know the United States – so, let me ask a question – How much money do you think the United States has spent since 1945 on the Cold War? Sometimes they ask this question then from the back of the audience comes in answer ‘billions and billions‘. A huge underestimate – billions and billions. The amount of money that the United States has spent on the Cold War since 1945 is approximately 10 trillion dollars. Trillion, that’s the big one with the ‘T’. What could you buy with 10 trillion dollars? The answer is: You could buy everything in the United States except the land. Everything. Every building, truck, bus, car, boat, plane, pencil, baby’s diaper. Everything in the United States except the land, that’s what we have spent on the Cold War. 

So, now let me ask: How certain was it that the Russians were going to invade? Was it 100% certain? Guess not since they never invaded. What if it was only let say 10% certain? What would advocates of big military buildup have said? We must be prudent. It’s not enough to count on only the most likely circumstance. If the worst happens and it’s really extremely dangerous for us we have to prepare for that. Remote contingencies if there is serious enough have the prepared for. It’s classic military thinking – you prepare for the worst case. 

And so now, I ask my friends who are comfortable with that argument, including the editorial page of the Wall Street Journal, why doesn’t that same argument apply to Global Warming. You don’t think it’s 100% likely? Fine. You are entitled to think that. If it’s only a small probability of it happening since the consequences are so serious, don’t you have to make some serious investment to prevent it or mitigate it? I think there’s a double standard of argument working and I don’t think we should permit it.

g. What can we do to stop climate change?


Now, let me indicate what is it you would do if you were took greenhouse warming seriously. And what I am going to try to argue is that virtually everyone of the things that you would do to ameliorate greenhouse warming make sense on completely separate grounds. They are worth doing apart from greenhouse warming unlike the defense buildup which made sense whatever except if you were confident there was a real danger of Soviet troops coming across the Elb. There is not other mitigating circumstance, the least efficient way to spend money if you want to pump the nation economy. It drew all sorts of scientific as well as fiscal resources out of the civilian economy. It is largely responsible for the economic chaos of the United States. 

Whereas, I will argue, spending  money on mitigating greenhouse warming makes an enormous amount of sense for other reasons. What are the mitigating steps? 

1. Chlorofluorocarbons

First, the greenhouse gas that is increasing most steeply is the CFC’s (chlorofluorocarbons). It would make a great deal of sense to simply wipe them out, prevent anymore production of CFC’s. Well, because CFC’s also imperil the ozone layer there is already not just a commitment from the major manufacturers of CFC’s to stop producing them, but there is an international agreement called the Montreal Protocol which most of the major industrial nations have signed, committing themselves to phase out CFC production by the turn of the millenium, by the year 2000. That’s an example of what can be done on these global environmental issues and since CFC’s are doubly dangerous – ozone depletion and greenhouse effect – the first step you would take is in fact being done. So, that’s a bit of an encouragement. We are not as immobile and resistant to these arguments as you might otherwise expect. 

2. Energy Efficiency 

Second, energy efficiency. 

If you can get more power to a house from a given power plant then for given amount of energy expenditure then you put less carbon dioxide into the atmosphere. Obviously, you are doing something important for greenhouse warming. 

One-third of the carbon dioxide that is generated in the United States, the worst CO2 polluter on the planet, by the way, comes from automobiles. Why do we permit automobiles that get 15 to 25 miles a gallon when the technology exists for automobiles to get 60 to 100 miles a gallon. That’s not a step which will bother anybody, except possibly adolescent young men who need to have extremely rapid acceleration for psychological reasons of their own. For all practical purposes much greater fuel efficiency in automobiles is perfectly possible. 

And likewise, across the entire spectrum of fossil fuel energy use in our society – fossil fuels being coal, oil, gas, wood, and so on. The stuff that when you burn it CO2 comes out. 

3. Alternative Energy Sources

The third thing you might want to do is to seek alternative energy sources, alternatives to fossil fuels. Why not have an energy source that doesn’t put carbon dioxide or other greenhouse gasses into the atmosphere. Is that wholly beyond our technological ability? I don’t think so. And, while there are a number of alternatives, some of which work in some places – some geographic locales – and not in others. The mix looks very promising. I am talking about: tidal, geothermal, wind, and especially solar power.

You know this solar power issue is very interesting and it has a strong political point. Maybe you remember Jimmy Carter when he was in the White house. For the young of heart in the audience, this was an early American president who preached energy efficiency and one of the largely symbolic gestures which he did was to install a solar-thermal heater on the roof of the White House to make some warm water for presidential showers. And, I have forgotten what the fraction of the White House’s own energy budget it accounted for – maybe it was 15, 20 percent or something like that – but it was a kind of a step in a direction which certainly, from what we have learned subsequently, we need to go.

The next president of the United States was Ronald Reagan and one of the first acts upon entering office was to rip the solar-thermal converter out of the roof of the White House. And one the earliest steps taken in his administration was to enormously reduce funding for solar and other alternative energy sources. We lost 10 years. Despite that, the progress in solar energy technology has been steady and impressive.

And, if you were to levy and environmental tax on the burning of fossil fuels to pay for the additional burden on the society from the increase of the greenhouse effect , even today, solar energy would be economically competitive with fossil fuels. And, if we were to spend some signifgicant research money on solar energy the price per kilowatt-hour would go down. 

There is a natural issue about nuclear energy. Fusion power which maybe we will have the next few decades is in principle clean as far as greenhouse gasses go. But, there is a variety of radioactive waste and other problems which have the be dealt with. Fission power, the kind of power plants we have today, some people believe they are a suitable stop gap between fossil fuels and whatever it is that we are going to have as the alternative later on. 

In my view there are some conditions that have to be satisfied by fission power plants:

  1. They have to be safe – Chernobyl certainly reminds us of that. 
  2. They have to be cost effective and the prices have soared through the roof. 
  3. Their radioactive waste has to be safely disposable not for 10 years into the future but hundreds or thousands because that is the half lives of radioactive waste. 
  4. And the fourth criteria now I would use is that they must not produce weapons grade uranium of plutonium, for separate topic, so as to not encourage a nuclear arms race. 

The burden of proof that fission power plants satisfy those criteria is on the shoulders of those who advocate it. I am not convinced that there is any fission power plant that satisfies those criteria. If there is then maybe it makes sense as a stop gap. If not, we are in a tighter squeeze and it’s even more important that we spend money on the development of alternative energy sources. 

4. Plant Trees 

Now, another thing you could do is plant trees. A tree is an engine for taking carbon dioxide out of the atmosphere and it does it. It’s not the only thing a tree does, but that is one of the things that trees are good for and its especially relevant to this issue. 

Plant forests that seems to be good advice to mitigate greenhouse warming. Instead, the human species is destroying forests and we are doing it at a rate of 1 acre of forest every second. Think of that: *snap* there goes an acre *snap* there goes an acre *snap* there goes an acre *snap* there goes an acre. We are doing something immensely stupid. 

5. Deal with the Global Population Crisis 

And then finally, and maybe the most important of all of the ways of mitigating greenhouse warming, is the deal with the world population crisis. Every human being has as right and a wish to a certain minimum way of life and that involves: cooking food – carbon dioxide goes into the atmosphere – and all of the other things that you do in your job, many of which involve more greenhouse warming. If we continue exponential population growth it will overwhelm any of the other measures that I have been talking about no matter how seriously they are approached. 

Now, what does it take to make some dent in population growth? Some people have the idea that all you have to do is to just make birth control apparatus, device, pharmaceuticals available and that’s the issue. That’s not the issue. It’s not that people, poor people, the billion poorest people on the planet are too dumb to understand that they shouldn’t have more children. That’s not the issue. The issue is that they are so poor that more children is a kind of social security to provide for their old age. More children is a way to have cheap labor to help with whatever dismal task on the little plot of land they work or whatever it is that they are doing that otherwise they couldn’t afford. 

Having children is not the, having lots of children is not the cause of poverty. It is the consequence of poverty, although the causality arrow goes both ways. And the clear indication of how this works is what has been documented all over the planet called the Demographic Transition. It works in Christian countries and Buddhist countries, capitalist countries, Communist countries of which there are hardly any left, but when there were it worked there. East and West, and it’s absolutely striking. When the per capita income is really low people have lots of children. When the per capita income rises to a pathetically low level by American affluent standards, but still higher that a lot of people have, the population growth rate automatically decreases. 

People then see that they can provide in a minimal way for their future. They have other – they have some discretionary capital which they then want to spend on something and their cost benefit analysis then works out so that they have fewer children. And, maybe we can think back to our great grandparents and remember what size families were common then and think how much larger it was than today. Is that because they were too stupid? It’s not. They made another kind of choice.


Now, let me quickly run through again this list and just remind you of why each of these steps makes sense by themselves even apart from greenhouse warming. 

Cut out the CFC’s we talked about that. That protects the very the fragile ozone layer.

Greater fuel efficiency. If for a given amount of fuel you get more power out that’s obviously good economics. And, you know, we hear about the danger of being dependent on foreign sources of oil, and this is used as a an argument by this administration, for example, to permit ecologically dangerous offshore oil drilling. Because we have to have domestic sources. We don’t want to be dependent on foreigners. But, if we make much more efficient use of the oil we already have then that’s the same a discovering new sources of oil. And on finding alternative energy sources, clearly that works in the same direction. If we had vast solar arrays that were absorbing sunlight and converting them into electricity then that would be an alternative to importing tankers worth of oil from some foreign country. And in addition, its a good technology to have against the day when the oil runs out. The sun doesn’t run out or at least not for a 5 billion years, and, I figure that’s good enough. 

Planting forests for, or at the least stopping to destroy forests, makes enormous sense in terms of species diversity – all of those organisms, mainly plants that we’re knocking off without knowing anything about them including their possible pharmacological and other benefits for human beings. And also we grew up in forests, we primates. We have a natural affinity to forests. We feel better, at least I will speak for myself, I like being in forests.

And then finally, on the population growth rate, it’s very clear – I don’t have to go through it for this audience – how important that is for the future stability, political and economic, food stuffs, and everything else of the planet even apart from the ecological issues. 

So, what I say to those who complain that it is too uncertain – beyond pointing out the standards that were applied to the Cold War ought to be applied here – I say look everyone of these steps makes good sense, makes good economic sense. And think of all of the industries that are implied by what I have just said, especially alternative energy sources. There is money to be made in developing a technology which will appropriately address greenhouse warming.


Well, I want to stop in a moment. I just want to make one or two summary remarks.

If you burn a lump of coal somewhere the carbon dioxide goes up in the atmosphere and you know carbon dioxide molecules are exceptionally stupid. They don’t know anything about national boundaries. They don’t have passports. They are wholly innocent of the important concept of national sovereignty. They just casually cross over national boundaries once after the other. There is a lesson – the world is a unity – the national boundaries have no bearing on these global environmental issues. No one nation can solve this problem by itself. It has to be all of the nations working together. 

What is more – there is no way to mitigate these problems so that we will introduce the mitigating technology or whatever it is today and then in 2 or 3 or 4 years or something comparable to political term of office the problem will be solved. Instead you introduce the mitigating circumstances now, and decades hence, when somebody you don’t even know will be holding your political office, the benefits will come. 

Solving these problems requires a transnational and transgenerational perspective. To my mind that is a very grownup kind of perspective. Deprovincializing, dechauvinising, an awareness of one species on one exquisite fragile planet and that’s why I think that these very serious global environmental issue may have a deep silver lining. The binding up of the planet. The end of our adolescence. The approach to the maturity of our species.

Thank you very much.

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