Freeman Dyson, physicist, mathematician, and professor at the Institute for Advanced Study, spoke June 5 at the monthly luncheon of the Princeton Regional Chamber of Commerce. In his speech Dyson said he was “promoting four heresies.” His second heresy, on global warming, was excerpted in the June 18 issue of U.S. 1. Below is the complete text of Dyson’s speech:

by Freeman Dyson

My first heresy says that the United States has less than a century left of its turn as top nation. Since the modern nation-state was invented around the year 1500, a succession of countries have taken turns at being top nation, first Spain, then France, Britain, America.

Each turn lasts about 150 years. Ours began in 1920, so it should end about 2070. The reason why each top nation’s turn comes to an end is that the top nation becomes over-extended, militarily, economically and politically. Greater and greater efforts are required to maintain the number one position. Finally the over-extension becomes so extreme that the structure collapses.

Already we can see in the American posture today some clear symptoms of over-extension. Who will be the next top nation? China is the obvious candidate. After that it might be India or Brazil. You should be asking yourselves, not how to live in an America-dominated world, but how to prepare for a world that is not America-dominated. That may be the most important problem for the next generation of Americans to solve.

How does a people that thinks of itself as number one yield gracefully to become number two? Since I grew up in England during the collapse of the British Empire, I have some experience in dealing with this problem.

2. Climate and Land Management

My second heresy will take longer to explain. It says that all the fuss about global warming is grossly exaggerated. Here I am opposing the holy brotherhood of climate model experts and the crowd of deluded citizens who believe the numbers predicted by the models.

Of course, they say, I have no degree in meteorology and I am therefore not qualified to speak. But I have studied the climate models and I know what they can do. The models solve the equations of fluid dynamics, and they do a very good job of describing the fluid motions of the atmosphere and the oceans. They do a very poor job of describing the clouds, the dust, the chemistry and the biology of fields and farms and forests.

They do not begin to describe the real world that we live in. The real world is muddy and messy and full of things that we do not yet understand. It is much easier for a scientist to sit in an air-conditioned building and run computer models, rather than to put on winter clothes and measure what is really happening outside in the swamps and the clouds. That is why the climate model experts end up believing their own models.

There is no doubt that parts of the world are getting warmer. Last summer I visited Greenland, the place where the warming is most spectacular. I talked with some of the local people. They all love the warming and hope it continues. It makes their lives a lot easier.

I am not saying that the warming does not cause problems. Obviously it does. Obviously we should be trying to understand it better. I am saying that the problems are grossly exaggerated. They take away money and attention from other problems that are more urgent and more important, such as poverty and infectious disease and public education and public health, and the preservation of living creatures on land and in the oceans, not to mention easy problems such as the timely construction of adequate dikes around the city of New Orleans.

I talk about the global warming problem because it is interesting, even though its importance is exaggerated. Consider the half of the land area of the earth that is not desert or ice-cap or city or road or parking-lot. This is the half of the land that is covered with soil and supports vegetation of one kind or another. Every year, it absorbs and converts into biomass a certain fraction of the carbon dioxide that we emit into the atmosphere.

We don’t know how big a fraction it absorbs, since we have not measured the increase or decrease of the biomass. But we can calculate the thickness, averaged over one half of the land area of the planet, of the biomass that would be produced if all the carbon that we are emitting by burning fossil fuels were absorbed. The average increase in thickness is one hundredth of an inch per year.

The point of this calculation is the very favorable rate of exchange between carbon in the atmosphere and carbon in the soil. To stop the carbon in the atmosphere from increasing, we only need to grow the biomass in the soil by a hundredth of an inch per year. Changes in farming practices such as no-till farming, avoiding the use of the plow, cause biomass to grow at least as fast as this. If we plant crops without plowing the soil, more of the biomass goes into roots which stay in the soil, and less returns to the atmosphere.

If we use genetic engineering to put more biomass into roots, we can probably achieve much more rapid growth of topsoil. I conclude from this calculation that the problem of carbon dioxide in the atmosphere is a problem of land management, not a problem of meteorology. No computer model of atmosphere and ocean can hope to predict the way we shall manage our land.

Instead of calculating world-wide averages of biomass growth, we may prefer to look at the problem locally. Consider a possible future, with China continuing to develop an industrial economy based largely on the burning of coal, and the United States deciding to absorb the resulting carbon dioxide by increasing the biomass in our topsoil. The quantity of biomass that can be accumulated in living plants and trees is limited, but there is no limit to the quantity that can be stored in topsoil.

To grow topsoil on a massive scale may or may not be practical, depending on the economics of farming and irrigation. It is at least a possibility to be seriously considered, that China could become rich by burning coal, while the United States could become environmentally virtuous by accumulating topsoil, with transport of carbon from mine in China to soil in America provided free of charge by the atmosphere, and the inventory of carbon in the atmosphere remaining constant.

We should take such possibilities into account when we listen to predictions about climate change and fossil fuels. If biotechnology takes over the planet in the next 50 years, as computer technology has taken it over in the last 50 years, the rules of the climate game will be radically changed.

When I listen to the public debates about climate change, I am impressed by the enormous gaps in our knowledge, the sparseness of our observations and the superficiality of our theories. Many of the basic processes of planetary ecology are poorly understood. They must be better understood before we can reach an accurate diagnosis of the present condition of our planet.

When we are trying to take care of a planet, just as when we are taking care of a human patient, diseases must be diagnosed before they can be cured. We need to observe and measure what is going on in the biosphere today and what went on in the past. Two things we know for sure. The biosphere was constantly changing in the past, and it will be constantly changing in the future. The idea that we can put a stop to change is a dangerous illusion.

3. The Wet Sahara

My third heresy is about the mystery of the wet Sahara. This is a mystery that has always fascinated me. At many places in the Sahara desert that are now dry and unpopulated, we find rock-paintings showing people with herds of animals.

The paintings are abundant and of high artistic quality, comparable with the more famous cave-paintings in France and Spain. The Sahara paintings are more recent than the cave-paintings. They come in a variety of styles and were probably painted over a period of several thousand years. The latest of them show Egyptian influences and must be contemporaneous with early Egyptian tomb paintings. Henri Lhote’s book, “The Search for the Tassili Frescoes,’’ has marvelous reproductions of 50 of the paintings.

The best of the herd paintings date from roughly 6,000 years ago. They are strong evidence that the Sahara at that time was wet. There was enough rain to support herds of cows and giraffes, which must have grazed on grass and trees. There were also some hippopotamuses and elephants. The Sahara then must have been like the Serengeti today.

At the same time, roughly 6,000 years ago, there were deciduous forests in Northern Europe where the trees are now conifers, proving that the climate in the far north was milder than it is today. There were also trees standing in mountain valleys in Switzerland that are now filled with famous glaciers. The glaciers that are now shrinking were much smaller six thousand years ago than they are today.

Six thousand years ago seems to have been the warmest and wettest period of the interglacial era that began 12,000 years ago when the last Ice Age ended. I would like to ask two questions. First, if the increase of carbon dioxide in the atmosphere is allowed to continue, shall we arrive at a climate similar to the climate of 6,000 years ago when the Sahara was wet?

Second, if we could choose between the climate of today with a dry Sahara and the climate of 6,000 years ago with a wet Sahara, should we prefer the climate of today? My third heresy answers yes to the first question and no to the second. It says that the warm climate of six thousand years ago with the wet Sahara is to be preferred, and that increasing carbon dioxide in the atmosphere may help to bring it back. I am not saying that this heresy is true. I am only saying that it will not do us any harm to think about it.

4. The Domestication of Biotechnology

My fourth heresy is about the domestication of biotechnology. Fifty years ago in Princeton, I watched the mathematician John von Neumann designing and building the first electronic computer that operated with instructions coded into the machine. Von Neumann did not invent the electronic computer. The computer called ENIAC had been running at the University of Pennsylvania five years earlier.

What von Neumann invented was software, the coded instructions that gave the computer agility and flexibility. It was the combination of electronic hardware with punch-card software that allowed a single machine to predict weather, to simulate the evolution of populations of living creatures, and to test the feasibility of hydrogen bombs.

Von Neumann understood that his invention would change the world. He understood that the descendants of his machine would dominate the operations of science and business and government. But he imagined computers always remaining large and expensive. He imagined them as centralized facilities serving large research laboratories or large industries.

He failed to foresee computers growing small enough and cheap enough to be used by housewives for doing income-tax returns or by kids for doing homework. He failed to foresee the final domestication of computers as toys for three-year-olds. He totally failed to foresee the emergence of computer-games as a dominant feature of 21st-century life. Because of computer-games, our grandchildren are now growing up with an indelible addiction to computers. For better or for worse, in sickness or in health, till death do us part, humans and computers are now joined together more durably than husbands and wives.

What has this story of von Neumann’s computer and the evolution of computer-games to do with biotechnology? Simply this, that there is a close analogy between von Neumann’s vision of computers as large centralized facilities and the public perception of genetic engineering today as an activity of large pharmaceutical and agribusiness corporations such as Monsanto. The public distrusts Monsanto because Monsanto likes to put genes for poisonous pesticides into food-crops, just as we distrusted von Neumann because von Neumann liked to use his computer for designing hydrogen bombs.

It is likely that genetic engineering will remain unpopular and controversial so long as it remains a centralized activity in the hands of large corporations.

I see a bright future for the biotechnical industry when it follows the path of the computer industry, the path that von Neumann failed to foresee, becoming small and domesticated rather than big and centralized. The first step in this direction was already taken recently, when genetically modified tropical fish with new and brilliant colors appeared in pet-stores.

For biotechnology to become domesticated, the next step is to become user-friendly. I recently spent a happy day at the Philadelphia Flower Show, the biggest flower show in the world, where flower-breeders from all over the world show off the results of their efforts. I have also visited the Reptile Show in San Diego, an equally impressive show displaying the work of another set of breeders. Philadelphia excels in orchids and roses, San Diego excels in lizards and snakes.

The main problem for a grandparent visiting the reptile show with a grandchild is to get the grandchild out of the building without actually buying a snake. Every orchid or rose or lizard or snake is the work of a dedicated and skilled breeder. There are thousands of people, amateurs and professionals, who devote their lives to this business.

Now imagine what will happen when the tools of genetic engineering become accessible to these people. There will be do-it-yourself kits for gardeners who will use genetic engineering to breed new varieties of roses and orchids. Also kits for lovers of pigeons and parrots and lizards and snakes, to breed new varieties of pets.

Genetic engineering, once it gets into the hands of housewives and children, will give us an explosion of diversity of new living creatures, rather than the monoculture crops that the big corporations prefer. New lineages will proliferate to replace those that monoculture farming and industrial development have destroyed. Designing genomes will be a personal thing, a new art-form as creative as painting or sculpture. Few of the new creations will be masterpieces, but all will bring joy to their creators and variety to our fauna and flora.

The final step in the domestication of biotechnology will be biotech games, designed like computer games for children down to kindergarten age, but played with real eggs and seeds rather than with images on a screen. Playing such games, kids will acquire an intimate feeling for the organisms that they are growing. The winner could be the kid whose seed grows the prickliest cactus, or the kid whose egg hatches the cutest dinosaur.

These games will be messy and possibly dangerous. Rules and regulations will be needed to make sure that our kids do not endanger themselves and others.

If domestication of biotechnology is the wave of the future, five important questions need to be answered. First, can it be stopped? Second, ought it to be stopped? Third, if stopping it is either impossible or undesirable, what are the appropriate limits that our society must impose on it? Fourth, how should the limits be decided? Fifth, how should the limits be enforced, nationally and internationally?

In considering each of these questions, it would be helpful to keep in mind the analogy between computer technology and biotechnology. The majority of people using domesticated biotechnology to cause trouble will probably be small fry, like the young computer hackers who spread computer viruses around on the internet. On the other hand, there is a big difference between a computer virus and a real virus like influenza or HIV.

If we allow kids to play around with roses and snakes, we still have to stop them from playing around with viruses. I do not attempt to answer these questions today. The future is in the hands of our children and grandchildren. We should give them the freedom to find their own answers.

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