Dreams of Earth and Sky

by Freeman Dyson

The practical consequence of the Stern policy would be to slow down the economic growth of China now in order to reduce damage from climate change a hundred years later. Several generations of Chinese citizens would be impoverished to make their descendants only slightly richer. According to Nordhaus, the slowing down of growth would in the end be far more costly to China than the climatic damage. About the much-discussed possibility of catastrophic effects before the end of the century from rising sea levels, he says only that “climate change is unlikely to be catastrophic in the near term, but it has the potential for serious damages in the long run.” The Chinese government firmly rejects the Stern philosophy, while the British government enthusiastically embraces it. The Stern Review, according to Nordhaus, “takes the lofty vantage point of the world social planner, perhaps stoking the dying embers of the British Empire.”

  The main deficiency of Nordhaus’s book is that he does not discuss the details of the “low-cost backstop” that might provide a climate policy vastly more profitable than his optimum policy. He avoids this subject because he is an economist and not a scientist. He does not wish to question the pronouncements of the Intergovernmental Panel on Climate Change, a group of hundreds of scientists officially appointed by the United Nations to give scientific advice to governments. The IPCC considers the science of climate change to be settled and does not believe in low-cost backstops. Concerning the possible candidates for a low-cost backstop technology he mentions in the sentence I previously quoted—for example, “low-cost solar power”—Nordhaus has little to say. He writes that “no such technology presently exists, and we can only speculate on it.” The “low-cost backstop” policy is displayed in his tables as an abstract possibility without any details. It is nowhere emphasized as a practical solution to the problem of climate change.

  At this point I return to the Keeling graph, which demonstrates the strong coupling between atmosphere and plants. The wiggles in the graph show us that every carbon dioxide molecule in the atmosphere is incorporated in a plant within a time of the order of twelve years. Therefore, if we can control what the plants do with the carbon, the fate of the carbon in the atmosphere is in our hands. That is what Nordhaus meant when he mentioned “genetically engineered carbon-eating trees” as a low-cost backstop to global warming. The science and technology of genetic engineering are not yet ripe for large-scale use. We do not understand the language of the genome well enough to read and write it fluently. But the science is advancing rapidly, and the technology of reading and writing genomes is advancing even more rapidly. I consider it likely that we shall have “genetically engineered carbon-eating trees” within twenty years, and almost certainly within fifty years.

  Carbon-eating trees could convert most of the carbon that they absorb from the atmosphere into some chemically stable form and bury it underground. Or they could convert the carbon into liquid fuels and other useful chemicals. Biotechnology is enormously powerful, capable of burying or transforming any molecule of carbon dioxide that comes into its grasp. Keeling’s wiggles prove that a big fraction of the carbon dioxide in the atmosphere comes within the grasp of biotechnology every decade. If one quarter of the world’s forests were replanted with carbon-eating varieties of the same species, the forests would be preserved as ecological resources and as habitats for wildlife, and the carbon dioxide in the atmosphere would be reduced by half in about fifty years.

  It is likely that biotechnology will dominate our lives and our economic activities during the second half of the twenty-first century, just as computer technology dominated our lives and our economy during the second half of the twentieth. Biotechnology could be a great equalizer, spreading wealth over the world wherever there is land and air and water and sunlight. This has nothing to do with the misguided efforts that are now being made to reduce carbon emissions by growing corn and converting it into ethanol fuel. The ethanol program fails to reduce emissions and incidentally hurts poor people all over the world by raising the price of food. After we have mastered biotechnology, the rules of the climate game will be radically changed. In a world economy based on biotechnology, some low-cost and environmentally benign backstop to carbon emissions is likely to become a reality.

  Global Warming: Looking Beyond Kyoto is the record of a conference held at the Yale Center for the Study of Globalization in 2005.‡ It is edited by Ernesto Zedillo, the head of the Yale Center, who served as the president of Mexico from 1994 to 2000 and was chairman of the conference. The book consists of an introduction by Zedillo and fourteen chapters contributed by speakers at the conference. Among the speakers was Nordhaus, contributing “Economic Analyses of the Kyoto Protocol: Is There Life After Kyoto?,” a sharper criticism of the Kyoto Protocol than we find in his own book.

  The Zedillo book covers a much wider range of topics and opinions than the Nordhaus book, and is addressed to a wider circle of readers. It includes “Is the Global Warming Alarm Founded on Fact?” by Richard Lindzen, a professor of atmospheric sciences at MIT, answering that question with a resounding no. Lindzen does not deny the existence of global warming, but considers the predictions of its harmful effects to be grossly exaggerated. He writes:

  Actual observations suggest that the sensitivity of the real climate is much less than that found in computer models whose sensitivity depends on processes that are clearly misrepresented.

  Answering Lindzen in the next chapter, “Anthropogenic Climate Change: Revisiting the Facts,” is Stefan Rahmstorf, a professor of physics of the oceans at Potsdam University in Germany. Rahmstorf sums up his opinion of Lindzen’s arguments in one sentence: “All this seems completely out of touch with the world of climate science as I know it and, to be frank, simply ludicrous.” These two chapters give the reader a sad picture of climate science. Rahmstorf represents the majority of scientists who believe fervently that global warming is a grave danger. Lindzen represents the small minority who are skeptical. Their conversation is a dialogue of the deaf. The majority responds to the minority with open contempt.

  In the history of science it has often happened that the majority was wrong and refused to listen to a minority that later turned out to be right. It may—or may not—be that the present is such a time. The great virtue of Nordhaus’s economic analysis is that it remains valid whether the majority view is right or wrong. Nordhaus’s optimum policy takes both possibilities into account. Zedillo in his introduction summarizes the arguments of each contributor in turn. He maintains the neutrality appropriate to a conference chairman and gives equal space to Lindzen and to Rahmstorf. He betrays his own opinion only in a single sentence with a short parenthesis: “Climate change may not be the world’s most pressing problem (as I am convinced it is not), but it could still prove to be the most complex challenge the world has ever faced.”

  The last five chapters of the Zedillo book are by writers from five of the countries most concerned with the politics of global warming: Russia, Britain, Canada, India, and China. Each of the five authors has been responsible for giving technical advice to a government, and each of them gives us a statement of that government’s policy. Howard Dalton, spokesman for the British government, is the most dogmatic. His final paragraph begins:

  It is the firm view of the United Kingdom that climate change constitutes a major threat to the environment and human society, that urgent action is needed now across the world to avert that threat, and that the developed world needs to show leadership in tackling climate change.

  The United Kingdom has made up its mind and takes the view that any individuals who disagree with government policy should be ignored. This dogmatic tone is also adopted by the Royal Society, the British equivalent of the US National Academy of Sciences. The Royal Society recently published a pamphlet addressed to the general public with the title “Climate Change Controversies: A Simple Guide.” The pamphlet says:

  This is not intended to provide exhaustive answers to every contentious argument that has been put forward by those who seek
to distort and undermine the science of climate change and deny the seriousness of the potential consequences of global warming.

  In other words, if you disagree with the majority opinion about global warming, you are an enemy of science. The authors of the pamphlet appear to have forgotten the ancient motto of the Royal Society, Nullius in Verba, which means, “Nobody’s word is final.”

  All the books that I have seen about the science and economics of global warming, including the two books under review, miss the main point. The main point is religious rather than scientific. There is a worldwide secular religion that we may call environmentalism, holding that we are stewards of the earth, that despoiling the planet with waste products of our luxurious living is a sin, and that the path of righteousness is to live as frugally as possible. The ethics of environmentalism are being taught to children in kindergartens, schools, and colleges all over the world.

  Environmentalism has replaced socialism as the leading secular religion. And the ethics of environmentalism are fundamentally sound. Scientists and economists can agree with Buddhist monks and Christian activists that ruthless destruction of natural habitats is evil and careful preservation of birds and butterflies is good. The worldwide community of environmentalists—most of whom are not scientists—holds the moral high ground and is guiding human societies toward a hopeful future. Environmentalism, as a religion of hope and respect for nature, is here to stay. This is a religion that we can all share, whether or not we believe that global warming is harmful.

  Unfortunately, some members of the environmental movement have also adopted as an article of faith the belief that global warming is the greatest threat to the ecology of our planet. That is one reason why the arguments about global warming have become bitter and passionate. Much of the public has come to believe that anyone who is skeptical about the dangers of global warming is an enemy of the environment. The skeptics now have the difficult task of convincing the public that the opposite is true. Many of the skeptics are passionate environmentalists. They are horrified to see the obsession with global warming distracting public attention from what they see as more serious and more immediate dangers to the planet, including problems of nuclear weaponry, environmental degradation, and social injustice. Whether they turn out to be right or wrong, their arguments on these issues deserve to be heard.

  Note added in 2014: This review stimulated a flow of letters and responses, too voluminous to be summarized here. The most useful exchange was with Lord May, who is one of the most influential scientists in the United Kingdom, having been the chief scientific adviser to the British government (1995–2000) and president of the Royal Society (2000–2005). Here are extracts from his letter and my reply:

  Lord May: The essay begins with a characteristically clear and elegant exposition of the annual uptake of carbon dioxide by plants, and the subsequent reemission from respiration or decay. This leads Dyson to the conclusion that “the average lifetime of a molecule of carbon dioxide in the atmosphere … is about twelve years.” Dyson correctly emphasizes that such a timescale is fundamental to discussions of global warming. Unfortunately, however, estimates of the characteristic “residence time” of a molecule of carbon dioxide in the atmosphere involve a complicated mélange of factors, leading to the conclusion that although almost half of newly added carbon dioxide molecules remain for only a decade or two, roughly a third stay for a century or more, and fully one fifth for a millennium.… This is why the residence time of such molecules is generally characterized as a century.

  This difference between twelve versus one hundred years is no minor pedantry. A major argument for the need for urgent action now, even though truly major consequences of global warming may lie some decades ahead, is that the carbon dioxide molecules we are putting into the atmosphere today are going to hang around, continuing to thicken the greenhouse gas blanket, for a long time.

  Dyson: Lord May and I have several differences of opinion, which remain friendly. But one of our disagreements is a matter of arithmetic and not a matter of opinion. He says that the residence time of a molecule of carbon dioxide in the atmosphere is about a century, and I say it is about twelve years.

  This discrepancy is easy to resolve. We are talking about different meanings of residence time. I am talking about residence without replacement. My residence time is the time that an average carbon dioxide molecule stays in the atmosphere before being absorbed by a plant. He is talking about residence with replacement. His residence time is the average time that a carbon dioxide molecule and its replacements stay in the atmosphere when, as usually happens, a molecule that is absorbed is replaced by another molecule emitted from another plant.… In my review I was discussing the use of carbon-eating plants to sequester carbon dioxide from the atmosphere.… Since we are discussing the effect of carbon-eating plants, my use of the short residence time without replacement is correct, and his use of the long residence time with replacement in that situation is wrong.

  *Yale University Press, 2008.

  †See Nicholas Stern, The Economics of Climate Change: The Stern Review (Cambridge University Press, 2007).

  ‡Yale Center for the Study of Globalization/Brookings Institution Press, 2008.

  7

  STRUGGLE FOR THE ISLANDS

  THE MOST DRAMATIC moment of our trip to the Galápagos Islands in May 2008 was on the last day. My wife and I were leaning over the railing on the deck of the tourist boat Integrity, watching an orca whale. The orca swam close to the boat, almost directly underneath us. Then, just ahead of the orca, a large sea turtle appeared. This was not one of the giant tortoises for which the islands are famous but an equally massive marine turtle. The females of the species come to the islands to lay their eggs under the sand on the beaches.

  My wife had met this turtle earlier in the day, when she was swimming in the ocean with a snorkel. Only a second after we saw the turtle from the boat, the orca snapped, biting through the turtle shell as if it were a pie crust. Immediately the sea turned red and fifty frigate birds appeared from nowhere to pick up the larger remaining scraps of flesh. After the frigate birds were done, flocks of smaller birds came to pick up the smaller scraps. The red sea rapidly faded. In less than a minute it was all over. It was like a scene from National Geographic on television, but real.

  Perhaps we were partly responsible for the turtle’s death, since the turtle and the orca were both attracted to the boat. If we had not come to disturb the normal rhythm of her life, the turtle might now be out of harm’s way, mother to a new batch of hatchlings. But in the ordinary course of nature, without boats and tourists, such a death is not unusual. We had seen nature doing her daily work, holding the balance impartially between predator and prey. Only in our eyes is nature beautiful and cruel.

  Galápagos: The Islands That Changed the World is a combination of four books in one.* It is first a picture book, second a guidebook, third a history book, and fourth a political manifesto. I will describe the four components in turn and then reflect upon their message. The picture book is a gallery of magnificent photographs of the islands and their nonhuman inhabitants, taken over many years by Tui De Roy and others. De Roy is a professional photographer who arrived on the islands with her family at the age of two and spent much of her life there. About fifty of the pictures are hers, including two portraits: of Darwin’s finches and of blue-footed boobies.

  Darwin’s finches are inconspicuous little birds that Darwin observed when he visited the islands in 1835. They later provided crucial evidence for his theory of the origin of species. Blue-footed boobies are big seabirds that walk around the islands on bright blue duck-feet. These two images exemplify the clash of cultures that compete in historic places around the world: the culture of preservation and the culture of exploitation. Scholars and scientists try to preserve historic sites, while local entrepreneurs try to exploit them. Darwin’s finches are the chief attraction of the Galápagos for professional biologists and historians of science
. Blue-footed boobies are the chief attraction for sellers of souvenirs in tourist shops.

  Other photographs in the book were taken by Daniel Fitter, who was our guide on the island of Santa Cruz. All visitors to the national park must be accompanied by a licensed guide. He walked with us into the farmland to find giant tortoises, who choose to live comfortably in the small irrigated area open to human settlement rather than in the more austere environment of the national park. One of Fitter’s photographs shows the small island Daphne Major, an uninhabited volcanic crater, silhouetted against a threatening sky. Daphne Major is famous as the worksite of Peter and Rosemary Grant, who camped there for several months every year for twenty years, laboriously studying the birds and incidentally raising two daughters.

  The island is small and the birds are tame enough so that the Grants could catch and label every finch that lived there and record its individual life history, from hatching and mating to parenting and mortality. They assigned each finch to one of the thirteen endemic species by measuring the size and shape of its beak. “Endemic” means a species that breeds in the islands and nowhere else. They discovered an astonishing fact that Darwin missed: evolution by natural selection sometimes moves fast. Darwin imagined that evolution must be slower than any possible human observation, requiring thousands or millions of years to form new species. The Grants observed hybridization and segregation of species happening within a few years, fast enough to be seen and accurately measured by humans.

  The reason why evolution in the Galápagos is fast is that climate and vegetation change abruptly from year to year, and natural selection is brutal. Wet and dry years unpredictably produce lush and sparse vegetation. In lush years, there are plenty of small, soft seeds, and birds with smaller beaks and quicker reproduction have an advantage. In drought years, soft seeds are scarce, and birds with larger beaks specialized to deal with unusually large, tough seeds have an advantage. Selection is fast because populations of birds with the wrong kind of beak to split seeds that happen to be abundant may be wiped out in a single season.