The idea that Earth is a living thing goes back at least as far as Plato, who according to Francis Bacon believed that the planet “was one entire, perfect, living creature.” But it was James Lovelock and his colleague Lynn Margulis who, in the early 1970s, developed a testable scientific hypothesis aimed at investigating Earth’s lifelike properties. Known as the Gaia hypothesis, it states that life on Earth works to keep conditions at the planet’s surface favorable to life itself. In 2006 this led to Lovelock joining the likes of Louis Agassiz and Charles Darwin in receiving geology’s most prestigious prize—the Geological Society’s Wollaston Medal. In presenting the award the society’s president acknowledged that the Gaia hypothesis had “opened up a whole new field of Earth Science study.”


Chris Jordan

An albatross chick on Midway Atoll, raised on plastic that its parents mistook for food from the polluted Pacific Ocean, September 2009; photograph by Chris Jordan

The Gaia hypothesis has now evolved, according to Lovelock, into a full-fledged scientific theory (in science hypotheses are held to be untested ideas put forward to explain facts, while theories have been tested and are generally considered true). Part of the testing came in 2001 when scientists from four international climate research programs reasserted the hypothesis’s basic tenets: (1) Earth “behaves as a single, self-regulating system”; (2) “human activities are significantly influencing Earth’s environment”; (3) Earth’s system is complex and difficult to predict, and “surprises abound”; (4) the system is characterized by “critical thresholds and abrupt changes”; and (5) Earth’s system has “moved well outside the range of natural variability exhibited over the last half million years at least.” Yet despite such support, the transformation of the hypothesis to the status of a theory is still widely disputed.

The Gaia concept and climate change science are intimately connected, and Lovelock has spent most of his career trying to understand the consequences of increased greenhouse gas concentrations in the atmosphere. In his latest book, The Vanishing Face of Gaia: A Final Warning, he argues that Earth’s system of self-regulation is being overwhelmed by greenhouse gas pollution and that Earth will soon jump from its current cool, stable state into a dramatically hotter one. All climatologists acknowledge the existence of such climatic jumps—as occurred for example at the end of the last ice age. But chaos theory dictates that the scale and timing of such leaps are inherently unpredictable, which means that they cannot be incorporated into the computer models of Earth’s climate system that such scientists use to project future climate change. Yet this is precisely what Lovelock attempts to do—using his own computer modeling—in The Vanishing Face of Gaia. A new climatic jump, he concludes, will occur within the next few years or decades, and will involve an abrupt increase in average global surface temperature of 9 degrees Celsius—from 15 to 24 degrees Celsius (59 to 75 degrees Fahrenheit). Such a shift, he contends, will trigger the collapse of our global civilization and the near extinction of humanity.

In contrast, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), which was released in 2007, predicts a likely rise of 2–3 degrees Celsius (4–6 degrees Fahrenheit) this century. Lovelock argues that the IPCC projections are incorrect because they do not include temperature jumps, yet as we’ve seen such jumps are widely held to be impossible to model. He also points out that data published subsequent to the IPCC’s research cut-off point of early 2005 show that their projections are too conservative. Support for this view has come from a climate science summit held in Copenhagen in March 2009 attended by 2,500 delegates, which concluded that “the worst-case IPCC scenario trajectories (or even worse) are being realised.”

So what makes Lovelock think he can predict the timing and scale of future climatic leaps? His findings are based on experiments conducted with a simple kind of computer model that is used by climate scientists to diagnose the accuracy of larger climate models. This revealed that signs of climatic instability are likely to appear as the concentration of CO2 reaches 400 parts per million (ppm). Then when CO2 reaches a concentration of 400–500 ppm, the computer model predicts a sudden rise in temperature of 9 degrees Celsius. But just before that major temperature jump a strange thing happens—the temperature dips for a few years. As Lovelock puts it, if his model

truly represents the Earth’s response to increasing carbon dioxide, it is scary because it implies that before the final jump to a desert world, the climate will briefly become cooler again. This warns that a cold summer, or even a series of them, is not proof that global heating has ended.

Another way of putting it is that normal climatic variation will precede Lovelock’s 9 degree jump in temperature. This is hardly useful as a predictive tool, and indeed Lovelock’s approach to the problem clearly will require further scientific corroboration before it is accepted.


But if we assume Lovelock is right, how close might we be to the temperature jump predicted in his model? Prior to the industrial revolution, the concentration of CO2 in the atmosphere was 280 ppm. Today it’s around 390 ppm. But the combined warming effect of all the greenhouse gases in the atmosphere, if expressed in terms of the warming potential of carbon dioxide, is around 430 parts per million. If Lovelock’s model is to be believed, the fatal jump could occur any day. Because such an imminent climate shift would have grave consequences, it would be rash to disregard his warning out of hand.

As we try to assess Lovelock’s highly individualistic work and decide whether his message is worth listening to, there is no better guide than John and Mary Gribbin’s James Lovelock: In Search of Gaia. Essentially a dual biography, it deftly recounts in alternating chapters the development of climate change theory and the life of Lovelock himself.

Born on July 26, 1919, into a working-class family, Lovelock believes that he was “a product…of the celebration of Armistice Night at the end of hostilities in World War 1.” A convert to the Quaker faith and until 1944 a conscientious objector, Lovelock graduated from Manchester University in 1941 and soon thereafter took up a position as a “glorified lab assistant” at the National Institute for Medical Research. There he seems to have been curious and skeptical about everything, and when medical staff explained to him that disinfectant sprays killed airborne bacteria because droplets bumped into them, he set about calculating the probability that a droplet of disinfectant would actually encounter an airborne bacterium.

The chances were so low, he discovered, that many bacteria would survive for at least a day after a room was sprayed, leading him to deduce that the sprays work because disinfectant evaporates from the droplets and, having evaporated into the atmosphere, it can kill bacteria. He tested this idea by using a nonevaporating disinfectant, which was ineffective, and an identical but evaporating one, which “killed bacteria like the clappers.” He was also the researcher who demonstrated that the common cold was transmitted via touch rather than through the air.

Lovelock’s exceptionally effective research method derives from a strong capacity for empathy. When working on a problem he quite literally tries to envisage himself in the role of the subject being considered: in the case just mentioned, a bacterium and a droplet in the vastness of the atmosphere; and presumably, when considering the responses of Gaia to CO2 pollution, Earth as a whole. Indeed he often describes Gaia as an elderly lady, and at ninety Lovelock is no youngster himself.

In 1946 Lovelock received a doctorate from the University of London for his studies in air hygiene. His work involved the invention of scientific instruments, the most influential of which allow for the detection of almost unimaginably small traces of pollutants. One such device, which remains in widespread use, is known as the electron capture detector. It operates like a conventional gas chromatograph—a machine in which samples of air are passed through a tube containing fine powder, which forces the various molecules in the samples to be absorbed at different points along the tube. But it also allows for the identification and counting of individual molecules of pollutants such as chlorofluorocarbons (CFCs—the chemicals responsible for the destruction of the ozone layer) in a sample of air.

Using the electron capture detector while on holiday on the west coast of Ireland in 1969, Lovelock discovered that the air contained 50 parts per trillion of a manufactured chemical known as CFC-11. This, he surmised, had blown in all the way from America, prompting him to wonder whether the entire atmosphere was already polluted with CFCs. To test this hypothesis, in 1971 he took his machine on a research vessel bound for the Antarctic. He discovered the pollutant everywhere, and within a few years the data he collected were being investigated by researchers interested in the destruction of the ozone layer. Strangely, Lovelock initially dismissed the idea that CFCs could be responsible for the ozone damage, and appeared as chief scientific witness during US Senate hearings for Du Pont, the main manufacturer of the offending chemicals. Because he presented an objective view of the science as it was known at the time, Lovelock claims that he could as well have appeared for the other side, if only they had asked him.

The concept of Gaia came to Lovelock suddenly “one afternoon in September 1965.” He was visiting the Jet Propulsion Laboratory in California when an astronomer brought him data demonstrating that the atmospheres of Mars and Venus were composed almost entirely of CO2. The high levels of oxygen in Earth’s atmosphere, resulting from the breakdown of CO2, stood in stark contrast. When he mentioned this to the astronomer Carl Sagan, Sagan told him of the “faint young sun paradox,” which states that while the sun was 25 percent cooler when Earth was young, our planet never froze over as it should have. It was then that “the image of the Earth as a living organism able to regulate its temperature and chemistry at a comfortable, steady state emerged in my mind,” Lovelock recalled.


The trail of scientific discoveries leading to this moment is long indeed; the Gribbins trace it back to the work of Robert Boyle, a founder of the Royal Society, who in the seventeenth century described the atmosphere as “exhalations of the terraqueous globe.” A century later Joseph Black demonstrated that the “exhalations” were a mixture of gases, and the first one he isolated was CO2, then known as “fixed air.” In the 1820s the French mathematician and physicist Jean-Baptiste Joseph Fourier began to ponder why Earth’s temperature was maintained at its current level. A keen student of how heat was transmitted, he tried to calculate how hot Earth should be, given its distance from the sun, and came up with a figure of -15 degrees Celsius (5 degrees Fahrenheit).

Something was clearly keeping Earth much warmer than it should be, and that “something,” Fourier realized, was in the atmosphere. It was John Tyndall who in 1859 discovered the precise mechanism. He realized that some colorless gases such as CO2 and water vapor behave very differently from other gases when exposed to radiant heat, for they absorb some of the heat energy, then reradiate some of it back toward Earth. In 1861 he published a landmark paper, stating that changes in the concentration of these gases in the atmosphere “must produce a change of climate” and that “such changes in fact may have produced all the mutations of climate which the researches of geologists reveal.”

The work of these pioneers was subsequently built upon by luminaries such as the Swedish scientist Svante Arrhenius, who first realized in 1904 that the concentration of CO2 in the atmosphere was increasing because of the burning of coal, and that this must eventually affect Earth’s climate. By 1938 the British physicist Guy Callendar had showed that Earth’s average surface temperature had increased during the first third of the twentieth century, a rise he attributed to the burning of fossil fuels (though his work was widely disbelieved at the time). By the 1970s the first computer models were producing projections of how temperature increases might play out in the future. Today, an entire scientific discipline, Earth System Science (called by Lovelock Gaia Science), is devoted to understanding the way that life regulates conditions such as the temperature on Earth’s surface.

As an independent scientist without an institutional affiliation, Lovelock is the quintessential outsider, and initially his Gaia hypothesis gained little credibility among scientists. Indeed, it was more often a source of ridicule than investigation. “The biologists were the worst,” Lovelock recalls.

They spoke against Gaia with the kind of dogmatic certainty I hadn’t heard since Sunday School. At least the geologists offered criticisms based on their interpretation of the facts.”

Some of the most important criticisms came from Richard Dawkins, who described Lovelock’s book Gaia as part of “the pop-ecology literature.” The hypothesis, Dawkins believed, did not take proper account of evolution by natural selection, with its requirement for competition between organisms. According to Dawkins:

There would have to have been a set of rival Gaias, presumably on different planets. Biospheres which did not develop efficient homeostatic regulation of their planetary atmospheres tended to go extinct. The Universe would have to be full of dead planets whose homeostatic regulation systems had failed, with, dotted around, a handful of successful, well-regulated planets of which Earth is one…. In addition we would have to postulate some kind of reproduction, whereby successful planets spawned copies of their life forms on new planets.

These criticisms were important to Lovelock, who became interested in testing whether Darwinian evolution could indeed produce an entity such as Gaia, and to do so he developed a computer model which became known as “daisyworld.”

Daisyworld is an attempt to see what happens on an imaginary planet in the same orbit around the sun as Earth, but with a very simple ecology. Only daisies grow there, and they vary from dark-colored to light. They can only grow if it is neither too hot (above 40°C) nor too cool (below 5°C), with an optimum temperature of 20°C. The only thing that affects the surface temperature of this model world is how shiny its surface is: if it’s bright then sunlight is reflected into space before it turns into heat energy; if dark, then lots of sunlight is turned into heat energy and so daisyworld heats up. A bright daisy will thus cool its surroundings, while a dark one will warm it.

With the “faint young sun paradox” in mind, Lovelock ran programs to simulate conditions as they have been throughout Earth’s history. Large clusters of light-colored daisies died off when their surroundings became too cool, while similar clumps of dark ones also died when it became too warm. Over numerous computer generations of daisies, the proportion of light and dark types became balanced so as to keep conditions at the surface relatively constant, and within the optimum temperature range for daisy growth.

This experiment sparked a wave of interest among researchers, and over the years daisyworld models have proliferated and become more complex. But always the results are the same: life as a whole (albeit virtual life) regulates conditions to suit itself. Calling daisyworld his “proudest scientific achievement,” Lovelock argues that it completely answers the criticism that Gaia could not evolve by the process of Darwinian natural selection.

This view is championed by Mark Staley, one of the foremost proponents of daisyworld-type modeling, who says of the models that the equilibrium state and optimal conditions to which the models return after each imbalance to the system “may appear to be the product of a cooperative venture, but it is in fact the outcome of Darwinian selection acting upon ‘selfish’ organisms.” Several real-world examples of daisyworld-like regulation have now been discovered. Among the most intriguing is the way coral reefs increase cloudiness in the air above them through the production of cloud-seeding chemicals, thus shading themselves from dangerous ultraviolet radiation. Another example concerns rain forests like the Amazon, which generate their own rainfall.

Such proofs have not convinced everyone, however, of the reality of Gaia. One such skeptic is paleontologist Peter Ward, whose book The Medea Hypothesis argues that life is ultimately self-destructive:

A characteristic of evolution is that its basic unit is the species, not the biosphere, and from this accrues a vicious, uncaring lethality toward other species that is one of the three most basic characteristics of life itself.

Ward’s hypothesis derives its name from the mythical Medea, wife of Jason of the Argonauts, who in an act of rage murdered all of her children. “This name thus seems appropriate for an interpretation of Earth life, which collectively has shown itself through many past episodes in deep time to the recent past, as well as in current behavior, to be inherently selfish and ultimately biocidal,” Ward muses.

At the heart of Ward’s argument is a particular interpretation of the great extinction crises documented in Earth’s geological record. These crises begin with the “methane disaster” of 3.7 billion years ago (when the spread of early methane-producing life forms is thought to have created a “cold buffer” in the atmosphere that almost ended life on Earth), and end with the ice ages, the last of which receded 20,000 years ago. The postulated mechanisms are varied but in almost all cases, Ward argues that it was life itself that destabilized the climate. He also argues that human behavior today is simply an extension of this inherent destabilizing tendency, and that our ever-growing population, destruction of biodiversity, and greenhouse gas pollution will soon bring about another great extinction crisis—about the only idea that Ward and Lovelock share in common.

Although Lovelock could not have been aware of Ward’s book, he has considered the problems raised by the Great Extinctions. As he tells the Gribbins:

Some unthinking critics of Gaia theory have pointed to these extinctions as evidence that the theory must be wrong, since Gaia is unable to sustain perfect conditions for life throughout all of geological time. “This does annoy me,” says Lovelock. “It’s like saying that because a person suffers a bout of flu, they aren’t alive. The whole point is that the planet recovers from these events, even disasters in which 90 percent of species have been wiped out. To me, this shows how effective Gaia is at bringing the Earth back from the brink of catastrophe to a healthy state. That’s what homeostasis is all about. ”

Like Lovelock, I find Ward’s book unconvincing, in large part because it does not address the proofs offered by Lovelock in support of Gaia, daisyworld among them. And Ward’s case is further weakened by our continued lack of knowledge surrounding the causes of past extinctions. It was, after all, only thirty-odd years ago that we discovered that the extinction of the dinosaurs was caused by the collision of an asteroid with Earth.

Hypotheses such as Gaia and Medea are important because they have implications for human survival, and because they influence the way we view ourselves. They also force scientists to grapple with social, moral, and philosophical issues well outside their expertise. In identifying the root of the climate problem Lovelock coins the word “polyanthroponemia”—a condition in which “humans overpopulate until they do more harm than good.” As he explains:

The presence of 7 billion people aiming for first-world comforts…is clearly incompatible with the homeostasis of climate but also with chemistry, biological diversity and the economy of the system.

But what does this imply, in an era of climatic turmoil, for public policy? Musing on its implications for his homeland, Lovelock writes:

We in Britain live on one of the safe havens where life can continue in the heat age. In certain ways the British are like passengers aboard a ship that has diverted to take on board refugees…but the captain and officers of the ship have to decide how many we can take…. Fairness suggests a lottery, but common sense rules out so simple a selection. The sick, the lame, and the old would have to stay behind and take their chances along with passengers who felt called to help them. On ships it used to be women and children first, but some men would be needed—what would be the right ratio of the sexes?

In the face of such a bleak prognosis, Lovelock’s principal suggestion is to try to adapt, for he believes that the changes to come are all but inevitable. Though he sees no hope in international agreements or collaborations, he falls back on “national cohesion” and an acceptance that “war and warlords are part of it” to see some of us through. This doubtless reflects Lovelock’s age: few younger people, I suspect, would agree.

Compounding Lovelock’s fatalistic prediction of the imminent collapse of our global civilization is his belief that almost everything we’re doing to stem the crisis is misguided. (He does concede that cutting back damaging land use practices such as forest clearance and “cautiously prepar[ing] to reduce emissions” are sensible.) Our efforts to develop biofuels and renewable energy, however, he sees as only making the problem worse. He posits that the pursuit of biofuels will lead to more land clearance and a diminution of our food supply. While this may be true in the case of ethanol derived from corn or sugarcane, it is certainly not true of more advanced techniques that derive biofuels from algae or crop and other waste.

Similarly, Lovelock views wind and conventional solar power as largely a waste of time because they are unable to deliver a consistent and sufficiently large supply of electricity, stating that “Europe’s massive use of wind as a supplement to baseload electricity will probably be remembered as one of the great follies of the twenty-first century.” Only nuclear power, he believes, offers us salvation. Lovelock has held these views for as long as he’s been writing about climate change: they have not altered significantly as the crisis has grown, or as wind and solar technologies have improved and “smart grid” solutions for using intermittent sources of supply have developed. They read here as an increasingly ingrained refrain, ever more disconnected from reality.

One of the strongest impressions one gets from The Vanishing Face of Gaia is that Lovelock disagrees with almost everyone. But it is the green movement that evokes his most piquant criticism. He sees Rachel Carson’s Silent Spring, a book that is often cited as starting the modern environmental movement, giving birth to what he calls a “narrow restrictive faith” that pushes “a partisan and contentious political cause, which at best was no more than a partial expression of the humanism of Christianity or Socialism, and at worst an anarchic extremism.” Indeed in places he goes further: “Now we have the urban environmentally friendly ideology, perhaps the most deadly of them all.” Yet for all this, there’s no overt criticism of the deceit of the coal and oil industries, which continue to pollute unabated.

Whatever one makes of this cranky and idiosyncratic book, one thing is clear. James Lovelock has told it as he sees it; his biographers tell us that he is “completely open and honest, almost to the point of naivety,” and at ninety he has nothing to lose, while readers, however skeptical, have much to gain.

This Issue

November 19, 2009