Homage to Gaia

by James Lovelock

  I am often told that I must be rich because of the patent royalties accumulating from the ECD invention. It is true that my name is on the patent for the ECD, but royalties there have been none. The US Government seized the patent soon after its issue in 1964. What happened was this. In 1958 Dr Sandy Lipsky invited me to spend a sabbatical at Yale University in the Department of Internal Medicine where he was a professor. I travelled there with all my family and spent eight happy months in the small Connecticut community of Orange just outside New Haven. It was a wholly different experience from the difficult times in Boston three years earlier. While at Yale I reduced the ECD to practice and it worked well enough to justify a paper, which Sandy Lipsky and I published in the Journal of the American Chemical Society. Before publication, the Department suggested that it would be wise to apply for a patent. If the device was a success and the patent granted we agreed a three-way share between the University, a patent agency and me. I was happy with this proposal; a third share seemed better than no share at all. But when the patent was issued in 1964, I received a curt notice from the US Surgeon General’s Department demanding that I assign the patent immediately to them. I refused equally curtly, saying that it was my invention, not theirs. Shortly after, a much more conciliatory letter came from the Dean of the School of Medicine of Yale asking me to reconsider and assign the patent to the US Government as requested by them. The reason given was that the Government was threatening to shut off grants to the Department unless I complied. The University told me that their agreement with the grant-funding agency included a clause that made all patents filed by the department I had worked in the property of the Surgeon-General. At the time I thought that the ECD was a minor invention and unlikely to be worth much. Certainly, I thought, not worth imposing hardship on my friends at Yale. Therefore, I assigned the patent. Looking back, I realize how naive I was to comply without at least a minor battle.

  The early ECD was an extraordinarily difficult device to use. It was prone to peculiar, even false results that frustrated scientists accused me of promoting a bogus device whose predictions were of no more use than those of a fortune teller. At times, I tended to agree with them, and it took several months to discover the cause of the ECD’s misbehaviour. It was, I found, due to the complex behaviour of the ionized gas inside the detector, complicated by the absorption of vapours on the detector surfaces. The cure for the electron capture detector’s bad habits came from an encounter with Ken McAffee, a physicist at the Bell Telephone Laboratories. He had developed a way to observe the drift of electrons in a gas that involved applying brief pulses of electrical potential. It occurred to me that most of the difficulties with the ECD were due to the slow collection of the free electrons in a weak electrical field, and that I could resolve these difficulties by collecting the electrons using a brief high-voltage pulse. It worked well: the high-potential pulses overcame the all-too-frequent contact potentials and space charges that unpredictably either enhanced or opposed electron collection. Later, I found that by observing the frequency of pulses needed to sustain a constant electron population, the detector became even more stable and reliable. This method is now the one almost universally used. Its only drawback is a non-linear response to strongly electron-attaching compounds.

  As I gained experience in the analysis of different molecular species by electron capture, I grew aware of an odd and interesting association between electron capture and biological activity. In 1960 and 1961, the last years of the Mill Hill apprenticeship, my experiments with the electron capture detector showed that a large proportion of the substances detected were in two main groups. The first group consisted of those important in metabolism, for example the alternate acids of the famous Krebs cycle, steroid and thyroid hormones, and other molecules important in the metabolism of living cells. The other group of substances the ECD detected were poisons, in particular, substances that interfered with metabolism, such as the nitro compounds, dinitrophenol or diodophenol, and all halogenated pesticides. The ECD also seemed to be uniquely sensitive to cancer-causing substances. Hydrocarbons, as oils or waxes, do not conduct electricity, nor do they react with electrons. But certain, special hydrocarbons, made of rings of carbon atoms fused together and called polycyclicaromatic hydrocarbons, capture electrons strongly. These unusual hydrocarbons included most of the carcinogenic ones. I could say that a tendency of a substance to capture electrons was all too often associated with carcinogenesis. Nowadays, whenever I come across a chemical substance that is strongly electron absorbing, I tend to regard it cautiously. I well recall critical scientists arguing that the apparent association between carcinogenesis and electron capture was illusory, since so many of the halocarbons were not carcinogenic. Vinyl chloride, chloroform, and trichloroethylene, they said, are substances safe enough for use as anaesthetics in surgery. Now, of course, we know them to be carcinogenic. I sometimes wonder about the phthalate esters. These ubiquitous plasticizers have long been a nuisance as electron-absorbing contaminants. We now suspect them to have a more sinister role as surrogate oestrogens.

  It was tempting to speculate that the free electron might be a fundamental particle of biology as well as of chemistry and physics. It was a challenging coincidence that each alternate acid of the Krebs cycle (the major pathway for the oxidation of lipids and carbohydrates) was one of the few organic compounds that reacted vigorously with free electrons. These include pyruvate, oxaloacetate, fumarate, ketoglutarate, and cis-aconitate. It is still unclear whether this association is real or coincidental, but there is no doubt that a remarkably high proportion of electron absorbers are biologically active, which makes the electron capture detector so important a device in environmental science.

  I tried at Mill Hill to use free electrons in equilibrium with molecules at room temperature as if they were a chemical reagent. To do this I borrowed a sewing needle from Janet Niven, a friend from my virology days. I placed the needle in a stream of mixed argon and methane gases and applied 10,000 volts of negative potential to it. There was a visible blue glow and a current of several microamperes flowed in the gas. The electrons released by the strong electric field near the needle point rapidly bounced among the gas molecules and became slowed to thermal energies. I let them flow towards substances like the acids of the Krebs cycle to see what happened. The experiments suggested that in nature a free electron is indeed a fundamental particle of biochemistry. But before I could complete these experiments, it was time to leave Mill Hill. I published the preliminaries in three papers, two in Nature and one as a Symposium record.

  While I was just experimenting, serious scientists were applying the detector to the practical analysis of pesticide residues in foodstuffs. In the USA, Watts and Klein of the FDA, and in the UK Goulden and his colleagues at Shell, together established the base data on the global distribution of pesticides and soon we realized that pesticides like DDT and dieldrin were everywhere and in all living things. This was the information that led Rachel Carson to write her seminal book, Silent Spring, a book that warned the world of the ultimate consequences if these chemicals continued to be used by farmers against all forms of life that are not livestock or crops. This important book has changed the course of politics and, in many parts of the world, her gloomy forecast of a silent spring has come true. Although not, as she predicted, by pesticide poisoning, but simply by habitat destruction.

  When I first heard of this use of the electron capture detector I was delighted. I shared with Rachel Carson a concern over damage to wildlife and to natural ecosystems. Some parts of the chemical industry reacted in a shameful and foolish way by trying to discredit her as a person. It did not work. Quite the reverse, it made Rachel Carson the first saint and martyr for the infant and innocent Green Movement.

  As environmentalism evolved, Rachel Carson’s vision and the data itself became corrupted. I do not mean that the data gathered was false, but so sensitive is the electron capture detector that it can detect utterly trivial quantiti
es of pesticides and other chemicals. Before we used the ECD, it would have been quite easy and reasonable to set zero as the lower permissible limit of pesticide residues in foodstuff. In practice, zero means the least detectable amount. After the electron capture detector appeared, zero as a limit became so low that to apply it in full would cause the rejection of nearly everything that was edible. Even organically grown vegetables and fruit, even wild vegetation, contains measurable levels of pesticides, so sensitive is the device.

  We needed common sense and the acceptance of the wisdom of the physician Paracelsus who said long ago, ‘The poison is the dose’. Even water is poisonous in excess. Even the deadly nerve gases are harmless at the level of a picogram, easily detectable by an electron capture detector. Unfortunately, common sense is a rare commodity. I listened with astonishment to a recent radio broadcast by a Green who argued that Paracelsus’s statement was no more than sophistry. Too many Greens are not just ignorant of science; they hate science. But despite this, they use the results gathered by the ECD and other instruments of science to support their crusades. The next intervention of the ECD into Green politics was in the relatively clear-cut problem of ozone depletion by halocarbons. I will describe my personal experiences in this ‘Ozone War’ in Chapter 8.

  This is not the place to discuss the theory of the electron capture detector, but it is an opportunity to mention a few interesting theoretical aspects of the device which otherwise are rarely revealed. I find it helpful to think of the detector as a small reaction vessel like a test tube, holding a dilute mixture of free electrons in an inert gas, and I look on these dilute electrons as a chemical reagent. When an electron is in equilibrium with a gas at room temperature it behaves as if it were a very large particle, larger even than most of the molecules it encounters. Unlike the fast-moving electrons that physicists encounter, the cool electron is no tiny billiard ball or point charge, it is a sizeable wave packet with a wavelength of seven nanometres at room temperature. The large size of the cool electron makes encounters with molecules more probable and accounts for the great sensitivity of the ECD. The chemical reaction between electrons and molecules is what physical chemists call second-order, and some of the problems faced by analysts arise from this fact. If the electron capture detector were insensitive and the number of molecules present were vastly greater than the number of electrons, the device would be proportional and predictable in its response. Unfortunately, with the compounds it detects sensitively (those which the analyst seeks to measure), the numbers of molecules in the detector are comparable with the number of electrons. In such circumstances, as textbook physical chemistry would tell you, the response of the detector to varying sample size is unlikely to be either proportional or easily predictable. Lack of sensitivity was not a complaint levelled at the electron capture detector. Even so, once we realized the possibilities of electron-attaching tags or tracers, that ultimate of detecting single molecules was the new destination.

  We are still far from taking a grab sample of air or water and finding in it one molecule of tracer. The best we can now do is to detect 100,000 molecules of tracer in a cubic centimetre of air. We have shown that certain fluorinated hydrocarbons can label air masses and let us follow their movement over thousands of miles. Andrew Watson has used the same technique to trace the movement of water masses in the oceans. We can now detect directly one part in 1014, an improvement made possible by signal processing using gas-switching techniques. This improvement makes it feasible to detect and measure tracer at one part in 1016 after a modest 100-fold concentration. Every year of this odyssey I have expected to find this simple device that anyone could make superseded by some impressive flight of high technology. Instead, its use seems to be expanding into new territories.

  8

  The Ozone War

  A dense haze that steals the sun’s warmth and blurs vision so that half a mile is the limit of seeing sometimes spoils summer days in England. I was puzzled about this haze because I could not remember seeing it as a boy or even before about 1950. I suspected that the haze was some form of air pollution like smog, but smogs in England were wintertime phenomena, fed by the smoke from open fires. The disastrous smog of 1952 killed nearly 4000 people in one night, and is still in our memories, but since then smokeless fuel has replaced the sulphurous coal and the winter sky, even in London, is clear. So, what was the new miasma that spoilt the summer air? What puritan phenomenon stopped us from enriching our eyes on the full-bosomed and lush English countryside? My scientist friends had nothing to offer in explanation; they even doubted my memories of clean air before the Second World War. One person whose writing led me to suspect that he would listen with sympathy to my concern was Hubert Lamb. He was a staff member of the meteorological office in Bracknell and I went there to see if he could explain it.

  In 1966 the Meteorological Office was in the new town of Bracknell. It was my first visit there and I was astonished to find that it was part of the Ministry of Defence. We English have always been paranoid about the weather but this seemed too much. Did we now see it as a national resource and treasure that needed the army to protect it? Intriguingly, the United States, then flexing its military muscles and obsessed with secrecy, put their weather bureau in the Department of Commerce. Perhaps they thought their weather good enough to sell. I propitiated the guards at this Ministry of Defence establishment, they gave me a pass for my visit and took me to Hubert Lamb’s office. He welcomed me warmly, but seemed embarrassed by an office rule that required him to charge me for my talk with him. The fee was £5. To have a charge to make upon scientific visitors clearly upset him, but the bureaucrats imposed it and I did not see it as either a source of indignation or something that was a deterrent. We enjoyed a lively discussion on weather phenomena and I stayed for lunch and met others who seemed equally interested in my haze observations. What seemed to turn on their interest and make them take me seriously was my presentation of my observations as graphs. These compared the haze in Wiltshire, as it changed with the season, with that in Los Angeles. The smog in rural Wiltshire in the summer was almost as bad as that in urban Los Angeles.

  By the late 1960s, it was a family ritual at Bowerchalke to measure the haze density using a sun photometer. We used a simple hand-held, battery-powered instrument that Robert McCormick, an NOAA meteorologist, had lent to me. Few such measurements were made in England and Hubert Lamb thought that visibility ranges, which had been observed daily at the meteorological stations throughout the British Isles, would have to do instead. They might provide some evidence on whether or not haziness had changed as time went by. My daughter, Christine, was as interested in this phenomenon as I was and had taken charge of the photometer readings. I arranged with Lamb for her to visit the Met office library and list the visibilities back to the start of the century. It was a disappointing exercise: no discernible trend was available from the records, but I am not the kind of scientist who is discouraged by one set of negative evidence. The haze of southern England looked to me like smog and I thought hard about gathering further evidence that would confirm or deny my ideas about its origin.

  It occurred to me that a chemical analysis of both clean and hazy air might provide evidence of the origin of the haze. I could have collected haze particles that obscured the air by impacting them on sticky microscope slides or I could have analysed the air for sulphur dioxide and other products of combustion. I decided not to do either of these things, partly because the known analytical methods were not sensitive enough, but mainly because the presence of small amounts of haze-producing chemicals in the air does not tell us where the air came from. They could have come from natural or agricultural emissions as well as urban industrial sources. What would be proof would be to detect in the country air some substance that originated unequivocally in an urban industrial region and which had no, or a negligible, source in the countryside. One class of substance that fitted this specification well was CFCs, then used in aerosol cans and in r
efrigerators. By far the greatest release of these compounds occurs in large cities. Better still, I had in my lab at Bowerchalke an apparatus able to detect and measure them easily, even at extreme dilution.

  So, in 1969 we started at Bowerchalke the simultaneous measurement of haze, wind direction, and the chlorofluorocarbon, FC11. Later the same year I took these measurements at Adrigole in far western Ireland. At both Adrigole and Bowerchalke the CFCs were more abundant when the air was hazy and it seemed that my notion that the haze was man-made was correct. I published the results in the Journal of Atmospheric Environment. I chose this journal because my friend, Jim Lodge, who was then on the staff of National Center for Atmospheric Research, was its editor. Having a friend as an editor eases the otherwise tedious process of satisfying the self-appointed tyranny of the peer-review system. The editor could at least select reviewers from a panel of reliable critics who would treat the paper reasonably and not from those who wanted a chance to vent their anger anonymously.

  The Atmospheric Environment paper suggested that southern England, and indeed, western Ireland, was sometimes during the summer immersed in the same kind of smog that plagued Los Angeles, but nobody outside my small circle of scientific acquaintances showed any interest at the time. In 1973 I collaborated with atmospheric scientists from Harwell and we showed that even in far western Ireland, foul air from Europe had ozone levels in it that were above the American Environmental Protection Agency’s safe limits. We published these findings in Nature, but again there was little interest from either environmental groups or the media. This small investigation might have ended, but I was curious about the fifty parts per trillion of one of the CFCs, FC11, in the clean Atlantic air. Had it drifted across the Atlantic from America? More excitingly, were the CFCs accumulating in the Earth’s atmosphere without any means for their removal? To find out, the only thing to do would be to travel by ship to the southern hemisphere and measure the CFCs as the ship travelled across the world.