Scientists and Gaia
Financial Times 2002
The Gaia hypothesis is a human observation about the relationship between life and its physical environment work on the surface of the Earth. It at once a very old idea and a very new one. What was first a kind of analogy has now become an integrative factor in modern science.
Looking back it is strange how uncongenial the idea was to the conventional wisdom when it was put forward in its present form over a quarter century ago. Unfamiliar ways of looking at the familiar, or any re-ordering of the intellectual furniture, tend to arouse emotional opposition far beyond rational argument: thus opposition to the idea of evolution by natural selection, continental drift and tectonic plate movement, and more recently cometary or asteroid impacts from space. The Gaia hypothesis challenges current habits of reductionism, and the tendency of many academics to put their subjects into boxes, shut the lid, and ignore what is going on in other boxes. In any case most of us are better at looking at the constituent elements of problems than in seeing the connections between them and understanding how the resulting system works.
Gaia is a supreme example of interdisciplinarity. It comes at a time when science as such is under challenge from a society somewhat disenchanted with it. Whether it be over civil nuclear power, asbestos, thalidomide or BSE, public scepticism over scientific claims has greatly increased. This has made many scientists defensive and reluctant to embrace wide new interpretative ideas of which Gaia is a good example.
There have been many definitions of the Gaia hypothesis, and I will not venture a new one. For good working purposes, I suggest that put forward by James Lovelock and Lynn Margulis in a joint paper in 1984:
"…..the evolution of a tightly coupled system whose constituents are the biota of their natural environment, which comprises the atmosphere, the oceans and the surface rocks."
Or more recently "symbiosis seen from space".
The mysteries of the relationship between the living and the non-living environment was recognized from the earliest days, and in many respects is the stuff of religion. Gods and goddesses were seen to embody specific elements, ranging from the vastness of the sky to the most local spring, and the notion that the Earth itself was alive came up regularly in Greek philosophy. Leonardo da Vinci saw the human body as a microcosm of the macrocosm which was the Earth. What was good for one was good for the other. Bruno was burnt at the stake just over 400 years ago for maintaining that the Earth was indeed alive, and that other planets could be so too. The geologist James Hutton saw the Earth as a self-regulating system in 1785, and T H Huxley saw likewise in 1877. Others, notably in Russia, have done so in a dispersed way ever since. But it was James Lovelock who in the 1960s brought forward the Gaia hypothesis in its present form, and has with Lynn Margulis worked on it ever since.
What is in a name? I remember a conversation with a distinguished scientist keen to rubbish "all that Gaia nonsense". When I protested and offered to rename it "geophysiology" , "earth systems science" or something similar, he brightened up and eventually confessed that "most of it must be right". The choice of the Greek goddess Gaia rather than of some Greek derived polysyllable, or worse of some terrible acronym, was a risk. On the one hand it was just too attractive for those in search of a new religion at a time when traditional religions were breaking down; on the other it was just too repulsive for those who liked to hide their science in their own coded vocabulary. The result was that some New Age travellers jumped aboard, and some otherwise sensible scientists jumped off. This is probably still the case. But as a hypothesis, Gaia is now winning.
The scientific communities of the four great international global change research programmes - the International Geosphere-Biosphere Programme (IGBP), the International Human Dimensions Programme on Global Environmental Change (IHDP), the World Climate Research Programme (WCRP) and the International Biodiversity Programme Diversitas - met at Amsterdam on 13 July 2001. They then adopted a Declaration on Global Change, signed by almost a thousand people, that stated squarely that
"the Earth system behaves as a single, self-regulating system, comprised of physical, chemical, biological and human components. The interactions and feed backs between the component parts are complex and exhibit multi-scale temporal and spatial variability."
Here indeed is the Gaia hypothesis. The same goes for the Earth systems science which is now the concern of the Geological Society of London with which the Gaia Society has recently merged. Whatever the label, Earth systems science or Gaia has now become a major subject of enquiry and research, and no longer has to justify itself.
It was, I think, Lynn Margulis who described Gaia as "a tough bitch". So she is. As representative of the whole system on Earth over its 3.8 billion years, it is her robustness which is so impressive and reassuring even when challenged as it were, from outside from time to time. Indeed according to some astrobiologists, the means of life were generated elsewhere. The system has survived the great extinctions from outside the Earth, and the great catastrophes from within it. This has required a remarkable ability not only to adapt to whatever may come, but also adapt to the physical environment for biological purposes. Gaia is a lady who remains the same underneath, but can wear many clothes for many weathers and many fashions. As the palaeontologist Richard Forty has well written "life made the surface of the earth what it is even while it was earth's tenant."
Of course Gaia has no particular tenderness for humans. We are no more than a small, be it immodest, part of the system. Only in the last tick of the clock of geological time did we make our appearance, and only in the last fraction of it did we make any impact on the system as a whole.
We now know how vulnerable our little planet is to human depredations. A periodical visitor from out of space would find more change in the last 200 years than in the last preceding 2000, and more change in the last 20 years than in the preceding 200. The association between humans and their environment, including the micro world in and around them, has changed at every change of human evolution: from vegetarians to meat eaters, from hunter gatherers to farmers, and from country to city dwellers. But the most radical divide was the industrial revolution which began in Britain some 250 years ago. Before then the effects of human activity were local, or at worse regional rather than global. All the civilizations of the past cleared land for cultivation, introduced plants and animals from elsewhere, and caused a variety of changes. The southern and eastern coasts of the Mediterranean are a case in point. The soils have now become sand, the trees are often camel grass, animals of all kinds have disappeared, and the clouds sail overhead to drop their rain somewhere else.
With the industrial revolution, all began to change. I suspect that the present generation - ours - is the first in which the magnitude of the effects on the earth as whole has become manifest. This clearly emerged in the Amsterdam Declaration. There it was stated that changes brought about by human activity
"to Earth's land surface, oceans, coasts and atmosphere and to biological biodiversity, the water cycle and biogeochemical cycles are clearly identifiable beyond their natural variability. They are equal to some of the great forces of nature in their extent and impact. Many are accelerating……[They] have the potential to switch the Earth's system to alternative modes of operation that may prove irreversible and less hospitable to humans and other life. The probability of a human-driven abrupt change in Earth's environment has yet to be quantified but is not negligible."
What are these changes? They fall into five main categories, all inter-linked. First there has been a giddy making increase in human numbers, rising from around one billion at the time of Thomas Malthus (who first drew attention to the relationship between population and resources), to two billion in 1930 and now over six billion. The world population is increasing by over eighty million people each year. There are over 450 million new people on the earth since the Rio Conference on Environment and Development in 1992. More than half our species now lives in cities, which are themselves like organisms drawing in resources and emitting wastes. In short we are spreading like dandelions, or any other species on a bonanza. Indeed it has been suggested that human multiplication is a case of malignant maladaption in which a species, like infected tissue in an organism, multiplies out of control, affecting everything else. In terms of factors of increase in the last century, air pollution rose by around 5, water use by 9, sulphur emissions by 13, energy use by 16, carbon dioxide emissions by 17, marine fish catch by 35, and industrial output by 40.
All this has profoundly affected the condition of the land. More people need more space and more resources. Soil degradation is widespread, and deserts are advancing. Such degradation is currently estimated to affect some 10% of the world's current agriculture area. Although more and more land, whatever its quality, is used for human purposes, increase in food supplies has not kept pace with increase in population. Today many of the problems are of distribution. But even countries generating food surpluses can see limits ahead. In the meantime industrial contamination of various kinds has greatly increased. To run our complex societies, we need copious amounts of energy, at present overwhelmingly derived from world dwindling resources of fossil fuels laid down hundreds of millions of years ago. We also have to deal with the mounting problems of waste disposal, including the toxic products of industry.
Next there has been increasing pollution of water, both salt and fresh. No resource is in greater demand than fresh water. At present such demand doubles every twenty-one years and seems to be accelerating. Yet supply in a world of over six billion people is the same as at the time of the Roman Empire in a world of two hundred to three hundred people. We are at present using some 160 billion tonnes more water every year than is replenished.
Then there have been changes in the chemistry of the atmosphere. Acidification from industry has affected wide areas downwind. Depletion of the protective atmospheric ozone layer permitting more ultra-violet radiation to reach the surface of the earth with so far unmeasured effects on organisms unadapted to it. Greenhouse gases are increasing at a rate which could change average world temperature, with big resulting variations in climate and local weather as well as sea levels. According to the estimates of the Intergovernmental Panel on Climate Change, we could be altering the global climate at rates far greater than would have occurred naturally in the last ten thousand years with unforeseeable consequences. Carbon levels in the atmosphere are now the highest in the last 160 thousand years, and rising fast.
Last humans are causing extinction of other organisms at many times the normal rate. Indeed the rate of extinction is reminiscent of the dinosaur extinction of 65 million years ago. The rising damage to the natural services on which we like all species depend is immeasurable. There is no conceivable substitute for such services. At present there is a creeping impoverishment of the biosphere. According to the Living Planet Index put forward by WWF in 2000, the state of the Earth's natural ecosystems has declined by about a third in the last thirty years while the ecological pressure of humanity has increased by about a half during the same period.
Like self regeneration environmental change rarely proceeds in curves. It goes in steps and thresholds. Due perhaps to the shortness of our individual lives and our lack of imagination we tend to believe that what we know - the current diversity of life and the climate around us - will only change within narrow limits; and that if nature is allowed to take its course, things will revert to where they were. Unfortunately history gives no foundation for this belief. As was well said in the Amsterdam Declaration, "the Nature of change is now occurring simultaneously in the Earth's system, their magnitudes and rates of change are out precedented. The Earth is currently operating in a no-analogue state." Again Gaia has no special tenderness for our species.
A question often asked is the measure of human responsibility for what is happening, and whether we have some God-given role in the process. There has for example been some talk, notably among the religiously inclined, about an alleged human obligation of "stewardship" of the Earth. If so, the Earth has had to wait a long time for the arrival of the stewards. Certainly the trilobites for over 250 million years without them. Looking at the human record of predation, exploitation and extinction of other forms of life since the current version of hominids appeared less than 150 thousand years ago, I am reminded of James Lovelock's remark that "humans are about as qualified to be stewards of the Earth as goats are to be gardeners."
Certainly there is a lot of human responsibility, but it is something very different. For most people it relates primarily to the interest we all have in looking after ourselves. On this reckoning we have two excellent reasons for trying to treat the current configuration of Gaia with more respect and understanding. In particular we need to maintain our own good health as well as that of the plants and animals, big and small, on which we depend for food. We pride ourselves on our medicine as if it were somehow detached from the natural world, but it is an obvious product of it. As well as conserving biodiversity at the level of species and ecosystems, we also need to cherish the genetic diversity that occurs within them. Modern agricultural techniques have lead to an excessive dependence on a few miracle strains of even few plants and animals. Without a large natural genetic reservoir, we make our food supplies vulnerable to disease as the Irish potato growers in the 19th century learnt to their cost.
Just as important are the ecological issues. At present we take as cost free a broadly regular climatic system with ecosystems, terrestrial and marine to match. We rely on forests and vegetation to produce soil, to hold it together and regulate water supplies by preserving catchment basins, recharging ground water and buffering extreme conditions. We rely upon soils to be fertile, and to absorb and break down pollutants. We rely on coral reefs and mangrove forests as spawning grounds for fish, and on deltas as shock absorbers for floods. There is no conceivable substitute for these natural services. Often we hardly notice them. In many cases we do not know the threshold which once passed, leads to their collapse or radical change. Yet we cannot continue to assume that they will continue to come for free forever.
All this raises obvious issues of human values. Such values constitute each person's world view. We tend to believe that greater material prosperity and welfare are overriding human priorities, that resources can be indefinitely exploited, and that economic growth of the traditional definition is good in itself: in short ever upwards and onwards with free markets, free trade and continuously rising consumption. With this goes an almost religious belief in technology as the universal fix: and extension of human capacity to adapt to and cope with whatever may arise. We live as what has been described as the technosphere in which the techno market blindly rules with little regard to human needs or aspirations. We tend to forget that information does not replace knowledge.
There is an accompanying spread of culture of rising expectations, nourished by world wide use of information technology through radio, television, email, the internet and the press. One consequence is a drive towards industrialization as a synonym for "development" and the catch-all answer to the world's manifest ills. With it has come globalization and an increasing homogenization of human culture, and a widening gap between rich and sophisticated, and poor and unsophisticated. As has been well said, globalization represents a kind of mutation in human civilization.
Another consequence is change in evolution itself. Human activity is changing the processes of natural selection, mutation and symbiosis, not just though genetic engineering and modification of organisms but also through large scale extinction of species and the ecosystems in which they have a place. We have yet to see whether there is any realistic prospect of developing a subspecies of super humans with genes tailored to specific requirements, but it is certainly not impossible in the future. Gaia may be able to take these changes, but it is not necessarily a Gaia we would happily recognize.
In fact human damage to the current life system of the planet is not incurable. Most of the solutions to the problems we have created are already well known. Take population increase. The overall rate is still rising, but in several parts of the world it is levelling off. The main factors are the improvement in the status of women, better provision for old age, wider availability of contraceptive devices, lower child mortality and better education, especially for girls and young women. Take degradation of land and water. We know how to look after them both if we try. We do not have to exhaust top soils, watch them erode into the sea, rely upon artificial aids to nature, illuminate the forests with their natural wealth of species, or poison the waters, fresh and salt. Take the atmosphere. We do not have to punch holes in the protective ozone layer. We do not have to rely on systems of energy generation which will affect climate and weather in such a fashion that change, even for the better, might put an over crowded world at risk. Take the way in which we conduct most scientific enquiry. We do not have to break down issue in to water tight compartments, and so miss the internal dynamics of the life system - Gaia - as a comprehensive whole.
Moreover understanding of the Gaian approach is already spreading fast, whether it is labelled Gaia or not. An example of the need for it is in the field of economics, where fashionable delusions about the supremacy of market forces are deeply entrenched, and the responsibilities of government to set the framework for economic activity and protect the public interest often ignored. At present there is an astonishing failure to recognize true costs. As has been well said (again?), markets are marvellous at determining prices but incapable at recognizing costs. Definition of costs requires a Gaian approach towards economics and towards measuring things, and this has to be brought back into pricing. In addition to traditional costs of research, process, production and so on, prices should reflect the costs involved in replacing a resource or substituting for it; and the costs of the associated environmental problems. Governments also have to get rid of perverse subsidies, for example those to the fossil fuel industry, the price of whose products is anyway artificially low in relation to the damage it does to the environment. We need a paradigm shift in which politicians and ecologists alike recognize that humans are more than mere producers or mere consumers.
One of the key points in the Amsterdam Declaration was that a new ethical framework for management of the Earth's system was urgently needed.
"the accelerating human transformation of the Earth's environment is not sustainable. Therefore the business-as-usual way of dealing with the Earth's system is not an option. It has to be replaced - as soon as possible - by deliberate strategies of management that sustain the Earth's environment while meeting social and economic development objectives."
This requires a radically new approach. If we are eventually to achieve a human society in harmony with nature, we must be guided by respect for it. No wonder that some have wanted to make a religion of Gaia or life as such. At least we need an ethical system in which the natural world has value not only to human welfare but also for and in itself. The British poet D H Laurence once wrote
"I am part of the sun as my eye is part of me. That I am part of the Earth, my feet know perfectly; and my blood is part of the sea".
Let the same exhilaration all.