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Earth Systems Science: Are We Pushing Gaia Too Hard?

Sir Crispin Tickell: "A periodical visitor from outer space would find more change [on Earth] in the last 200 years than in the preceding 2000, and more change in the last 20 years than in the preceding 200"

Earth Systems Science: Are We Pushing Gaia Too Hard?

The text of the 46th Annual Bennett Lecture for the 50th Anniversary of Geology at the University of Leicester given by Sir Crispin Tickell, a member of the Leicester i-Science Advisory Board

Earth system science is both very old and very new. It goes back to before science as such was defined, and goes forward to examine how the physical and living elements on the surface of the Earth combine.

That surface is wafer thin. The biologist E O Wilson once wrote of a hypothetical journey from the centre of the Earth:

“For the first twelve weeks you travel through furnace-hot rock and magma devoid of life. Three minutes to the surface, five hundred meters to go, you encounter the first organisms, bacteria feeding on nutrients that have filtered into the deep water-bearing strata. You breach the surface and for ten seconds glimpse a dazzling burst of life, tens of thousands of species of micro-organisms, plants and animals within a horizontal line of sight. Half a minute later almost all are gone. Two hours later only the faintest traces remain consisting largely of people in airliners who are filled in turn with bacteria.”

I begin in this way to underline the limited and precarious character of all life on Earth in its physical environment. We can attempt to distinguish the geosphere from the biosphere, and even the biosphere from the noosphere (or sphere of human intelligence), but none can be fully understood except as parts of a single integrated system.

No wonder that this unity was recognized from the earliest days. Indeed it was the stuff of religion. Gods and goddesses were seen to embody specific elements, ranging from 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 the microcosm of the Earth, and the Earth as the macrocosm of the human body. He did not know as well as we now do that the human body is itself a macrocosm of tiny elements of life – bacteria, parasites, viruses – often at war with each other, and together constituting around half our body cells. 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 it likewise in 1877. Vernadsky (1863-1945) saw the functioning of the biosphere as a geological force, moving, processing and recycling billions of tons of surface material every year. This created a dynamic disequilibrium, which in turn promoted the diversity of life.

But it was James Lovelock who brought this together into the Gaia hypothesis. There have been many definitions of it, 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”.

Looking back it is strange how uncongenial the observation was to the practitioners of 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 rearrangement of the intellectual furniture, tend to arouse emotional opposition far beyond rational argument: thus opposition to the idea of evolution by natural selection, of continental drift and tectonic plate movement, and more recently of cometary or asteroid impacts from space. Gaia theory challenges current habits of reductionism, and the tendency of some academics to put their subjects into boxes, shut the lid, and ignore what is going on in other boxes. 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.

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 scientific polysyllable, or, worse, some 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 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 theory, 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 over a thousand people, which stated squarely that

“the Earth System behaves as a single, self-regulating system, comprised of physical, chemical, biological and human components. The interactions and feedbacks between the component parts are complex and exhibit multi-scale temporal and spatial variability.”

Here indeed is Gaia theory. The same goes for the earth systems science which is now the concern of the Geological Society of London (with which the Gaia Society 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. Over 3.8 billion years, it is her robustness which is so impressive and reassuring. She has survived the great extinctions from outside the Earth, and the great catastrophes from within it. This has required a remarkable resilience whereby physical and biological mechanisms have adapted to new circumstances. Gaia is a lady who has remained broadly the same underneath, but can wear many clothes for many weathers and many fashions. She has no particular tenderness for humans. We are no more than a small, albeit immodest, part of her. Only in the last tick of the clock of geological time did humans make their appearance, and only in the last fraction of it did they make any impact on the earth system as a whole.

But that impact has been enormous. A periodical visitor from outer space would find more change in the last 200 years than in the 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 beginning of the industrial revolution 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.

For the world as a whole there has been a vast increase in the rate of weathering of the Earth’s surface due to deforestation, over grazing of pastures and crop cultivation. It may be hard to believe, but the annual rate of this unintended Earth movement is now considerably higher than the aggregate rate of global weathering before the rise of agriculture. A good illustration is what has happened to the southern and eastern coasts of the Mediterranean. 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.

The magnitude of these changes was well brought out in the Amsterdam Declaration: There it was stated that changes brought about by human activities

“… to Earth’s land surface, oceans, coasts and atmosphere and to biological diversity, the water cycle and biogeochemical cycles are clearly identifiable beyond 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 six main categories, all inter-linked. First there has been a giddying 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) at the end of the 18th century, to two billion in 1930 and now over six billion. The world population is increasing by over eighty million people each year. 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 five, water use by nine, sulphur emissions by thirteen, energy use by sixteen, carbon dioxide emissions by seventeen, and industrial output by forty.

All this has profoundly affected the condition of the land surface. More people need more space and more resources. Soil degradation is currently estimated to affect some 10% of the world’s current agricultural 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. Application of bio-technology, itself with some dubious aspects, can never hope to meet likely shortfalls.

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 dwindling resources of fossil fuels laid down hundreds of millions of years ago. To illustrate this point, I believe that a million kilos of prehistoric material is needed to produce a 42 litre tank of petrol. Every day we consume the equivalent in petrol of all the vegetation that grows on the Earth every year. 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 little more than three hundred million 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. Global dimming caused by pollution is another factor. 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 750,000 years, and rising fast.

Next 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 the World Wide Fund for Nature (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.

Lastly comes the still uncertain consequences of technology. Recently the Astronomer Royal looked at the possible result of inadvertence, criminality, use of exotic weapons, nano technology, and excessive dependence on technology, and concluded that the chances of our civilization surviving this century were no more than 50%.

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 changes now occurring simultaneously in the Earth System, their magnitudes and rates of change are unprecedented. 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 managed 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 150,000 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 humans carry heavy responsibilities, but stewardship is not the best way to describe them. For most people they relate 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. 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 led to an excessive dependence on a few miracle strains of even fewer 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 and cocoa growers in the 20th 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 to 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 worldview. We tend to believe that greater material prosperity and welfare are overriding human priorities, that resources can be indefinitely exploited, and that economic growth on the traditional definition is good in itself: in short ever upwards and onwards with freer markets, freer trade and continuously rising consumption. With this goes an almost religious belief in technology as the universal fix: an extension of human capacity to adapt to and cope with whatever may arise

There is an accompanying spread of culture of rising expectations, nourished by world wide use of information technology through radio, television, e-mail, 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 globalisation and an increasing homogenisation of human culture, and a widening gap between rich and sophisticated on one hand, and poor and unsophisticated on the other. As has been well said, globalisation 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 through 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 long future. In his fantasy The Time Machine of 1898, H G Wells foresaw a genetic division of humanity into Eloi (or upper worlders) and Morlocks (or lower worlders) in perpetual struggle against each other. Of course Gaia was still there, but, so far as humans were concerned, it was not 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 human population increase. Overall population 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, and better education, especially for girls and young women. Take degradation of land and water. We know how to cope if we try. We do not have to exhaust top soils, watch them erode into the sea, rely upon artificial aids to nature, destroy 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 human relationships. We do not have to widen the gaps between rich and poor, or even to think of creating a genetically favoured master class. Take the way in which we conduct most scientific enquiry. We do not have to break down issues into watertight compartments, and so miss the internal dynamics of the life system as a whole.

Moreover understanding of the Gaian approach is already spreading fast, whether it be 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 responsibility of government to set the framework for economic activity and protect the public interest is often ignored. At present there is an astonishing failure to recognize true costs. Markets are marvellous at determining prices but incapable of recognizing costs. Definition of costs requires a Gaian approach towards economics and towards measuring values, and this has to be brought back into pricing. In addition to the traditional costs of research, process, production and so on, prices should reflect the costs involved in replacing a resource or substituting for it, and of course the costs created by the environmental problems associated with it. In short 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 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 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.”

Some of these ideas have recently been explored in detail by Jared Diamond in his new book entitled Collapse: How Societies Choose to Fail or Survive. Of the factors which bear on success or failure is human treatment of each society’s physical environment, and reaction to such processes as climate change and human population increase. In some cases, of which the classic example is Easter Island, society simply collapsed. In others society learnt to identify and recover from mistakes. There are, as Diamond points out, lurches between accelerating environmental damage and accelerating environmental protection.

The main difference between the past and today is that our problems are global. As James Lovelock recently pointed out, Gaia is currently trapped in a vicious circle of positive feedback. The human footprint is everywhere. What happens in one place very soon affects what happens in others. Information travels almost instantaneously world wide. Nation states exercise diminishing control while global institutions have yet to acquire accountability. There is a constant battle between short-term private advantage and long-term public interest. Here disasters like the Asian tsunami may eventually lead to a greater sense of global responsibility with action to match it.

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 take us all.

Sir Crispin Tickell is a distinguished former diplomat and the Chancellor of the University of Kent.

  • Reproduced by kind permission of Sir Crispin and the Gaia Circular of the Geological Society of London
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