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

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

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

" 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

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

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