. 10
( 16)


The presence of life therefore in¬‚uences and effectively controls the environ-
ment to which living systems in turn adapt. It is the close match of the environ-
ment to the needs of life and its development that seems so remarkable and
which Lovelock has brought to our notice. He gives many examples; I will quote
244 W H Y S H O U L D W E B E CO NC E R N E D?

one concerned with oxygen in the atmosphere. There is a critical connection
between the oxygen concentration and the frequency of forest ¬res.6 Below an
oxygen concentration of 15%, ¬res cannot be started even in dry twigs. At con-
centrations above 25% ¬res burn extremely ¬ercely even in the damp wood of
a tropical rainforest. Some species are dependent on ¬res for their survival; for
instance, some conifers require the heat of ¬re to release their seeds from the
seed pods. Above 25% concentration of oxygen there would be no forests; below
15%, the regeneration that ¬res provide in the world™s forests would be absent.
The oxygen concentration of 21% is ideal.
It is this sort of connection that has driven Lovelock to propose that there is
tight coupling between the organisms that make up the world of living systems
and their environment. He has suggested a simple model of an imaginary world
called Daisyworld (see box below), which illustrates the type of feedback mecha-
nisms that can lead to this coupling and exert control. This model is similar to
one he proposed for the biological and chemical history of the Earth during the
¬rst 1000 million years after primitive life ¬rst appeared on the Earth some
3500 million years ago.
The real world is, of course, enormously more complex than Daisyworld,
which is why the Gaia hypothesis has led to so much debate. Lovelock™s ¬ rst
statement in 1972 of the hypothesis was that ˜Life, or the biosphere, regulates
or maintains the climate and the atmospheric composition at an optimum
for itself.™7 In his later writings he introduced the analogy between the Earth
and a living organism, introducing a new science which he calls geophysiol-
ogy8 “ a more recent book is entitled Gaia: The Practical Science of Planetary
An advanced organism such as a human being has many built-in mecha-
nisms for controlling the interactions between different parts of the organism
and for self-regulation. In a similar way, Lovelock argues, the ecosystems on
the Earth are so tightly coupled to their physical and chemical environments
that the ecosystems and their environment could be considered as one organ-
ism with an integrated ˜physiology™. In this sense he believes that the Earth is
That elaborate feedback mechanisms exist in nature for control and for
adaptation to the environment is not in dispute. But many scientists feel that
Lovelock has gone too far in suggesting that ecosystems and their environment
can be considered as a single organism. Although Gaia has stimulated much
scienti¬c comment and research, it remains a hypothesis.9 What the debate has
done, however, is to emphasise the interdependencies that connect all living
systems to their environment “ the biosphere is a system in which is incorpo-
rated a large measure of self-control.

There is the hint of a suggestion in the Gaia hypothesis that the Earth™s feed-
backs and self-regulation are so strong that we humans need not be concerned
about the pollution we produce “ Gaia has enough control to take care of any-
thing we might do. Such a view fails to recognise the effect on the Earth™s sys-
tem of substantial disturbances, in particular vulnerability of the environment
with respect to its suitability for humans. To quote Lovelock:

Gaia, as I see her, is no doting mother tolerant of misdemeanours, nor is
she some fragile and delicate damsel in danger from brutal mankind. She
is stern and tough, always keeping the world warm and comfortable for
those who obey the rules, but ruthless in her destruction of those who
transgress. Her unconscious goal is a planet ¬t for life. If humans stand
in the way of this, we shall be eliminated with as little pity as would be
shown by the micro-brain of an intercontinental ballistic nuclear missile
in full ¬‚ight to its target.

The Gaia scienti¬c hypothesis can help to bring us back to recognise two
things: ¬ rstly, the inherent value of all parts of nature, and secondly our depend-
ence, as human beings, on the Earth and on our environment. Michael Northcott
has pointed out, for instance, that Gaian theory ˜suggests all human beings, all
.12 Gaia
creatures, are relationally interconnected by carbon cycle of the planet™
remains a scienti¬ c theory “ although some have seen it as a religious idea,
supporting ancient religious beliefs. Many of the world™s religions have drawn
attention to the close relationship between humans and the Earth.
The Native American tribes of North America lived close to the Earth. One
of their chiefs when asked to sell his land expressed his dismay at the idea and
said, ˜The Earth does not belong to man, man belongs to the Earth. All things
.™13 An ancient Hindu saying, ˜The
are connected like the blood that unites us all
Earth is our mother, and we are all her children™ also emphasises a feeling of
closeness to the Earth. Those who have worked closely with indigenous peoples
have given many examples of the care with which, in a balanced way, they look
after the trees, plants and animals in their local ecosystem
The Islamic religion teaches the value of the whole environment, for instance
in a saying of the prophet Mohammed: ˜He who revives a dead land will be
rewarded accordingly, and that which is eaten by birds, insects and animals out
of that land will be charity provided by God™ “ so pointing both to our duty to
care for the natural environment and our obligation to allow all living creatures
their rightful place within it .16
Judaism and Christianity share the stories of creation in the early chapters
of the Bible that emphasise the responsibility of humans to care for the Earth “
we shall refer to these stories again later on in the chapter. Further on in the
Daisyworld and life on the early Earth
Daisyworld is an imaginary planet spinning on its axis and orbiting a sun rather like our own. Only daisies
live in Daisyworld; they are of two hues, black and white. The daisies are sensitive to temperature. They
grow best at 20 °C; below 5 °C they will not grow and above 40 °C they wilt and die. The daisies in¬‚uence
their own temperature by the way they absorb and emit radiation: black ones absorb more sunlight and
therefore keep warmer than white ones.
In the early period of Daisy-
world™s history (Figure 8.1), the
Brightness of the Sun and temperature increases
sun is relatively cool and the black
daisies are favoured because, by
absorbing sunlight, they can keep
their temperature closest to 20 °C.
Most of their white cousins die
Figure 8.1 Daisyworld. because they re¬‚ect sunlight and
fail to keep above the critical 5 °C.
However, later in the planet™s history, the sun becomes hotter. Now the white daisies can also ¬‚ourish; both
sorts of daisies are present in abundance. Later still as the sun becomes even hotter the white daisies become
dominant as conditions become too warm for the black ones. Eventually, if the sun continues to increase its
temperature even the white ones cannot keep below the critical 40 °C and all the daisies die.
Daisyworld is a simple model employed by Lovelock to illustrate the sort of feedbacks and self-regulation
that occur in very much more complex forms within the living systems on the Earth.11
Lovelock proposes a similar simple model as a possible description of the early history of life on the Earth
(Figure 8.2). The dashed line shows the temperature that would be expected on a planet possessing no life
but with an atmosphere consisting, like our present
atmosphere, mostly of nitrogen with about 10%
carbon dioxide. The rise in temperature occurs

because the sun gradually became hotter during
this period. About 3500 million years ago primi-
tive life appeared. Lovelock, in this model, assumes
just two forms of life, bacteria that are anaerobic
photosynthesisers “ using carbon dioxide to build
up their bodies but not giving out oxygen “ and
Gases (%)

bacteria that are decomposers, converting organic

matter back to carbon dioxide and methane. As
Methane life appears the temperature decreases as the con-
centration of the greenhouse gas, carbon dioxide,
decreases. At the end of the period about 2300
4.0 3.5 3.0 2.5 2.0
Time (billions of years before present)
million years ago, more complicated life appears;
Figure 8.2 Model of the Earth™s early history, as pro- there is an excess of free oxygen and the methane
posed by Lovelock.
abundance falls to low values, leading to another
fall in temperature, methane also being a green-
house gas. The overall in¬‚uence of these biological processes has been to maintain a stable and favourable
temperature for life on the Earth.

Old Testament detailed instructions are given regarding care for the land and
the environment. 17 Christianity was described by William Temple, Archbishop
of Canterbury 60 years ago, as ˜the most materialistic of the great religions™.
Because of its central belief that God became human in Jesus (an event Christians
call the Incarnation), Temple goes on to say ˜by the very nature of its central
doctrine Christianity is committed to a belief ¦n the reality of matter and its
place in the divine scheme™ .18 For the Christian, the twin doctrines of Creation
and Incarnation demonstrate God™s interest in and concern for the Earth and
the life it contains .
In looking for themes that emphasise the unity between humans and their
environment, we need not con¬ ne ourselves to the Earth. There is a very much
larger sphere in which a similar perspective of unity is becoming apparent.
Some astronomers and cosmologists, overwhelmed by the size, scale, complex-
ity, intricacy and precision of the Universe, have begun to realise that their
quest for an understanding of the evolution of the Universe right from the Big
Bang some 14 000 million years ago is not just a scienti¬ c project but a search
for meaning. 19 Why else has Stephen Hawking™s book A Brief History of Time20
become one of the bestsellers of our time?
In this new search for meaning, the perspective has arisen that the Universe
was made with humans in mind “ an idea expressed in some formulations of
the ˜anthropic principle™. 21 Two particular pointers emphasise this. Firstly, we
have already seen that the Earth itself is ¬ tted in a remarkable way for advanced
forms of life. Cosmology is telling us that, in order for life on our planet to be
possible, the Universe itself at the time of the Big Bang and in its early history
needed to be ˜¬ ne- tuned™ to an incredible degree. 22 Secondly, there is the remark-
able fact that human minds, themselves dependent on the whole Universe for
their existence, are able to appreciate and understand to some extent the fun-
As Albert Einstein
damental mathematical structure of the Universe™s design.
commented, ˜The most incomprehensible thing about the universe is that it is
comprehensible .™ In the theory of Gaia, the Earth itself is central and humans
are just one part of life on Earth; the insights of cosmology suggest that humans
have a particular place in the whole scheme of things.
This section has recognised the intrinsic unity and interdependencies that
exist not only on our Earth but also within the whole Universe, and the particu-
lar place that we humans have in the Universe. Being aware of these has large
implications for our attitude to our environment .

Environmental values
What do we value in the environment and how do we decide what we need to
preserve, to foster or improve? At the basis of our discussion so far have been
248 W H Y S H O U L D W E B E CO NC E R N E D?

several assumptions regarding the value or importance of different fundamen-
tal attitudes or actions, some of which I have associated with ideas that come
from the underlying environmental science. Is it legitimate, however, to make
connections of this kind between science and values? It is often argued that
science itself is value free. But science is not an activity in isolation. As Michael
Polanyi has pointed out, the facts of science cannot sensibly be considered apart
from the participation and the commitment of those who discover those facts
or incorporate them into wider knowledge.24
In the methodology and the practice of science are many assumptions of
value. For instance, that there is an objective world of value out there to dis-
cover, that there is value in the qualities of elegance and economy in scienti¬c
theory, that complete honesty and cooperation between scientists are essential
to the scienti¬c enterprise. Further, progress in science demands a balanced
view of all the data relevant to the area of investigation, not distorted by vested
interests or personal or political agendas.
Values can also be suggested from the perspective of the underlying science
as we have shown earlier in the chapter.25 For instance, we have described the
Earth in terms of balance, interdependency and unity. Since all of these are
critical to the Earth as we know it, we can argue that they are of fundamental
value and worth preserving. We have also provided some scienti¬c evidence
that humans have a particular place in the overall scheme of the natural world,
that they possess special knowledge “ which suggests that they also possess
special responsibility.
Moving away from science, we have already referred to values related to the
environment that come from our basic experiences as human beings. These are
often called ˜shared values™ because they are common to different members of
a human community “ which may be a local community, a nation or ultimately
the global community taking in the whole human race. An outstanding example
is the conservation of the Earth and its resources, not just for our generation but
for future generations. Other examples may involve how resources are used now
for the bene¬t of the present generation of humans and how they are shared
between different communities or nations. Holmes Rolston shows that in these
areas of shared values, natural values (valuing the natural world) and cultural
values (interpersonal, social and community values) belong together. He writes
of ˜a domain of hybrid values ¦ the resultant of integrated in¬‚uences from
nature and culture™.26
When shared values are applied to real situations, however, con¬‚icts often
arise. For instance, how much should we forgo now in order to make provision
for future generations, or how should resources be shared between different

countries, for instance between those in the relatively rich ˜North™ and those in
the relatively poor ˜South™? How do we exercise our responsibility as humans to
share the Earth with other parts of the creation? How much resource should be
deployed to maintain particular ecosystems or to prevent loss of species? How
do we apply principles of justice and equity in the real world? Discussion within
and between human communities can assist in the de¬nition and application
of such shared values.
Many of these shared values have their origins in the cultural and religious
backgrounds of human communities. Discussions about values need therefore
to recognise fully the cultural and religious traditions, beliefs and assumptions
that underlie many of our attitudes and reasoning about ethical concerns.
An obstacle to the recognition of religious assumptions in the attempt to
establish environmental values is the view that religious belief is not consistent
with a scienti¬c outlook. Some scientists maintain that only science can provide
real explanations based on provable evidence whereas the assertions of religion
cannot be tested in an objective way.27 Other scientists, however, have suggested
that the seeming inconsistency between science and religion arises because of
misunderstandings about the questions being addressed by the two disciplines
and that there is more in common between the methodologies of science and
religion than is commonly thought.28
Scientists are looking for descriptions of the world that ¬t into an overall
scienti¬c picture. They are working towards making this picture as complete
as possible. For instance, scientists are looking for mechanisms to describe the
˜¬ne-tuning™ of the Universe (these are known as ˜Theories of Everything™!)
mentioned earlier. They are also looking for mechanisms to describe the inter-
dependencies between living systems and the environment.
But the scienti¬c picture can only depict part of what concerns us as human
beings. Science deals with questions of ˜how™ not questions of ˜why™. Most ques-
tions about values are ˜why™ questions. Nevertheless, scientists do not always
draw clear distinctions between the two. Their motivations have often been
associated with the ˜why™ questions. That was certainly true of the early scien-
tists in the sixteenth and seventeenth centuries, many of whom were deeply
religious and whose main driving force in pursuit of the new science was that
they might ˜explore the works of God™.29
That science and religion should be seen as complementary ways of look-
ing at truth is a point made strongly by Al Gore in Earth in the Balance30 which
lucidly discusses current environmental issues such as global warming. He
blames much of our lack of understanding of the environment on the modern
approach, which tends to separate scienti¬c study from religious and ethical
250 W H Y S H O U L D W E B E CO NC E R N E D?

issues. Science and technology are often pursued with a clinical detachment and
without thinking about the ethical consequences. ˜The new power derived from
scienti¬c knowledge could be used to dominate nature with moral impunity,™
he writes.31 He goes on to describe the modern technocrat as ˜this barren spirit,
precinct of the disembodied intellect, which knows the way things work but not
the way they are™.32 However, he also points out that ˜there is now a powerful
impulse in some parts of the scienti¬c community to heal the breach™33 between
science and religion. In particular, as we pursue an understanding of the Earth™s
environment, it is essential that scienti¬c studies and technological inventions
are not divorced from their ethical and religious context.

Stewards of the Earth
The relationship between humans and the Earth that I have been advocating
is often described as one of stewardship. We are on the Earth as its stewards.
The word implies that we are carrying out our duty as stewards on behalf of
someone else “ but whom? Some environmentalists see no need to answer the
question speci¬cally, others might say we are stewards on behalf of future gen-
erations or on behalf of a generalised humanity. A religious person would want
to be more speci¬c and say that we are stewards on behalf of God. The religious
person would also argue that to associate the relationship of humans to God
with the relationship of humans to the environment is to place the latter rela-
tionship in a wider, more integrated, context “ providing additional insights
and a more complete basis for environmental stewardship.34
In the Judaeo-Christian tradition in the story of creation in the early chapters
of the Bible is a helpful ˜model™ of stewardship “ that of humans being ˜garden-
ers™ of the Earth. It is not only appropriate for those from those particular tra-
ditions “ it is a model that can be widely applied. That story tells that humans
were created to care for the rest of creation “ the idea of human stewardship
of creation is a very old one “ and were placed in a garden, the Garden of Eden,
˜to work it and take care of it™.35 The animals, birds and other living creatures
were brought to Adam in the garden for him to name them.36 We are left with a
picture of the ¬rst humans as ˜gardeners™ of the Earth “ what does our work as
˜gardeners™ imply? I want to suggest four things:

• A garden provides food and water and other materials to sustain life and
human industry. Part of the garden in the Genesis story contained mineral
resources “ ˜the gold of that land is good; aromatic resin and onyx are also
there™.37 The Earth provides resources of many kinds for humans to use as
they are needed.

• A garden is to be maintained as a place of beauty. The trees in the Garden
of Eden were ˜pleasing to the eye™. 38 Humans are to live in harmony with
the rest of creation and to appreciate the value of all parts of creation.
Indeed, a garden is a place where care is taken to preserve the multiplic-
ity of species, in particular those that are most vulnerable. Millions of
people each year visit gardens that have been especially designed to show
off the incredible variety and beauty of nature. Gardens are meant to be
• A garden is a place where humans, created as described in the Genesis story
in the image of God,39 can themselves be creative. Its resources provide for
great potential. The variety of species and landscape can be employed to
increase the garden™s beauty and its productivity. Humans have learnt to
generate new plant varieties in abundance and to use their scienti¬c and
technological knowledge coupled with the enormous variety of the Earth™s
resources to create new possibilities for life and its enjoyment. However,
the potential of this creativity is such that increasingly we need to be
aware of where it can take us; it has potential for evil as well as for good.
Further, good gardeners intervene in natural processes with a good deal of
• A garden is to be kept so as to be of benefit to future generations. In
this context, I shall always remember Gordon Dobson, a distinguished
scientist, who in the 1920s developed new means for the measurement of
ozone in the atmosphere. His home outside Oxford in England possessed
a large garden with many fruit trees. When he was 85, a year or so before
he died, I remember finding him hard at work in his garden replacing a
number of apple trees; in doing so he clearly had future generations in

How well do we humans match up to the description of ourselves as gardeners
caring for the Earth? Not very well, it must be said; we are more often exploiters
and spoilers than cultivators. Some blame science and technology for the prob-
lems, although the fault must lie with the craftsman rather than with the tools!
Others have tried to place part of the blame on attitudes40 that they believe
originate in the early chapters of Genesis, which talk of human beings hav-
ing rule over Creation and subduing it.41 Those words, however, should not be
taken out of context “ they are not a mandate for unrestrained exploitation. The
Genesis chapters also insist that human rule over Creation is to be exercised
under God, the ultimate ruler of Creation, and with the sort of care exempli¬ed
by the picture of humans as ˜gardeners™. Why, therefore, do humans so often fail
to get their act together?
252 W H Y S H O U L D W E B E CO NC E R N E D?

The Garden of Eden, Jan Brueghel.

Equity “ intergenerational and international
In our world community of human beings we are not all equal. Equality may be
cited as an aim but before it can be pursued its terms need careful de¬nition.
Reality is full of inequities of many kinds. In the context of global warming,
because it is long term and global, two equity issues are particularly impor-
tant “ both have already been mentioned. Firstly, there is our responsibility
to future generations. A basic instinct is that we wish to see our children and
grandchildren well set up in the world and wish to pass on to them some of our
most treasured possessions. A similar desire would be that they inherit from
us an Earth which has been well looked after and which does not pose to them
more dif¬cult problems than those we have had to face. But such an attitude
is not universally held. I remember well, after a presentation in 1990 I made
on global warming to Mrs Thatcher™s Cabinet at Number Ten, Downing Street
in London, a senior politician commented that the problem would not become
serious in his lifetime and could be left for its solution to the next generation. I

do not think he had appreciated that the longer we delay in taking action, the
larger the problem becomes and the more dif¬cult to solve. There is a need to
face up to the problem now for the sake of the next and subsequent generations.
We have no right to act as if there is no tomorrow. We also have a responsibility
to give to those who follow us a pattern for their future based on the principle
of sustainable development.
The second major equity issue is that of international equity where climate
change creates an enormous challenge to the international community. The
world™s developed and richest nations have largely grown their wealth over
200 years from the cheap and bountiful energy available from coal, oil and gas
without realising the damage that would do to the Earth and its climate “ dam-
age that will fall disproportionately on the poorest countries and people in the
world. It is not just a problem of the past but the current disparity between the
industrialised and the developing world in carbon dioxide emissions from fossil
fuel burning continues to be very large (Figure 10.4). This disparity presents a
strong moral imperative to the developed world, ¬rstly to take strong action to
reduce their carbon emissions and so reduce the damage they are continuing
to cause, secondly to use their wealth and their skills to assist the developing
world to develop their energy sources as sustainably as possible, and thirdly to
¬nd ways of providing some compensation for the damage already caused.42
This is in fact an imperative expressed in the international Framework
Convention on Climate Change (FCCC) (see Chapter 10) that states because of
the bene¬ts so far received by developed countries, they have to be the ¬rst to
take action.

The will to act
Many of the principles I have been enunciating are included at least implicitly
in the declarations, conventions and resolutions that came out of the United
Nations Conference on Environment and Development held in Rio de Janeiro
in June 1992; indeed, they form the background of many statements emanat-
ing from the United Nations or from of¬cial national sources. We are not short
of statements of ideals. What tend to be lacking are the capability and resolve
to carry them out. Sir Crispin Tickell, a British diplomat who has lectured
widely on the policy implications of climate change, has commented ˜Mostly
we know what to do but we lack the will to do it.™43
Many recognise this lack of will to act as a ˜spiritual™ problem (using the word
spiritual in a general sense), meaning that we are too obsessed with the ˜mate-
rial™ and the immediate and fail to act according to generally accepted values
and ideals particularly if it means some cost to ourselves or if it is concerned
254 W H Y S H O U L D W E B E CO NC E R N E D?

with the future rather than with
the present. We are only too aware
of the strong temptations we
experience at both the personal
and the national levels to use the
world™s resources to gratify our
sel¬shness and greed. Because of
this, it has been proposed that at
the basis of stewardship should
be a principle extending what
has traditionally been considered
wrong44 “ or in religious parlance
as sin “ to include unwarranted
pollution of the environment or
lack of care for it.45
Those with religious belief tend
to emphasise the importance of
coupling together the relationship
The United Nations Conference on Environment and Development
held in Rio de Janerio in 1992 (also known as the ˜Earth Summit™) of humans to the environment
resulted in several declarations, agendas and conventions, which to the relationship of humans to
formed the framework for the Kyoto Protocol of 1997.
God.46 It is here, religious believ-
ers would argue, that a solution
for the problem of ˜lack of will™ can be found. That religious belief can provide
an important driving force for action is often also recognised by those who look
elsewhere than religion for a solution.


This chapter has particularly pointed out that action addressing environmental
problems is dependent not only on knowledge about them but on the values
we place on the environment and our attitudes towards it. Assessments of
environmental value and appropriate attitudes can be developed from the

• The perspectives of balance, interdependence and unity in the natural world
generated by the underlying science.
• A recognition “ some would argue suggested by the science “ that humans
have a special place in the Universe, which in turn implies that humans have
special responsibilities with respect to the natural world.

• A recognition that to damage the environment or to fail to care for it is to
do wrong.
• An interpretation of human responsibility in terms of stewardship of the
Earth based on ˜shared™ values, generally recognised by human communi-
ties, that strives for equity and justice as between different human commu-
nities and different generations.
• A recognition of the importance of the cultural and religious basis for the
principles of stewardship “ humans as ˜gardeners™ of the Earth is suggested
as a ˜model™ of such stewardship.
• The moral imperative for the sharing of wealth and skills based on recognition
of the wealth created in developed countries through the availability of cheap
fossil fuel energy and the damage caused by fossil fuel burning that falls dis-
proportionately on developing countries that in their turn need to develop.
• A recognition that, just as the totality of damage to the environment is the
sum of the damage done by a large number of individuals, the totality of
action to address environmental problems is the sum of a large number of
individual actions to which we can all contribute.47

The pursuit of many of these issues and their practical outworking involves the
principle of sustainable development to which I shall return in later chapters
(Chapter 9, page 272 and Chapter 12, page 393).
Finally, let me recall some words of Thomas Huxley, an eminent biologist
from the nineteenth century, who emphasised the importance in the scienti¬c
enterprise of ˜humility before the facts™. An attitude of humility is also one that
lies at the heart of responsible stewardship of the Earth.
In the next chapter we shall re¬‚ect on the uncertainties associated with the
science of global warming and consider how they can be taken into account in
addressing the imperative for action. For instance, should action be taken now
or should we wait until the uncertainties are less before deciding on the right
action to take?

1 There is a debate regarding the relationship of humans to the environment.
Should humans be at the centre of the environment with everything else
and other life related to the human centre “ in other words an anthropocen-
tric view? Or should higher prominence be given to the non-human part of
nature in our scheme of things and in our consideration of values “ a more
ecocentric view? If so, what form should this higher prominence take?
256 W H Y S H O U L D W E B E CO NC E R N E D?

2 How far can science be involved in the generation and application of envi-
ronmental values?
3 How far do you think environmental values can be generated through
debate and discussion in a human community without reference to the
cultural or religious background of that community?
4 It has been suggested that religious belief (especially strongly held belief) is
a hindrance in the debate about environmental values. Do you agree?
5 Should we strive for universally accepted values with respect to the environ-
ment? Or is it acceptable for different communities to possess different values?
6 Identify and list as many values as you can that belong to the categories
natural and cultural (see page 265). In what ways do items in these
categories ˜belong together™?
7 What principles underlie the concept of intergenerational equity? Suggest how it
might be applied in practice. Suggest limits that might be set to its application.
8 A moral imperative was outlined in the equity section. What principles lie
behind such an imperative? Are such principles universally held?
9 Equity is frequently imported into arguments about how the costs of dam-
age due to global warming, of adaptation or mitigation, should be shared
between nations in the light of their varying responsibilities for both past
and present emissions. Look up the Green Development Rights website and
the many other similar sites sponsored by NGOs concerned with this issue.
Summarise the various proposals for sharing and analyse the arguments
presented. What do you think are the strongest arguments and on what
principles are they based?
10 An argument for religious belief that is sometimes put forward, irrespec-
tive of whether the belief is considered to have any foundation, is that such
belief motivates people more strongly than other driving forces. Do you
agree with this argument?
11 Explain how the cultural or religious traditions in which you have been
brought up have in¬‚uenced your view of environmental concern or action.
How have these in¬‚uences been modi¬ed because you now hold (or do not
hold) de¬nite religious beliefs?
12 Discuss the term ˜stewardship™, often used as a description of the relation of
humans to the environment. Does it imply too anthropocentric a relationship?
13 Discuss the model of humans as ˜gardeners™ of the Earth. How adequate is
the picture it presents of the relationship of humans to the environment?
14 Do you agree with Thomas Huxley when he spoke of the importance of
humility before the scienti¬c facts? How important do you think humility
is in this context and in the wider context of the application of scienti¬c
knowledge to environmental concern?

15 Because of the formidability of the task of stewardship of the Earth, some
have suggested that it is beyond the capability of the human race to tackle
it adequately. Do you agree?
16 In Chapter 9 (see box on page 280) the concept of Integrated Assessment and
Evaluation is introduced which involves all the natural and social science disci-
plines. In what ways could ethical or religious values be introduced into such
evaluations? Is it appropriate and necessary that they be included?
17 It has been said that it is not easy for humans to make connection, espe-
cially of a moral kind, between taking a trip in an aircraft and a ¬‚ooding
disaster in Bangladesh. Can you suggest how this connection can be pre-
sented so that it appears relevant?
18 Brazil has proposed to the FCCC that nations should contribute to the
solution of climate change in proportion to the damage from their historic
emissions. Look up the UNFCCC website www.unfccc.int and other sources
and ¬nd information about the Brazilian Proposal. What are its advantages
and disadvantages? How do you think it could be modi¬ed so as to make it
acceptable to all countries?
19 Climate change will impact on the world™s poor more than on the world™s
rich people. Find out and compare how caring for the poor, especially
those in regions or countries most disadvantaged by climate change, is
approached by the world™s major religions and by secular societies.

Gore, A. 1992. Earth in the Balance. Boston, Mass.: Houghton Mif¬‚in Company.
Lovelock J. E. 1988. The Ages of Gaia. Oxford: Oxford University Press.
Northcott, M. 2007. A Moral Climate: The Ethics of Global Warming. London: Darton,
Longman and Todd.
Russell C. 1994. Earth, Humanity and God. London: UCL Press. A review of
environmental prospects for the planet from a Christian perspective.
Polkinghorne J. 1988. Science and Creation. London: SPCK; Polkinghorne, J. 1996.
Beyond Science. Cambridge: Cambridge University Press. (On science, religion,
values and culture).
Houghton J. 1995. The Search for God: Can Science Help? London: Lion Publishing,
recently reprinted and available from Regent College, Vancouver book shop or the
John Ray Initiative, www.jri.org.uk. Chapters on science and religion and one on
global warming.
Berry R. J. (ed.) 2006. Environmental Stewardship. London: T & T Clark. Collection of
25 articles and essays on environmental stewardship.
Spencer, N. White, R. 2007. Christianity, Climate Change and Sustainable Living.
London: SPCK. The challenge of achieving sustainability addressed especially to
258 W H Y S H O U L D W E B E CO NC E R N E D?

1 Gore, A. 1992. Earth in the Balance. Boston, Mass.: 20 Hawking, S. 1989. A Brief History of Time. London:
Houghton Mif¬‚ in Company. Bantam.
2 Carson, R. 1962. Silent Spring. Boston, Mass.: 21 See for instance Davies, The Mind of God; also
Houghton Mif¬‚ in Company. Barrow, J., Tipler, F. J. 1986. The Anthropic Cosmological
3 See box in Chapter 9, page 272. Principle. Oxford: Oxford University Press.
4 See Lean, G., Hinrichsen, D., Markham, A. 1990. Atlas 22 Barrow and Tipler, The Anthropic Cosmological
of the Environment. London: Arrow Books. Principle; Gribbin, J., Rees, M. 1991. Cosmic
5 Lovelock, J. E. 1979. Gaia. Oxford: Oxford University Coincidences. London: Black Swan.
Press; Lovelock, J. E. 1988. The Ages of Gaia. Oxford: 23 Davies, The Mind of God.
Oxford University Press. 24 Polanyi, M. 1962. Personal Knowledge. London:
6 Lovelock, The Ages of Gaia, pp. 131“3. Routledge and Kegan Paul.
7 Lovelock, J. E., Margulis, L. 1974. Tellus, 26, 1“10. 25 The relation of science to value is explored in Rolston,
8 Lovelock, J. E. 1990. Hands up for the H. III. 1999. Genes, Genesis and God. Cambridge:
Gaia hypothesis. Nature, 344, 100“12; also Cambridge University Press, Chapter 4.
Lovelock, J. E. 1991. Gaia: The Practical Science of Planetary 26 Rolston, H. III. 1988. Environmental Ethics.
Medicine. London: Gaia Books. Philadelphia, Penn.: Temple University Press, p. 331.
9 Colin Russell discusses Gaia as a scienti¬c hypothesis 27 See, for instance, Dawkins, R. 1986. The Blind
and also its possible religious connections in The Watchmaker. Harlow: Longman. Dawkins, R. 2006.
Earth, Humanity and God. London: UCL Press, 1994. The God Delusion, Bantam Press.
10 Lovelock, The Ages of Gaia, p. 212. 28 See, for instance, McGrath, A., McGrath, J. C. 2007.
11 For more details see Lovelock, The Ages of Gaia. The Dawkins Delusion? London: SPCK. Polkinghorne, J.
12 Northcott, M. A Moral Climate. 2007. London: Darton, 1986. One World. London: SPCK; Polkinghorne, J. 1986.
Longman and Todd, p. 163. Beyond Science. Cambridge: Cambridge University
13 Quoted by Gore, Earth in the Balance, p. 259. Press; Houghton, The Search for God.
14 Quoted by Gore, Earth in the Balance, p. 261. 29 See, for instance, Russell, C. 1985. Cross-Currents:
15 Ghillean Prance, Director of Kew Gardens in the Interactions between Science and Faith. Leicester:
UK, provides examples from his extensive work in Intervarsity Press.
countries of South America in his book The Earth 30 Gore, Earth in the Balance.
under Threat. Glasgow: Wild Goose Publications, 31 Ibid., p. 252.
1996. 32 Ibid., p. 265.
16 Khalil, M. H. 1993. Islam and the ethic of 33 Ibid., p. 254.
conservation. Impact (Newsletter of the Climate 34 See Berry R.J. (ed.) 2006. Environmental Stewardship.
Network Africa), December, 8. London: T&T clark; also Berry R.J. (ed.) 2007. When
17 A number of injunctions were given to the Jews Enough is Enough. Leicester: Invervarsity Press.
in the Old Testament regarding care for plants 35 Genesis 2:15.
and animals and care for the land; for example, 36 Genesis 2:19.
Leviticus 19:23“25, Leviticus 25:1“7, Deuteronomy 37 Genesis 2:12.
25:4. 38 Genesis 2:9.
18 Temple, W. 1964. Nature, Man and God. London: 39 Genesis 1:27.
Macmillan (¬rst edition 1934). 40 The best-known exposition of this position is,
19 See for instance Davies, P. 1992. The Mind of God. for instance, White, L. Jr. 1987. The historical
London: Simon and Schuster. I have also addressed roots of our ecological crisis. Science, 155, 1203“7;
this theme in Houghton, J. T. 1995. The Search for God: see Russell, The Earth, Humanity and God, for a
Can Science Help? London: Lion Publishing “ recently commentary on this thesis.
reprinted by the John Ray Initiative www.jri.org.uk. 41 Genesis 1:26“8.
N OT E S F O R C H A P T E R 8

and Jane Lubchenco and published under the
42 Brazil has proposed to the Framework Convention
title Revelation and the Environment: AD 95“1995.
on Climate Change that nations should contribute
Singapore: World Scienti¬c Publishing, 1997.
to the solution of climate change in proportion to
46 In Judaeo-Christian teaching the coupling of these
the damage from their historic emissions, a proposal
two relationships begins with the Creation stories
that has been widely analysed, exposing the
in Genesis. These stories go on to describe how
dif¬culty raised by the uncertain nature of much of
humans disobeyed God (Genesis 3) and broke the
the past data; see www.unfccc.int.
partnership. But the Bible continually explains
43 The Doomsday Letters, broadcast on BBC Radio 4, UK,
how God offers a way back to partnership. A few
chapters on in Genesis (9:8“17), the basis of the
44 Patriarch Bartholomew of Constantinople and Pope
relationship between God and Noah is a covenant
John Paul II have both addressed this point “ see
agreement in which ˜all life on the Earth™ is
Northcott, A Moral Climate, p. 153.
included as well as humans. A relationship based
45 This was the ¬ rst of the principles that came out
on covenant is also the basis of the partnership
of a symposium (called the Patmos Principles since
between God and the Jewish nation in the Old
the climax of the symposium, held in celebration
Testament. But, after many times when that
of the 1900th anniversary of the writing of the
relationship was broken, the Old Testament
Book of Revelation, was on the island of Patmos)
prophets looked forward to a new covenant based
I attended in 1995 sponsored by the Ecumenical
not on law but on a real change of heart (Jeremiah
Patriarch Bartholomew I of the Greek Orthodox
31:31“34). The New Testament writers (for example
Church and Prince Philip in his capacity as
Hebrews 8:10“11) see this new covenant being
President of the World Wildlife Fund. An
worked out through the life and particularly
extremely eclectic group of scientists, politicians,
through the death and resurrection of Jesus,
environmentalists and theologians attended
the Son of God. Jesus promised his followers the
from a wide range of religious backgrounds and
Holy Spirit (John 15, 16), whose in¬‚uence would
beliefs. John, the Metropolitan of Pergamon,
enable the partnership between them and God to
who was chairman of the symposium™s scienti¬c
work. Paul, in his letters, is constantly referring
committee, kept emphasising that we should
to the dependent relationship which forms the
consider pollution of the environment, or lack
basis of his own partnership with God (Galatians
of care for the environment, as a sin “ not only
2:20, Philippians 4:13) and which has been the
against nature but a sin against God. His message
experience of millions of Christians down the
struck a strong chord with the symposium. The
centuries. Included in Paul™s theology is the whole
principle goes on to explain that this new category
of Creation (Romans 8:19“22).
of sin should include activities that lead to ˜species
47 Edmund Burke, a nineteenth-century British
extinction, reduction in genetic diversity, pollution
politician said, ˜no one made a greater mistake than
of the water, land and air, habitat destruction
he who did nothing because he could only do so
and disruption of sustainable life styles™. The
little™ “ quoted at the end of Chapter 12.
symposium™s report is edited by Sarah Hobson
9 Weighing the uncertainty

Pocerady power station in the Czech Republic is the backdrop to a commerical crop of sun¬‚owers

T HIS BOOK is intended to present clearly the current scienti¬c position on global warming.
A key part of this presentation concerns the uncertainty associated with all parts of the scien-
ti¬c description, especially with the prediction of future climate change, which forms an essential
consideration when decisions regarding action are being taken. However, uncertainty is a relative
term; utter certainty is not often demanded on everyday matters as a prerequisite for action. Here
the issues are complex; we need to consider how uncertainty is weighed against the cost of possible
action. First, we address the scienti¬c uncertainty.

The scienti¬c uncertainty
Before considering the ˜weighing™ process and the cost of action, we begin by
explaining the nature of the scienti¬c uncertainty and how it has been addressed
by the scienti¬c community.
In earlier chapters I explained in some detail the science underlying the
problem of global warming and the scienti¬c methods that are employed for
the prediction of climate change due to the increases in greenhouse gases. The
basic physics of the greenhouse effect is well understood. If atmospheric car-
bon dioxide concentration doubles and nothing else changes apart from atmos-
pheric temperature, then the average global temperature near the surface will
increase by about 1.2 °C. That ¬gure is not disputed among scientists.
However, the situation is complicated by feedbacks and regional variations.
Numerical models run on computers are the best tools available for addressing
these complications because they are able effectively to add together all the
non-linear interactions. Although they are highly complex, climate models are
capable of giving useful information of a predictive kind. As was explained in
Chapter 5, con¬dence in the models comes from the considerable skill with
which they simulate present climate and its variations (including perturbations
such as the Pinatubo volcanic eruption) and from their success in simulating
past climates; these latter are limited as much by the lack of data as by inad-
equacies in the models.
However, model limitations remain, which give rise to uncertainty (see box
below). The predictions presented in Chapter 6 re¬‚ected these uncertainties, the
largest of which are due to the models™ failure to deal adequately with clouds
and with the effects of the ocean circulation. These uncertainties become of
greatest importance when changes on the regional scale, for instance in regional
patterns of rainfall, are being considered.
With uncertainty in the basic science of climate change and in the predictions of
future climate, especially on the regional scale, there are bound also to be uncer-
tainties in our assessment of the impacts of climate change. As Chapter 7 shows,
however, some important statements can be made with reasonable con¬dence.
Under nearly all scenarios of increasing carbon dioxide emissions this century, the
rate of climate change is likely to be large, probably greater than the Earth has seen
for many millennia. Many ecosystems (including human beings) will not be able to
adapt easily to such a rate of change. The most noticeable impacts are likely to be
on the availability of water (especially on the intensity of heat waves, the frequency
and severity of droughts and ¬‚oods), on the distribution (though possibly not on
the overall size) of global food production and on sea level in low-lying areas of
the world. Further, although most of our predictions have been limited in range
262 W E I G H I N G T H E U N C E R TA I N T Y

The reasons for scienti¬c uncertainty
The Intergovernmental Panel on Climate Change1 has described the scienti¬c uncertainty as follows.
There are many uncertainties in our predictions particularly with regard to the timing, magnitude and
regional patterns of climate change, due to our incomplete understanding of:

• sources and sinks of greenhouse gases, which affect predictions of future concentrations,
• clouds, which strongly in¬‚uence the magnitude of climate change,
• oceans, which in¬‚uence the timing and patterns of climate change,
• polar ice-sheets, which affect predictions of sea level rise.

These processes are already partially understood, and we are con¬dent that the uncertainties can
be reduced by further research. However, the complexity of the system means that we cannot rule out

to the end of the twenty-¬rst century, it is clear that by the century beyond 2100
the magnitude of the change in climate and the impacts resulting from that
change are likely to be very large indeed.
The statement in the box regarding scienti¬c uncertainty was formulated
for the IPCC 1990 Report. Eighteen years later it remains a good statement of
the main factors that underlie scienti¬c uncertainty. That this is the case does
not imply little progress since 1990. On the contrary, as the subsequent IPCC
Reports show, a great deal of progress has taken place in both scienti¬c under-
standing and the development of models. There is now much more con¬dence
that the signal of anthropogenic climate change is apparent in the observed
climate record. Models now include much more sophistication in their sci-
enti¬c formulations and possess increased skill in simulating the important
climate parameters. For regional scale simulation and prediction, regional
climate models (RCMs) with higher resolution have been developed that are
nested within global models (see Chapters 5 and 6). These RCMs are beginning
to bring more con¬dence to regional projections of climate change. Further,
over the last decade, a lot of progress has been made with studies in various
regions of the sensitivity to different climates of these regions™ resources, such
as water and food. Coupling such studies with regional scenarios of climate
change produced by climate models enables more meaningful impact assess-
ments to be carried out2 and also enables appropriate measures to be assessed.
Particularly in some regions large uncertainties remain; it will be seen for
instance from Figure 6.7 that current models perform better for some regions
than for others.

Summarised in Figure 9.1
Socio-economic assumptions
are the various components
that are included in the
development of projections
Emissions scenarios
of climate change or its

Policy responses: adaptation and mitigation
impacts. All of these possess
uncertainties that need to
Concentration projections
be aggregated appropriately
(Greenhouse gases and aerosols)
in arriving at estimates of

Interactions and feedbacks
uncertainties in different
impacts. Radiative forcing projections

Assessments Sea level projections Climate scenarios

Because of the scienti¬c
uncertainty, it has been nec- Global change scenarios
essary to make a large effort
to achieve the best assess-
ment of present knowledge
and to express it as clearly
as possible. For these reasons
Figure 9.1 The cascade of uncertainties in projections to be considered in
the IPCC was set up jointly developing climate and related scenarios for climate change impact, adap-
by two United Nations™ bod- tation and mitigation assessment.
ies, the World Meteorological
Organization (WMO) and the
United Nations Environmental Programme (UNEP).3 The IPCC™s ¬rst meeting in
November 1988 was timely; it was held just as strong political interest in global
climate change was beginning to develop. The Panel realised the urgency of
the problem and, under the overall chairmanship of Professor Bert Bolin from
Sweden, established three working groups, one to deal with the science of cli-
mate change, one with impacts and a third one to deal with policy responses.
The IPCC has produced four main comprehensive Reports,4 in 1990, 1995, 2001
and 2007, together with a number of special reports covering particular issues.
Previous chapters have already referred widely to these reports.
I would like to say more about the Physical Science Assessment Working Group
(of which I was chairman from 1988 until 1992 and co-chairman from 1992 until
2002).5 Its task has been to present in the clearest possible terms our knowledge
of the science of climate change together with our best estimate of the climate
264 W E I G H I N G T H E U N C E R TA I N T Y

change over the twenty-¬rst century that is likely to occur as a result of human
activities. In preparing its reports the Working Group realised from the start that
if they were to be really authoritative and taken seriously, it would be necessary
to involve as many as possible of the world scienti¬c community in their produc-
tion. A small international organising team was set up at the Hadley Centre of the
United Kingdom Meteorological Of¬ce at Bracknell and through meetings, work-
shops and a great deal of correspondence most of those scientists in the world (both
in universities and government-supported laboratories) who are deeply engaged in
research into the science of climate change were involved in the preparation and
writing of the reports. For the ¬rst report, 170 scientists from 25 countries contrib-
uted and a further 200 scientists were involved in its peer review. For the Fourth
Assessment Report in 2007, these numbers had grown to 152 lead authors and over
500 contributing authors and over 600 involved in the two-stage review process
during which 30 000 written review comments were received and processed.
In addition to the comprehensive, thorough and intensively reviewed back-
ground chapters that form the basic material for each assessment, each report
includes a Summary for policymakers (SPM), the wording of which is approved
in detail at a plenary meeting of the Working Group, the object being to reach
agreement on the science and on the best way of presenting the science to
policymakers with accuracy and clarity. The plenary meeting which agreed
unanimously the 2007 SPM, held in Paris in January 2007, was attended by
representatives of 113 countries, a number of scientists representing the lead
authors of the scienti¬c chapters together with representatives from non-gov-
ernmental organisations. There has been very lively discussion at these plenary
meetings, most of which has been concerned with achieving the most informa-
tive and accurate wording rather than fundamental dispute over scienti¬c
During the preparation of the reports, a considerable part of the debate
amongst the scientists has centred on just how much can be said about the
likely climate change in the twenty-¬rst century. Particularly to begin with,
some felt that the uncertainties were such that scientists should refrain from
making any estimates or predictions for the future. However, it soon became
clear that the responsibility of scientists to convey the best possible information
could not be discharged without making estimates of the most likely magnitude
of the change coupled with clear statements of our assumptions and the level
of uncertainty in the estimates. Weather forecasters have a similar, although
much more short-term, responsibility. Even though they may feel uncertain
about tomorrow™s weather, they cannot refuse to make a forecast. If they do
refuse, they withhold from the public most of the useful information they pos-
sess. Despite the uncertainty in a weather forecast, it provides useful guidance

to a wide range of people. In a similar way the climate models, although subject
to uncertainty, provide useful guidance for policy.
An important feature of the Third and Fourth Science Assessments has
been the presentation of uncertainty wherever possible in terms of probabili-
ties. Words to express uncertainty have been associated with probabilities, for
instance, very likely (more than 90% probability), likely (more than 67%), etc. This
has substantially increased the value of future climate projections especially
when considering the impacts of climate change and policy concerning adapta-
tion to them.
I have given these details of the work of the Physical Science Assessment Group
in order to demonstrate the degree of commitment of the scienti¬c community
to the understanding of global climate change and to the communication of the
best scienti¬c information to the world™s politicians and policymakers. After all,
the problem of global environmental change is one of the largest problems fac-
ing the world scienti¬c community. No previous scienti¬c assessments on this
or any other subject have involved so many scientists so widely distributed both
as regards their countries and their scienti¬c disciplines. The IPCC Reports can
therefore be considered as authoritative statements of the contemporary views
of the international scienti¬c community.
A further important strength of the IPCC is that, because it is an intergovern-
mental body, governments are involved in its work. In particular, government
representatives assist in making sure that the presentation of the science is
both clear and relevant from the point of view of the policymaker. Having been
part of the process, governments as well as scientists are in a real sense own-
ers of the resulting assessments “ an important factor when it comes to policy
In the presentation of the IPCC assessments to politicians and policymakers,
the degree of scienti¬c consensus achieved has been of great importance in
persuading them to take seriously the problem of global warming and its
impact. In the run-up to the United Nations Conference on Environment and
Development (UNCED) at Rio de Janeiro in June 1992, the fact that they accepted
the reality of the problem led to the formulation of the international Framework
Convention on Climate Change (FCCC) which was signed by over 160 countries “
President George Bush, Snr, signed for the United States and the United States
Senate subsequently unanimously rati¬ed it. It has often been commented that
without the clear message that came from the world™s scientists, orchestrated
by the IPCC, the world™s leaders would never have agreed to sign the Climate
After the publicity arising from the Earth Summit in 1992, debate concerning
the scienti¬c ¬ndings of the IPCC intensi¬ed in the world™s press. Some of this
266 W E I G H I N G T H E U N C E R TA I N T Y

Rajendra Pachauri, chairman of IPCC, and other members of the IPCC delegation with Al Gore at the Nobel
Peace Prize celebrations in Oslo, December 2007.

was honest scienti¬c debate “ argument and debate are, after all, intrinsic to the
scienti¬c process. Some, however, was stimulated by strong vested interests par-
ticularly in the United States that attempted to discredit the work of the IPCC
and to persuade the public at large either of the absence of scienti¬c evidence
for global warming or even if it were occurring that it was not an issue requir-
ing urgent attention.6 From my standpoint from within the IPCC, these attacks
tended to lead to enhanced clarity and accuracy in our reports although for the
public at large the propagation of so much misleading material created a great
deal of misunderstanding and confusion.7
Over the past 20 years as the global climate has steadily warmed and scienti¬c
effort to understand climate change has grown, evidence that climate change
is bringing with it serious adverse impacts has continued to strengthen and to
be widely recognised. This is well illustrated by the statement published in June
2005 by the Academies of Science of the world™s 11 most important countries (the
G8 plus India, China and Brazil) endorsing the conclusions of the IPCC and urg-
ing the governments meeting at the G8 summit that year in Edinburgh to take

urgent action to address climate change.8 The world™s top scientists could not have
spoken more strongly. A further endorsement of the IPCC and its work came in
2007 with the award of Nobel Peace Prizes to the IPCC and to Al Gore.
I have illustrated the work of the IPCC by describing in some detail the activ-
ity of the Physical Science Assessment Working Group. The IPCC has two other
Working Groups that have followed similar procedures and have dealt with the
Impacts of Climate Change, with Adaptation and Mitigation strategies and with
the Economics and Social Dimensions of Climate Change. Contributions to their
work have not only come from natural scientists; increasingly social scientists,
especially economists, have become involved. In these social science areas much
fresh ground has been broken as consideration has been given to questions of
what, in the global context, might form the basis of appropriate political and
economic response to climate change. The rest of this chapter and the following
chapters will draw heavily on their work.

Narrowing the uncertainty
A key question constantly asked by policymakers is: ˜How long will it be before
scientists are more certain about the projections of likely climate change, in
particular concerning the regional and local detail?™ They were asking that
question 20 years ago and then I generally replied that in 10 to 15 years we
would know a lot more. As we have already seen, there is now more con¬dence
that anthropogenic climate change has been detected and more con¬dence too
in climate change projections than was the case a decade ago. However, some
of the key uncertainties remain and their reduction is urgently needed. Not
surprisingly, policymakers are still asking for more certainty. What can be done
to provide it?
For the basic science of change, the main tools of progress are observations
and models. Both need further development and expansion. Observations are
required to detect climate change in all its aspects as it occurs and also to vali-
date models. That means that regular, accurate and consistent monitoring of
the most important climate parameters is required with good coverage in both
space and time. Monitoring may not sound very exciting work, often even less
exciting is the rigorous quality control that goes with it, but it is absolutely
essential if climate changes are to be observed and understood. Because of this,
a major international programme, the Global Climate Observing System (GCOS)
has been set up to orchestrate and oversee the provision of observations on a
global basis. Models are needed to integrate all the scienti¬c processes that are
involved in climate change (most of which are non-linear, which means they
cannot be added together in any simple manner) so that they can assist in the
268 W E I G H I N G T H E U N C E R TA I N T Y

Space observations of the climate system
For forecasting the weather round the world “ for airlines, for shipping, for many other applications and
for the public “ meteorologists rely extensively on observations from satellites. Under international agree-
ments, ¬ve geostationary satellites are spaced around the equator for weather observation; moving pic-
tures from them have become familiar to us on our television screens. Information from polar orbiting
satellites is also available to the weather services of the world to provide input into computer models of the
weather and to assist in forecasting (see for instance Figure 5.4).

Figure 9.2 The ENVISAT Earth Observation Satellite of the European Space Agency
launched in 2002. Instruments included in its payload are: the Advanced Along-
Track Scanning Radiometer (AATSR), the Michelson Interferometer for Passive
Atmospheric Sounding (MIPAS), the MEdium Resolution Imaging Spectrometer
(MERIS), the SCanning Image Absorption spectroMeter for Atmospheric CartograpHY
(SCIAMACHY), the MicroWave Radiometer (MWR), the Global Ozone Monitoring by
Observation of Stars (GOMOS), the Radar Altimeter “ second generation (RA-2), the
Advanced Synthetic Aperture Radar (ASAR), and other instruments for communica-
tion and exact tracking. DORIS stands for Doppler Orbitography and Radiopositioning
Integrated by Satellite. In its 800-km Sun-synchronous orbit with the solar array
deployed, it measures 26 m — 10 m — 5 m and weighs 8.1 tonnes.

These weather observations provide a basic input to climate models. But for climate prediction and
research, comprehensive observations from other components of the climate system, the oceans, ice and
land surface are required. ENVISAT, a satellite launched by the European Space Agency in 2002, is one
example of the most recent generation of large satellites in which the latest techniques are directed to
observing the Earth (Figure 9.2). The instruments are directed at the measurement of atmospheric tem-
perature and composition including aerosols (MIPAS, SCIAMACHY and GOMOS), sea surface temper-
ature and topography, the latter for ocean current information (AATSR and RA-2), information about
ocean biology and land surface vegetation (MERIS) and sea-ice coverage and ice-sheet topography (ASAR
and RA-2).

analysis of observations and provide a method of projecting climate change into
the future.
Take, for instance, the example of cloud-radiation feedback that remains the
source of greatest single uncertainty associated with climate sensitivity.9 It was
mentioned in Chapter 5 that progress with understanding this feedback will be
made by formulating better descriptions of cloud processes for incorporation
into models and also by comparing model output, especially of radiation quan-
tities, with observations especially those made by satellites. To be really useful
such measurements need to be made with extremely high accuracy “ to within
the order of 0.1% in the average radiation quantities “ that is proving highly
demanding. Associated with the better measurements of clouds is the need for
all aspects of the hydrological (water) cycle to be better observed.
There is also inadequate monitoring at present of the major oceans of the
world, which cover a large fraction of the Earth™s surface. However, this is begin-
ning to be remedied with the introduction of new methods of observing the
ocean surface from space vehicles (see box) and new means of observing the
interior of the ocean. But not only are better physical measurements required:
to be able to predict the detailed increases of greenhouse gases in the atmos-
phere, the problems of the carbon cycle must be unravelled; for this, much
more comprehensive measurements of the biosphere in the ocean as well as
that on land are needed.
Stimulated by internationally organised observing programmes such as the
GCOS, space agencies around the world have been very active in the develop-
ment of new instruments and the deployment of advanced space platforms that
are beginning to provide many new observations relevant to the problems of
climate change (see box).
270 W E I G H I N G T H E U N C E R TA I N T Y

Alongside the increased understanding and more accurate predictions of cli-
mate change coming from the community of natural scientists, much more
effort is now going into studies of human behaviour and activities, how they
will in¬‚uence climate through changes in emissions of greenhouse gases and
how they in turn might be affected by different degrees of climate change.
Much better quanti¬cation of the impacts of climate change will result from
these studies. Economists and other social scientists are pursuing detailed work
on possible response strategies and the economic and political measures that
will be necessary to achieve them. It is also becoming increasingly realised that
there is an urgent need to interconnect more strongly research in the natural
sciences with that in the social sciences. The integrated framework presented
in Chapter 1 (Figure 1.5) illustrates the scope of interactions and of required
integration between all the intellectual disciplines involved.

Sustainable development
So much for uncertainty in the science of global warming. But how does this
uncertainty map on to the world of political decision-making? A key idea is that
of sustainable development.
One of the remarkable movements of the last few years is the way in which
problems of the global environment have moved up the political agenda. In
her speech at the opening in 1990 of the Hadley Centre at the United Kingdom
Meteorological Of¬ce, Margaret Thatcher, the former British Prime Minister,
explained our clear responsibility to the environment:

We have a full repairing lease on the Earth. With the work of the IPCC, we
can now say we have the surveyor™s report; and it shows there are faults
and that the repair work needs to start without delay. The problems do not
lie in the future, they are here and now: and it is our children and grand-
children, who are already growing up, who will be affected.

Many other politicians have similarly expressed their feelings of responsibility
for the global environment. Without this deeply felt and widely held concern,
the UNCED conference at Rio, with environment as the number one item on its
agenda, could never have taken place.
But, despite its importance, even when concentrating on the long term, the
environment is only one of many considerations politicians must take into
account. For developed countries, the maintenance of living standards, full
employment (or something close to it) and economic growth have become domi-
nant issues. Many developing countries are facing acute problems in the short
term: basic survival and large debt repayment; others, under the pressure of large

This multitemporal radar image, from
ENVISAT™s Advanced Synthetic Aperture
Radar (ASAR) instrument, is composed
of two images “ one acquired on 26 July
2007 and another on 12 April 2007 “ and
highlights the ¬‚ooding in Bangladesh and
parts of India brought on by two weeks
of persistent rain. ASAR is able to peer
through clouds, rain or local darkness, and
is well suited for differentiating between
waterlogged and dry land. Areas in black
and white denote no change, while areas
outlined in blue are potentially ¬‚ooded
spots. Areas in red may also indicate ¬‚ood-
ing, but could also be related to agricultural

increases in population, are looking for
rapid industrial development. However,
an important characteristic of environ-
mental problems, compared with many
of the other issues faced by politicians, is
that they are long term and potentially
irreversible “ which is why Tim Wirth,
the Under Secretary of State for Global
Affairs in the United States Government
during the Clinton Administration, said,
˜The economy is a wholly owned subsidi-
ary of the environment.™ More recently
Gordon Brown, in a speech in 2005
when he was the UK™s Chancellor of the
Exchequer, said:10

Environmental issues “ including
climate change “ have traditionally
been placed in a category separate
from the economy and economic
policy. But this is not longer ten-
able. Across a range of environmen-
tal issues “ from soil erosion to the depletion of marine stocks, from water
scarcity to air pollution “ it is clear now not just that economic activity is
their cause, but that these problems in themselves threaten future economic
activity and growth.
272 W E I G H I N G T H E U N C E R TA I N T Y

Sustainable development: how is it de¬ned?
A number of de¬nitions of sustainable development have been produced. The following two well cap-
ture the idea.
According to the Bruntland Commission Report Our Common Future presented in 1987, sustainable
development is ˜meeting the needs of the present without compromising the ability of future generations
to meet their own needs™.
A more detailed de¬nition is contained in the White Paper This Common Inheritance, published by
the United Kingdom Department of the Environment in 1990: ˜sustainable development means living on
the Earth™s income rather than eroding its capital™ and ˜keeping the consumption of renewable natural
resources within the limits of their replenishment™. It recognises the intrinsic value of the natural world
explaining that sustainable development ˜means handing down to successive generations not only man-
made wealth (such as buildings, roads and railways) but also natural wealth, such as clean and adequate
water supplies, good arable land, a wealth of wildlife and ample forests™.
Further discussion of sustainable development and its de¬nition is in Chapter 12, page 393.

A balance, therefore, has to be struck between the provision of necessary
resources for development and the long-term need to preserve the environment.
That is why the Rio Conference was about Environment and Development. The
formula that links the two is called sustainable development (see box below) “
development that does not carry with it the overuse of irreplaceable resources
or irreversible environmental degradation.
The idea of sustainable development echoes what was said in Chapter 8, when
addressing more generally the relationship of humans to their environment and
especially the need for balance and harmony. The Climate Convention signed at
the Rio Conference also recognised the need for this balance. In the statement of
its objective (see box on pages 291“2 in Chapter 10), it states the need for stabilisa-
tion of greenhouse gas concentrations in the atmosphere. It goes on to explain
that this should be at a level and on a timescale such that ecosystems are allowed
to adapt to climate change naturally, that food production is not threatened and
that economic development can proceed in a sustainable manner.
It is also increasingly realised that the idea of sustainability not only applies
to the environment but also to human communities “ a theme addressed in
Chapter 8. Sustainable development is often therefore assumed to include wider
social factors as well as environmental and economic ones. The provision of
social justice and equity are important components of a drive to sustainable
communities. Considerations of equity include not only equity between nations
but also equity between generations: we should not leave the world in a poorer

state for the next generation. These and other aspects of sustainability are con-
sidered further in Chapter 12.

Why not wait and see?
The debate about climate change not only addresses how much action is required
but also when it needs to be taken. In the light of scienti¬c uncertainty, it has
often been argued that the case is not strong enough for much action to be taken
now. What we should do is to obtain as quickly as possible, through appropriate
research programmes, much more precise information about future climate
change and its impact. We would then, so the argument goes, be in a much bet-
ter position to decide on relevant action. However, such a wait-and-see attitude
is inadequate for a number of reasons.
In the ¬rst place, enough is already known for it to be realised that the rate of
climate change due to increasing greenhouse gases will almost certainly bring
substantial deleterious effects and pose a large problem to the world. It will hit
some countries much more than others. Those worst hit are likely to be those
in the developing world that are least able to cope with it. Some countries may
actually experience a more bene¬cial climate. But in a world where there is
increasing interdependence between nations, no nation will be immune from
the effects. Further, as we saw in Chapter 6 (Figure 6.4a), because of the time
taken for the oceans to warm, we are already committed to substantially more
climate change than has yet been experienced.
Secondly, the timescales of both atmospheric and human responses are
long. Carbon dioxide emitted into the atmosphere today will contribute to the
increased concentration of this gas and the associated climate change for over
100 years. The more that is emitted now, the more dif¬cult it will be to reduce
atmospheric carbon dioxide concentration to the levels that will eventually be
required. With regard to the human response, the major changes that are likely
to be needed, for instance in large-scale infrastructure, will take many decades.
Large power stations that will produce electricity in 30 or 40 years™ time are
being planned and built today. The demands that are likely to be placed on all
of us because of concerns about global warming need to be brought into the
planning process now. Trends from 2000 until the present strongly reinforce
this argument. Although much consideration and talk has been given to ways of
reducing emissions, a signi¬cant upturn in global emissions of carbon dioxide
has in fact occurred since 2000 (more on this in Chapter 10) which points to the
need for even more urgent action.
Thirdly, many of the required actions not only lead to substantial reductions
in greenhouse gas emissions but they are good to do for other reasons which
274 W E I G H I N G T H E U N C E R TA I N T Y

bring other direct bene¬ts “ such proposals for action are often described as
˜no regrets™ proposals. Many actions addressing increased ef¬ciency lead also to
net savings in cost (sometimes called ˜win“win™ measures). Other actions lead to
improvements in performance or additional comfort.
Fourthly, there are more general bene¬cial reasons for some of the proposed
actions. In Chapter 8 it was pointed out that humans are far too pro¬‚igate in
their use of the world™s resources. Fossil fuels are burnt and minerals are used,
forests are cut down and soil is eroded without any serious thought of the needs
of future generations. The imperative of the global warming problem will help
us to use the world™s resources in a more sustainable way. Further, the techni-
cal innovation that will be required in the energy industry “ in energy ef¬-
ciency and conservation and in renewable energy development “ will provide


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