. 8
( 13)


which there is the positive feedback of additional carbon dioxide
emissions. In a warmer world longer periods of heat stress will have
an effect on human health; warmer temperatures will also encour-
age the spread of certain tropical diseases, such as malaria, to new
r Economists have attempted to estimate the average annual cost in mon-
etary terms of the impacts that would arise under the climate change
due to a doubling of pre-industrial atmospheric carbon dioxide concen-
tration. If some allowance is added for the impact of extreme events,
the estimates are typically around one or two per cent of GDP for
developed countries and around ¬ve per cent or more for developing
countries. Later chapters will compare them with the cost of taking
action to slow the onset of global warming or reduce its overall mag-
nitude. But it is important to realise that these attempts at monetary
Table 7.5 Examples of climate variability and extreme climate events and their impacts—
Representative examples of projected impactsa (all high
Projected changes during the twenty-¬rst century
in extreme climate phenomena and their con¬dence of occurrence in some areas)
Higher maximum temperatures, more hot days Increased incidence of death and serious illness in older age
and heat waves over nearly all land areas groups and urban poor.
(very likely) Increased heat stress in livestock and wildlife.
Shift in tourist destinations.
Increased risk of damage to a number of crops.
Increased electric cooling demand and reduced energy supply

Higher (increasing) minimum temperatures, fewer Decreased cold-related human morbidity and mortality.
cold days, frost days and cold waves over Decreased risk of damage to a number of crops, and increased
nearly all land areas (very likely) risk to others.
Extended range and activity of some pest and disease vectors.
Reduced heating energy demand.

More intense precipitation events (very likely, Increased ¬‚ood, landslide, avalanche and mudslide damage.
over many areas) Increased soil erosion.
Increased ¬‚ood runoff could increase recharge of some
¬‚oodplain aquifers.
Increased pressure on government and private ¬‚ood insurance
systems and disaster relief.

Increased summer drying over most mid-latitude Decreased crop yields.
continental interiors and associated risk of Increased damage to building foundations caused by ground
drought (likely) shrinkage.
Decreased water resource quantity and quality.
Increased risk of forest ¬re.

Increase in tropical cyclone peak wind intensities, Increased risks to human life, risk of infectious disease
mean and peak precipitation intensities (likely, epidemics and many other risks.
over some areas)b Increased coastal erosion and damage to coastal buildings and
Increased damage to coastal ecosystems such as coral reefs and

Intensi¬ed droughts and ¬‚oods associated with El Decreased agricultural and rangeland productivity in drought-
Ni˜ o events in many different regions (likely)
n and ¬‚ood-prone regions.
(see also under droughts and intense Decreased hydro-power potential in drought-prone regions.
precipitation events)

Increased Asian summer monsoon precipitation Increase in ¬‚ood and drought magnitude and damages in
variability (likely) temperate and tropical Asia.

Increased intensity of mid-latitude storms (little Increased risks to human life and health.
agreement between current models) Increased property and infrastructure losses.
Increased damage to coastal ecosystems.
These impacts can be lessened by appropriate response measures.
Changes in regional distribution of tropical cyclones are possible but have not been established.

Table SPM-2 from Watson, R. et al. (eds.) 2001. Climate Change 2001: Synthesis Report. Contributions of
Working Groups I, II and III to the Third Assessment Report of the Intergovernmental Panel on Climate Change.
Cambridge: Cambridge University Press. For de¬nition of likely, very likely, etc. see Note 1 in Chapter 4.
190 The impacts of climate change

costing can only represent a part of the overall impact story. Any
assessment of impacts has to take into account the cost in human
terms and the large social and political disruption some of the impacts
will bring. In particular, it is estimated that there could be up to three
million new environmental refugees each year or over 150 million by
the middle of the twenty-¬rst century.
It is important to bear in mind that these estimates of overall impact have
concentrated on the doubled carbon dioxide scenario (in other words, the
next ¬fty or sixty years). Soon after the end of the twenty-¬rst century,
under the scenarios with higher carbon dioxide emissions (in other words,
if strong action is not taken to curb emissions), a further doubling of the
equivalent carbon dioxide concentration will have occurred and it will be
continuing to rise. The impacts of the additional climate change which
would occur with a second effective doubling of carbon dioxide will be
substantially more severe than those of the ¬rst doubling.
That, of course, is a lot further away in time; perhaps for that reason it
has not been given much attention. However, because of the long life-time
of some greenhouse gases, because of the long memory of the climate
system, because some of the impacts may turn out to be irreversible and
also because of the time taken for human activities and ecosystems to
respond and change course, it is important to have an eye on the longer
term. The much more severe impacts that can be expected at longer
time horizons (see Table 7.4) increase the imperative now to take the
necessary action.
However, many will ask why we should be concerned about the state
of the Earth so far ahead in the future. Can we not leave it to be looked
after by future generations? The next chapter will give something of my
personal motivation for caring about what happens to the Earth in the
future as well as now.

1 For your local region, ¬nd out about its water supply and how the water is
used (e.g. by domestic users, agriculture, industry, etc.). What are likely to be
the trends in its use over the next ¬fty years due, for instance, to population
changes or changes in agriculture or industry? What are the possibilities for
increased supply and how might these be affected by climate change?
2 For your local area, ¬nd out about current environmental problems such
as sea level rise due to subsidence, over-use of ground water, air pollution
affecting forests. Which of these are likely to be exacerbated by climate
change? Try to estimate by how much.
3 For your local region, identify the possible impacts of climate change over
the next one hundred years and quantify them as far as you can. Attempt to
make an estimate of the cost of the damage for each impact. How far could
adaptation reduce each type of damage?
Notes 191

4 From the information in Chapter 6, make estimates of possible climate
change by the middle of next century for typical regions of boreal forest.
Then estimate from Figure 7.13 for the each of the three tree species what
loss of productivity might occur in each case.
5 Make an estimate of the total volume of ice in the Greenland and Antarc-
tic ice-caps. What proportion would have to melt to increase the sea
level by the six metres or so which occurred during the last interglacial
6 In the past, human communities have adapted to changes of many kinds
including some changes in climate. It is sometimes argued that, because the
adaptability of human beings is not fully allowed for, the likely damage from
the impacts of climate change in the future tends to be overestimated. Do
you agree?
7 In economic cost“bene¬t analyses, it is often necessary to attach a value to a
˜statistical life™.71 It is not human life itself that is being valued but a change
in the risk of death averaged over a population of human beings. One way
of attempting this valuation is to consider a person as an economic agent
capable of producing economic output. However, the preferred approach is
to value a statistical life on the basis of what individuals are willing to pay
or accept for changes in the risk of death. This approach tends to produce
very different money values between developed countries and developing
countries. Do you think this is defensible? Give up to ¬ve examples of the
analysis of particular environmental problems for which you think it would
be useful to include the valuation of a statistical human life. Look for values
that have been attributed in different circumstances. Do questions of equity
have any relevance in your examples?

Notes for Chapter 7
1 For comprehensive detail about climate change impacts, see McCarthy, J. J.,
Canziani, O., Leary, N. A., Dokken, D. J., White, K. S. (eds.) 2001. Climate
Change 2001: Impacts, Adaptation and Vulnerability. Contribution of Work-
ing Group II to the Third Assessment Report of the Intergovernmental Panel
on Climate Change. Cambridge: Cambridge University Press.
2 From Summary for policymakers. McCarthy, Climate Change 2001: Im-
pacts, p. 6.
3 See, for instance, Global Environmental Outlook 3 (UNEP Report). 2002.
London: Earthscan. See also Goudie, A. 2000. The Human Impact on the
Natural Environment, ¬fth edition. Massachusetts: MIT Press.
4 For further details see Church, J. A., Gregory, J. M. et al. 2001. Changes in sea
level. In Houghton, J. T., Ding, Y., Griggs, D. J., Noguer, M., van der Linden,
P. J., Dai, X., Maskell, K., Johnson, C. A. (eds.) Climate Change 2001: The
Scienti¬c Basis. Contribution of Working Group I to the Third Assessment
Report of the Intergovernmental Panel on Climate Change. Cambridge:
Cambridge University Press, Chapter 11.
5 See, for instance, van der Veen, C. J. 1991. State of balance of the cryosphere.
Reviews of Geophysics, 29, pp. 433“55.
192 The impacts of climate change

6 For a comprehensive account of the impact of climate change on Bangladesh
see Warrick, R. A., Ahmad, Q. K. (eds.) 1996. The Implications of Climate
and Sea Level Change for Bangladesh. Dordrecht: Kluwer.
7 Nicholls, R. J., Mimura, N. 1998. Regional issues raised by sea level rise
and their policy implications. Climate Research, 11, pp. 5“18.
8 Broadus, J. M. 1993. Possible impacts of, and adjustments to, sea-level rise:
the case of Bangladesh and Egypt. In Warrick, R. A., Barrow, E. M., Wigley,
T. M. L. (eds.) 1993 Climate and Sea-level Change: Observations, Projec-
tions and Implications. Cambridge: Cambridge University Press, pp. 263“
75. Note that, because of variations in the ocean structure, sea-level rise
would not be the same everywhere. In Bangladesh it would be somewhat
above average (see Gregory, J. M. 1993. Sea-level changes under increas-
ing CO2 in a transient coupled ocean-atmosphere experiment. Journal of
Climate, 6, pp. 2247“62).
9 From Muhtab, F. U. 1989. Effect of Climate Change and Sea Level Rise on
Bangladesh. London: Commonwealth Secretariat.
10 See Chapter 4 in Warrick, R. A., Ahmad, Q. K. (eds.) 1996. The Implications
of Climate and Sea Level Change for Bangladesh. Dordrecht: Kluwer.
11 Broadus, 1993. In Warrick, Climate and Sea-level Change, pp. 263“
12 Milliman, J. D. 1989. Environmental and economic implications of rising
sea level and subsiding deltas: the Nile and Bangladeshi examples. Ambio,
18, pp. 340“5.
13 From a report entitled Climate Change due to the Greenhouse Effect and
its Implications for China. 1992. Gland, Switzerland: Worldwide Fund for
14 Day, J. W. et al. 1993. Impacts of sea-level rise on coastal systems with
special emphasis on the Mississippi river deltaic plain. In Warrick, Climate
and Sea-level Change, pp. 276“96.
15 Clayton, K. M. 1993. Adjustment to greenhouse gas induced sea-level rise on
the Norfolk coast: a case study. In Warrick, Climate and Sea-level Change,
pp. 310“21.
16 Nicholls, R. J., Mimura, N. 1998. Regional issues raised by sea-level rise and
their policy implications. Climate Research, 11, 5“18. See also de Ronde,
J. G. 1993. What will happen to the Netherlands if sea-level rise accelerates?
In Warrick, Climate and Sea-level Change, pp. 322“35.
17 See Nurse, L., Sem, G. et al. 2001. Small island states. In McCarthy, Climate
Change 2001: Impacts, Chapter 17.
18 Bijlsma, L. 1996. Coastal zones and small islands. In Watson, R. T.,
Zinyowera, M. C., Moss, R. H. (eds.) 1996. Climate Change 1995: Impacts,
Adaptations and Mitigation of Climate Change: Scienti¬c-Technical Anal-
yses. Contribution of Working Group II to the Second Assessment Report of
the Intergovernmental Panel on Climate Change. Cambridge: Cambridge
University Press, Chapter 9.
19 McLean, R. F., Tsyban, A. et al. 2001. Coastal zones and marine ecosystems.
In McCarthy, Climate Change 2001: Impacts, Chapter 6.
Notes 193

20 From Figure 3.6 in Watson, R. et al. (eds.) 2001. Climate Change 2001:
Synthesis Report. Contribution of Working Groups I, II and III to the Third
Assessment Report of the Intergovernmental Panel on Climate Change.
Cambridge: Cambridge University Press.
21 See Table 11.8 from Shiklomanov, I. A., Rodda, J. C. (eds.) 2003. World
Water Resources at the Beginning of the 21st Century. Cambridge: Cam-
bridge University Press.
22 Lal, M. et al. 2001. In McCarthy, Climate Change 2001: Impacts,
Chapter 11.
23 Quoted by Geoffrey Lean in ˜Troubled waters™, in the colour supplement to
the Observer newspaper, 4 July 1993.
24 Lal, M. et al. 2001. In McCarthy, Climate Change 2001: Impacts, Chapter
11. See also Arnell, N. W. 1999. Climate change and global water resources.
Global Environmental Change, 9, S51“S67.
25 Gleick, P. H. 1990. Vulnerability of water systems. In Waggoner, P. E. 1990.
Climate Change and US Water Resources. New York: Wiley, pp. 223“40.
26 Rosenberg, N. J. (ed.) 1993. Towards an integrated impact assessment of
climate change: the MINK study. Climatic Change, 24, nos. 1“2. Dordrecht:
Kluwer Academic Publishers.
27 The MINK study on water resources is described in Frederick, K. D. 1993.
Climatic Change, 24, pp. 83“115.
28 Over the 1980s and the 1990s ten major droughts each affecting ¬ve to ten
million people were recorded in the Sahel “ see the OFDA/CRED Interna-
tional Data Base, www.cred.be/emdat, and Global Environmental Outlook
3 (UNEP Report). 2002. London: Earthscan, pp. 276“8.
29 Dracup, J. A., Kendall, D. R. 1990. Floods and droughts. In Waggoner,
Climate Change and US Water Resources, pp. 243“67.
30 See, for instance, Maurits la Riviere, J. W. 1989. Threats to the world™s
water. Scienti¬c American, 261, pp. 48“55. See also Bullock, P. 1996. Land
degradation and deserti¬cation. In Watson, R. T., Zinyowera, M. C., Moss,
R. H. (eds.) Climate Change 1995: Impacts, Adaptations and Mitigation
of Climate Change: Scienti¬c-Technical Analyses. Contribution of Working
Group II to the Second Assessment Report of the Intergovernmental Panel
on Climate Change. Cambridge: Cambridge University Press, Chapter 4.
31 Waggoner, P. E. 1990. Climate Change and US Water Resources. New York:
32 See Arnell, N., Liu, C. et al. 2001. Hydrology and water resources. In
McCarthy, Climate Change 2001: Impacts, Chapter 4.
33 See UNCCD website, www.unccd.int/.
34 Crosson, P. R., Rosenberg, N. J. 1989. Strategies for agriculture. Scienti¬c
American, 261, September, pp. 78“85.
35 Gitay, H. et al. 2001. Ecosystems and their goods and services. In McCarthy,
Climate Change 2001: Impacts, Chapter 5, Section 3.
36 Information in proposal for an International Research Institute for Climate
Prediction. Report by Moura, A. D. (ed.) 1992. Prepared for the International
Board for the TOGA project. Geneva: World Meteorological Organisation.
194 The impacts of climate change

37 Reilly, J. et al. 1996. Agriculture in a changing climate. In Watson, Climate
Change 1995: Impacts, Chapter 13.
38 More detail in Gitay, H. et al. 2001. Ecosystems and their goods and services.
In McCarthy, Climate Change 2001: Impacts, Chapter 5, Section 3; also
for an estimate of the global effect of CO2 fertilisation on ecosystems see
Melillo, J. M. et al. 1993. Global climate change and terrestrial net primary
production. Nature, 363, pp. 234“40.
39 The statement in this sentence and the sentence following are from The
summary for policymakers in Watson, R. et al. (eds.) 2001. Climate Change
2001: Synthesis Report. Contribution of Working Groups I, II and III to
the Third Assessment Report of the Intergovernmental Panel on Climate
Change. Cambridge: Cambridge University Press. However, because of the
many factors involved in the studies, regarding many of which there are
large uncertainties, the IPCC only ascribed medium con¬dence (see Note
1. in Chapter 4 for explanations of IPCC con¬dence statements) to these
40 See Global Environmental Outlook 3 (UNEP Report). 2002. London:
Earthscan, pp. 63“5.
41 Parry, M. et al. 1999. Climate change and world food security: a new as-
sessment. Global Environmental Change, 9, S51“S67.
42 From Watson, Climate Change 2001: Synthesis Report, paragraph 5.17.
43 Miko, U. F. et al. 1996. Climate change impacts on forests. In Watson,
Climate Change 1995: Impacts, Chapter 1. See also Gitay, H. et al. 2001.
Ecosystems and their goods and services. In McCarthy, Climate Change
2001: Impacts, Chapter 5, Section 5.6.3.
44 Lean, J., Rowntree, P. R. 1993. A simulation of the impact of Amazonian
deforestation on climate using an improved canopy representation. Quar-
terly Journal of the Royal Meteorological Society, 119, pp. 509“30. Similar
results with somewhat larger reductions in rainfall have been reported by
Henderson-Sellers, A. et al. 1993. Tropical deforestation: modelling lo-
cal to regional scale climate change. Journal of Geophysics Research, 98,
pp. 7289“315.
45 Mylne, M. F., Rowntree, P. R. 1992. Modelling the effects of albedo change
associated with tropical deforestation. Climatic Change, 21, pp. 317“43.
46 Quoted in Mitchell, J. F. B. et al. 1990. Equilibrium climate change and its
implications for the future. In Houghton, J. T., Jenkins, G. J., Ephraums, J. J.
(eds.) 1990. Climate Change: the IPCC Scienti¬c Assessments. Cambridge:
Cambridge University Press, pp.131“72.
47 Cox, P. M., Betts, R. A., Collins, M., Harris, P., Huntingford, C., Jones, C.
D. 2004. Amazon dieback under climate-carbon cycle projections for the
21st century. Theoretical and Applied Climatology, in press.
48 Gates, D. M. 1993. Climate Change and its Biological Consequences.
Sunderland, Mass.: Sinauer Associates Inc., p. 77.
49 Bowes, M. D., Sedjo, R. A. 1993. Impacts and responses to climate change
in forests of the MINK region. Climatic Change, 24, pp. 63“82.
Notes 195

50 Melillo, J. M. et al. 1996. Terrestrial biotic responses to environmental
change and feedbacks to climate. In Houghton, J. T., Meira Filho, L. G.,
Callander, B. A., Harris, N., Kattenberg, A., Maskell, K. (eds.) Climate
Change 1995: the Science of Climate Change. Cambridge: Cambridge
University Press, Chapter 9. See also Miko, U. F. et al. 1996. Climate
change impacts on forests. In Watson, Climate Change 1995: Impacts,
Chapter 1.
51 Gitay, H. et al. 2001. Ecosystems and their goods and services. In McCarthy,
Climate Change 2001: Impacts, Technical Summary Section 4.3.
52 Detail in The summary for policymakers in Watson, R. et al. (eds.) 2001.
Climate Change 2001: Synthesis Report. Contribution of Working Groups
I, II and III to the Third Assessment Report of the Intergovernmental Panel
on Climate Change. Cambridge: Cambridge University Press, pp. 68“69,
paragraph 3.18. Myers, N. et al. 2000. Nature, 403, pp. 853“8 has pro-
posed concentrating conservation effort in selected places with exceptional
concentrations of biodiversity.
53 From McG. Tegert, W. J., Sheldon, G. W., Grif¬ths, D. C. (eds.) 1990. Climate
Change: the IPCC Impacts Assessment. Canberra: Australian Government
Publishing Service, pp. 6“20. Although made in 1990 this statement remains
true in 2003.
54 Sale, P. F. 1999. Nature, 397, pp. 25“7. More information regarding
diversity in corals available on World Resources Institute Website
55 More information about impact on corals in McLean, R. F. A. et al. 2001.
Coastal zones and marine ecosystems. In McCarthy, Climate Change 2001:
Impacts, Chapter 6, Section 6.4.5 .
56 For more detail see, McMichael, A. J., Githeko, A. et al. 2001. Human
health. In McCarthy, Climate Change 2001: Impacts, Chapter 9. See also
McMichael, A. J. 1993. Planetary Overload. Cambridge: Cambridge Uni-
versity Press.
57 Kalkstein, I. S. 1993. Direct impact in cities. Lancet, 342, pp. 1397“9.
58 Information on India from Dr. Rajendra K. Pachauri, Tata Energy Research
Institute. Information regarding Europe from World Meterological Organi-
zation, Geneva.
59 Nicholls, N. 1993. El Ni˜ o-Southern Oscillation and vector-borne disease.
Lancet, 342, pp. 1284“5. The El Ni˜ o cycle is described in Chapter 5.
60 See Global Environmental Outlook 3 (UNEP Report). 2002. London: Earth-
scan, pp. 274“5.
61 As an example of progress with respect to disaster preparedness, the Inter-
national Red Cross has recently formed a Climate Change Unit based in the
62 PAHO Report 1999 Conclusions and Recommendations: Meeting on Reval-
uation of Preparedness and Response to Hurricanes George and Mitch,
quoted in McMichael, A. et al. 2001. Human health. In McCarthy, Climate
Change 2001: Impacts, Chapter 9.
196 The impacts of climate change

63 See Global Environmental Outlook 3 (UNEP Report). 2002. London: Earth-
scan, pp. 272.
64 Studies by Cline, Fankhauser, Nordhaus and Tol presented in Pearce, D. W.
et al. 1996. The social costs of climate change. In Bruce, J., Hoesung
Lee, Haites, E. (eds.) 1996. Climate Change 1995: Economic and Social
Dimensions of Climate Change. Cambridge: Cambridge University Press,
Chapter 6.
65 Smith, J. B. et al. 2001. Vulnerability to climate change and reasons
for concern: a synthesis. In McCarthy, Climate Change 2001: Impacts,
Chapter 19, Box 19.
66 Nordhaus, W. D., Boyer, J. 2000. Warming the World: Economic Models of
Global Warming. Massachusetts: MIT Press, pp. 87“91.
67 Mendelsohn, R., Neumann, J. E. (eds.) 1999. The Impact of Climate Change
on the United States Economy. Cambridge: Cambridge University Press. As
an example, this recent set of studies for the United States ¬nds that assuming
more realistic adaptation and the application of damage estimates to a 2060
economy rather than to a 1990 economy tends to reduce the impact estimates
in the early 1990 studies and for some cases produces net bene¬ts for the
US economy. However, no account has been taken of the impact of extreme
events in these studies.
68 Cline, W. R. 1992. The Economics of Global Warming. Washington DC:
Institute for International Economics, Chapter 2.
69 Myers, N., Kent, J. 1995. Environmental Exodus: an Emergent Crisis
in the Global Arena. Washington DC: Climate Institute; also Adger, N.,
Fankhauser, S. 1993. Economic analysis of the greenhouse effect: optimal
abatement level and strategies for mitigation. International Journal of En-
vironment and Pollution, 3, pp. 104“19.
70 Adger, N., Fankhauser, S. 1993. Economic analysis of the greenhouse effect:
optimal abatement level and strategies for mitigation. International Journal
of Environment and Pollution, 3, pp. 104“19.
71 See, for instance, Pearce, D. W. et al. 1996. The social costs of climate
change. In Bruce, J., Hoesung Lee, Haites, E. (eds.) 1996. Climate Change
1995: Economic and Social Dimensions of Climate Change. Cambridge:
Cambridge University Press, Chapter 6, pp. 196“7.
Chapter 8
Why should we be concerned?

I have been describing the likely changes in climate that may occur as
a result of human activities, and the impact these may have in different
parts of the world. But large and potentially devastating changes are likely
to be a generation or more away. So why should we be concerned? What
responsibility, if any, do we have for the planet as a whole and the great
variety of other forms of life that inhabit it, or for future generations of
human beings? And does our scienti¬c knowledge in any way match up
with other insights, for instance ethical and religious ones, regarding our
relationship with our environment? In this chapter I want to digress from
the detailed consideration of global warming (to which I shall return)
in order brie¬‚y to explore these fundamental questions and to present
something of my personal viewpoint on them.

Earth in the balance
Al Gore, Vice-President of the United States in the Clinton Administra-
tion, entitled his book on the environment Earth in the Balance,1 imply-
ing that there are balances in the environment that need to be maintained.
A small area of a tropical forest possesses an ecosystem that contains
some thousands of plant and animal species, each thriving in its own
ecological niche in close balance with the others. Balances are also im-
portant for larger regions and for the Earth as a whole. These balances
can be highly precarious, especially where humans are concerned.
One of the ¬rst to point this out was Rachel Carson in her book Silent
Spring,2 ¬rst published in 1962, which described the damaging effects
of pesticides on the environment. Humans are an important part of the

198 Why should we be concerned?

global ecosystem; as the size and scale of human activities continue to
escalate, so can the seriousness of the disturbances caused to the overall
balances of nature. Some examples of this were given in the last chapter.
It is important that we recognise these balances, in particular the
careful relationship between humans and the world around us. It needs
to be a balanced and harmonious relationship in which each generation
of humans should leave the Earth in a better state, or at least in as good a
state as they found it. The word that is often used for this is sustainabil-
ity “ politicians talk of sustainable development (see box in Chapter 9,
page 226). This principle, and its link with the harmonious relationship
between humans and nature, was given prominent place by the United
Nations Conference on Environment and Development held at Rio de
Janeiro in Brazil in June 1992. The ¬rst principle in a list of twenty-seven
at the Rio Declaration adopted by the Conference is ˜Human beings are
at the centre of concerns for sustainable development. They are entitled
to a healthy and productive life in harmony with nature.™3
However, despite such statements of principle from a body such as
the United Nations, many of the attitudes that we commonly have towards
the Earth are not balanced, harmonious or sustainable. Some of these are
brie¬‚y outlined in the following paragraphs.

Humankind has over many centuries been exploiting the Earth and its
resources. It was at the beginning of the Industrial Revolution some two
hundred years ago that the potential of the Earth™s minerals began to
be realised. Coal, the result of the decay of primaeval forests and laid
down over many millions of years, was the main source of energy for the
new industrial developments. Iron ore to make steel was mined in vastly
increased quantities. The search for other metals such as zinc, copper
and lead was intensi¬ed until today many millions of tonnes are mined
each year. Around 1960, oil took over from coal as the dominant world
source of energy; oil and gas between them now supply over twice the
energy supplied by coal.
We have not only been exploiting the Earth™s mineral resources.
The Earth™s biological resources have also been attacked. Forests have
been cut down on a large scale to make room for agriculture and for
human habitation. Tropical forests are a particularly valuable resource,
important for maintaining the climate of tropical regions. They have
also been estimated to contain perhaps half of all the Earth™s biological
species. Yet only about half of the mature tropical forests that existed
a few hundred years ago still stand.4 At the present rate of destruction
virtually all will be gone by the end of the twenty-¬rst century.
˜Back to nature™ 199

Great bene¬ts have come to humankind through the use of fossil
fuels, minerals and other resources. Yet, much of this exploitation has
been carried out with little or no thought as to whether this use of natural
resources has been a responsible one. Early in the Industrial Revolution it
seemed that resources were essentially limitless. Later on, as one source
ran out others became available to more than take its place. Even now, for
most minerals new sources are being found faster than present sources
are being used. But the growth of use is such that this situation cannot
continue. In many cases known reserves or even likely reserves will
begin to run out during the next hundred or few hundred years. These
resources have been laid down over many millions if not billions of
years. Nature took about a million years to lay down the amount of
fossil fuel that we now burn worldwide every year “ and in doing so it
seems that we are causing rapid change of the Earth™s climate. Such a
level of exploitation is clearly not in balance, not harmonious and not

˜Back to nature™
Almost the reverse of this attitude is the suggestion that we all adopt
a much more primitive lifestyle and give up a large part of industry
and intensive farming “ that we effectively put the clock back two or
three hundred years to before the Industrial Revolution. That sounds
very seductive and some individuals can clearly begin to live that way.
But there are two main problems.
The ¬rst is that it is just not practical. The world population is now
some six times what it was two hundred years ago and about three times
that of ¬fty years ago. The world cannot be adequately fed without
farming on a reasonably intensive scale and without modern methods
of food distribution. Further, most people that have them would not be
prepared to be without the technical aids “ electricity, central heating,
refrigerator, washing machine, television and so on “ which give the
freedom, the interest and the entertainment which is so much taken for
granted. Moreover, increasing numbers of people in the developing world
are also taking advantage of and enjoy these aids to a life of less drudgery
and more freedom.
The second problem is that it fails to take account of human creativ-
ity. Human scienti¬c and technical development cannot be frozen at a
given point in history, insisting that no further ideas can be developed. A
proper balance between humans and the environment must leave room
for humans to exercise their creative skills.
Again, therefore, a ˜back to nature™ viewpoint is neither balanced
nor sustainable.
200 Why should we be concerned?

The technical ¬x
A third common attitude to the Earth is to invoke the ˜technical ¬x™. As
a senior environmental of¬cial from the United States said to me some
years ago, ˜We cannot change our lifestyle because of the possibility of
climate change, we just need to ¬x the biosphere.™ It was not clear just
what he supposed the technical ¬xes would turn out to be. The point
that he was making is that, in the past, humans have been so effective at
developing new technology to meet the problems as they arise, can it not
be assumed that this will continue? Concern about the future then turns
into ¬nding the ˜¬xes™ as they are required.
On the surface the ˜technical ¬x™ route may sound a good way to
proceed; it demands little effort and no foresight. It implies that damage
can be corrected when it has been created rather than avoided in the ¬rst
place. But damage already done to the environment by human activities
is causing problems now. It is as if, in looking after my home, I decided
not to carry out any routine maintenance but ˜¬xed™ the failures as they
occurred. For my home that would be a high-risk route to follow: failure
to rewire when necessary could easily lead to a disastrous ¬re. A similar
attitude to the Earth is both arrogant and irresponsible. It fails to recognise
the vulnerability of nature to the large changes that human activities are
now able to generate.
Science and technology possess enormous potential to assist in car-
ing for the Earth, but they must be employed in a careful, balanced and
responsible way. The ˜technical ¬x™ approach is neither balanced nor

Future generations
Having described attitudes that are not balanced or harmonious in their
relationship to the Earth and that fail to contribute to sustainability, I now
turn to describe attitudes to the environment that are more acceptable in
terms of the criteria I have set.
Firstly, there is our responsibility to future generations. It is a basic
instinct that we wish to see our children and our 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 I made on
global warming to the British 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
The unity of the Earth 201

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

The unity of the Earth
A second point of view sees us as having some responsibility, not just
for all generations of humanity, but also for the larger world of all living
things. We are, after all, part of that larger world. There is good scien-
ti¬c justi¬cation for this. We are becoming increasingly aware of our
dependence on the rest of nature and of the interdependencies that exist
between different forms of life, between living systems and the physical
and chemical environment that surrounds life on the Earth “ and indeed
between ourselves and the rest of the universe.
The scienti¬c theory named Gaia after the Greek Earth goddess
and publicised particularly by James Lovelock emphasises these inter-
dependencies. Lovelock5 points out that the chemical composition of
the Earth™s atmosphere is very different from that of our nearest plane-
tary neighbours, Mars and Venus. Their atmospheres, apart from some
water vapour, are almost pure carbon dioxide. The Earth™s atmosphere,
by contrast, is seventy-eight per cent nitrogen, twenty-one per cent oxy-
gen and only 0.03% carbon dioxide. So far as the major constituents are
concerned, this composition has remained substantially unchanged over
many millions of years “ a fact that is very surprising when it is realised
that it is a composition that is very far from chemical equilibrium.
This very different atmosphere on the Earth has come about because
of the emergence of life. Early in the history of life, plants appeared
which photosynthesise, taking in carbon dioxide and giving out oxygen.
There followed other living systems which ˜breathe™, taking in oxygen
and giving out carbon dioxide. The presence of life therefore in¬‚uences
and effectively controls the environment to which living systems in turn
adapt. It is the close match of the environment to the needs of life and
its development which seems so remarkable and which Lovelock has
emphasised. He gives many examples; I will quote 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 ¬fteen per cent, ¬res cannot be started even in dry
twigs. At concentrations above twenty-¬ve per cent ¬res burn extremely
¬ercely even in the damp wood of a tropical rain forest. Some species are
202 Why should we be concerned?

dependent on ¬res for their survival; for instance, some conifers require
the heat of ¬re to release their seeds from the seed pods. Above twenty-
¬ve per cent concentration of oxygen there would be no forests; below
¬fteen per cent, the regeneration that ¬res provide in the world™s forests
would be absent. The oxygen concentration of twenty-one per cent is
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 mechanisms that can lead to tight coupling and exert
control. This model is similar to the 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
The real world is, of course, enormously more complex than Daisy-
world, which is why the Gaia hypothesis has led to so much debate.
Lovelock™s ¬rst statement in 1972 of the hypothesis7 was that ˜Life, or
the biosphere, regulates or maintains the climate and the atmospheric
composition at an optimum for itself.™ In his later writings he introduced
the analogy between the Earth and a living organism, introducing a new
science which he calls geophysiology8 “ a more recent book is entitled
Gaia, the Practical Science of Planetary Medicine.
An advanced organism such as a human being has many built-in
mechanisms 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 organism with an integrated ˜physiology™. In this
sense he believes that the Earth is ˜alive™.
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 incorporated a large measure of
There is the hint of a suggestion in the Gaia hypothesis that the Earth™s
feedbacks 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 anything we might do. Such a view fails to recognise
Daisyworld and life on the early Earth

Daisyworld is an imaginary planet spinning on its self-regulation that occur in very much more com-
axis and orbiting a sun rather like our own. Only plex forms within the living systems on the Earth.
daisies live in Daisyworld; they are of two hues, Lovelock proposes a similar simple model as a
black and white. The daisies are sensitive to tem- possible description of the early history of life on
perature. They grow best at 20 —¦ C, below 5 —¦ C they the Earth (Figure 8.2). The dashed line shows the
will not grow and above 40 —¦ C they wilt and die. temperature which would be expected on a planet
The daisies in¬‚uence their own temperature by the possessing no life but with an atmosphere consist-
way they absorb and emit radiation: black ones ab- ing, like our present atmosphere, mostly of nitrogen
sorb more sunlight and therefore keep warmer than with about ten per cent carbon dioxide. The rise in
white ones. temperature occurs because the sun gradually be-
In the early period of Daisyworld™s history (Fig- came hotter during this period. About 3500 mil-
ure 8.1), the sun is relatively cool and the black lion years ago primitive life appeared. Lovelock, in
daisies are favoured because, by absorbing sunlight, this model, assumes just two forms of life, bacteria
they can keep their temperature closest to 20 —¦ C. that are anaerobic photosynthesisers “ using carbon
dioxide to build up their bodies but not giving out
Most of their white cousins die because they re¬‚ect
sunlight and fail to keep above the critical 5 —¦ C. oxygen “ and bacteria that are decomposers, con-
verting organic matter back to carbon dioxide and
However, later in the planet™s history, the sun be-
methane. As life appears the temperature decreases
comes hotter. Now the white daisies can also ¬‚our-
as the concentration of the greenhouse gas, carbon
ish; both sorts of daisies are present in abundance.
dioxide, decreases. At the end of the period about
Later still as the sun becomes even hotter the white
daisies become dominant as conditions become too 2300 million years ago, more complicated life ap-
pears; there is an excess of free oxygen and the
warm for the black ones. Eventually, if the sun con-
methane abundance falls to low values, leading to
tinues to increase its temperature even the white
ones cannot keep below the critical 40 —¦ C and all another fall in temperature, methane also being a
greenhouse gas. The overall in¬‚uence of these bio-
the daisies die.
logical processes has been to maintain a stable and
Daisyworld is a simple model employed by
Lovelock11 to illustrate the sort of feedbacks and favourable temperature for life on the Earth.

Figure 8.1 Daisyworld.
Brightness of the sun and temperature increases

Figure 8.2 Model of the
Earth™s early history, as
proposed by Lovelock.
204 Why should we be concerned?

the the effect on the Earth™s system of substantial disturbances, in par-
ticular vulnerability of the environment with respect to its suitability for
humans. To quote Lovelock,10 ˜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 ruth-
less 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 dependence, as human beings, on the Earth and on our environment.
Gaia remains a scienti¬c theory. But some have been quick to see 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,12 ˜The Earth does not belong to man, man
belongs to the Earth. All things are connected like the blood that unites
us all.™ An ancient Hindu saying,13 ˜The 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.14
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 emphasising both our duty to care for the natural environ-
ment and our obligation to allow all living creatures their rightful place
within it.15
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 Old Testament detailed instructions are given regarding
care for the land and the environment.16 Christianity was described by
William Temple, Archbishop of Canterbury sixty 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
Environmental values 205

committed to a belief . . . in the reality of matter and its place in the
divine scheme™.17 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, complexity, 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 ¬fteen thousand million
years ago is not just a scienti¬c project but a search for meaning.18
Why else has Stephen Hawking™s book A Brief History of Time,19 in
selling over six million copies, become one of the bestsellers of our
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™.20 Two particular pointers em-
phasise 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 it-
self at the time of the Big Bang and in its early history needed to be
˜¬ne-tuned™ to an incredible degree.21 Secondly, there is the remarkable
fact that human minds, themselves dependent on the whole universe for
their existence, are able to appreciate and understand to some extent the
fundamental mathematical structure of the universe™s design.22 As Al-
bert Einstein 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 particular 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 several assumptions regarding the value or importance of dif-
ferent fundamental attitudes or actions, some of which I have associated
206 Why should we be concerned?

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 sci-
ence is not an activity in isolation. As Michael Polanyi23 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.
In the methodology and the practice of science are many assump-
tions of value. For instance, that there is an objective world of value out
there to discover, that there is value in the qualities of elegance and econ-
omy in scienti¬c theory, that complete honesty and cooperation between
scientists are essential to the scienti¬c enterprise.
Values can also be suggested from the perspective of the underlying
science as we have shown earlier in the chapter.24 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 re-
lated 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 gen-
erations. 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.™25
When shared values are applied to real situations, however, con¬‚icts
often arise. For instance, how much should we forego 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
Environmental values 207

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 at-
tempt 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.26
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.27
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 mecha-
nisms 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 interdependencies 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 questions 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 scientists 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™.28
That science and religion should be seen as complementary ways
of looking at truth is a point made strongly by Al Gore in Earth in the
Balance29 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 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.30 He goes
on to describe the modern technocrat as ˜this barren spirit, precinct of
208 Why should we be concerned?

the disembodied intellect, which knows the way things work but not
the way they are™.31 However, he also points out32 that ˜there is now
a powerful impulse in some parts of the scienti¬c community to heal
the breach™ 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 advo-
cating 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 stew-
ards 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 generations 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 rela-
tionship of humans to the environment is to place the latter relationship
in a wider, more integrated, context “ providing additional insights and
a more complete basis for environmental stewardship.33
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 ˜gardeners™ of the Earth. It is not only appropriate for those from
those particular traditions “ 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™.34 The
animals, birds and other living creatures were brought to Adam in the
garden for him to name them.35 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:
r 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™.36 The Earth provides resources of many kinds for
humans to use as they are needed.
r A garden is to be maintained as a place of beauty. The trees in the
Garden of Eden were ˜pleasing to the eye™.37 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
The will to act 209

preserve the multiplicity 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 enjoyed.
r A garden is a place where humans, created as described in the Genesis
story in the image of God,38 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 restraint.
r A garden is to be kept so as to be of bene¬t 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 ¬nding him hard at work in his
garden replacing a number of apple trees; in doing so he clearly had
future generations in mind.

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 problems, although the fault must lie with the
craftsman rather than with the tools! Others have tried to place part of
the blame on attitudes39 that they believe originate in the early chapters
of Genesis, which talk of human beings having rule over creation and
subduing it.40 Those words, however, should not be taken out of con-
text “ 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?

The will to act
Many of the principles I have been enunciating are included at least
implicitly in the declarations, conventions and resolutions which came
out of the United Nations Conference on Environment and Development
210 Why should we be concerned?

held in Rio de Janeiro in June 1992; indeed, they form the background
of many statements emanating 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 impli-
cations of climate change, has commented ˜Mostly we know what to do
but we lack the will to do it™.41
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 ˜material™ and the immediate and fail to act according to gen-
erally accepted values and ideals particularly if it means some cost to
ourselves or if it is concerned 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 grat-
ify 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 wrong “ or in religious parlance as sin “
to include unwarranted pollution of the environment or lack of care
for it.42
Those with religious belief tend to emphasise the importance of
coupling together the relationship of humans to the environment to the
relationship of humans to God.43 It is here, religious believers 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
One of the main messages of this chapter is that action addressing
environmental problems depends not only on knowledge about them
but on the values we place on the environment and our attitudes to-
wards it. In the chapter I have suggested that assessments of envi-
ronmental value and appropriate attitudes can be developed from the

r The perspectives of balance, interdependence and unity in the natural
world generated by the underlying science.
r 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.
r A recognition that to damage the environment or to fail to care for it
is to do wrong.
r An interpretation of human responsibility in terms of stewardship of
the Earth based on ˜shared™ values generally recognised by different
Questions 211

human communities and that strives for equity and justice as between
different human communities and different generations.
r A recognition of the importance of the cultural and religious basis for
the principles of stewardship “ humans as ˜gardeners™ of the Earth is
a possible ˜model™ of such stewardship.
r 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.44

I shall return to the practical outworking of some of these issues in
later chapters especially Chapter 12. Finally, let me recall some words of
Thomas Huxley, an eminent biologist from last 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 anthropocentric
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?
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 be-
lief) is a hindrance in the debate about environmental values. Do you
5 Should we strive for universally accepted values with respect to the envi-
ronment? Or is it acceptable for different communities to possess different
6 Identify and list as many values as you can that belong to the categories
natural and cultural (see page 206). In what ways do items in these categories
˜belong together™?
212 Why should we be concerned?

7 An argument for religious belief which is sometimes put forward, irrespective
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?
8 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?
9 Discuss the term ˜stewardship™, which is often used as a description of the
relation of humans to the environment. Does it imply too anthropocentric a
10 Discuss the model of humans as ˜gardeners™ of the Earth. How ade-
quate is the picture it presents of the relationship of humans to the
11 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?
12 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?
13 In Chapter 9 (see box on page 237) the concept of Integrated Assessment
and Evaluation is introduced that involves all the natural and social sci-
ence disciplines. In what ways could ethical or religious values be intro-
duced into such evaluations? Is it appropriate and necessary that they be

Notes for Chapter 8
1 Gore, A. 1992. Earth in the Balance. New York: Houghton Mif¬‚in
2 Carson, R. 1962. Silent Spring. New York: Houghton Mif¬‚in Company.
3 See box in Chapter 9 on page 231.
4 See Lean, G., Hinrichsen, D., Markham, A. 1990. Atlas of the Environment.
London: Arrow Books.
5 Lovelock, J. E. 1979. Gaia. Oxford: Oxford University Press; Lovelock, J. E.
1988. The Ages of Gaia. Oxford: Oxford University Press.
6 Lovelock, The Ages of Gaia, pp. 131“3.
7 Lovelock, J. E., Margulis, L. 1974. Tellus, 26, pp. 1“10.
8 Lovelock, J. E. 1990. Hands up for the Gaia hypothesis. Nature, 344, pp. 100“
12, also Lovelock, J. E. 1991. Gaia: the Practical Science of Planetary
Medicine. London: Gaia Books.
9 Colin Russell discusses Gaia as a scienti¬c hypothesis and also its possible
religious connections in The Earth, Humanity and God. London: UCL Press,
Notes 213

10 Lovelock, The Ages of Gaia, p. 212.
11 For more details see Lovelock, The Ages of Gaia.
12 Quoted by Al Gore, Earth in the Balance, p. 259.
13 Quoted by Al Gore, Earth in the Balance, p. 261.
14 Ghillean Prance, Director of Kew Gardens in the UK, provides examples
from his extensive work in countries of south America in his book The Earth
Under Threat. Glasgow: Wild Goose Publications, 1996.
15 Khalil, M. H. 1993. Islam and the Ethic of Conservation. Impact (Newsletter
of the Climate Network Africa), December, p. 8.
16 A number of injunctions were given to the Jews in the Old Testament regard-
ing care for plants and animals and care for the land; for example, Leviticus
19:23“25, Leviticus 25:1“7, Deuteronomy 25:4.
17 Temple, W. 1964. Nature, Man and God. London: Macmillan (¬rst edition
18 See for instance Davies, P. 1992. The Mind of God. London: Simon and
Schuster. I have also addressed this theme in Houghton, J. T. 1995. The
Search for God: can Science Help? London: Lion Publishing.
19 Hawking, S. 1989. A Brief History of Time. London: Bantam Press.
20 See for instance Davies, The Mind of God; also Barrow, J., Tipler, F. J.
1986. The Anthropic Cosmological Principle. Oxford: Oxford University
21 Barrow and Tipler, The Anthropic Cosmological Principle; and Gribbin, J.,
Rees, M. 1991. Cosmic Coincidences. London: Black Swan.
22 Davies, The Mind of God.
23 Polanyi, M. 1962. Personal Knowledge. London: Routledge and Kegan Paul.
24 The relation of science to value is explored in Rolston, H. III. 1999.
Genes, Genesis and God. Cambridge: Cambridge University Press,
Chapter 4.
25 Rolston, H. III. 1988. Environmental Ethics. Philadelphia: Temple Univer-
sity Press, p. 331.
26 See, for instance, Dawkins, R. 1986. The Blind Watchmaker. London:
27 See, for instance, Polkinghorne, J. 1986. One World. London: SPCK;
Polkinghorne, J. 1986. Beyond Science. Cambridge: Cambridge University
Press; Houghton, The Search for God.
28 See, for instance, Russell, C. 1985. Cross-currents: Interactions between
Science and Faith. Leicester, UK: Intervarsity Press.
29 Gore, Earth in the Balance.
30 Gore, Earth in the Balance, p. 252.
31 Gore, Earth in the Balance, p. 265.
32 Gore, Earth in the Balance, p. 254.
33 For expositions of a Christian view of the environment, see Elsdon, R.
1992. Greenhouse Theology. Tunbridge Wells: Monarch; Russell, The Earth,
Humanity and God.
34 Genesis 2:15.
35 Genesis 2:19.
214 Why should we be concerned?

36 Genesis 2:12.
37 Genesis 2:9.
38 Genesis 1:27.
39 The best-known exposition of this position is, for instance, White, L. Jr.
1987. The historical roots of our ecological crisis. Science, 155, pp. 1203“
7; see Russell, The Earth, Humanity and God, for a commentary on this
40 Genesis 1:26“28.
41 The Doomsday Letters, broadcast on BBC Radio 4, UK, 1996.
42 This was the ¬rst of the principles that came out of a symposium (called
the Patmos Principles since the climax of the symposium, held in celebra-
tion of the 1900th anniversary of the writing of the Book of Revelation,
was on the island of Patmos) I attended in 1995 sponsored by the Ecu-
menical Patriarch Bartholomew I of the Greek Orthodox Church and Prince
Philip in his capacity as President of the World Wildlife Fund. An extremely
eclectic group, scientists, politicians, environmentalists and theologians at-
tended from a wide range of religious backgrounds and beliefs. John, the
Metropolitan of Pergamon, who was chairman of the symposium™s scien-
ti¬c committee, kept emphasising that we should consider pollution of the
environment, or lack of care for the environment, as a sin “ not only against
nature but a sin against God. His message struck a strong chord with the
symposium. The principle goes on to explain that this new category of sin
should include activities that lead to ˜species extinction, reduction in ge-
netic diversity, pollution of the water, land and air, habitat destruction and
disruption of sustainable life styles™. The symposium™s report is edited by
Sarah Hobson and Jane Lubchenco and published under the title Revelation
and the Environment:“ AD95“1995. Singapore: World Scienti¬c Publishing,
43 In Judaeo-Christian teaching the coupling of these two relationships be-
gins with the Creation stories in Genesis. These stories go on to describe
how humans disobeyed God (Chapter 3) and broke the partnership. But the
Bible continually explains how God offers a way back to partnership. A
few chapters on in Genesis (9:8“17), the basis of the relationship between
God and Noah is a covenant agreement in which ˜all life on the Earth™ is
included as well as humans. A relationship based on covenant is also the
basis of the partnership between God and the Jewish nation in the Old Tes-
tament. But, after many times when that relationship was broken, the Old
Testament prophets looked forward to a new covenant based not on law but
on a real change of heart (Jeremiah 31:31“34). The New Testament writ-
ers (for example Hebrews 8:10“11) see this new covenant being worked
out through the life and particularly through the death and resurrection of
Jesus, the Son of God. Jesus promised his followers the Holy Spirit (John
15, 16), whose in¬‚uence would enable the partnership between them and
God to work. Paul, in his letters, is constantly referring to the depen-
dent relationship which forms the basis of his own partnership with God
Notes 215

(Galatians 2:20, Philippians 4:13) and which has been the experience of
millions of Christians down the centuries. Included in Paul™s theology is the
whole of creation (Romans 8:19“22).
44 Edmund Burke, a nineteenth century British politician said, ˜no one made a
greater mistake than he who did nothing because he could only do so little.™
“quoted at the end of Chapter 12.
Chapter 9
Weighing the uncertainty

This book is intended to present clearly the current scienti¬c position
on global warming. A key part of this presentation concerns the uncer-
tainty associated with all parts of the scienti¬c description, especially with
the prediction of future climate change, which forms an essential con-
sideration 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 com-
plex; we need to consider how uncertainty is weighed against the cost
of possible action. First of all 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 underly-
ing 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 carbon dioxide concentration doubles and
nothing else changes apart from atmospheric temperature, then the av-
erage 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 avail-
able for addressing these problems. Although they are highly complex,

The scienti¬c uncertainty 217

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 also from their success in simulating past climates; these
latter are limited as much by the lack of data as by inadequacies in the
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 loom largest 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 uncertainties in our assessment of the impacts of cli-
mate change. As Chapter 7 shows, however, some important general
statements can be made with reasonable con¬dence. Under nearly all
scenarios of increasing carbon dioxide emissions next 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 be-
ings) will not be able to adapt easily to such a rate of change. The most

The reasons for scienti¬c uncertainty
The Intergovernmental Panel on Climate Change1 has described the sci-
enti¬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:
r sources and sinks of greenhouse gases, which affect predic-
tions of future concentrations,
r clouds, which strongly in¬‚uence the magnitude of climate
r oceans, which in¬‚uence the timing and patterns of climate
r 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. How-
ever, the complexity of the system means that we cannot rule out
218 Weighing the uncertainty

noticeable impacts are likely to be on the availability of water (especially
on 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 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 for-
mulated for the IPCC 1990 Report. Over ten years later it remains a
good statement of the main factors that underly scienti¬c uncertainty.
That this is the case does not imply little progress in the past decade.
On the contrary, as the subsequent IPCC Reports show, a great deal of
progress has been made in scienti¬c understanding and in the develop-
ment 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 scienti¬c
formulations and possess increased skill in simulating the important
climate parameters. For regional scale simulation and prediction, re-
gional 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 projec-
tions 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 cli-
mate models enables more meaningful impact assessments 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 6.5 that current models perform better for some regions than for
Summarised in Figure 9.1 are the various components that are in-
cluded in the development of projections of climate change or its impacts.
All of these possess uncertainties that need to be aggregated appropri-
ately in arriving at estimates of uncertainties in different impacts.

The IPCC assessments
Because of the scienti¬c uncertainty, it has been necessary to make a
large effort to achieve the best assessment of present knowledge and to
express it as clearly as possible. For these reasons the IPCC was set up
jointly by two United Nations™ bodies, the World Meteorological Or-
ganization (WMO) and the United Nations Environmental Programme
The IPCC assessments 219

Figure 9.1 The cascade of
Socio-economic assumptions
uncertainties in projections
(WGII/Ch 3; WGIII/Ch 2 - SRES)


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