. 10
( 13)


to their average from 2008“12, called the ¬rst commitment period. The
Protocol also required that a second commitment period be de¬ned for
which negotiations must start no later than 2005. The Protocol carries
inbuilt mechanisms that could lead to stronger action and be expanded
over time to include developing countries.
The basic structure of the Protocol and the commitments required
by different countries were agreed at a meeting of the Conference of the
Parties in Kyoto in November 1997. But the Protocol is a highly complex
agreement and over the next three years intense negotiations followed
regarding the details “ the range of gases covered, the basis for comparing
them and the rules for monitoring, reporting and compliance. Further the
Protocol incorporates a range of mechanisms (see box below) of a kind
The Kyoto Protocol 247

Table 10.2 Greenhouse gases covered by the Kyoto Protocol and their
global warming potentials (GWPs) on a mass basis relative to carbon
dioxide and for a time horizon of 100 years

Greenhouse gas Global warming potential (GWP)

Carbon dioxide (CO2 ) 1
Methane (CH4 ) 23
Nitrous oxide (N2 O) 296
from 12 to 12 000a
Hydro¬‚uorocarbons (HFCs)
from 5000 to 12 000a
Per¬‚uorocarbons (PFCs)
Sulphur hexa¬‚uoride (SF6 ) 22200

Table 6.7 from Ramaswamy, V. et al. 2001. 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.
Range of values for different HFCs or PFCs “ for more information about HFCs
see Moomaw, W. R., Moreira, J. R. et al. 2001. Technological and economic
potential of greenhouse gas emissions reduction. In Metz, B., Davidson, O.,
Swart, R., Pan, J. (eds.) 2001. Climate Change 2001: Mitigation. Contribution
of Working Group III to the Third Assessment Report of the Intergovernmental
Panel on Climate Change. Cambridge: Cambridge University Press, Chapter
3 and its appendix.

that are unprecedented in an international treaty and that enable countries
to offset their domestic emission obligations against the absorption of
emissions by ˜sinks™ (e.g. through forestation) or by investment in or
trading with other countries where it might be cheaper to limit emissions.
The emissions controlled by the Protocol are from six greenhouse
gases (Table 10.2) that can be converted into an amount of carbon-
dioxide-equivalent through the use of their global warming potentials
(GWPs) which were introduced in Chapter 3 page 52.
The details of the Protocol were ¬nally agreed at a meeting of the
Conference of the Parties in Marrakesh in October/November 2001.
Much of the detailed discussion related to the inclusion of carbon
sinks, especially from forests and from land-use change. Because of the
large uncertainties regarding the magnitude of such sinks, considerable
doubts were expressed regarding their inclusion in the Protocol arrange-
ments. However, it was agreed that they should be included in a limited
way and detailed regulations were agreed concerning the inclusion of
248 A strategy for action to slow and stabilise climate change

afforestation, reforestation and deforestation activities and certain kinds
of land-use change. Capping arrangements were also set up that limit
the extent to which removals of carbon dioxide from these activities are
allowed to offset emissions elsewhere.1

The Kyoto mechanisms
The Kyoto Protocol includes three special mechanisms to assist in emis-
sions reductions.

Joint implementation (JI) allows industrialised countries to implement
projects that reduce emissions or increase removals by sinks in the ter-
ritories of other industrialised countries. Emissions reduction units gen-
erated by such projects can then be used by investing Annex I countries
to help meet their emission targets. Examples of JI projects could be the
replacement of a coal-¬red power plant with a more ef¬cient combined
heat and power plant or the reforestation of an area of land. JI projects are
expected to be mainly in EIT (economies in transition) countries where
there is more scope for cutting emissions at low cost.
The Clean Development Mechanism (CDM) allows industrialised
countries to implement projects that reduce emissions in developing
countries. The certi¬ed emission reductions generated can be used by
industrialised countries to help meet their emission targets, while the
projects also help developing countries to achieve sustainable develop-
ment and contribute to the objective of the Convention. Examples of
CDM projects could be a rural electri¬cation project using solar panels
or the reforestation of degraded land.
Emissions Trading allows industrialised countries to purchase ˜assigned
amount units™ of emissions from other industrialised countries that ¬nd it
easier, relatively speaking, to meet their emissions targets. This enables
countries to utilise lower cost opportunities to curb emissions or increase
removals, irrespective of where those opportunities exist, in order to
reduce the overall cost of mitigating climate change.

The detailed regulations concerning the implementation of these mech-
anisms state that projects will only be approved if they lead to real,
measurable and long-term bene¬ts related to the mitigation of climate
change and that they are additional to any that would have occurred
without the project.

Before the Marrakesh meeting in 2001 the United States had an-
nounced its withdrawal from the Protocol. Despite this by the end of
2003 120 countries had rati¬ed the Protocol and the Annex I countries
that had rati¬ed represented 44% of Annex I country emissions. For the
Forests 249

Protocol to come into force ¬fty-¬ve countries have to ratify together
with suf¬cient Annex I countries to represent ¬fty-¬ve per cent of Annex
I country emissions. With rati¬cation by Russia towards the end of 2004,
the Protocol will come into force on 16 February 2005.
Concern has often been expressed about the likely cost of implemen-
tation of the Kyoto Protocol. Cost studies have been carried out using a
number of international energy-economic models. For nine such stud-
ies, the range of values in impacts on the gross domestic product (GDP)
of participating countries is as follows.2 In the absence of emissions
trading, estimated reductions in projected GDP in the year 2010 are be-
tween 0.2% and 2% compared with a base case with no implementation
of the Protocol. With emissions trading between Annex I countries, the
estimated reductions in GDP are between 0.1% and 1.1%. If emissions
trading with all countries is assumed through ideal CDM (see box be-
low) implementation, the estimated reductions in GDP are substantially
less “ between 0.01% and 0.7%. Although there are differences between
countries, most of the large range in the results is due to differences in the
models and can be considered as an expression of the large uncertainties
inherent in such studies at the present stage of development.
The Kyoto Protocol is an important start to the mitigation of cli-
mate change through reductions in greenhouse gas emissions. With its
complexity and its diversity of mechanisms for implementation, it also
represents a considerable achievement in international negotiation and
agreement. It will stem the continuing growth of emissions from many
industrialised countries and achieve a reduction overall compared with
1990 from those Annex I countries that participate. The much more sub-
stantial longer-term reductions that are likely to be necessary for the
decades that follow the ¬rst commitment period will be discussed later
in the chapter.

We now turn to the situation of the world™s forests and the contribution
that they can make to the mitigation of global warming. Action here can
easily be taken now and is commendable for many other reasons.
Over the past few centuries many countries, especially those at mid
latitudes, have removed much of their forest cover to make room for
agriculture. Many of the largest and most critical remaining forested
areas are in the tropics. However, during the last few decades, the ad-
ditional needs of the increasing populations of developing countries for
agricultural land and for fuelwood, together with the rise in demand for
tropical hardwoods by developed countries, has led to a worrying rate
of loss of forest in tropical regions (see box below). In many tropical
250 A strategy for action to slow and stabilise climate change

countries the development of forest areas has been the only hope of
subsistence for many people. Unfortunately, because the soils and other
conditions were often inappropriate, some of this forest clearance has not
led to sustainable agriculture but to serious land and soil degradation.3
Measurements on the ground and observations from orbiting satel-
lites have been combined to provide estimates of the area of tropical
forest lost. Over the decades of the 1980s4 and 1990s the average loss
was about one per cent per year (see box below) although in some
areas it was considerably higher. Such rates of loss cannot be sustained
if much forest is to be left in ¬fty or a hundred years™ time. The loss of
forests is damaging, not only because of the ensuing land degradation
but also because of the contribution that loss makes to carbon emissions
and therefore to global warming. There is also the dramatic loss in bio-
diversity (it is estimated that over half the world™s species live in tropical
forests) and the potential damage to regional climates (loss of forests can
lead to a signi¬cant regional reduction in rainfall “ see box on page 173).
For every square kilometre of a typical tropical forest there is about
25 000 tonnes of biomass (total living material) above ground, containing
about 12 000 tonnes of carbon.6 It is estimated that burning or other
destruction from deforestation turns about two-thirds of this carbon into
carbon dioxide. Approximately the same amount of carbon is also stored
below the surface in the soil. On this basis, from the destruction of about

The world™s forests and deforestation5
The total area covered by forest is almost one-third of the world™s land
area, of which ninety-¬ve per cent is natural forest and ¬ve per cent
planted forest. About forty-seven per cent of forests worldwide are trop-
ical, nine per cent subtropical, eleven per cent temperate and thirty-three
per cent boreal.
At the global level, the net loss in forest area during the 1990s was an
estimated 940 000 km2 (2.4% of total forest area). This was the combined
effect of a deforestation rate of about 150 000 km2 per year and a rate of
forest increase of about 50 000 km2 per year. Deforestation of tropical
forests averaged about one per cent per year.
The area under forest plantations grew by an average of about
3000 km2 per year during the 1990s. Half of this increase was the result
of afforestation on land previously under non-forest land use, whereas
the other half resulted from conversion of natural forest.
In the 1990s, almost seventy per cent of deforested areas changed
to agricultural land, predominantly under permanent rather than shifting
Forests 251

150 000 km2 per annum over the decades of the 1980s and 1990s (see
box above) about 1.2 Gt of carbon would enter the atmosphere as carbon
dioxide. Although there are substantial uncertainties in the numbers,
they approximately tally with the IPCC estimate, quoted in Chapter 3
(see Table 3.1), of the carbon as carbon dioxide entering the atmosphere
each year from land-use change (mostly deforestation) of 1.7 ± 0.8 Gt
per year “ a signi¬cant fraction of the current total emissions of carbon
dioxide into the atmosphere from human activities.
Reducing deforestation can therefore make a substantial contribution
to slowing the increase of greenhouse gases in the atmosphere, as well as
the provision of other bene¬ts such as guarding biodiversity and avoiding
soil degradation. These bene¬ts are being increasingly recognised and
developing countries in tropical regions where there are large areas of
natural forest are beginning to concentrate seriously on the management
of their forests, on limiting the extent of deforestation or planning for
substantial afforestation. Other large areas of forest lie at higher latitudes
where developed countries are also taking action to increase forest area
so as to contribute to the mitigation of global warming.
Let us look at the possibilities for afforestation. For every square
kilometre, a growing forest ¬xes between about 100 and 600 tonnes of
carbon per year for a tropical forest and between about 100 and 250
tonnes for a boreal forest.7 To illustrate the effect of afforestation on
atmospheric carbon dioxide, suppose that an area of 100 000 km2 , a little
more than the area of the island of Ireland, were planted each year for
forty years “ starting now. By the year 2045, 4 000 000 km2 would have
been planted; that is roughly half the area of Australia. During that forty
years, the forests would continue to grow and uptake carbon for twenty
to ¬fty years or more after planting (the actual period depending on the
type of forest and site conditions) “ and, assuming a mixture of tropical,
temperate and boreal forest, between about 20 and 50 Gt of carbon
from the atmosphere would have been sequestered. This accumulation of
carbon in the forests is equivalent to between about ¬ve and ten per cent
of the likely emissions due to fossil fuel burning up to 2045.
But is such a tree planting programme feasible and is land on the scale
required available? The answer is almost certainly, yes. Studies have been
carried out that have identi¬ed land which is not presently being used for
croplands or settlements, much of which has supported forests in the past,
of an area totalling about 3 500 000 km2 .8 About 2 200 000 km2 of this
total is land that is technically suitable at mid and high latitudes “ all of
this is deemed to be available. In tropical regions, of the 22 000 000 km2
actually deemed suitable, only six per cent or 1 300 000 km2 is consid-
ered to be actually available because of additional cultural, social and
economic constraints. These studies have also considered in detail how
252 A strategy for action to slow and stabilise climate change

much carbon could be sequestered between the years 1995 and 2050 by
a programme of afforestation on this land. It is estimated to be between
50 and 70 Gt of carbon, to which a further 10“20 Gt can be added if the
rate of tropical deforestation were to be slowed. Estimates of the cost of
carrying out the programme have also emerged from the studies; they
are considerably lower than those estimated earlier in the 1990s. When
expressed per tonne of carbon sequestered they typically fall between
$US 1 and 10 (the lower values in developing countries) not includ-
ing land and transaction costs, but also not including the value of local
bene¬ts (for instance, watershed protection, maintenance of biodiver-
sity, education, tourism and recreation) which might be derived from
the programme and which, in some circumstances, might offset most of
the programme™s cost. Compare this ¬gure with the estimate given in
Chapter 9 of between $US 50 and 100 for the cost per tonne of carbon
of the likely damage due to global warming. The programme therefore
appears as a potentially attractive one for alleviating the rate of change
of climate due to increasing greenhouse gases in the relatively short
Let me insert here a note of caution. As with many environmental
projects the situation, however, may not be as simple as it seems at ¬rst.
One complicating factor is that introducing forest can change the albedo9
of the Earth™s surface. Dark green forests absorb more of the incoming
solar radiation than arable cropland or grassland and so tend to warm the
surface. This is particularly noticeable in winter months when unforested
areas may possess highly re¬‚ecting snow cover. Calculations show that,
particularly at high latitudes, the warming due to this ˜albedo effect™ can
offset a signi¬cant fraction of the cooling that arises from the additional
carbon sink provided by the forest.10
A possible afforestation programme has been presented in order to
illustrate the potential for carbon sequestration. Once the trees are fully
grown, of course, the sequestration ceases. What happens then depends
on the use that may be made of them. They may be ˜protection™ forests, for
instance for the control of erosion or for the maintenance of biodiversity;
or they may be production forests, used for biofuels or for industrial tim-
ber. If they are used as fuel for energy generation (see Chapter 11), they
add to the atmospheric carbon dioxide but, unlike fossil fuels, they are a
renewable resource. As with the rest of the biosphere where natural recyc-
ling takes place on a wide variety of timescales, carbon from wood fuel
can be continuously recycled through the biosphere and the atmosphere.
However, although there is a useful potential contribution from af-
forestation to the mitigation of climate change, it can only provide a
small part of what is required. An approximate upper bound for the
Reduction in the sources of methane 253

reduction that could be achieved in the twenty-¬rst century through the
enhancement of carbon uptake by land-use change has been estimated
at 40“70 ppm11 (equivalent to a storage of 85“150 Gt). Compare this
with the range in carbon dioxide concentration in 2100 of about 400 ppm
that results from different SRES emission scenarios (Figure 6.1) or with
the increase of up to 300 ppm by 2100 because of the possible effect of
climate-carbon cycle feedbacks (see Figure 3.5).

Reduction in the sources of methane
Methane is a less important greenhouse gas than carbon dioxide, con-
tributing perhaps ¬fteen per cent to the present level of global warming.
The stabilisation of its atmospheric concentration would contribute a
small but signi¬cant amount to the overall problem. Because of its much
shorter lifetime in the atmosphere (about twelve years compared with
100“200 years for carbon dioxide), only a relatively small reduction in
the anthropogenic emissions of this gas, about eight per cent, would be
required to stabilise its concentration at the current level.
In Figures 6.1 and 6.2 are shown the emissions and the atmospheric
concentrations of methane estimated for the various SRES scenarios,
assuming no special action to reduce them. Of the various sources of
methane listed in Table 3.3, there are three sources arising from human
activities that could rather easily be reduced at small cost.12 Firstly,
methane emission from biomass burning would be cut by, say, one-third
if deforestation were drastically curtailed.
Secondly, methane production from land¬ll sites could be cut by at
least a third if more waste were recycled or used for energy generation
by incineration or if arrangements were made on land¬ll sites for the
collection of methane gas (it could then be used for energy production
or if the quantity were insuf¬cient it could be ¬‚ared, turning the methane
into carbon dioxide which molecule-for-molecule is less effective than
methane as a greenhouse gas). Waste management policies in many
countries already include the encouragement of such measures.
Thirdly, the leakage from natural gas pipelines from mining and other
parts of the petrochemical industry could at little cost (probably even at
a saving in cost) also be reduced by, say, one-third. An illustration of the
scale of the leakage is provided by the suggestion that the closing down
of some Siberian pipelines, because of the major recession in Russia,
has been the cause of the fall in the growth of methane concentration
in the atmosphere from 1992 to 1993. Improved management of such
installations could markedly reduce leakage to the atmosphere, perhaps
by as much as one-quarter overall.
254 A strategy for action to slow and stabilise climate change

Fourthly, with better management, options exist for reducing
methane emissions from sources associated with agriculture.13
Reductions from these four sources could reduce anthropogenic
methane emissions by over 60 000 000 tonnes per annum which would
be more than adequate to stabilise the concentration of methane in the
atmosphere at about or below the current level. Put another way, the
reduction in methane emissions from these sources would be equivalent
to a reduction in annual carbon dioxide emissions producing about one-
third of a gigatonne of carbon14 or a little less than ¬ve per cent of total
greenhouse gas emissions “ a useful contribution towards the solution
of the global warming problem.
Because the lifetime of methane in the atmosphere is relatively short,
a small reduction in methane emissions will quickly lead to its stabilisa-
tion as required by the Climate Convention objective. The same, however,
is not true of the stabilisation of carbon dioxide concentration with its
much longer and rather complicated lifetime. It is to that we shall now

Stabilisation of carbon dioxide concentrations
Carbon dioxide, as we have seen, is the most important of the greenhouse
gases that result from human activities. Under all the SRES scenarios,
the concentration of carbon dioxide rises continuously throughout the
twenty-¬rst century and apart from scenario B1 none come anywhere
near to stabilisation of concentration by 2100.
What sort of emissions scenario would stabilise the carbon dioxide
concentration? Suppose for instance that it were possible to keep global
emissions for the whole of the twenty-¬rst century at the same level as
in the year 2000, would that be enough? Stabilising concentrations is,
however, very different from stabilising emissions. With constant emis-
sions after the year 2000, the concentration in the atmosphere would
continue to rise and would approach 500 ppm by the year 2100. After
that carbon cycle models predict that, because of the long time con-
stants involved, the carbon dioxide concentration would still continue to
increase, although more slowly, for many centuries.
Examples of scenarios that would lead to stabilisation of atmospheric
carbon dioxide concentration at different levels are shown in Figure 10.1.
Note that stabilisation at any level shown in the ¬gure, even at an ex-
tremely high level, requires that anthropogenic carbon dioxide emissions
eventually fall to a small fraction of current emissions. This highlights
the fact that to maintain a constant future carbon dioxide concentra-
tion, emissions must be no greater than the level of persistent natural
Stabilisation of carbon dioxide concentrations 255

sinks. The main known such sink is due to the dissolution of calcium
carbonate from the oceans into ocean sediments that, for high levels of
carbon dioxide concentration, is probably less than 0.1 Gt per year.15
In the work presented in Figure 10.1, many different pathways to
stabilisation could have been chosen. The particular emission pro¬les
illustrated in Figure 10.1 begin by following the current average rate of
increase of emissions and then provide a smooth transition to the time of
stabilisation. To a ¬rst approximation, the stabilised concentration level
depends more on the accumulated amount of carbon emitted up to the
time of stabilisation than on the exact concentration path followed en
route to stabilisation. This means that alternative pathways that might
assume higher emissions in earlier years would require steeper reduc-
tions in later years. Table 10.3 lists the accumulated emissions for the
period 2001“2100 for the different stabilisation pro¬les and also those
for the SRES scenarios. It shows that if the atmospheric concentration of
carbon dioxide is to remain below about 500 ppm, the future global an-
nual emissions averaged over the twenty-¬rst century cannot exceed the
current level of global annual emissions. Figure 10.1(c) shows the pro-
jected global mean surface temperature response to the carbon dioxide
concentration pro¬les shown in Figure 10.1(a).
The main results shown in Table 10.3 do not include the effect of
climate feedbacks on the carbon cycle (see box in Chapter 3 on page 40).
Two of the feedbacks are important in the context of the consideration
of stabilisation scenarios; namely, increased respiration from the soil as
the temperature rises and die-back especially from forests as the climate
changes. As we saw in Chapter 3, the effect of these feedbacks could
lead to the biosphere becoming a substantial source of carbon dioxide
during the twenty-¬rst century. The size of that source will depend on
the amount of climate change. To take it into account, the accumulated
amount of that source has to be subtracted from the ¬gures in Table 10.3
to arrive at the emissions from fossil fuel burning that would lead to
different stabilisation levels. Some of the estimates of what would need
to be subtracted are large “ for instance, for the 450 ppm and 550 ppm
stabilisation scenarios, they are as large as 200 Gt and 300 Gt respectively
during the twenty-¬rst century.16 In which case, if these estimates are
con¬rmed, emissions scenarios that are aiming at 450 ppm stabilisation
(but not allowing for the feedbacks), when the feedbacks are included,
would in fact achieve around 550 ppm, and aiming at 550 ppm would in
fact achieve around 750 ppm.
It is instructive also to look at annual emissions of carbon dioxide
expressed per capita. Averaged over the world in 2000 they were just
over one tonne (t) (as carbon) per capita but they varied very much from
256 A strategy for action to slow and stabilise climate change

Emissions, concentrations, and temperature changes corresponding
to different stabilisation levels for CO2 concentrations
(a) CO2 emissions (Gt C)
(b) CO2 concentration
A2 1,100
18 1,000
A1B 800
10 700
8 600
0 300
2000 2050 2100 2150 2200 2250 2300 2000 2050 2100 2150 2200 2250 2300

(c) Global mean temperature change
Sea level rise
WRE profiles
5 WRE 1000
WRE 750
A2 WRE 650
WRE 550
3 2
WRE 450
2000 2050 2100
SRES scenarios
2000 2050 2100 2150 2200 2250 2300

Figure 10.1 (a) Emission pro¬les of carbon dioxide that would lead to
stabilisation of carbon dioxide concentration in the atmosphere at levels of 450,
550, 650, 750 and 1000 ppm according to the concentration pro¬les shown in
(b), estimated from carbon cycle models, without the effects of climate carbon
cycle feedbacks included. The shaded area illustrates the range of uncertainty in
the estimates that includes the effects of climate carbon cycle feedbacks (e.g.
the low boundary of the shading is the pro¬le of the 450 ppm stabilisation curve
with the feedbacks included). Also shown are three of the SRES emissions
scenarios (A1B, A2 and B1) and the concentrations that would result from them.
(c) Global mean temperature changes for the stabilisation pro¬les in (a)
estimated in the same way as for Figure 6.4. The black spots indicate the year in
which stabilisation of carbon dioxide concentration is achieved. It is assumed
that emissions of gases other than carbon dioxide follow the SRES A1B scenario
until the year 2100 and are constant thereafter. The shaded area indicates the
effect of a range of climate sensitivity across ¬ve stabilisation cases (see caption
to Figure 6.4) and the bars on the right-hand side show the range at the year
2300 for the different pro¬les. The diamonds show the equilibrium (very
long-term) warming for each stabilisation level using average climate model
results. Also shown for comparison are temperature increases in the year 2100
estimated for the three SRES scenarios.
The choice of stabilisation level 257

Table 10.3 Total anthropogenic carbon dioxide emissions in Gt carbon
accumulated from 2001“2100 inclusive for SRES scenarios and for
stabilisation scenarios (calculated using the Bern carbon cycle model a
with no carbon cycle feedbacks)

Case Accumulated CO2 emissions (GtC) 2001 to 2100

SRES Scenarios
A1B 1415
A1T 985
A1FI 2105
A2 1780
B1 900
B2 1080
Stabilisation scenarios
450 ppm 600
550 ppm 900
650 ppm 1100
750 ppm 1200
1000 ppm 1300

Adapted from Table 5 of Technical summary. In Houghton, J. T., Meira Filho,
L. G., Callander, B. A., Harris, N., Kattenberg, A., Maskell, K. (eds.) 1996.
Climate Change 1995: The Science of Climate Change. Cambridge: Cambridge
University Press.

country to country (Figure 10.2). For developed countries and transi-
tional economy countries in 2000 they averaged 2.8 t (ranging down-
wards from about 5.5 t for the USA) while for developing countries they
averaged about 0.5 t. Looking ahead to the years 2050 and 2100, even if
the world population rises to only about seven billion (as with SRES scen-
arios A1 and B1) under the pro¬les of carbon dioxide emissions leading
to stabilisation at concentrations of 450 ppm and 550 ppm (Figure 10.1)
the per capita annual emissions averaged over the world would be about
0.6 t and 1.1 t respectively for 2050 and 0.3 and 0.7 t respectively for
210017 “ much less than the current value of about 1 t.

The choice of stabilisation level
The last few sections have addressed the main greenhouse gases and how
their concentrations might be stabilised. To decide how the appropriate
stabilisation levels should be chosen as targets for the future we look
to the guidance provided by the Climate Convention Objective (see box
258 A strategy for action to slow and stabilise climate change

Emissions (tonnes of carbon per captita)

Canada, Australia, New Zealand

OECD Europe
Other EIT
Middle East

China America
Other Asia
Africa India
0 6000
1000 2000 3000 4000

Population (million)

Figure 10.2 Carbon dioxide emissions in 2000 from different countries or
groups of countries expressed per capita and population.

on page 243), which states that the levels and the timescales for their
achievement should be such that dangerous interference with the climate
system must be prevented, that ecosystems should be able to adapt nat-
urally, that food production must not be threatened and that economic
development can proceed in a sustainable manner. We do not yet know
enough to pick precisely the levels or the timescales under the criteria
the Climate Convention is prescribing, but perhaps already some limits
can be set.
Firstly, considering the most important greenhouse gas, carbon diox-
ide, as we have already noted its long life in the atmosphere provides
severe constraints on the future emission pro¬les that lead to stabilisation
at any level. It will be clear, for instance, from Figure 10.1 that stabil-
isation below about 400 ppm would require an almost immediate drastic
reduction in emissions. Such reduction could only be achieved at a large
cost and with some curtailment of energy availability and would almost
certainly breach the criterion which requires ˜that economic development
can proceed in a sustainable manner™.
What about the upper end of the choice of level? Here we refer
to the likely impacts of climate change under a situation in which the
atmospheric concentration of carbon dioxide has doubled from its pre-
industrial value of 280 ppm to about 560 ppm. Many of the impacts
described in Chapter 7 with their associated costs apply to this situation.
We also noted there that in estimating these costs there were components
The choice of stabilisation level 259

of the damage that could not be quanti¬ed in money terms. But even if
only the costs that can be estimated in terms of money are considered,
in Chapter 9 it was pointed out that estimates of the cost of the likely
damage of the impacts at that level of climate change were larger than the
costs of stabilising carbon dioxide concentration at levels above about
500 ppm (Figure 9.4). We also noted that, beyond the doubled carbon
dioxide situation, the damage due to greenhouse gas climate change is
likely to rise substantially more rapidly as the amount of carbon dioxide
in the atmosphere increases. A further factor is the rate of climate change
(see Figure 10.1(c)) which, with all the pro¬les except possibly the two
lowest, is likely to be such that some important ecosystems may not be
able to adapt to it (see Chapter 7). Studies18 show that stabilisation below
550 ppm should avoid some of the worst impacts; for instance, some of
the large-scale die-back of forests and the transition of the biosphere
from a source to a sink for carbon dioxide (see box in Chapter 3 on page
40) which would otherwise occur around the middle of the twenty-¬rst
century. Considering carbon dioxide alone, these considerations suggest
that the range between about 400 ppm and 550 ppm is where further
careful consideration of the choice of the target stabilisation level should
be made.
Although carbon dioxide is the most important greenhouse gas, other
gases also make a contribution to climate change. The combined effect
of the increases to 1990 of the gases methane, nitrous oxide and the
CFCs19 is to add a forcing equivalent to that from an additional 60 ppm
or so of carbon dioxide (see Chapter 6, page 124). The effect of these
other gases also needs to be taken into account in our overall discussion
of the Climate Convention Objective of stabilisation. Even if there were
no further increase in these minor gases, the 1990 forcing would still
require to be added to future projections of change. The effect of this,
if turned into equivalent amounts of carbon dioxide, would be that the
450 ppm carbon-dioxide-only level would become about 520 ppm and
the 550 ppm level would become about 640 ppm of equivalent carbon
dioxide.20 This means that, if it is considered that the climate effects of
doubled pre-industrial carbon dioxide concentration should be an upper
limit, when the increases in other gases are allowed for, the stabilisation
limit for carbon dioxide only is about 490 ppm.
How realistic is it to assume that the concentration of the other gases
will not change? We saw earlier that the Montreal Protocol should ensure
that the CFCs are stabilised in concentration over the next decade or two.
We also saw, for methane, that means are available that are not costly
and that, if taken, could stabilise methane concentrations at about today™s
levels. There is more uncertainty about nitrous oxide as its sources and
sinks are not well known. However, it is only a small contributor to
260 A strategy for action to slow and stabilise climate change

the forcing to date (equivalent to about 10 ppm of carbon dioxide); any
increase in the future is not likely to have a large effect.
In this simple argument regarding the in¬‚uence of other gases on
the choice of a concentration level for carbon dioxide stabilisation that
might be acceptable under the terms of the Climate Convention Objec-
tive, the concept of equivalent carbon dioxide concentration has proved
a useful tool. But it must not be used blindly. For any detailed consid-
eration of the choice of level, there are other scienti¬c factors to be
included. Firstly, there are the other contributors to radiative forcing and
climate change; for instance, tropospheric ozone and aerosols that are
very inhomogeneous in their distribution. Their likely effect, although
small compared with that of carbon dioxide, also needs to be taken into
account. Secondly, there are the different regional climate responses and
different timescales of responses that result from the different green-
house gases or from aerosols. Thirdly, there are the effects of particular
feedbacks (e.g. carbon dioxide fertilisation) or impacts (e.g. acid rain
from aerosols).
The choice of a target stabilisation level for greenhouse gases ac-
cording to the criteria listed in the Objective of the Climate Convention
involves scienti¬c, economic, social and political factors. In Chapter 9
(see box on page 237) the concept of Integrated Assessment and Eval-
uation was introduced that involves employment of the whole range of
disciplines in the natural and social sciences. Taking all factors into
consideration will involve different kinds of analysis, cost bene¬t anal-
ysis (which was considered brie¬‚y in Chapter 9), multicriteria analysis
(which takes into account factors that cannot be expressed in monetary
terms) and sustainability analysis (which considers avoidance of particu-
lar thresholds of stress or of damage). Further, because much uncertainty
is associated both with many of the factors that have to be included and
with the methods of analysis, the process of choice is bound to be an
evolving one subject to continuous review “ a process often described
as sequential decision making.
Taking account of considerations such as those above, let me mention
statements that have come from two very different bodies regarding their
view of where the choice of a stabilisation level at the present time could
or should be made. Firstly, the European Union has proposed setting a
limit for the rise in global average temperature of 2 —¦ C.21 Since the best
estimate of global average temperature rise for doubled pre-industrial
carbon dioxide (560 ppm) is 2.5 —¦ C, a rise of 2 —¦ C would occur with a
carbon dioxide concentration of about 430 ppm allowing for the effect
of other gases at their 1990 levels. The second statement comes from
Lord John Browne, the Group Chief Executive of British Petroleum, one
Realising the Climate Convention Objective 261

of the world™s largest oil companies. He recognises the dangers of global
warming and the challenge it presents and has stated that, for carbon
dioxide, ˜stabilisation in the range 500“550 ppm is possible, and with
care could be achieved without disrupting economic growth.™22

Realising the Climate Convention Objective
Having decided on a choice of stabilisation level, a large question re-
mains: how can the nations of the world work together to realise it in
The Objective of the Climate Convention is largely concerned with
factors associated with the requirement for sustainable development. In
Chapter 9, four principles were enunciated that should be at the basis
of negotiations concerned with future emissions reductions to mitigate
climate change. One of these was the Principle of Sustainable Devel-
opment. The others were the Precautionary Principle, the Polluter-Pays
Principle and the Principle of Equity. This latter Principle includes in-
tergenerational equity, or weighing the needs of the present generation
against those of future generations, and international equity, or weighing
the balance of need between industrial and developed nations and the de-
veloping world. Striking this latter balance is going to be particularly dif-
¬cult because of the great disparity in current carbon dioxide emissions
between the world™s richest nations and the poorest nations (Figure 10.2),
the continuing demand for fossil fuel use in the developed world and the
understandable desire of the poorer nations to escape from poverty
through development and industrialisation. This latter is particularly
recognised in the Framework Convention on Climate Change (see box at
the beginning of the chapter) where the growing energy needs of devel-
oping nations as they achieve industrial development are clearly stated.
An example of how the approach to stabilisation for carbon dioxide
might be achieved is illustrated in Figure 10.3. It is based on a proposal
called ˜Contraction and Convergence™ that originates with the Global
Commons Institute (GCI),23 a non-governmental organisation based in
the UK. The envelope of carbon dioxide emissions is one that leads to
stabilisation at 450 ppm (without climate feedbacks included), although
the rest of the proposal does not depend on that actual choice of level.
Note that, under this envelope, global fossil-fuel emissions rise by about
¬fteen per cent to about 2025; they then fall to less than half the current
level by 2100. The ¬gure illustrates the division of emissions between
major countries or groups of countries as it has been up to the present.
Then the simplest possible solution is taken to the sharing of emissions
between countries and proposes that, from some suitable date (in the
262 A strategy for action to slow and stabilise climate change

Figure 10.3 Illustrating the ™Contraction and Convergence™ proposal of the
Global Commons Institute for achieving stabilisation of carbon dioxide
concentration. The envelope of carbon dioxide emissions illustrated is one that
leads to stabilisation at 450 ppm (but the effect of climate carbon cycle
feedbacks is not included). For major countries or groups of countries, up to the
year 2000, historic emissions are shown. After 2030 allocations of emissions are
made on the basis of equal shares per capita on the basis of population
projections for that date. From now until 2030, smooth ™convergence™ from the
present situation to that of equal shares is assumed to occur. In the upper part of
the diagram the per capita contributions that apply to different countries or
groups of countries are shown. For OECD and FSU see Glossary.

¬gure, 2030 is chosen), emissions are allocated on the basis of equal
shares per capita. From now until 2030 the division is allowed to converge
from the present situation to that of equal per capita shares. Hence the
˜contraction and convergence™. The further proposal is that arrangements
to trade the carbon dioxide allocations are made.
The ˜Contraction and Convergence™ proposal addresses all of the four
principles mentioned above. In particular, through its equal per capita
sharing arrangements it addresses head-on the question of international
equity “ and the proposed trading arrangements ensure that the greatest
˜polluters™ pay. Its simple and appealing logic means that it is a strong
candidate for providing a long-term solution. What has yet to be worked
is how the ˜convergence™ part of the proposal can be implemented, but
then any proposal for a solution will have to address the problem of
Another example of a pathway to stabilisation during the twenty-¬rst
century of carbon dioxide concentration is set out in a study sponsored
Summary of the action required 263

by the World Energy Council and published in 1993.24 An ˜ecologically
driven scenario™ “ Scenario C “ of global carbon dioxide emissions is
described that leads to stabilisation at about 450 ppm (without carbon
feedbacks included) “ see Figure 11.4. Under that scenario, global carbon
dioxide emissions grow by about ten per cent (from 1990 levels) by
the year 2050; they then fall by sixty per cent by 2100 (Table 11.2).
For the ¬rst two decades of the twenty-¬rst century, the World Energy
Council provide detailed projections for Scenario C that recognise the
requirement for international equity. Up to the year 2020, emissions
from fossil fuels in the developing world are allowed to approximately
double, while those from developed countries fall by about thirty per
cent (Figure 11.5). In 2020, global emissions from developing countries
would be sixty per cent of the total for the world compared with about
one-third in 1990. After 2020 reductions in emissions in all countries
would be required.
As the World Energy Council point out in their report, achievement
of such a scenario will be far from easy. It requires three essential in-
gredients. The ¬rst is an aggressive emphasis on energy saving and con-
servation. Much here can be achieved at zero net cost or even at a cost
saving. Though much energy conservation can be shown to be econom-
ically advantageous, it is unlikely to be undertaken without signi¬cant
incentives. However, it is clearly good in its own right, it can be started
in earnest now and it can make a signi¬cant contribution to the reduction
of emissions and the slowing of global warming. The second ingredient
is an emphasis on the development of appropriate non-fossil fuel energy
sources leading to very rapid growth in their implementation. The third
is the transfer of technologies to developing countries that will enable
them to apply the most appropriate and the most ef¬cient technologies
to their industrial development, especially in the energy sector.

Summary of the action required
This chapter has suggested some actions that can be taken to slow climate
change and ultimately to stabilise it as required by the internationally
agreed Climate Convention.
Some actions have already been taken that have an effect on global
emissions of greenhouse gases, namely:

r the reduction by some countries of carbon dioxide emissions in the
year 2000 to 1990 levels, and
r the provisions of the Montreal Protocol regarding the emissions of
CFCs and CFC substitutes.
264 A strategy for action to slow and stabilise climate change

Other actions that can be taken now to slow climate change, that can be
done at little or no net cost and that are good to do for other reasons are
the following:
r a reduction of deforestation,
r a substantial increase in afforestation,
r some relatively easy-to-do reductions in methane emissions,
r an aggressive increase in energy saving and conservation measures,
r increased implementation of renewable sources of energy supply.

For the longer term, as well as increased emphasis on these actions, the
world needs to begin to follow an energy scenario that will lead to the sta-
bilisation of carbon dioxide concentration in the atmosphere. The choice
of a target stabilisation level following the guidance of the Climate Con-
vention involves the consideration of many factors and, because of the
uncertainties, will necessarily be subject to continuous review. We have
presented arguments suggesting that, at the current state of knowledge,
the range 400“500 ppm in carbon dioxide concentration is where further
detailed consideration of costs and impacts should be concentrated. A
proposal called ˜Contraction and Convergence™ meets the requirement
for international equity through eventual agreement for equal alloca-
tions per capita coupled with arrangements for allocations™ trading. A
study by the World Energy Council has detailed an energy scenario that
would lead to the stabilisation of carbon dioxide concentration by about
2100. Its realisation will require very rapid growth in the implementa-
tion of appropriate non-fossil fuel energy sources; it will also require that
means be provided to enable developing countries to apply appropriate
and ef¬cient technologies to their industrial development, especially in
the energy sector “ matters that will be addressed in detail in the next

1 From Figure 10.1, what are the rates of change of global average temperature
for the pro¬les shown that lead to stabilisation of carbon dioxide concentration
at different levels? From information in Chapter 7 or from elsewhere, can you
suggest a criterion involving rate of change that might assist in the choice
of a stabilisation level for carbon dioxide concentration as required by the
Objective of the Climate Convention?
2 From the formula in Note 20 and the information in Figure 3.8 and Table 6.1,
calculate the contributions from the various components of radiative forcing
(including aerosol) to the equivalent carbon dioxide concentration in 1990.
How valid do you think is it to speak of equivalent carbon dioxide for com-
ponents such as aerosol and tropospheric ozone?
Notes 265

3 From the information in Table 6.1 and the formula in Note 20, calculate
the equivalent carbon dioxide concentration including the well mixed green-
house gases for SRES scenarios A1B and A2 in 2050 and 2100.
4 Associated with the choice of stabilisation level under the criteria of the
Objective of the Climate Convention, different kinds of analysis were men-
tioned; cost“bene¬t analysis, multicriteria analysis and sustainability anal-
ysis. Discuss which analysis is most applicable to each of the criteria in the
Objective. Suggest how the analyses might be presented together so as to
assist in the overall choice.
5 From the information available in previous chapters and using the criteria
laid out in the Climate Convention Objective, what stabilisation levels of
greenhouse gas concentrations do you think should be chosen?
6 The arguments concerning the choice of stabilisation level and the action to
be taken have concentrated on the likely costs and impacts of climate change
before the year 2100. Do you think that information about continuing climate
change or sea level rise (see Chapter 7) after 2100 should be included and
taken into account by decision makers, or is that too far ahead to be of
7 The international response to global warming is likely to lead to deci-
sions being taken sequentially over a number of years as knowledge re-
garding the science, the likely impacts and the possible responses becomes
more certain. Describe how you think the international response might
progress over the next twenty years. What decisions might be taken at what
8 Explain how the ˜Contraction and Convergence™ proposal meets the four
principles listed in Chapter 9 and elaborated in Chapter 10. Suggest the
political or economic arguments that might be used to argue against the
proposal. Can you suggest other ways of sharing emissions between countries
that might achieve agreement more easily?
9 Find out the details of any plans for afforestation in your country. What
actions or incentives could make it more effective?
10 Assume a snow-covered area at latitude 60—¦ with an albedo of ¬fty per cent
is replaced by partially snow-covered forest with an albedo of twenty per
cent. Make an approximate comparison between the ˜cooling™ effect of the
carbon sink provided by the forest and the ˜warming™ effect of the added
solar radiation absorbed, averaged over the year.

Notes for Chapter 10
1 More details of the Kyoto Protocol and of the detailed arrangements for
the inclusion of carbon sinks can be found in Watson, R. T., Noble,
I. R., Bolin, B., Ravindranath, N. H., Verardo, D. J., Dokken, D. J. (eds.)
2000. Land Use, Land-Use Change and Forestry. A Special Report of the
IPCC. Cambridge: Cambridge University Press and on the FCCC web site
266 A strategy for action to slow and stabilise climate change

2 More details in Watson, R. et al. (eds.) 2001. Climate Change 2001: Synthe-
sis Report. Contribution of Working Groups I, II and III to the Third Assess-
ment Report of the Intergovernmental Panel on Climate Change. Cambridge:
Cambridge University Press, question 7. Also, Hourcade, J.-C., Shukla, P.
et al. Global, regional and national costs and ancillary bene¬ts of mitigation.
In Metz, B., Davidson, O., Swart, R., Pan, J. (eds.) 2001. Climate Change
2001: Mitigation. Contribution of Working Group III to the Third Assess-
ment Report of the Intergovernmental Panel on Climate Change. Cambridge:
Cambridge University Press, Chapter 8.
3 More detail in Global Environmental Outlook 2000, UNEP. London:
Earthscan. Also eds. Tolba, M. K., El-Kholy, O. A. (eds.) 1992. The World
Environment 1972“1992. London: Chapman and Hall, pp. 157“82.
4 See Tolba, The World Environment 1972“1992, p. 169.
5 From Global Environmental Outlook 3 (UNEP Report). 2002. London:
Earthscan. pp. 91“2.
6 Bolin, B., Sukumar, R. et al. 2000. Global perspective. In Watson, Land Use,
Chapter 1. Also Salati et al. 1991. In Jager, J., Ferguson, H. L. (eds.) Climate
Change: Science, Impacts and Policy; Proceedings of the Second World
Climate Conference. Cambridge: Cambridge University Press, pp. 391“5;
also Leggett, J. et al. 1992. Emission scenarios for the IPCC: an update. In
Houghton, J. T., Callender, B. A., Varney, S. K. (eds.) Climate Change 1992:
the Supplementary Report to the IPCC Assessments. Cambridge: Cambridge
University Press, p. 89; also Houghton, R. A. 1991. Climate Change, 19,
pp. 99“118.
7 Bolin, B., Sukumar, R. et al. 2000. Global perspective. In Watson, Land
Use, Chapter 1, p 26.
8 Brown, S. et al. 1996. Management of forests for mitigation of greenhouse
gas emissions. 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 Analyses. Contribution of Working Group II
to the Second Assessment Report of the Intergovernmental Panel on Cli-
mate Change. Cambridge: Cambridge University Press, Chapter 24. Simi-
lar areas have been quoted in Watson, Land Use, Policymakers Summary,
and also in Kauppi, P., Sedjo, R. et al. Technical and economic potential of
options to enhance, maintain and manage biological carbon reservoirs and
geo-engineering. In Metz, B., Davidson, O., Swart, R., Pan, J. (eds.) 2001.
Climate Change 2001: Mitigation. Contribution of Working Group III to
the Third Assessment Report of the Intergovernmental Panel on Climate
Change. Cambridge: Cambridge University Press, Chapter 4.
9 For de¬nition see Glossary.
10 Betts, R. A. 2000. Offset of the potential carbon sink from boreal forestation
by decreases in surface albedo. Nature, 408, 187“90.
11 From Policymakers summary. 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.
Notes 267

12 Hourcade, J. C. et al. 1996. A review of mitigation cost studies. In Bruce, J.,
Hoesung Lee, Haites, E. (eds.) 1996. Climate Change 1995: Economic and
Social Dimensions of Climate Change. Cambridge: Cambridge University
Press, Chapter 9.
13 Cole, V et al. 1996. Agricultural options for mitigation of greenhouse gas
emissions. In Watson, Climate Change 1995: Impacts.
14 This ¬gure is calculated by multiplying the sixty million tonnes by the global
warming potential for methane which, for a time horizon of 100 years, is
about 23 (Table 10.2), then by 12/44 to put it into tonnes of carbon.
15 Prentice, I. C. et al. 2001. The carbon cycle and atmospheric carbon dioxide.
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.
16 Cox, P. M. et al. 2000. Acceleration of global warming due to carbon cycle
feedbacks in a coupled climate model. Nature, 408, pp. 184“7; Jones, C. D.
et al. 2003. Tellus, 55B, pp. 642“58.
17 Additional climate-carbon cycle feedbacks have been ignored in this calcu-
18 Arnell, N. W. et al. 2002. The consequences of CO2 stabilisation for the
impacts of climate change. Climatic Change, 53, pp. 413“46.
19 Allowing, for the CFCs, a reduction in their forcing because of stratospheric
ozone destruction. Further, only the well-mixed greenhouse gases have been
considered here. Tropospheric ozone and sulphate aerosols are not well
mixed but have signi¬cant radiative forcing effects (see Figure 3.8). Their
effects are of opposite sign and when globally averaged are of similar mag-
nitude so to some degree might be considered to compensate for each other.
20 Note that, although the amount of forcing from the minor gases is the same,
when turned into equivalent carbon dioxide, the amounts added increase
with the carbon dioxide concentration to which the amount is added. This is
because the relationship between radiative forcing (R in W m’2 ) and con-
centration (C in ppm) is non-linear. The relationship is R = 5.3 ln (C/C0 )
where C0 is the pre-industrial CO2 concentration.
21 European Commission Communication on a Community Strategy on Cli-
mate Change; Council of Ministers Conclusion, 25“26 June 1996.
22 From speech to Institutional Investors Group, London, 26 November 2003.
23 Further details on the GCI web site, www.gci.org.uk.
24 World Energy Council Commission Report, Energy for Tomorrow™s World.
London: World Energy Council, 1993. The World Energy Council is an
international body that links together the World™s Energy Industries.
Chapter 11
Energy and transport for the future

We ¬‚ick a switch and energy ¬‚ows. Energy is provided so easily for the
developed world that thought is rarely given to where it comes from,
whether it will ever run out or whether it is harming the environment.
Energy is also cheap enough that little serious attention is given to con-
serving it. However, most of the world™s energy comes from the burning
of fossil fuels, which generates a large proportion of the greenhouse gas
emissions into the atmosphere. If these emissions are to be reduced, a
large proportion of the reduction will have to occur in the energy sec-
tor. There is a need, therefore, to concentrate the minds of policymakers
and indeed of everyone on our energy requirements and usage. This
chapter looks at how future energy might be provided in a sustainable
manner.1 It also addresses how basic energy services might be made avail-
able to the more than two billion in the world who as yet have no such

World energy demand and supply
Most of the energy we use can be traced back to the Sun. In the case
of fossil fuels (coal, oil and gas) it has been stored away over millions
of years in the past. If wood (or other biomass including animal and
vegetable oils), hydro-power, wind or solar energy itself is used, the
energy has either been converted from sunlight almost immediately or
has been stored for at most a few years. These latter sources of energy
are renewable; they will be considered in more detail later in the chapter.
The only common form of energy that does not originate with the Sun is
nuclear energy; this comes from radioactive elements that were present
in the Earth when it was formed.

World energy demand and supply 269


Natural gas
Gigatonnes of oil equivalent per year

Other (includes traditional fuels)



1900 1930
1880 1920 1970 1980 1990
1870 1890 1910 1950 1960

Figure 11.1 Growth in the rate of energy use and in the sources of energy
since 1860 in thousand millions of tonnes of oil equivalent (Gtoe) per year. In
terms of primary energy units, 1 Gtoe = 41.87 exajoules (1 exajoule (EJ)
= 1018 J). Of the ™other™ in 2000, approximately 0.9 Gtoe is attributed to
traditional fuels, 0.7 Gtoe to nuclear energy and 0.6 Gtoe to hydro and other
renewables (source: Report of G8 Renewable Energy task Force, July 2001).

Until the Industrial Revolution, energy for human society was pro-
vided from ˜traditional™ sources “ wood and other biomass and animal
power. Since 1860, as industry has developed, the rate of energy use
has multiplied by about a factor of thirty (Figure 11. 1), at ¬rst mostly
through the use of coal followed, since about 1950, by rapidly increasing
use of oil and then more recently by the use of natural gas. In 2000 the
world consumption of energy was about 10 000 million tonnes of oil
equivalent (toe). This can be converted into physical energy units to give
an average rate of energy use of about thirteen million million watts (or
13 terawatts = 13 — 1012 W).2
Great disparities exist in the amount of energy used per person in
various parts of the world. The two billion poorest people in the world
(less than $US 1000 annual income per capita) each use an average of
only 0.2 toe of energy annually while the billion richest in the world (more
than $US 22 000 annual income per capita) use nearly twenty-¬ve times
that amount at 5 toe per capita annually.3 The average annual energy use
per capita in the world is about 1.7 toe, an average consumption of energy
of about 2.2 kilowatts (kW). The highest rates of energy consumption
are in North America where the average citizen consumes an average
of about 11 kW. Over one-third of the world™s population rely wholly
on traditional fuels (wood, dung, rice husks, other forms of ˜biofuels™)
and do not currently have access to commercial energy in any of its
270 Energy and transport for the future

It is interesting to see how the energy we consume is used.4 Tak-
ing the world average for commercial energy (i.e. omitting ˜traditional
energy™), about twenty-two per cent of primary energy is used in trans-
portation, about forty-one per cent by industry, about thirty-four per
cent in buildings (two-thirds in residential buildings and one-third in
commercial buildings) and about three per cent in agriculture. It is also
perhaps interesting to know how much energy is used in the form of
electricity. Rather more than one-third of primary energy goes to make
electricity at an average ef¬ciency of conversion of about one-third. Of
this electrical power about half, on average, is utilised by industry and
the other half in commercial activities and in homes.
How much is spent on energy? Taking the world as a whole, the
amount spent per year by the average person for the 1.7 toe of energy
used, is about ¬ve per cent of annual income. Despite the very large
disparity in incomes, the proportion spent on primary energy is much
the same in developed countries and developing ones.
How about energy for the future? If we continue to generate most
of our energy from coal, oil and gas, do we have enough to keep us
going? Current knowledge of proven recoverable reserves (Figure 11.2)
indicates that known reserves of fossil fuel will meet demand for the
period up to 2020 and substantially beyond. Before mid century, if de-
mand continues to expand, oil and gas production will come under in-
creasing pressure. Further exploration will be stimulated, which will
lead to the exploitation of more sources, although increased dif¬culty
of extraction can be expected to lead to a rise in price. So far as coal is
concerned, there are operating mines with resources for production for
well over a hundred years.
Estimates have also been made of the ultimately recoverable fossil
fuel reserves, de¬ned as those potentially recoverable assuming high but
not prohibitive prices and no signi¬cant bans on exploitation. Although
these are bound to be somewhat speculative,5 they show that, at current
rates of use, reserves of oil and gas are likely to be available for l00
years and of coal for more than l000 years. In addition to fossil fuel
reserves considered now to be potentially recoverable there are reserves
not included in Figure 11.2, such as the methane hydrates, which are
probably very large in quantity but from which extraction would be
much more dif¬cult.
Likely reserves of uranium for nuclear power stations should also be
included in this list. When converted to the same units (assuming their
use in ˜fast™ reactors) they are believed to be at least 3000 and possibly as
high as 12 000 Gtoe, substantially greater than likely fossil fuel reserves.
For at least the twenty-¬rst century, suf¬cient fossil fuels in total are
available to meet likely energy demand. It is considerations other than
Future energy projections 271

Gt C
4 000
Conventional reserves
3 500
Conventional resources (upper estimate)

Unconventional reserves and resources
3 000

2 500

2 000
A2 WRE1000
1 500
Historical WRE550
1 000 fossil fuel
Reserves and resources Emissions SRES scenarios Stabilisation scenarios

Figure 11.2 Carbon in oil, gas and coal reserves and resources compared with historic fossil fuel carbon
emissions over the period 1860“1998 and with cumulative carbon emissions up to the year 2100 from a range of
SRES scenarios and scenarios leading to stabilisation of carbon dioxide concentrations. Data for current estimates
of reserves and resources are shown in the left-hand columns. Unconventional oil and gas includes tar sands, shale
oil, other heavy oil, coal bed methane, deep geopressured gas, gas in aqui¬ers, etc. Gas hydrates (clathrates) that
amount to an estimated 12 000 GtC are not shown. Note that if by the year 2100 cumulative emissions associated
with SRES scenarios are equal to or smaller than those for stabilisation scenarios, this does not imply that these
scenarios equally lead to stabilisation.

availability, in particular environmental considerations, that will provide
limitations on fossil fuel use.

Future energy projections
In Chapter 6 were described the SRES scenarios sponsored by the IPCC
that detail, for the twenty-¬rst century, a range of possibilities regarding
future energy demand (based on a range of assumptions concerning
population, economic growth and social and political development), how
that demand might be met and what carbon dioxide emissions might
result. In that chapter were also described the implications for those
scenarios regarding climate change. Chapter 10 presented the imperative
set out by the Framework Convention on Climate Change (FCCC) in its
Objective that carbon dioxide concentrations in the atmosphere must
be stabilised so that continued anthropogenic climate change can be
272 Energy and transport for the future

Energy intensity and carbon intensity

An index that provides an indication of a country™s USA the highest, with more than a factor of two
energy ef¬ciency is the ratio of annual energy con- between the lowest and the highest.
sumption to gross domestic product (GDP) known Of importance too in the context of this chap-
as the energy intensity. Figure 11.3 shows that ter is the carbon intensity, which is a measure of
from 1971 to 1996 for Organisation for Economic how much carbon is emitted for a given amount of
Co-operation and Development (OECD) countries energy. This can vary with different fuels. For in-
GDP increased by a factor of two while energy con- stance, the carbon intensity of natural gas is twenty-
sumption increased by about ¬fty per cent, the result ¬ve per cent less than that of oil and forty per cent
being a decrease in energy intensity of about twenty less than that of coal. For renewable sources the car-
per cent or an average of about one per cent per year. bon intensity is small and depends largely on that
Within the OECD there are substantial differences which originates during manufacture of the equip-
between countries. Denmark, Italy and Japan have ment making up the renewable source (e.g. during
the lowest energy intensities and Canada and the manufacture of solar cells).

Figure 11.3 Energy intensity averaged over OECD countries 1971“96.

avoided. Scenarios of carbon dioxide emissions that would be consistent
with various stabilisation levels were presented there and arguments put
forward for a target level for atmospheric concentration of carbon dioxide
in the range of 450 to 500 ppm. How the world™s energy producers and
consumers can meet the challenge of this target is addressed by this
Future energy projections 273

Figure 11.4 Scenarios of carbon dioxide emissions during the twenty-¬rst
century from fossil fuel burning for WEC scenarios A, B and C (details in Tables
11.1 and 11.2). It is only scenario C that leads to stabilisation of carbon dioxide
concentrations as required by the Objective of the Climate Convention.

One of the bodies that has considered how such a target can be met
is the World Energy Council (WEC), who have constructed four detailed
energy scenarios (Figure 11.4) for the period to 2020, extended with less
detail to 2100.6 Three of the scenarios (more details in box on pages
276“7) make assumptions (more details in the box below) that fall within
the range of those made by the SRES scenarios. The fourth scenario C,
which is described as ˜ecologically driven™, assumes that environmental
pressures have a large in¬‚uence on energy demand and growth. For all
these scenarios, except WEC scenario C, atmospheric concentrations of
carbon dioxide continue to rise throughout the twenty-¬rst century. It
is WEC scenario C, if achieved, that is consistent with carbon dioxide
stabilisation with a target in the range 450“500 ppm.
Details of the scenarios to the year 2020 are shown in Figures 11.5
and 11.6. As can be seen from Figure 11.5, it is only in the devel-
oped world that there is potential for containing future energy demand.
274 Energy and transport for the future

Figure 11.5 Primary energy demand by economic groupings of countries for
WEC scenarios.

Figure 11.6 Primary energy supply mix for WEC scenarios.

Population growth and the need for economic development in developing
countries make it inevitable that they will, for many decades, consume
increased amounts of energy. For all the scenarios to 2020, fossil fuels
continue to dominate the energy mix (Figure 11.6). The contribution
from nuclear power is assumed to grow in all the cases. New renewable
energy sources play an increasing role, although apart from Case C their
contribution is small.
For the ˜ecologically driven™ WEC scenario C the energy demand
in 2020 is about thirty per cent more than that in 1990 and thirty per
cent less than that for scenario A. Scenario C assumes that there will
be large increases in ef¬ciency (or a large decrease in energy intensity)
leading to a reduced energy demand and also, following the results of
Future energy projections 275

Figure 11.7 Energy
transitions over two
Traditional Gas Hydro centuries. Under ™dynamics
as usual™ energy supplies
Coal New renewables
continue to evolve from
Oil Biofuels
high to low carbon fuels
and towards electricity as
the dominant energy
80 carrier “ from increasingly
distributed sources “ driven
Primary energy share %

by demands for security,
cleanliness and




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