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Reduction in sources of greenhouse gases other
than carbon dioxide
Methane, nitrous oxide and the halocarbons are greenhouse gases, less impor-
tant than carbon dioxide, all of which show increases at the present time. In
Figures 6.1 and 6.2 and Table 6.1 are shown the emissions, atmospheric con-
centrations and radiative forcing of these gases estimated for the twenty-¬rst
century under the various SRES scenarios, assuming no special action to reduce
them. Is it possible that these further increases can be slowed or eliminated? We
consider them in turn.
Methane contributes about 15% to the present level of global warming
(Figure 10.1). The stabilisation of its atmospheric concentration would contrib-
ute a small but signi¬cant amount to the overall problem. Because of its much
shorter lifetime in the atmosphere (about 12 years compared with 100“200 years
for carbon dioxide), only a relatively small reduction in the anthropogenic emis-
sions of this gas, about 8%, would be required to stabilise its concentration at
the current level. Of the various sources of methane listed in Table 3.2, there are
four sources arising from human activities that could rather easily be reduced
at small cost.18
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
As wastes break down, methane is produced that can be captured and burnt for power generation. The carbon
dioxide then released has much less impact as a greenhouse gas than the methane that would otherwise be released.


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 about 1992.
Improved management of such installations could markedly reduce leakage to
the atmosphere.
Fourthly, with better management, options exist for reducing methane emis-
sions from sources associated with agriculture, for instance, by adjustments to
the diet of cattle or to the details of rice cultivation.19
Reductions from these four sources could reduce anthropogenic meth-
ane emissions by more than 60 million tones per year “ enough to stabilise
methane concentration in the atmosphere at 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 of about 1.4 Gt 20
or about 3% of total greenhouse gas emissions “ a useful contribution towards
the solution of the global warming problem.21
It was noted in Chapter 3 (page 50) that the growth in global atmospheric
methane concentrations had largely halted since the late 1990s. However,
since early 2007 there is evidence of renewed growth 22 which may be more
pronounced in the northern hemisphere. Some increase from methane emis-
sions from natural sources may be expected because of the in¬‚uence of global
warming on various natural methane reservoirs (see Chapter 3). Prominent
among these are the very large reservoirs under the tundra at high latitudes
(see box on page 48“9 and Table 7.5). As the cover of Arctic summer sea ice
has reduced and as northern Siberia has warmed, more evidence of local
307
S TA B I L I S AT I O N O F C A R B O N D I OX I D E CO N C E N T R AT I O N S




methane emissions has emerged. Further studies are needed to ascertain
whether these are connected with the recent growth in global methane con-
centration. As the Arctic warms further, the possibility exists of much larger
releases in the longer term, especially if global average temperature rise is
not halted.
Turning now to nitrous oxide which contributes about 7% to the present level
of global warming and which is growing at about 0.25% per year. Much of its
growth appears to rise from emissions associated with the use of nitrogen fer-
tilisers. Careful management of the use of such fertilisers and other changes in
agricultural practice could largely stem the continuing increase.
For halocarbons for many of which the manufacture is being phased out, the
most important concern is that disposal of products containing these gases, for
instance of foams or refrigeration equipment, is carefully controlled so as to
minimise leakage to the atmosphere and to ensure that their atmospheric con-
centration gradually reduces during the twenty-¬rst century.
In this section we have seen that options are available for stemming the
growth and possibly reducing the concentrations of greenhouse gases other
than carbon dioxide. In the following section, stabilisation of carbon dioxide
concentrations will be considered together with stabilisation of the combined
effect of greenhouse gases considered together. Some reductions in the concen-
trations of methane, nitrous oxide and halocarbons will be seen as important
contributions to achieving this overall stabilisation.
Because the lifetime of methane in the atmosphere is relatively short, a small
reduction in methane emissions will quickly lead to its stabilisation as required
by the Climate Convention objective. The same 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 turn.


Stabilisation of carbon dioxide concentrations
Carbon dioxide, as we have seen, is the most important of the greenhouse gases
that is increasing through human activities. As we saw in Chapter 3, emissions
of carbon dioxide into the atmosphere from anthropogenic sources result from
fossil fuel burning (about 80%) and from land-use changes (about 20%) “ mainly
deforestation. Reduction in emissions from land-use changes was considered
earlier in the chapter. Reductions in emissions from fossil fuel burning will be
the subject of the next chapter.
Under all the SRES scenarios, the concentration of carbon dioxide rises continu-
ously throughout the twenty-¬rst century and apart from scenarios B1 and A1T
none comes anywhere near to stabilisation of concentration by 2100. Since the
308 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E




year 2000, the growth of global carbon dioxide emissions (Figure 10.1) at close to
3% per year has been faster than assumed in most of the SRES scenarios where
the average growth was around 1%. During the 1980s and 1990s global carbon
dioxide emissions grew at an average of just over 1% per year, the average during
the 1990s being kept down because of substantial falls in emissions in the former
Soviet Union and eastern Europe. Projections for the next few years indicate that
global emissions are likely to continue rising at about the current rate.
Here we consider what sort of emissions scenario would lead to stabilisation
of the carbon dioxide concentration. Suppose for instance that it were pos-
sible to keep global emissions for the future at the same level as now, would
that be enough? Stabilising concentrations is, however, very different from
stabilising emissions. With constant emissions from now, the concentration
in the atmosphere would continue to rise, would reach at least 500 ppm by the
year 2100 and continue to increase thereafter, although more slowly, for many
centuries. Further, because of the long lifetime of carbon dioxide in the atmos-
phere, even if very severe action is taken to curb emissions, stabilisation of its
concentration and hence stabilisation of climate will take many decades.
A large number of studies focusing on climate stabilisation and emissions
pro¬ les leading to stabilisation of greenhouse gases have been brought together
in the IPCC AR4 Report, where they have been grouped together under cat-
egories leading to different stabilisation levels. For each of the chosen levels,
the range of emissions pro¬ les shown by the studies to bring about stabilisa-
tion of carbon dioxide concentration is shown in Figure 10.2 and Table 10.3.
Studies that have included greenhouse gases other than carbon dioxide have
been put together with carbon dioxide-only studies through the use of carbon
dioxide equivalent CO2e (for de¬ nition see Chapter 6, page 147).
Note that stabilisation at any level shown in the ¬gure, even at an extremely
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 concentration, emissions must even-
tually be no greater than the level of persistent natural sinks. The main known
such sink is due to the dissolution of calcium carbonate from the oceans into
ocean sediments which, for high levels of carbon dioxide concentration, is prob-
ably less than 0.1 GtC per year.23 This means, for instance, that for the lowest
category in Figure 10.2, anthropogenic emissions of greenhouse gases need to
fall close to zero by 2100.
In the work presented in Figure 10.2, many different pathways to stabilisa-
tion could have been chosen. The particular emission pro¬les illustrated in
Figure 10.2 begin by following the current average rate of increase of emis-
sions and then provide a smooth transition to the time of stabilisation. To a
309
S TA B I L I S AT I O N O F C A R B O N D I OX I D E CO N C E N T R AT I O N S




(a) (b)
10
140




Equilibrium global average temperature
World CO2 emissions (GtCO2 yr “1)




increase above pre-industrial (°C)
120
8
100

80 6
V
60
IV
4 III
40
II
I
20
2
0

0
“20
1940 1960 1980 2000 2020 2040 2060 2080 2100 280 300 400 500 600 700 800 900 1000
Year Greenhouse gas concentration stabilisation level (ppm CO2)

I: 445“490 ppm CO2 e III: 535“590 ppm CO2 e V: 710“855 ppm CO2 e Post-SRES range
II: 490“535 ppm CO2 e IV: 590“710 ppm CO2 e VI: 855“1130 ppm CO2 e

Figure 10.2 (a) Global carbon dioxide emissions for 1940“2000 and emissions ranges for categories of
stabilisation scenarios from 2000 to 2100; colours show stabilisation scenarios grouped according to
different levels (categories I to VI in inset and Table 10.3). The range shown covers the 10th to 90th
percentiles of the full scenario distribution (numbers of scenarios included in Table 10.3). The thin dashed
lines denote the lower end of the range for that category in cases where there is overlap between the
categories. To convert Gt CO2 to Gt C, divide by 3.66. The thick dashed black lines indicate the range
of emissions scenarios published since 2000. (b) Relationship between stabilisation level and the likely
equilibrium global average temperature increase above pre-industrial level; the dark blue line assumes
a best estimate of climate sensitivity of 3 °C and the colours indicate the effect of a range in climate
sensitivity from 2 to 4.5 °C. For calculating the equilibrium temperature, the simple relationship Teq = T 2—CO2
— ln([CO2]/280)/ln(2) is employed with mean, lower and upper values of T 2—CO2 of 3, 2 and 4.5 °C. The
relationship between radiative forcing (R in W m “2) and concentration (C in ppm) is R = 5.3ln (C/C0) where
C0 is the pre-industrial CO2 concentration of 280 ppm.


¬ 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 assume higher emissions in earlier years would
require steeper reductions in later years. For instance, if the atmospheric con-
centration of carbon dioxide is to remain below about 550 ppm, the future glo-
bal annual emissions averaged over the twenty-¬ rst century cannot exceed the
level of global annual emissions in the year 2000. For lower levels of stabilisa-
tion, to bring down the twenty-¬ rst-century accumulated emissions to a much
lower level will require urgent and large carbon dioxide emissions reductions.
Note also that for the lowest stabilisation level, Category 1, in Figure 10.2a
some of the scenarios later in the century require negative emissions implying
a need for substantial removal of CO2 from the atmosphere.
Table 10.3 Characteristics of stabilisation scenarios and resulting long-term equilibrium global averagea

Anthropogenic Change in global Global average temperature
addition to Peaking increase above pre-industrial
CO2 equivalent CO2 emissions in
radiative forcing concentration 2050 (per cent of at equilibrium, using ˜best Number of
year for CO2
at stabilisation at stabilisationb emissionsa, c 2000 emissions) estimate™ climate sensitivityd, e assessed
(percent)a, c
Category (W m’ 2) (ppm) (year) (°C) scenarios

I 2.5“3.0 445“490 2000“2015 ’85 to ’50 2.0“2.4 6
II 3.0“3.5 490“535 2000“2020 ’60 to ’30 2.4“2.8 18
III 3.5“4.0 535“590 2010“2030 ’30 to +5 2.8“3.2 21
IV 4.0“5.0 590“710 2020“2060 +10 to +60 3.2“4.0 118
V 5.0“6.0 710“855 2050“2080 +25 to +85 4.0“4.9 9
VI 6.0“7.5 855“1130 2060“2090 +90 to +140 4.9“6.1 5
a
The emission reductions to meet a particular stabilisation level reported in the mitigation studies assessed here might be underestimated due to missing
carbon cycle feedbacks
b
Atmospheric CO2 concentrations were 379 ppm in 2005. The best estimate of total CO2 equivalent concentration in 2005 for all long-lived greenhouse
gases is about 455 ppm, while the corresponding value including the net effect of all anthropogenic forcing agents e.g. aerosols is 375 ppm CO2e.
c
Ranges correspond to the 15th to 85th percentile of the scenario distribution. CO2 emissions are shown so multi-gas scenarios can be compared with
CO2-only scenarios.
d
The best estimate of climate sensitivity is 3 °C.
e
Note that global average temperature at equilibrium is different from expected global average temperature at the time of stabilisation of greenhouse
gas concentrations due to the inertia of the climate system. For the majority of scenarios assessed, stabilisation of greenhouse gas concentrations occurs
between 2100 and 2150. For Categories I or II, equilibrium temperature may be reached earlier.
311
T H E C H O I C E O F S TA B I L I S AT I O N L E V E L




Figure 10.3 Global CO2 emission pro¬les that 50
would stabilise CO2 at 450 ppm (pink) and




Emissions (GtCO2 /yr -1)
550 ppm (light blue). The shaded areas show 40

the range of uncertainty arising because of the
climate“carbon-cycle feedback (see text). Also 30

shown are emissions pro¬les for the IEA scenarios
20
ACT Map (red) and BLUE Map (blue) for fossil
fuel emissions (see Chapter 11, page 332) to both
10
of which has been added a constant 7.3 GtCO2
(2GtC) per year to allow for emissions from
0
deforestation and land use change. A further 1950 2000 2050 2100
Year
pro¬le (green) shows the effect on the BLUE
Map pro¬le if emissions from deforestation and
land use change are halted completely by 2050.

Many of the scenarios included in compiling the results shown in Figure
10.2 and Table 10.3 do not include the effect of climate feedbacks on the car-
bon cycle (see box in Chapter 3 on page 48“9). Two of the feedbacks are impor-
tant in the context of the consideration of stabilisation scenarios; namely,
increased respiration from the soil as the temperature rises and a decrease in
net uptake of carbon by plants in some regions as the climate warms (e.g. in
forests this can be perceived as dieback). The area over which such decrease
occurs becomes larger for greater warming. 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. In Figure 10.3 are shown pro¬les for
stabilisation of carbon dioxide alone at 450 and 550 ppm both without these
climate change feedbacks included (the upper line) and with the range of feed-
backs represented by the models studied in the IPCC 2007 Report, the largest
value of the combined feedbacks being that derived by the Hadley Centre in
the UK. Compared with no feedback, the effect of this largest value is to reduce
the accumulated emissions allowable in the twenty-¬rst century, for instance,
for the 450 ppm and 550 ppm stabilisation scenarios, by about 600 Gt CO2 and
900 Gt CO2 respectively.24 Also under this largest feedback case, emissions
scenarios not allowing for feedback that are aiming at 450 ppm stabilisation,
when the feedbacks are included, would in fact achieve around 500 ppm.


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 appropriate stabilisation lev-
els should be chosen as targets for the future we look to the guidance provided
312 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E




by the Climate Convention Objective (see box on pages 291“2), which states that
the levels and timescales for their achievement should be such that danger-
ous interference with the climate system is avoided, that ecosystems are able
to adapt naturally, that food production is not threatened and that economic
development can proceed in a sustainable manner.
The balancing of these scienti¬c, economic, social and political criteria
presents a large challenge. In Chapter 9 (see box on page 280) the concept of
Integrated Assessment and Evaluation was introduced which involves employ-
ment of the whole range of disciplines in the natural and social sciences. Taking
all factors into consideration will involve different kinds of analysis, cost“ben-
e¬t analysis (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 particular thresholds
of stress or of damage). Further, because uncertainty is associated both with
many of the factors that have to be included and with the methods of analy-
sis, the process of choice is bound to be an evolving one subject to continuous
review “ a process often described as sequential decision-making.
In Figure 10.2 were presented options for the stabilisation of carbon dioxide
and other greenhouse gases in terms both of the concentration of CO2e (a) and
of the global average temperature increase since pre-industrial times (b). It is
the latter measure that is closer to what actual climate change is all about. The
information in Figure 10.2 and Table 10.3 covers a wide range of possible tem-
perature increases up to over 6 °C. However, attention has recently focused on
the lower end of the range, between 2 and 3 °C.
In Chapter 7 we found that many of the studies of impacts of climate change had
been made under the assumption that the atmospheric CO2e concentration had
doubled from its pre-industrial value of 280 ppm to about 560 ppm and that the glo-
bal average temperature had increased from its pre-industrial value by a best esti-
mate of 3 °C “ an estimate that was raised in the 2007 IPCC Report from its earlier
value of 2.5 °C (see Chapter 6, page 143). We enumerated in Chapter 7 the substan-
tial impacts that apply to this situation together with estimates of their associated
costs.25 In Chapter 9 it was pointed out, even considering only those costs that can
be estimated in terms of money, that estimates of the cost of the likely damage of
impacts at that level of climate change were substantially larger than the mitiga-
tion costs of stabilising CO2e concentration at doubled pre-industrial CO2. We also
noted that damage due to anthropogenic climate change is likely to rise more rap-
idly as the amount of carbon dioxide in the atmosphere increases. These considera-
tions suggest that limits set at 560 ppm CO2e or 3 °C would be too high.
A widely publicised target for the maximum allowable rise in global aver-
age temperature is 2 °C. It was proposed by the European Union over 10 years
313
T H E C H O I C E O F S TA B I L I S AT I O N L E V E L




ago26 and has been recently reiterated by the EU,27 by governments (e.g. by
Chancellor Merkel of Germany before the 2007 G8 conference) and by many
other organisations.28
How important is it to aim at 2 °C rather than say 3 °C? Further perspec-
tive on this can be obtained from Table 7.1 which indicates that the impacts
at 2 °C above pre-industrial are substantially less severe compared with those
at 3 °C, for instance in terms of water stress, extinction of species, coral mor-
tality, decreased crop productivity, ocean acidity, increased ¬‚oods, droughts
and storms and risk of more rapid sea level rise. As an example, we can turn
to Figure 6.12 to compare more quantitatively the risk of drought for differ-
ent increases in global average temperature. Noting from Figure 6.4a, that for
the A2 SRES scenario, as followed by Figure 6.12, global average temperature
increases by 2 °C and 3 °C above the pre-industrial value by about 2050 and 2075
respectively. As mentioned in Chapter 6 (page 158) and shown in Figure 6.12
the proportion of land area under extreme drought increased from around 1%
in 1980 to 2% or 3% now and is projected to increase to about 10% in 2050 and
20% in 2075, indicating a likelihood of a rise from today in the risk of extreme
droughts of a factor of up to 8 for a rise of 3 °C in global average temperature
compared with a factor of up to 4 for a 2 °C rise.
Stabilisation below 2 °C might also avoid some of the worst impacts; for
instance, some of the large-scale dieback of forests and the transition of the
biosphere from a sink to a source for carbon dioxide (see box in Chapter 3 on
page 48“9) that would otherwise occur around the middle of the twenty-¬rst
century. It would also reduce the risk mentioned earlier in the chapter of large-
scale release of methane as the Arctic ocean or tundra warm.
How achievable is 2 °C? From Figure 10.1b and Table 10.3, it can be seen that
2 °C implies an equilibrium radiative forcing of 2.5 W m’2 and about 450 ppm
stabilisation for CO2e. Since these are best estimates, what we can say is that
450 ppm CO2e and 2.5 W m’2 should provide a 50% chance of achieving 2 °C.
We now need to know what 450 ppm CO2e implies for CO2 itself. As was
explained in Chapter 6 page 149 (see also Figure 3.11), the negative radiative
forcing of anthropogenic aerosols at the present time approximately balances
the positive contributions from greenhouse gases other than carbon diox-
ide. Earlier in the chapter, it was pointed out that options are available for
preventing further increases and reducing the contributions from methane,
nitrous oxide and halocarbons. Also aerosol scenarios show little reduction
in the magnitude of the aerosol contribution during the next few decades.29
These considerations provide a rational basis for the time being for coupling
the 2 °C temperature target with a stabilisation target of 450 ppm for CO2 alone
(Figure 10.3). A similar argument couples together a 3 °C temperature target
314 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E




with 550 ppm for carbon dioxide alone. It is in fact these assumptions that are
made in Chapter 11 when the challenging implications of such targets are pre-
sented for the future of the energy and transport sectors.
In accepting the targets of 2 °C and 450 ppm as a basis for action, I must
however inject two notes of caution. The ¬rst is that the calculations I have
presented are based on best estimates only. They have not allowed for uncer-
tainties; 450 ppm stabilisation for carbon dioxide only provides a 50% chance of
achieving 2 °C. An 80% chance of achieving 2 °C would require stabilisation at
about 380 ppm, the current atmospheric carbon dioxide level.30
The second point of caution pertains to the future of sulphate aerosols that
provide the largest component towards aerosol cooling mentioned in the last
paragraph. Because they lead to serious low level pollution and also to ˜acid rain™,
there is large pressure to control and reduce the sulphur dioxide emissions that
are the precursors of sulphate aerosols. Reductions can also be expected as the
consumption of coal and oil is phased out. Many future aerosol scenarios there-
fore show large reductions of sulphur emissions especially during the second
half of the twenty-¬rst century. Now, because the life time of aerosols in the
atmosphere is very short (a few days) reductions in aerosol emissions lead almost
immediately to large changes in aerosol concentrations and hence also in radia-
tive forcing. Compensating changes in forcing through changes in CO2 emissions
can only occur much more slowly because of the long life time of carbon dioxide
in the atmosphere (Chapter 3 page 37). This means that, in order to maintain
a 2 °C target for global average temperature rise, reductions in global sulphur
dioxide emissions need to be anticipated well in advance by matching reduc-
tions in CO2 emissions. In fact, that anticipation should begin now; it will likely
mean that global CO2 emissions should be reduced close to zero by 2050 and total
greenhouse gas (CO2e) emissions to zero before the end of the century. I return to
these issues in the section entitled A Zero Carbon Future in Chapter 11, page 378.
Is it possible to consider targets lower than 2 °C and 450 ppm carbon dioxide?
Considering the most important greenhouse gas, carbon dioxide, 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. The concentration
of carbon dioxide in the atmosphere is already above 380 ppm which means
(Figure 10.2) that stabilisation of carbon dioxide alone below 400 ppm would
require an 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 that requires ˜that economic devel-
opment can proceed in a sustainable manner™.
Many are, however, asking the question whether a 2 °C target will be ade-
quate to stabilise the climate against very damaging and irreversible change.
315
R E A L I S I N G T H E C L I M AT E C O N V E N T I O N O B J E C T I V E




Prominent among these is Professor James Hansen at the NASA Institute for
Space Studies at New York. In a recent paper,31 Hansen argues largely from
palaeoclimate evidence that a 350 ppm target is necessary to avoid the dan-
ger of rapid collapse of the Greenland and West Antarctic ice-sheets and other
serious non-linear processes (see Table 7.5). Such a target could only be real-
ised after substantial overshoot in the early years and would probably also
require a large programme over many decades of sequestration of carbon diox-
ide already in the atmosphere. The possibility of such a programme has also
recently been proposed by Professor Wally Broecker of Columbia University in
the USA.32 Targets such as that aimed at 2 °C that may be set now are bound to
be reviewed and revised during the next few years and decades as more infor-
mation becomes available regarding how ˜dangerous™ climate change can be
de¬ned and avoided.




Realising the Climate Convention Objective
Having recommended a choice of stabilisation level, a large question remains:
how can the nations of the world work together to realise it in practice?
It is instructive ¬rst to look at annual emissions of greenhouse gases expressed
as CO2e and per capita. Averaged over the world in 2004 they were about 6.5 t
CO2e (∼1.8 t C) per capita but they varied very much from country to country
(Figure 10.4). For developed countries, including transitional economy coun-
tries, in 2000 they averaged 16 t CO2e (ranging downwards from about 25 t for
the USA) while for developing countries they averaged about 4 t. Looking ahead
to the years 2050 and 2100, even if the world population rises to only 9 billion,
under the pro¬le of carbon dioxide emissions leading to stabilisation at concen-
trations of 450 ppm (Figure 10.3) the per capita annual emissions averaged over
the world would be between 1 and 2 t CO2e for 2050 and less than 0.4 t CO2e for
210033 “ much less than the current value of about 6.5 t.
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 Development. The others were the
Precautionary Principle, the Polluter-Pays Principle and the Principle of Equity.
This last principle includes intergenerational 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 developing world. Striking this latter balance is going to be
316 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E



35
Non-Annex I:
Annex I:
Population
Population
30 80.3%
19.7%

25
t CO2e per capita


20
Average Annex I:
16.1 t CO2e per capita
USA and Canada: 19.4%


15
Other non-Annex I: 2.0%
Russia and EIT: 9.7%

Middle East: 3.8%
10 and M&T: 11.4%
JANZ: 5.2%




Latin Average non-Annex I:
5 America 4.2t CO2e per capita
Europe




&
Caribbean China and
10.3% East Asia: 17.3% Africa: 7.8% India and South Asia: 13.1%
0
0 1000 2000 3000 4000 5000 6000 7000
Cumulative population in millions

Figure 10.4 Year 2004 distribution of regional per capita greenhouse gas emissions (all
gases included in the Kyoto Protocol including land-use change) expressed as carbon
dioxide equivalent emissions in 2004 from different countries or groups of countries
plotted against population. The percentages in the bars indicate a region™s share in
global greenhouse gas emissions. EIT, economies in transition; M & T, Malta and
Turkey; JANZ, Japan, Australia and New Zealand. To convert tonnes CO2 to tonnes C,
divide by 3.66.


particularly dif¬cult because of the great disparity in current carbon dioxide
emissions between the world™s richest nations and the poorest nations (Figure
10.4), 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 last is particularly recognised in the
Framework Convention on Climate Change (see box on pages 291“2) where the
growing energy needs of developing nations as they achieve industrial devel-
opment are clearly stated. In Chapter 8 on page 253, this current international
inequity was presented as a challenging moral imperative to the developed
world.
An example of how an approach to stabilisation for carbon dioxide might be
achieved is illustrated in Figure 10.5. It is based on a proposal called ˜Contraction
and Convergence™ that originates with the Global Commons Institute (GCI),34 a
non-governmental organisation based in the UK. The envelope of carbon diox-
ide emissions is one that leads to stabilisation at about 450 ppm (without cli-
mate 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 15% 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
317
R E A L I S I N G T H E C L I M AT E C O N V E N T I O N O B J E C T I V E



25
USA
20

15
FSU Tonnes CO2 per capita
10
OECD less USA
5
China
Rest of world
0
India


30
Rest of world
GtCO2
India
20
China
FSU
OECD less USA
10
USA

0
1800 1900 2000 2030 2100 2200
Year
Figure 10.5 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.

the simplest possible solution is taken to the sharing of emissions between
countries and proposes that, from some suitable date (in the ¬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 prin-
ciples 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. The
value of the proposal is that it clearly suggests some of the principal ingredients
of a long-term solution. However, the discussions taking place at the moment
and the other proposals that have been put forward35 demonstrate that any inter-
national agreement is bound to be more elaborate and to differentiate appro-
priately between countries. In particular it will have to take account, not just
318 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E




of very large differences between countries in their emissions but also of large
differences in the threat of damage from climate change, the requirement for
adaptation and in their needs and responsibilities especially within the energy
sector.
Substantial complications arise in these negotiations because of international
entanglement of responsibility for greenhouse gas emissions. This is well illus-
trated by looking at the component of emissions that may be embedded in a
country™s exports. For instance in 2005, 44% of China™s CO2 emissions were
embedded in exports of goods and services mainly to Europe, north America
and Australia.35 Other complications arise in the allocation of responsibility
for emissions from internation aviation, a sector where emissions are rising
rapidly.
The Conference of Parties (COP 13) of the FCCC, meeting in Bali in late 2007,
particularly addressed international action post-Kyoto. The conference set
up negotiations to begin immediately and to be completed by 2009 to bring
about:

A shared vision for long-term cooperative action, including a long-term global goal
for emission reductions, to achieve the ultimate objective of the Convention, in accord-
ance with the provisions and principles of the Convention, in particular the principle
of common but differentiated responsibilities and respective capabilities, and taking
into account social and economic conditions and other relevant factors.

Signi¬cant progress was also made at the Bali meeting in addressing the impor-
tant areas of adaptation, deforestation and technology transfer.
The setting of targets at the international level is, of course, only the ¬ rst
part of the action required. For these targets to be realised requires action at
all levels from the international to the national down to the local and eventu-
ally at the level of the individual. Five essential ingredients are required. The
¬ rst is an aggressive emphasis on energy saving and conservation. Much here
can be achieved at zero net cost or even at a cost saving. Though much energy
conservation can be shown to be economically 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 large contribu-
tion to the reduction of emissions and the slowing of global warming. The sec-
ond ingredient is priority on the development of appropriate non-fossil fuel
energy sources (e.g. carbon capture and storage applied to coal-¬ red power
stations and renewable energy sources) together with very rapid growth in
their implementation. The third ingredient is moving rapidly to a halting of
tropical deforestation. The fourth is the transfer of technologies to develop-
ing countries that will enable them to apply the most appropriate and the
319
S UM M A RY




most ef¬cient technologies to their industrial development, especially in the
energy sector. The ¬ fth ingredient is to act in all these ways with the utmost
urgency. Figures 10.2 and 10.3 and Table 10.3 demonstrate that to achieve the
2 °C target emissions need to peak by about 2015 and then rapidly reduce (see
Figure 11.27). The required concentration of national and international effort
is unprecedented.
Earlier in the chapter we noted that the Kyoto Protocol introduced various
measures aimed at the stimulation of emissions reductions in ef¬cient and
cost-effective ways. Measures that include incentives, regulation, taxation
and emissions trading will be part of follow-on international agreements and
national policies. The challenge is to make sure not only that they achieve the
necessary reductions but that they also prove bene¬cial in terms of their social
and political implications. The next chapter will present some of these chal-
lenges as they concern the energy sector.




SUMM ARY

This chapter has outlined international action to combat climate change
beginning with the Framework Convention on Climate Change (FCCC) agreed
by all nations in 1992. The FCCC™s Objective is to achieve stabilisation of
greenhouse gases and hence of climate at a level that ensures that dangerous
interference with the climate system is avoided, that ecosystems can adapt
naturally, that food production is not threatened and that economic develop-
ment can proceed in a sustainable manner.
In 2005, the Kyoto Protocol came into force under which developed coun-
tries, except USA and Australia, agreed, by 2012 to make reductions in carbon
dioxide emissions averaging about 5% below 1990 levels.
A post-Kyoto agreement is now under negotiation. Key to that agreement
will be a global target limiting future climate change as required by the FCCC
together with proposals for international action to achieve it. At the end of
2007, at the Bali Conference, all nations set out a timetable for an agreement
by the end of 2009. The biggest challenges are to ensure fairness between
developed and developing countries and to prepare ¬nancial and other meas-
ures that will ensure targets will be achieved.
Arguments have been put forward for a target, supported by many experts,
governments and international bodies, that would limit global average tem-
perature rise to no greater than 2 °C above its pre-industrial level. On the
assumption of no further increases in greenhouse gases other than carbon
320 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E




dioxide, a 50% chance of reaching the 2 °C target implies a stabilisation level
for carbon dioxide of no more than 450 ppm.
The achievement of this target will not come easily. It will require much
determination and consistent political will. Urgent and aggressive actions
have to begin now, many of which also bring further bene¬ts. The necessary
action is affordable and its cost much less than the cost of inaction. Further
much of the action is good to do for other reasons. The most important areas
of action are:
• rapid reduction in tropical deforestation and increase in afforestation;
• aggressive increase in energy saving and conservation measures,
• rapid movement to sources of energy free of carbon emissions, e.g through
carbon capture and storage and renewable energy sources;
• some relatively easy-to-do reductions in emissions of greenhouse gases
other than carbon dioxide, especially methane.
The next chapter presents implications for the energy and transport
sectors.
Will the 2 °C target be adequate to stabilise the climate against very damag-
ing and irreversible change? Many are asking this question. Further evidence
obtained during the next few years is likely to demand a serious reappraisal
with the possibility of even more severe targets.



Q U E S TI O N S
1 From Figure 10.2, what are the rates of change of global average tem-
perature 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 the caption to Figure 10.2 and the information in
Figure 3.11 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 components such as aerosol and
tropospheric ozone?
3 From the information in Table 6.1 and the formula in the caption to
Figure 10.2, calculate the equivalent carbon dioxide concentration, including
321
QUESTIONS




(1) the well-mixed greenhouse gases and (2) total aerosols, 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 mentioned; cost“
bene¬t analysis, multicriteria analysis and sustainability analysis. 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 con-
tinuing 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 importance?
7 Compare the growth of emissions since 1990 in the major countries of the
world36 and comment on the policies they appear to be following regarding
future emissions.
8 Given the need for reducing emissions as quickly as possible, do you think
national and international bodies are deciding and acting with suf¬cient
urgency. If not, how might more urgent action be achieved?
9 The international response to global warming is likely to lead to decisions
being taken sequentially over a number of years as knowledge regarding
the science, the likely impacts and the possible responses becomes more
certain. Describe how you think the international response might progress
over the next 20 years. What decisions might be taken at what time?
10 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 coun-
tries that might achieve agreement more easily?
11 Find out the details of any plans for afforestation in your country. What
actions or incentives could make it more effective?
12 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.
322 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E




F URTHER READING AND REFERENCE
Parry, M., Canziani, O., Palutikof, J., van der Linden, P., Hanson, C. (eds.) 2007. Climate
Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working
Group II to the Fourth Assessment Report of the Intergovernmental Panel on
Climate Change. Cambridge: Cambridge University Press.
Technical Summary
Chapter 5 Food, ¬bre and forest products
Chapter 19 Assessing key vulnerabilities and the risk from climate change
Chapter 20 Perspectives on climate change and sustainability
Metz, B., Davidson, O., Bosch, P., Dave, R., Meyer, L. (eds.) 2007. Climate Change 2007:
Mitigation of Climate Change. Contribution of Working Group III to the Fourth
Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge:
Cambridge University Press.
Technical Summary
Chapter 2 Framing issues (e.g. links to sustainable development, integrated assessment)
Chapter 3 Issues relating to mitigation in the long-term context
Chapter 8 Agriculture
Chapter 9 Forestry
Chapter 10 Waste management
Chapter 11 Mitigation from a cross-sectoral perspective
Chapter 12 Sustainable development and mitigation
Chapter 13 Policies, instruments and cooperative Agreements
IPCC AR4 Synthesis Report, Summary for Policymakers and Full Report (52 pages)
available on www.ipcc.ch
Stern, N. 2006. The Economics of Climate Change. Cambridge: Cambridge University
Press. The Stern Review: especially Chapters 3 to 6 in Part II on the cost of climate-
change impacts.
Lynas, M. 2008. Six Degrees. London: HarperCollins. A readable and challenging
account of the probable impacts of climate change in different parts of the world at
different levels of global warming. Winner of the Royal Society™s award for the best
popular science book of the year.



N OTE S F O R C HA P TE R 10
Report. Contribution of Working Groups I, II and III to
1 More details of the Kyoto Protocol and of the detailed
the Third Assessment Report of the Intergovernmental
arrangements for the inclusion of carbon sinks
Panel on Climate Change. Cambridge: Cambridge
can be found in Watson, R. T., Noble, I. R., Bolin, B.,
University Press, question 7, pp. 108ff. See also
Ravindranath, N. H., Verardo, D. J., Dokken, D. J. (eds.)
Hourcade, J.-C., Shukla, P. et al . Global, regional and
2000. Land Use, Land-Use Change and Forestry. A Special
national costs and ancillary bene¬ts of mitigation.
Report of the IPCC. Cambridge: Cambridge University
Chapter 8, in Metz, B., Davidson, O., Swart, R.,
Press and on the FCCC website: www.unfccc.int/
Pan, J. (eds.) 2001. Climate Change 2001: Mitigation.
resource/convkp.html
Contribution of Working Group III to the Third
2 More details in Watson, R. and the Core Writing
Assessment Report of the Intergovernmental Panel on
Team (eds.) 2001. Climate Change 2001: Synthesis
323
N OT E S F O R C H A P T E R 10



Climate Change. Cambridge: Cambridge University 17 From Summary policymakers. In Houghton, J. T.,
Press. Ding, Y., Griggs, D. J., Noguer, M., van der
3 See Stern, N. 2006 The Economics of Climate Change. Linden, P. J., Dai, X., Maskell, K., Johnson, C. A. (eds.)
Cambridge: Cambridge University Press. Chapter 15 Climate Change 2001: The Scienti¬c Basis. Contribution
for a review of practical issues concerned with of Working Group I to the Third Assessment Report of the
carbon trading. Intergovernmental Panel on Climate Change. Cambridge:
4 For a critical dialogue regarding carbon trading see Cambridge University Press.
Carbon Trading, Development Dialogue No. 48. Dag 18 Energy Technology Perspectives 2008, International
Hammarskjöld Foundation, Uppsala, 2006. Energy Agency, Paris, Chapter 14. Available online
5 More detail in Global Environmental Outlook GEO at www.iea.org.
3 (UNEP). 2002. London: Earthscan and Global 19 Chapter 8, in Metz et al. (eds.) Climate Change 2007:
Environmental Outlook GEO 4 (UNEP). 2007. Nairobi, Mitigation.
Kenya: UNEP 20 This ¬gure is calculated by multiplying the
6 Bolin, B., Sukumar, R. et al. 2000. Global perspective. 60 million tonnes by the global warming
Chapter 1, in Watson, et al. (eds.) Land Use. potential for methane which, for a time horizon of
7 Information from Jonas Lowe at the Hadley Centre, 100 years, is about 23 (Table 10.2).
UK Met. Of¬ce. 21 See Bousquet, P. et al. 2006. Nature, 443, 439“43 for
8 From Global Environmental Outlook 3, pp. 91“2; see also an analysis of methane sources and sinks since
www.fao.org/forestry. 1985 with a suggestion that emissions may soon
9 Stern, Economics of Climate Change, p. 244. begin to rise again.
10 A programme, Reduction of Emissions from 22 Rigby, M. et al. 2008. Geophys. Res. Lett. 35, L22805,
Deforestation in Developing Countries (REDD), doi: 10.1029/2008GL036037.
has been initiated by the Forestry 8 countries, 23 Prentice, I. C. et al. 2001. The carbon cycle and
responsible for 80% of the world™s forest cover, with atmospheric carbon dioxide. In Houghton et al. (eds.)
the aim of attracting international funding for Climate Change 2001: The Scienti¬c Basis.
forest preservation. 24 Cox, P. M. et al. 2000. Acceleration of global warming
11 Bolin and Sukumar, p 26. due to carbon cycle feedbacks in a coupled climate
12 Stern, Economics of Climate Change, p. 612. model. Nature, 408, 184“7; Jones, C. D. et al. 2003.
13 Watson et al. (eds.) Land Use, Policymakers Tellus, 55B, 642“58.
Summary, and also in Kauppi, P., Sedjo, R. et al. 25 See also Fig. 3.25, in Metz et al. (eds.) Climate Change
Technical and economic potential of options to 2007: Mitigation.
enhance, maintain and manage biological carbon 26 European Commission Communication on a
reservoirs and geo-engineering. Chapter 4, in Metz Community Strategy on Climate Change; Council
et al. (eds.) Climate Change 2001: Mitigation. of Ministers Conclusion, 25“26 June 1996.
14 Stern, Economics of Climate Change, Chapter 9. 27 European Council of Ministers 2005. Climate
15 For de¬nition see Glossary. Strategies. Brussels: ECM.
16 Betts, R. A. 2000. Offset of the potential carbon 28 For examples of 2 °C target, see World Wildlife Fund
sink from boreal forestation by decreases in at www.wwf.org.uk/climate/
surface albedo. Nature, 408, 187“90. Also 29 Fig. 3.12, in Metz et al. (eds.) Climate Change 2007:
Solomon, S., Qin, D., Manning, M., Chen, Z., Mitigation.
Marquis, M., Averyt, K. B., Tignor, M., Miller, H.L. 30 Table 3.9, in Metz et al. (eds.) Climate Change 2007:
(eds.) 2007. Climate Change 2007: The Physical Science Mitigation.
Basis. Contribution of Working Group I to the Fourth 31 Hansen, J. et al. 2008. Target atmospheric CO2:
Assessment Report of the Intergovernmental Panel on where should humanity aim? Open Journal on
Climate Change. Cambridge: Cambridge University Atmospheric Sciences, 2, 217“31 and James Hansen,
Press, Chapter 2. Bjerknes Lecture at American Geophysical
324 A S T R AT E G Y F O R AC T I O N TO S LO W A N D S TA B I L I S E C L I M AT E C H A N G E



Union, 17 December 2008 at www.columbia.edu/ 34 Further details on the GCI website:
njeh1/2008/AGUBjerknes_20081217.pdf. www.gci.org.uk
32 Kunzig, R., Broecker, W. S. 2008. Fixing Climate. 35 See for instance Baer, P., Athanasiou, T. 2007. No.
London: Pro¬le Books. M. Meinshausen 2006. 30, Frameworks and Proposals. Global Issue Papers.
What does a 2˚C target mean for greenhouse Washington, DC: Heinrich Böll Foundation.
gas concentrations? Avoiding Dangerous Climate 36 More detail in World Energy Outlook, International
Change. Cambridge: Cambridge University Press. Energy Agency 2008, p. 386ff.
pp.268“279. 37 Information on emissions available from many
33 Additional climate carbon-cycle feedbacks have sources, e.g. International Energy Agency and World
been ignored in this calculation. Resources Institute.
Energy and transport for
11
the future




70 000 solar panels form a photovoltaic array generating 15 megawatts of solar power for the Nellis
Air Force Base, Nevada.




W E FLICK 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
conserving it. However, most of the world™s energy comes from the burning of fossil fuels, which
generates the major 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
sector. 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. It also addresses how basic energy services might be made available to the
more than 2 billion people in the world who as yet have no such provision.
326 E N E RG Y A N D T R A N S P O R T F O R T H E F U T U R E




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), hydropower,
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 other forms of energy that do not originate with the
Sun are nuclear energy and geothermal energy, both of which result from the
presence of radioactive elements in the Earth when it was formed.
Until the Industrial Revolution, energy for human society was provided 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 over 30 (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 2005 the world consumption of primary energy was about 11 400
million tonnes of oil equivalent (toe). This can be converted into physical energy
units to give an average rate of primary energy use of about 15 million million
watts (or 15 terawatts = 15 — 1012 W).1
Great disparities exist in the amount of energy used per person in various
parts of the world. The 2 billion poorest people in the world (less than $US1000
annual income per capita) each use an average of only 0.2 toe of energy annu-
ally while the billion richest in the world (more than $US22 000 annual income
per capita) use nearly 25 times that amount at 5 toe per capita annually.2 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 aver-
age of about 11 kW. About 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 forms.
In Figure 11.2 is shown how the energy we consume is generated and used.
Also summarised are the energy ¬‚ows from source to users in the main sec-
tors and the size of the various resources that are available using conventional
technologies. Taking the world average approximately 25% of primary energy
is used in transport, 35% in industry and 40% in buildings (two-thirds in resi-
dential buildings and one-third in commercial buildings). It is also interest-
ing 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,
327
WO R L D E N E RG Y D E M A N D A N D S U P P LY




StatoilHydra™s Sleipner T gas platform off the Norwegian coast which is sequestering one
million tonnes of carbon dioxide per year.
328 E N E RG Y A N D T R A N S P O R T F O R T H E F U T U R E



12
Gigatonnes of oil equivalent per year




10

Natural gas
8 Oil
Coal
6 Other (includes traditional fuels)


4


2


0
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2005
Year

Figure 11.1 Growth in the rate of primary energy use and in the sources of energy from 1860 to 2005 in
thousand millions of tonnes of oil equivalent (Gtoe) per year. In terms of primary energy units, 1 Gtoe = 41.9
exajoules. Of the ˜other™ in 2005, approximately 1.2 Gtoe is attributed to traditional fuels, 0.7 Gtoe to
nuclear energy and 0.3 Gtoe to hydropower and other renewables (source for data up to 2000: Report of
G8 Renewable Energy Task Force, July 2001; from 2000 to 2005 Fig. TS 13 in IPCC AR4 WGIII 2007).


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 5%
of annual income. Despite the very large disparity in incomes, the proportion
spent on primary energy is much the same in developed countries and develop-
ing 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 at cur-
rent rates of use, known reserves of fossil fuel will meet demand at least until
2050. But before then, if demand continues to expand, oil and gas production
will come under increasing 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 100 years.
Estimates have also been made of the ultimately recoverable fossil fuel
reserves, de¬ned as those potentially recoverable assuming high but not prohib-
itive prices and no signi¬cant bans on exploitation. Although these are bound
to be somewhat speculative, they show that, at current rates of use, reserves
329
WO R L D E N E RG Y D E M A N D A N D S U P P LY



Combined Losses
Uranium Solar and other Heat and Power
resource 158.8
6.4
0.7
0.8
(U235 once 10.6 4.2
Wind 0.1
through cycle)
7400 EJ 0.7 0.7
111
Geothermal
Uranium Electricity
0.9 0.7
resource
Biomass 3.1 172.3
(U235 plus 2.3
U238 fertility)
220 000 EJ 8.7
36.1
49.5 26.1
10.7
0.2 28.4
7.1
Coal Hydro 0
21.4
resource 10.1
10.1 Buildings
100 000 EJ 0.5
0.6
Nuclear 121.3
29.9 29.9



Coal
79
116.5
0
4.4
20.9
Industry
CO2 emissions
10 600 Mt/yr “1 105.1
1.5

00 0
0 0
0
0 Hydrogen 0
Gas
Gas 36.6
resource
0
95.3 SynFuels
0
13 500 EJ 24.5
0.6
23.6
0.6
CO2 emissions 0
5300 Mt/yr “1
Conventional 1.9
12.2
oil resource Transport
10 000 EJ
82.4
Oil
20.9
27.9
165

77.9



CO2 emissions
10 200 Mt/yr “1




Figure 11.2 Global energy ¬‚ows (EJ in 2004) from primary energy through carriers to end-users and losses
in transmission, etc. Related carbon dioxide emissions from coal, oil and gas combustion are also shown as
well as the size of known resources. Further energy conversions occur in the end-use sectors. Peat is included
with coal, organic waste is included with biomass. The resource ef¬ciency ratio by which fast-neutron
technology increases the power-generation capability per tonne of natural uranium varies greatly in different
assessments. In this diagram the ratio used is up to 240 : 1.

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™ reac-
tors) they are believed to be substantially greater than likely fossil fuel reserves
(Figure 11.2).
Human-made lights which highlight developed or populated areas of the Earth™s surface, including the seaboards
of Europe, the eastern United States and Japan.


It is considerations other than availability, in particular environmental con-
siderations, 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, eco-
nomic growth and social and political development), how that demand might
be met and what greenhouse gas emissions might result. In that chapter were
also described the implications for those scenarios regarding climate change.
Chapter 10 explained the imperative set out by the Framework Convention on
Climate Change (FCCC) in its Objective that greenhouse gas concentrations in
the atmosphere must be stabilised so that continued anthropogenic climate
change can be avoided. Scenarios of carbon dioxide equivalent (CO2e) emissions
that would be consistent with various stabilisation levels were also presented.
Arguments were put forward for limiting the rise in global atmospheric tem-
perature to 2 °C above its pre-industrial level implying a target level for atmos-
pheric concentration of carbon dioxide equivalent of about 450 CO2e. How the
world™s energy producers and consumers can meet the challenge of such a tar-
get is addressed by this chapter.
331
F U T U R E E N E RG Y P ROJE C T I O N S




Energy intensity and carbon intensity
An index that provides an indication of a country™s energy ef¬ciency is the ratio of annual energy consumption to
gross domestic product (GDP) known as the energy intensity. Figure 11.3 shows that from 1970 to 2005 world
total GDP increased by a factor of about 3 while energy consumption increased by a factor of about 2, the result
being a decrease in energy intensity of about 30% or an average of about 1% per year. There are substantial
differences between countries. Within the OECD, Denmark, Italy and Japan have the lowest energy intensities
and Canada and the USA the highest, with more than a factor of 2 between the lowest and the highest.
Of importance too in the context of this chapter is the carbon intensity, which is a measure of how
much carbon is emitted for a given amount of energy. This can vary with different fuels. For instance, the
carbon intensity of natural gas is 25% less than that of oil and 40% less than that of coal. For renewable
sources the carbon intensity is small and depends largely on that which originates during manufacture of
the equipment making up the renewable source (e.g. during manufacture of solar cells). Figure 11.3 shows
that the average carbon intensity for the globe has reduced only a little since 1970.
The Kaya Identity expresses the level of energy-related carbon dioxide emissions as the product of four
indicators, namely carbon intensity, energy intensity, gross domestic product per capita and the popu-
lation, the global averages for which are all plotted in Figure 11.3. For the reductions in global carbon
dioxide emissions required in the future, energy and carbon intensities have to reduce more quickly than
income and population growth taken together.


Index 1970 = 1
3.0
Income (GDP“ppp)
2.8
Energy (TPES)
CO2 emissions
2.6
Income per capita (GDP“ppp/cap)
2.4
Population
Carbon intensity (CO2/TPES)
2.2
Energy intensity (TPES/GDP“ppp)
2.0
Emission intensity (CO2/GDP“ppp)
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
1970 1975 1980 1985 1990 1995 2000
Year
Figure 11.3 Relative global development for the period 1970“2004 of gross domestic
product (GDP measured in purchasing power parity: ppp), total primary energy supply
(TPES), carbon dioxide emissions (from fossil fuel burning, gas ¬‚aring and cement
manufacture) and population. In dashed lines are shown income per capita, energy
intensity, carbon intensity of energy supply and emission intensity.
332 E N E RG Y A N D T R A N S P O R T F O R T H E F U T U R E




Many national and international bodies and some energy industries have
studied future energy scenarios and how they might be achieved. The most
comprehensive of these are those by the International Energy Agency pre-
sented to year 2030 in its annual volume World Energy Outlook 3 and in more
detail to 2050 in its Energy Technology Perspectives.4 Three scenarios of inter-
est are presented (Figure 11.4). The ¬ rst is a reference or baseline scenario
that assumes energy carbon dioxide emissions continue to rise with minimal
environmental constraints throughout the period; in 2050 emissions are 2.3
times up on their level in 2005 “ similar to the SRES A2 scenario (Figure 6.1).
As we have already seen in Chapter 10, with this scenario global warming
and climate change will continue unchecked. The second, called the ACT Map
scenario, brings energy carbon dioxide emissions back to their 2005 level by
2050 and the third, the BLUE Map scenario, returns emissions to their 2005
level by 2025 and reduces them by a further factor of 2 by 2050. As shown
in Chapter 10 (Figures 10.2 and 10.3), these scenarios are broadly consistent
with stabilised carbon dioxide concentrations of 550 ppm CO2e for ACT and
450 ppm CO2e for BLUE. Also in Figure 11.4 are shown the share of emissions
and emissions reductions by different sectors and illustrative options for how
these reductions might be made. Reference to these options will be made later
in the chapter where more detail regarding different sectors or technologies
is presented.
Listed below are some key ¬ndings of the IEA that illustrate how achieve-
ment of these reducing scenarios can make the world™s energy sector more
sustainable.5

• For the Baseline scenario in 2050, OECD countries account for less than one-
third of global carbon dioxide emissions. Population growth (see Chapter 12,
page 393) and the need for economic development make it inevitable that
developing countries will, for many decades, consume increased amounts of
energy. Global emissions can only be halved if developing countries and tran-
sition economies contribute very substantially.
• There is an urgent need for aggressive and determined action in the next
decade6. There is a danger that investments made in this period, due to the
long lifespan of capital equipment such as buildings, industrial installations
and power plants, could be the subject of economically wasteful early replace-
ment or refurbishment if emission reduction targets are to be met. The BLUE
scenario already envisages 350 GW of coal-¬red power being replaced before
the end of its lifespan.
• Deep emission cuts will require extensive application of energy ef¬ciency
measures, carbon capture and storage (CCS), renewable energy technologies
333
F U T U R E E N E RG Y P ROJE C T I O N S




(a)
70
Buildings
60 Industry
Emissions (Gt CO2)




Transport
50
Upstream
40
Power sector
30

20

10

0
0 2005 Baseline Baseline ACT Map BLUE Map
2030 2050 2050 2050




(b)
70 CCS industry and
transformation (9%)
Baseline emissions 62 Gt
60
CCS power generation (10%)
Emissions (Gt CO 2)




50 Nuclear (6%)
40 Renewables (21%)
Power generation efficiency
30 and fuel switching (7%)
End-use fuel switching (11%)
20
End-use electricity
BLUE map emissions 14 Gt
efficiency (12%)
10
WEO 2007 450 ppm case ETP 2008 analysis End-use fuel efficiency (24%)
0
2005 2010 2015 2020 2025 2030 2035 2040 2045 2050
Year




(c)
70
Power sector (38%)
Baseline emissions 62 Gt
60
Industry (19%)
Emissions (Gt CO 2)




50 Buildings (17%)
40 Transport (26%)

30

20
BLUE map emissions 14 Gt
10
WEO 2007 450 ppm case ETP 2008 analysis
0
2005 2010 2015 2020 2025 2030 2035 2040 2045 2050
Year

Figure 11.4 (a) Global energy-related carbon dioxide emissions in the Baseline, ACT
Map and BLUE Map scenarios of the International Energy Agency (IEA) showing division
into sectors. (b) and (c) Illustrative options for contributions to emissions reductions
2005“50 for the BLUE Map scenario by source (b) and by sector (c). In (c) reductions
from electricity savings have been allocated to end-use sectors.
334 E N E RG Y A N D T R A N S P O R T F O R T H E F U T U R E




and nuclear. The transport sector especially will require new solutions with
substantial cost.
• Electricity will play an increasing role as a carbon-dioxide-free energy carrier.
The near elimination of emissions in the power sector is key to achieving
deep emission reductions worldwide. Advances in new technologies are key

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