Sustainability and policy - Climate Change: Biological and Human Aspects - page 506

25 000

Population 8.7 billion

Per-capita energy

≈

≈ 2.3 toe

20 000

?

New for 2044
Renewable energy
Nuclear
Coal
Natural gas
Oil

?

15 000

Population 6.37 billion
Per-capita energy 1.6 toe

10 000

Population 3.27 billion
Per-capita energy 1 toe

5000

0

1964 2004 2044

Year

Fig. 8.10 Past,presentandlikelyfutureglobalenergydemands,for1964,2004and2044.

Exactly how great is this problem of managing fossil carbon emissions? To get
an idea of the scale of the problem we can look at the energy demands of the past
40 years, the present and the likely demands of the future. Energy demand is the main
contributor to atmospheric carbon dioxide, the principal anthropogenic greenhouse
gas. To date, how we have met this energy demand?
Forecasting the future is not possible with any certainty but it is possible to make
some reasonable assumptions to underpin a scenario. In this case the scenario is
depicted in Figure 8.10. Three fundamental assumptions are made. One is that future
global population growth follows the median UN forecast but, as the 2010 revision
gave a higher mid-21st-century population estimate, this assumption based on the
earlier UN estimate is more conservative (UN Population Division of the Department
of Economic and Social Affairs, 2002, 2010). Second, future energy demand is a
middle IPCC SRES (IPCC, 2000) and so close to many of the IPCC scenarios
including those used in the 2007 assessment report. Finally, at least part of the energy
contribution in 2044 will be similar to that in 2004. In other words, that we will be
consuming at least a similar amount of coal, generating at least as much from HEP,
etc., plus additional energy to allow for the economic and population growth that will
take place between now and then.
In short, the assumption is that both global per-capita energy consumption and
population will grow over the next 40 years up to 2044 but that this growth will
be less than that which actually took place since 1964. Under this scenario global
energy consumption approximately doubles to 2044. Indeed, the International Energy
Agency in 2005 forecast that global energy consumption would be even higher: it
forecast an energy increase between 2005 and 2030 of over 52%. So, the assumption
of 50% growth by 2044 can be considered a conservative one.
Given the aforementioned facts, then if fossil emissions in 2044 are to be held
at 2004 levels then annually we need to find a similar amount of non-greenhouse-
impacting energy to the total energy used in 2004. The options, of course, are renew-
able energy, nuclear power and fossil fuels with carbon capture. Figure 8.10 visually