Environmental Engineering Reference
In-Depth Information
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Climate change threatens the basic elements of life, i.e. access to water, food, health and
the use of land and the environment.
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There is still time to avoid the worst impacts of climate change if action is taken now.
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Stabilization at 550 ppm of all greenhouse gases is recommended, but this would involve
strong action.
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The costs of stabilizing the climate are signifi cant (1% of global GDP) but manageable.
Delay would be dangerous and much more expensive, perhaps as costly as 20% of global
GDP.
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Action demands an international response.
The key actions should include:
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Increase in effi ciency of energy use.
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Strict emissions trading rules to support the transition to low carbon development paths.
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Extensive use of renewable and other low carbon technologies.
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Technology cooperation and fi vefold increased in low carbon technologies R&D.
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Reduction in deforestation.
The major focus of the Stern Report is the economics of climate stabilization. Figure 1.5
shows estimates of costs of low carbon technologies in 2015, 2025 and 2050 that may be
used to constrain CO
2
emissions. The costs are expressed as a central estimate, with a range,
and as a percentage of the fossil fuel alternative in the appropriate year. Due to learning
effects the costs fall over time. The ranges refl ect judgements about the probability distribu-
tion of unit costs and the variability of fossil fuel prices. The 0% line indicates that the costs
are the same as the corresponding fossil fuel option. As expected, the uncertainties are large
even for short term predictions. Onshore wind is shown to be particularly attractive with
photovoltaic (PV) cells becoming very attractive beyond 2025.
On the basis of the costs of the low carbon technologies and assumptions on possible rates
of uptake over time, the Stern Report estimates the distributions of emissions savings by
technology for 2025 and 2050 for the desirable climate stabilization at 550 ppm. These esti-
mates are shown in Figure 1.6. Energy effi ciency and carbon capture and storage (CCS) play
a major role in this scenario and will be discussed later in this chapter. Contributions from
wind, solar, biofuels, hydro and distributed combined heat and power (dCHP) through elec-
tricity generation provide the remaining savings; and these are the technologies to be addressed
in later chapters of this topic.
1.2.5 Effi cient Energy Use
Figure 1.6 stresses that effi ciency measures are projected to make the largest contribution in
climate change mitigation. It is therefore a surprise that the important topic of rational and
effi cient use of energy is rarely pursued vigorously in national or supranational plans in spite
of the fact that study after study has shown that this route provides the most cost effective
way to meet sustainability goals.
In most countries, regulations and fi nancial incentives are now in place to encourage energy
effi ciency but their effect is modest and national energy consumption fi gures continue to
