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PART THREE / MITIGATION
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Numerous studies show that between 10% and 30% gains in energy efficiency are feasible at little or no real cost. They can be achieved over the next two to three decades through known technical measures to improve conservation of energy and materials, and
through better management practices. In many countries efficiency gains of 50%-60% are technically achievable on the same timescale, provided finance and technology is made available, says the IPCC. Such gains would reduce the demand for energy, so reducing greenhouse gas emissions wherever that energy is generated by burning fossil fuels.
Improvements in energy efficiency are essential and will require strong policy measures' to offset growth in energy demand. The good news is that these can often be incorporated into existing investment strategies. By 2100 the world's commercial energy systems will be replaced at least twice, allowing new energy-efficiency and non-fossil fuel technologies to be incorporated - provided the right policy decisions are taken early. There is immediate potential for energy efficiency in industrialised countries that could reduce emissions by a quarter in industry and by a third in trans-portation without compromising comfort and performance. In transportation valuable design measures including switching to vehicles with light weight construction and low air resistance. Also, changes in transport systems, mobility patterns and lifestyles, use of alternative fuels and changes in land-use policy could make a total reduction in transportation emissions of 40% by 2025, as well as having other benefits, such as reducing local air pollution. | |||||||
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Meanwhile, changes in building construction, more efficient lighting and appliances such as refrigerators and air-conditioning systems, could remove a quarter of the projected increase in offices and homes without diminishing services. More trees and reflective buildings would reduce air-conditioning bills in hot countries.
Additionally, industrial manufacturers and city authorities could reduce emissions by recycling materials, eliminating solvents, capturing and using methane from landfills etc. Energy could also be generated much more efficiently. Thermal efficiency in the world's power stations currently averages 30% - that is, more than two-thirds of the energy is lost. Thermal efficiency could be increased with new plant to 60%. Combined heat and power systems, which re-use waste heat from power plants, would further improve fuel conversion efficiency. Fossil fuels could be avoided altogether by switching. Solar, biomass, wind, hydro and geothermal energy-generating technologies are already widely used, accounting for 20% of world primary energy consumption. In the longer term, says the IPCC, renewables could meet a major part of the world's demand for energy. Biomass burning does not add to CO2 emissions, provided that what is burnt is replaced by new crops. | |||||||
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There are many combinations of energy options and improvements in energy efficiency that could yield deep reductions in CO2 emissions within 50 to 100 years. Combinations analysed by the IPCC could reduce current emissions by around a third to 4 billion tonnes of carbon a year by 2050, and to 2 billion tonnes by 2100. But 'many of the technologies being developed would need initial support to enter the market, and to reach sufficient volume to lower costs to become competitive'.
Forests, pastures and fields could all be managed better to reduce emissions of greenhouse gases and enhance their roles as carbon sinks. Foresters should maintain existing forest cover, slow deforestation, encourage natural regeneration of degraded forests, establish tree plantations, and promote agroforestry. Improvements in agricultural productivity in developing countries could leave increasing amounts of land spare for growing biomass energy, says the IPCC. Estimates of how much additional carbon could be stored in forest and agricultural systems over the next 50 years range from eight to 40% of the projected emissions over the same period. | |||||||
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But warnings are given against suggested 'geo engineering' solutions to warming - such as putting solar reflectors into space or injecting sulphate aerosols into the upper atmosphere to mimic volcanic eruptions. These, it says, 'are generally likely to be ineffective, expensive or to have serious environmental and other effects'.
Policy makers, it concludes, should now consider a range of policies, including:
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