6. How could greenhouse gas emissions be reduced?

     6.1. How is Climate Change a unique problem?
     6.2. What are the options for reducing greenhouse gas emissions?
     6.3. What would be the costs of implementing the Kyoto Protocol?
     6.4. What are the ways and means for mitigation?
     6.5. What in the current knowledge needs to be improved?

6.1. How is Climate Change a unique problem?

Climate change2 is a problem with unique charateristics. It is global, long term (up to centuries), and involves complex interactions between climatic, environmental, economic, political, institutional, social and technological processes. Alternative development paths4 can result in very different greenhouse gas emissions. More...

Climate change mitigation1 would both be affected by, and have impacts on, broader socio-economic policies and trends, such as those relating to development, sustainability and equity. More...

Key considerations of climate change mitigation options concern the differences in the distribution of technological, natural and financial resources among and within nations and regions, and between generations, as well as differences in mitigation costs. More...

Lower emissions scenarios would require different patterns of energy resource development. More...

6.2. What are the options for reducing greenhouse gas emissions?

6.2.1. Since 1995, there has been significant and faster than anticipated technical progress in greenhouse gas emissions reduction. The options over the next 20 years would include improving energy efficiency for buildings, transport and manufacturing, conversion to natural gas for energy supply, as well as low-carbon energy supply systems such as biomass, wind, nuclear and hydroelectric power systems, the reduction of methane and nitrous oxide emissions in agriculture and, with some applications, the minimization of fluorinated gas emissions (see Table SPM.1 for estimates; half of these potential emissions reductions may be achieved with direct benefits exceeding direct costs). More...

6.2.2. Forests and agricultural lands provide significant carbon mitigation potential, which would not necessarily be permanent but it may allow time for other options to be further developed and implemented. The global potential could be in the order of 100 GtC by 2050, equivalent to about 10% to 20% of the fossil fuel emissions during that period. More...

6.2.3. Social learning and innovation, as well as changes in institutional structures could contribute to climate change mitigation. Changes in collective rules and individual behavior may have significant effects on greenhouse gas emissions, but would take place within complex institutional, regulatory and legal settings. More...

6.3. What would be the costs of implementing the Kyoto Protocol?

6.3.1. Estimates of cost and benefits of mitigation actions differ because of (i) how welfare is measured, (ii) the scope and methodology of the analysis, and (iii) the underlying assumptions built into the analysis, including: changes in demographics, economic growth, personal mobility, technological and fiscal innovations, the level and timing of mitigation actions, implementation measures, and financial computations. More...

6.3.2. Some sources of greenhouse gas emissions could be limited at no cost or with a negative net social cost, by bringing benefits such as: reduction of market or institutional imperfections that impede cost-effective measures, societal benefits from reductions in air pollution ("ancillary benefits"), and reductions in existing distortionary taxes financed by emission taxes or permits ("revenue recycling"). More...

6.3.3. For developed countries, the cost estimates to implement the Kyoto Protocol vary between studies and regions and depend strongly upon the assumptions regarding the use of the Kyoto mechanisms. Most studies project GDP reductions in 2010 of about 0.2% to 2% without emission trading and of about 0.1% to 1.1% with emission trading. More...

6.3.4. The cost of stabilizing CO2 concentrations by 2100 increases significantly as the concentration stabilization level declines. More...

6.3.5. Some industries are likely to suffer from greenhouse gas reduction efforts, such as: coal, possibly oil and gas, and certain energy-intensive sectors such as steel production. Others are likely to benefit, such as renewable energy industries and services. More...

6.3.6. Developing countries would also be affected by the implementation of the Kyoto Protocol:
- Oil-exporting countries would see a reduction in their oil revenue.
- Other countries may be affected by a reduction in their exports to developed countries,
- but may benefit economically from some relocation of carbon-intensive industries (carbon leakage).
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6.4. What are the ways and means for mitigation?

The successful implementation of greenhouse gas mitigation options needs to overcome many technical, economic, political, cultural, social, behavioral and/or institutional barriers which prevent the full exploitation of the technological, economic and social opportunities of these mitigation options. More...

6.4.1. The portfolio of government climate policy instruments may include: emissions/carbon/energy taxes, tradable or non-tradable permits, provision and/or removal of subsidies, deposit/refund systems, technology or performance standards, energy mix requirements, product bans, voluntary agreements, government spending and investment, and support for research and development. More...

6.4.2. The effectiveness of climate change mitigation could be enhanced when climate policies are integrated with the non-climate objectives of national and sectorial policy development, to achieve the long-term changes required by both sustainable development and climate change mitigation. More...

6.4.3. Coordinated actions among countries and sectors may help to reduce mitigation costs, address competitiveness concerns, potential conflicts with international trade rules, and carbon leakage. More...

6.4.4. Climate change decision-making is essentially a sequential process under general uncertainty. The relevant question is not “what is the best course for the next 100 years”, but rather “what is the best course for the near term given the expected long-term climate change and accompanying uncertainties”. More rapid near-term action would decrease environmental and human risks associated with rapid climate changes. More...

6.4.5. Any international regime could be designed in a way that enhances both its efficiency and its equity. The development of an effective regime on climate change must give attention to sustainable development and non-economic issues. More...

6.5. What in the current knowledge needs to be improved?

The priorities for narrowing gaps between current knowledge and policy-making needs are:

• Further exploration of the regional, country and sector specific potentials of technological and social innovation options.
• Economic, social and institutional issues related to climate change mitigation in all countries.
• Methodologies for analysis of the potential of mitigation options and their cost, with special attention to comparability of results.
• Evaluating climate mitigation options in the context of development, sustainability and equity.
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