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Box SPM-2 (WGIII) Mitigation potential and analytical approaches

The concept of “mitigation potential” has been developed to assess the scale of GHG reductions that could be made, relative to emission baselines, for a given level of carbon price (expressed in cost per unit of carbon dioxide equivalent emissions avoided or reduced). Mitigation potential is further differentiated in terms of “market potential” and “economic potential”.

Market potential is the mitigation potential based on private costs and private discount rates which might be expected to occur under forecast market conditions, including policies and measures currently in place, noting that barriers limit actual uptake [2.4].

Economic potential is the mitigation potential, which takes into account social costs and benefits and social discount rates, assuming that market efficiency is improved by policies and measures and barriers are removed [2.4].

Studies of market potential can be used to inform policy makers about mitigation potential with existing policies and barriers, while studies of economic potentials show what might be achieved if appropriate new and additional policies were put into place to remove barriers and include social costs and benefits. The economic potential is therefore generally greater than the market potential.

Mitigation potential is estimated using different types of approaches. There are two broad classes – “bottom-up” and “top-down” approaches, which primarily have been used to assess the economic potential.

Bottom-up studies are based on assessment of mitigation options, emphasizing specific technologies and regulations. They are typically sectoral studies taking the macro-economy as unchanged. Sector estimates have been aggregated, as in the TAR, to provide an estimate of global mitigation potential for this assessment.

Top-down studies assess the economy-wide potential of mitigation options. They use globally consistent frameworks and aggregated information about mitigation options and capture macro- economic and market feedbacks.

Bottom-up and top-down models have become more similar since the TAR as top-down models have incorporated more technological mitigation options and bottom-up models have incorporated more macroeconomic and market feedbacks as well as adopting barrier analysis into their model structures.

Bottom-up studies in particular are useful for the assessment of specific policy options at sectoral level, e.g. options for improving energy efficiency, while top-down studies are useful for assessing cross-sectoral and economy-wide climate change policies, such as carbon taxes and stabilization policies.

However, current bottom-up and top-down studies of economic potential have limitations in considering life-style choices, and in including all externalities such as local air pollution. They have limited representation of some regions, countries, sectors, gases, and barriers. The projected mitigation costs do not take into account potential benefits of avoided climate change.

Source & © IPCC Climate Change 2007:  "Mitigation, Summary for Policymakers" (2007), p7

Related publication:
Climate Change (2007) homeClimate Change 2007 Update
Other Figures & Tables on this publication:

Figure SPM-1. (WGI) Changes in Greenhouse Gases from Ice-core and Modern Data

Figure SPM-2. (WGI) Radiative Forcing Components

Figure SPM-3. (WGI) Changes in Temperatures, Sea Level and Snow Cover between 1850 and 2010

Figure SPM-4. (WGI) Global and Continental Temperature Change

Figure SPM-5. (WGI) Multi-model Averages and Assessed Ranges for Surface Warming

Figure SPM-6. (WGI) AOGCM Projections of Surface Temperatures

Figure SPM-7. (WGI) Projected Patterns of Precipitation Changes

Figure SPM-1. (WGII) Changes in physical and biological systems and surface temperature 1970-2004

Figure SPM-2. (WGII) Key impacts as a function of increasing global average temperature change

Figure SPM-1. (WGIII) Emissions of different greenhouse gases 1970-2004

Figure SPM-2. (WGIII) Relative global development of indicators of income, energy supply, CO2 emissions and population for 1970 to 2004

Figure SPM-3a. (WGIII) Distribution of regional per capita greenhouse gas emissions

Figure SPM-3b. (WGIII) Distribution of regional greenhouse gas emissions per unit of income

Figure SPM-4. (WGIII) Global greenhouse gas emissions for 2000, 2030 and 2100

Figure SPM-5a/5b. (WGIII) Estimated global economic mitigation potential

Figure SPM-6. (WGIII) Estimated economic mitigation potential in 2030 as a function of carbon price

Figure SPM-7. (WGIII) Emissions pathways of mitigation scenarios for alternative categories of stabilization levels

Figure SPM-8. (WGIII) Relationship between stabilization scenario categories and equilibrium global mean temperature change

Figure SPM-9. (WGIII) Cumulative emissions reductions for alternative mitigation measures for 2000 to 2030 (left-hand panel) and for 2000-2100 (right-hand panel)

Global greenhouse gas emissions 1970-2004

Table SPM-1. (WGI) Observed rate of sea level rise and estimated contributions from different sources.

Table SPM-2. (WGI) Recent trends, assessment of human influence on the trend, and projections for extreme weather events for which there is an observed late 20th century trend.

Table SPM-3. (WGI) Projected globally averaged surface warming and sea level rise at the end of the 21st century.

Table SPM-1. (WGII) Examples of possible impacts of climate change due to changes in extreme weather and climate events based on projections to the mid- to late 21st century. These do not take into account any changes or developments in adaptive capacity. Examples of all entries are to be found in chapters in the full Assessment (see source at top of columns). The first two columns of the table (shaded yellow) are taken directly from the Working Group I Fourth Assessment (Table SPM-2). The likelihood estimates in Column 2 relate to the phenomena listed in Column 1.

Table SPM-4. (WGIII) Estimated global macro-economic costs in 2030a for least-cost trajectories towards different long-term stabilization levels.b,c

Table SPM-5. (WGIII) Characteristics of post-TAR stabilization scenarios [Table TS 2, 3.10]a

Table SPM-6. (WGIII) Estimated global macro-economic costs in 2050 relative to the baseline for least-cost trajectories towards different long-term stabilization targetsa [3.3, 13.3]

Table SPM-7. (WGIII) Selected sectoral policies, measures and instruments that have shown to be environmentally effective in the respective sector in at least a number of national cases.

Table SPM-1. (WGIII) Global economic mitigation potential in 2030 estimated from bottom-up studies.

Table SPM-2. (WGIII) Global economic mitigation potential in 2030 estimated from top-down studies.

Table SPM-3. (WGIII) Key mitigation technologies and practices by sector. Sectors and technologies are listed in no particular order. Non-technological practices, such as lifestyle changes, which are cross-cutting, are not included in this table (but are addressed in paragraph 7 in this SPM).

Figure SPM-2. (WGII) Key impacts as a function of increasing global average temperature change

Figure SPM-6. (WGIII) Estimated economic mitigation potential in 2030 as a function of carbon price

Likelihood

The Emission Scenarios of the IPCC Special Report on Emission Scenarios (SRES)

Box SPM-2 (WGIII) Mitigation potential and analytical approaches

Box SPM-3 (WGIII) Assumptions in studies on mitigation portfolios and macro-economic costs

Box SPM-4 (WGIII) Modelling induced technological change

Parties & Observers of the UNFCCC