National and sectoral GHG mitigation potential: a comparison across models
This paper focuses on greenhouse gas (GHG) mitigation potential of developed countries to provide a comparative assessment across key economies.
Determining comparability of effort amongst developed countries in implementing measurable, reportable and verifiable nationally appropriate GHG mitigation commitments or actions is a key issue for the UNFCCC COP-15 negotiations in Copenhagen, as developed country parties are expected to agree on quantified emissions limitation and reduction objectives for the post-2012 climate change regime.
A number of indicators have been proposed to reflect comparability of effort and differences in national circumstances; key amongst these are greenhouse gas (GHG) emissions (per capita), GDP per capita, as well as GHG mitigation potential.
GHG mitigation potential is defined in this paper as the level of GHG emission reductions that could be realized, relative to the projected emission baseline in a given year, for a given carbon price. Estimates of GHG mitigation potential projected in the future can be obtained via models. These estimates vary depending on the type of model employed and on the parameters and underlying assumptions used.
This comparative analysis of model results aims to:
- Identify areas of agreement in results across different models;
- Enhance understanding of what is driving any differences in results; and
- Indicate possible gaps and areas for improvement in data or modelling analysis.
Overall, such a comparative analysis can enhance transparency and contribute to a better informed climate change policy-making process.
This paper compares model estimates of national and sectoral GHG mitigation potential across six key OECD GHG-emitting economies around the world: Australia, Canada, the EU, Japan, Mexico and the US. Data for these countries were obtained across the time horizon of 2005-2050 from a total of 19 models, including models that are used to inform climate policy-makers in each of these economies. For these six economies, this paper examines the model structure, baseline and policy assumptions, and then compares GHG mitigation potential estimates across the available models.
Due to differences in regional and economy-wide aggregation across these models, GHG mitigation potential is compared across 5 models for Australia, 9 models for Canada, 12 models for the EU, 8 models for Japan, 5 across Mexico, and 13 models across the US.