Modeling Post-2012 Climate Policy Scenarios

The Center, in collaboration with the Battelle Memorial Institute, is modeling a range of post-2012 global climate policy scenarios. Interim results from this innovative modeling exercise [1] were presented at a side event at the UN climate change talks in Bonn, Germany, in June 2008.

The aim of this initiative is to visualize and to assess alternative post-2012 architectures incorporating different types of climate commitments, including absolute economy-wide emission targets, policy-based commitments, and sectoral agreements [2]. The scenarios are not intended as “proposals” for a future framework. Rather, they are meant to illustrate a range of possible approaches in order to better understand their relative merits.

The modeling is the latest in a series of analyses building on the core finding of our Climate Dialogue at Pocantico [3]: engaging all the major economies in an effective post-2012 climate effort requires a flexible framework allowing countries to take on different types of commitments. The six policy scenarios modeled represent different combinations of:

• Economy-wide emissions targets (absolute, intensity-based, and “no lose”);
• Policy-based commitments (national policy packages including measures such as efficiency standards or sectoral intensity targets);
• Sectoral agreements (uniform or differentiated standards applied to a given sector in all countries); and
• Funding commitments to support adaptation and technology deployment in developing countries.

The specific configurations of the six scenarios are described in the presentation [1].

The analysis compares the projected emissions, economic, and technology impacts of the six scenarios to a “business-as-usual” reference scenario, and to idealized “economically efficient” emission pathways for achieving CO₂ concentrations of 450, 550, and 650 ppmv. (There is no prescribed environmental outcome in the six policy scenarios; the aim was for all to achieve outcomes in the range of 450-600 ppmv.)

Preliminary insights from the analysis include the following:

• Environmental Effectiveness – A range of policy mixes can deliver near- and medium-term emission reductions consistent with achieving a reasonable long-term environment outcome – provided they are stringent enough. The particular policy sets prescribed in these scenarios result in CO₂ concentrations in 2100 in the range of 550 ppm. However, if the policies described were to be made more stringent, any of these architectural frameworks could produce stronger environmental outcomes.
• Equity – A range of policy mixes can produce a reasonable distribution of costs. In scenarios with full global emissions trading, mitigation costs are redistributed through trading, and targets can be differentiated to achieve a desired distribution of costs. However, a reasonable distribution of costs also can be achieved in scenarios in which only some regions have economy-wide targets and others participate through other types of commitments.
• Economic Efficiency – Over the long term, emission reduction efforts will be more economically efficient if a regime transitions to full coverage of emissions and to full global emissions trading. In the nearer term, scenarios employing policies other than economy-wide targets diverge from the idealized “efficient” emissions pathway to a greater or lesser degree, depending on the specific policies assumed. One question that emerges is whether allowing a range of commitment types at this stage – and, in so doing, sacrificing some economic efficiency – is a reasonable tradeoff to deliver the effort, equity, and broad participation needed to put economies on track toward meeting the long-term objective of preventing dangerous climate change.

Another round of modeling based on revised policy scenarios is planned, with a final report expected in late 2008.

Previous work building on the Climate Dialogue at Pocantico [3] includes:

Adaptation to Climate Change: International Policy Options [4]
Policy-Based Commitments in a Post-2012 Climate Framework [5]
International Sectoral Agreements in a Post-2012 Climate Framework [6]
Towards an Integrated Multi-track Climate Framework [7]

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