A shared understanding of long-term goals must be at the centre of international frameworks to support large reductions in greenhouse gas emissions reductions around the world.
A broadly similar price of carbon is necessary to keep down the overall costs of making these reductions, and can be created through tax, trading or regulation. Creating a transparent and comparable carbon price signal around the world is an urgent challenge for international collective action.
Securing broad-based and sustained co-operation requires an equitable distribution of effort across both developed and developing countries. There is no single formula that captures all dimensions of equity, but calculations based on income, per capita emissions and historic responsibility all point to developed countries taking responsibility for emissions reductions of at least 60% from 1990 levels by 2050.
The Kyoto Protocol has established valuable institutions to underpin international emissions trading. There are strong reasons to build on and learn from this approach. There are also opportunities to use the UNFCCC dialogue and the review of the effectiveness of the Kyoto Protocol to explore ways to improve.
Private sector trading schemes are now at the heart of international flows of carbon finance. Linking and expanding regional and sectoral emissions trading schemes, including sub-national and voluntary schemes, requires greater international co-operation and the development of appropriate new institutional arrangements.
Common but differentiated responsibilities should be reflected in future international frameworks, including through a greater range of commitments and multi-stage approaches.