After the failure of the Copenhagen conference to produce a clear vision of climate policy many stakeholders in the energy, environment and financial fields are uncertain about the future of carbon emission trading.

Cap and trade legislation has become stalled in the US Senate, and the White House has tried to move climate legislation forward. But it has become such a tender issue that proponents have started using a new term: pollution reduction.

The climate bill that passed the US House would set the stage for a market in which cleaner firms sell credits to dirtier firms. The logic is that carbon emissions overall would be lowered without requiring expensive retooling. A managing director of Warburg Pincus said the value of the market could range from $3 trillion to $13 trillion.