An all party group of MP's has today issued a stark warning to the government that it must significantly strengthen its proposed climate change bill if it is to have any hope of tackling global warming.

The report from the Environmental Audit Committee – Beyond Stern: from the Climate Change Programme Review to the Draft Climate Change Bill – praises the concept behind the bill, arguing that regular carbon emission targets overseen by an independent committee would help focus governments on long- and short-term emission reduction strategies and depoliticise climate change policy.

However, it also heavily criticises the draft bill, claiming that the government targets of a 26 to 32 percent emission reduction by 2020 and a 60 percent reduction by 2050 are "clearly incoherent" with the current scientific consensus on how to mitigate climate change.

EAC chairman Tim Yeo said, "the 2020 and 2050 targets need to be significantly strengthened, in accordance with the latest science of where we need to be to limit global warming to 2oC".

Some scientific reports have argued that a reduction in emissions of 90 percent by 2030 is what is actually required as after temperatures reach two degrees above pre-industrial levels natural emission feed back loops will kick in that will make climate change all but irreversible.

The report further criticises the decision to set a target range for emission cuts, recommending that the goal of a 26 to 32 percent reduction in emissions should be changed to at least 32 percent.

The Committee also calls upon the government to include emissions from international aviation and shipping in the bill and argues that it should limit the extent to which businesses are allowed to buy in carbon credits from other countries to contribute to their emission reductions.

Environmentalists have long argued that allowing businesses to buy such credits provides them with an easy means of hitting emission reduction targets without making significant changes to their own processes.

The report recommends that the government should tackle this problem by adopting a code of practice for reporting UK emissions that clearly distinguishes "between reductions achieved within the UK and reductions funded by the UK but taking place abroad".

Finally, the report calls for greater involvement from the Treasury in developing climate change policy. "The 2006 Climate Change Programme Review successfully involved the joined-up work of officials from several different departments and external bodies," it argues. "But one major failure was the exclusion of fiscal policy, which remained the preserve of the Treasury. In the future, there must be an integrated approach to climate change policy-making, which considers the use of taxes and incentives alongside other measures."

Environment Secretary Hilary Benn defended the bill in its current form, arguing that it is the first of its kind in the world and that the government is committed to tackling emissions from the airline industry by including it in the EU's emissions trading scheme. He added that the 60 percent target was " ambitious by any standard" and that the target would remain "under review in the light of emerging scientific evidence and other developments".

The EAC's recommendations are likely to receive a mixed response from the business community, with the call for much more stringent targets and a clamp down on the market in foreign carbon credits offset by the prospect of improved incentives from the Treasury and greater transparency in the government's climate change plans.

It has also been argued by some experts, such as the Cambridge Programme for Industry's Craig Bennett, that stricter emissions targets now would be preferable to a situation where firms make long-term investments based on emission reduction targets of 32 percent by 2020 or 60 percent by 2050 only to find that these cuts are insufficient and deeper cuts are needed.