It may well be we need to bring forward the net zero date from 2050.
Ed Miliband has insisted the government must show leadership on climate change action and not just on setting targets.
The Labour former energy secretary welcomed moves by the UK to aim to cut emissions to "net zero" by 2050, with legislation to guarantee this target in law.
But he cautioned the government must back this up with the right policies, including bringing forward the date to phase out new petrol and diesel vehicles.
Speaking in the Commons, Mr Miliband also welcomed the five-year review mechanism before adding: "It may well be we need to bring forward the net zero date from 2050. That may well not be the original intention of the review mechanism but it may be necessary.
"Can I, however, ask the Secretary of State to recognise that in its advice the Climate Change Committee said very specifically that as well as setting the target itself, the government must put in place the policies to meet the target.
"That means, as they said, a 2030 cut-off date for new petrol and diesel vehicles - not 2040. A proper decarbonisation plan for our 27 million homes, which we don't have.
"And an end to what I believe is now economically illiterate, which is a moratorium on onshore wind given it is now our cheapest fuel available. So can the secretary of state assure us that henceforth that there'll be leadership not just on targets but also on action?"
Business Secretary Greg Clark, in his reply, said: "We are not credited simply with leadership in terms of legislation and targets but with achievements.
"We are, of the major industrialised countries, the world's leader in decarbonising our economy at the same time as growing that economy, and that is something that I think we should be proud of."
Lib Dem climate change spokeswoman Wera Hobhouse said: "The Liberal Democrats are setting out more ambitious targets to achieve net zero greenhouse gas emissions by 2045, together with clear interim targets to make sure we don't kick the can down the road."
She added: "Today's announcement is somewhat in contradiction with other Government policies on, for example, fracking, fossil fuel, and withdrawal from the European Union, which undermines international cooperation."
Mr Clark said he was "disappointed" with Ms Hobhouse's remarks, and said the timetable of reaching net zero by 2050 is correct for the UK. He said it is "always possible" to review this progress and said in five years' time, there will be an assessment of the progress made so far.
Plaid Cymru MP Ben Lake (Ceredigion) asked Mr Clark whether the Government would review policies on fracking and fossil fuels to make sure they comply with the emissions targets.
Mr Clark replied: "The Climate Change Committee that advises not just the House, but the country on this, do recognise that there will be the need for a transition and gas and oil will be required in that.
"In that context, and recognising the jobs that are generated by them and the exports that are generated by them, it seems to me we should do that as efficiently and with the best deployment of technology as we possibly can."
Former Green party leader Caroline Lucas said: "The committee recommended that the emission reduction effort needs to be done here at home, not outsourced to poorer countries.
"Carbon offsetting basically slows decarbonisation, it deprives poorer countries of the low-hanging fruit that they need in order to meet their own reduction targets. Will you review the decision to rely on dodgy loopholes and make sure that the domestic action is all done here at home?"
Mr Clark replied: "The Climate Change Act includes the use of credits, that was part of the legislation passed, and the Climate Change Committee have not recommended that we should repeal that part of the act, that is not their recommendation, just that we should not aim to make use of them.
"And we agree with their recommendation, we support it, we accept it, we agree with it precisely, so we won't be making use of them."
Richard Wheeler and Josh Thomas are members of the political staff of the Press Association.