The government yesterday appeared to undertake something of a u-turn, announcing amendments to its climate change bill that would see it publish an " annual indicative range" for emissions as part of its five year carbon budget.

The government has repeatedly resisted calls for annual emission targets, arguing they would hamper its ability to cope with adverse weather or economic conditions and insisting that five year carbon budgets offered a more flexible means of ensuring the long term goal of cutting emissions by 60 per cent by 2050 is met.

But in amendments to the bill tabled yesterday Defra has adopted a compromise position that will see the new independent climate change committee set annual indicative ranges for emission levels, designed to help ensure the government is on track to meet its five year targets.

A spokesman for Defra said that the annual target ranges would not be legally binding, but would provide greater reassurances that the government is on track with its efforts to cut emissions. "It still doesn't make sense to have annual targets as the weather plays a big role in determining emission levels," he said. "But having annual ranges means that if we find that we are missing them we can take measures to rectify the problem."

He added that the climate change committee would use a "transparent formula" to calculate the ranges and that it would set the ranges on a year-by-year basis.

The move raises the prospect of the government having to crank up emission reduction measures and legislation in the immediate aftermath of a year where adverse weather conditions or an unexpected spike in economic activity results in higher than anticipated carbon emissions.

The amendments also give the climate change committee a statutory duty to assess the long term emission reduction target on an annual basis. The committee has already been tasked with analysing whether the 60 per cent target should be increased to 80 per cent and whether international shipping and aviation should be included in the calculations.

Environment Secretary Hilary Benn said that annual checks were required to keep pace with the changing scientific consensus. "The scientific evidence has moved rapidly, and as part of a new global climate deal, developed countries may have to cut their emissions by as much as 80 per cent by 2050," he said. " That's why we announced a review of the UK target last year. This review will now be a statutory duty, and I've asked the Committee to provide their advice on both the 2050 target and on the first three carbon budgets by 1 December this year."

The proposed changes were welcomed by Friends of the Earth, which had been campaigning for the government to adopt annual emission targets as part of the new law. "The findings of this review have brought us one step closer to a stronger and more effective climate law," said Friends of the Earth's Martyn Williams.