Last May, David Cameron promised the coalition would be the “greenest government ever”. This year environmentguardian.co.uk is going to track his progress.

The current rating on the green-o-meter is a light-hearted attempt to track the serious matter of how the coalition is faring. It assesses the government’s delivery on all aspects of the environment, from climate change, wildlife and conservation to energy efficiency, transport and renewable power, as covered by the stories below.

Swing history

30 November: Damian Carrington, head of environment, writes: Greg Barker, minister at the department of energy and climate change, defends the government’s green record, saying it is “underpromising and overdelivering”. What he is arguing is that policies are being delivered – e.g. Green deal, Green investment bank – but they are not shouting about them. But words matter. Transforming a nation to a sustainable, secure, low-carbon economy needs leadership from the very top to give investors the confidence needed to commit the huge sums needed. That means chancellor George Osborne’s stunningly contemptuous attack on green action in his Autumn statement were fatal for the ambition to be the greenest government ever. So the green-o-meter plunges to a new low: 1.5.

24 November: Damian Carrington, head of environment, writes: The government has finally got its Green Deal out the door. This ambitious plan to refurbish 14m homes to make them more energy efficient is much needed to keep bills and carbon emissions down, though a successful roll out is challenging. Chris Huhne also came out fighting on the effect of his policies on energy bills: they will curb the inevitable increases. On the negative side, the necessary but bungled reform of the solar power subsidies has really dented confidence across the renewable industry. On balance, half a point up, to 2.5.

21 October 2011: Damian Carrington, head of environment, writes: David Cameron’s detoxifying pledge to be the greenest government ever is in mortal peril. The latest blows including cuts to support for clean, sustainable energy and the collapse of the UK’s only bidder for £1bn to build the UK’s first carbon capture and storage demonstration plant.

5 October 2011: Damian Carrington, head of environment, writes: Bong! Down the green-o-meter plunges, from 3.5 to 2.5. Why? Principally because of the low-carbon clanger the Chancellor George Osborne dropped at the Conservative party conference, wrongly blaming green taxes for soaring energy costs and backing away from UK climate leadership. David Cameron’s speech gave only the most cursory, passing mention to green policies. The ludicrous pledge to raise the motorway speed limit to 80mph and the unnecessary squandering of £250m on bring back some weekly bin collections were also negative marks, as was the bungle over the renewable heat incentive. I attended all four political party conferences – yes the Greens in Sheffield too. Green issues were relatively low key at all of them, though Labour’s pledge to break the big six energy companies’ “stranglehold” was a rare standout idea. However, only the Conservatives appeared to be actively moving away from green issues. Despite the energy and climate change ministers continuing to push forward big policies, the environment department remains feeble. But it is the change of tone from the two men running the world’s sixth biggest economy that matters. You don’t become the greenest government ever by telling people the nation’s green ambition is to be mediocre.

13 July 2011: Damian Carrington writes: The UK’s electricity system has started on the road to major reform. It’s a huge step forward from the free-for-all market we have now, which kept prices down for a while, but utterly failed to invest in the future. Chris Huhne’s plan is not as strong as it needs to be on renewables and cutting energy use – that’s less pressing if you have bet much of your money on nuclear, as Decc have. There’s also a lot of detail to work out. All in all, up goes the green-o-meter to 3.5.

6 July 2011: Damian Carrington writes: The UK government not only met its 10:10 campaign pledge to cut the carbon emissions from its own operations by 10% in a year, it achieved a cut of 14% and promised a 25% cut by 2015. That’s real action and leading from the front. Up goes the green-o-meter to 3.0.

14 June 2011: It could have been a double whammy for the environment department, with two flagship policies arriving within a week: the natural environment white paper and the national waste review. Both laudably aimed to redefine attitudes, to valuing the natural world and dumping rubbish, respectively. But, concluded, Damian Carrington, neither delivered. Back down to a below-par 2.5.

23 May 2011: Another cabinet battle, another green win. Nick Clegg announces the details of the green investment bank, revealing a strong, independent bank with £3bn guaranteed for starters. The GIB can still only borrow from 2015, but overall the news suggests supporters of the green economy are defeating the “dark forces” of the old economy in the Treasury. It’s enough to push the green-o-meter up from 2.5 to 3.0.

17 May 2011: After a cabinet battle, prime minister David Cameron committed the UK government to accepting official advice to set an ambitious and legally binding target for the 2020s, equivalent to a 50% cut in greenhouse gas emissions by 2027. Damian Carrington wrote: “Winning that argument was a significant political victory. But in terms of green policy that will deliver an economy fit for an evermore crowded and consuming planet, it was only a disaster avoided. Nonetheless, with politics being the art of the possible, the green-o-meter moved up half a notch, to recognise a step in the right direction.”

23 March 2011: UK budget day was a green catastrophe, sending the green-o-meter plummeting to 2.0, an all time low. George Monbiot called it “the blackest budget in living memory, from the team that claims to be the greenest government ever.” Damian Carrington’s analysis of the green investment bank that can’t borrow, the boosts for motoring and flying and a feeble carbon floor price, concludes: “There was a golden chance to use the wreckage of the recession to build a greener, cleaner and more sustainable economy, creating jobs and tackling climate change. But when it mattered, the old politics and the old economics won.”

11 March 2011: The green-o-meter moved up another notch to 3.5, following the government’s ‘green week’, which delivered £860m for clean, green heating, continued promises to cut the government’s own emissions and pumped up the pressure on other departments to accelerate the green agenda.

17 February 2011: We moved the green-o-meter up from 2.5 to 3, off the back of David Cameron’s u-turn on the forest sell-off in England, despite recent news of a 40% cut to the Carbon Trust’s budget.

31 January 2011: We moved the green-o-meter down from 3 to 2.5, because of the detail contained in the government’s forest consultation and news that the Energy Saving Trust is to have its funding cut by half.

18 January 2011: We moved the green-o-meter down from 3.5 to 3, following John Vidal’s expose of government spinning on the state of UK wildlife and nature reserves and reader feedback on Damian Carrington’s blog.