Why is the government drifting so far from its green pledges?

In 2006, as director of Friends of the Earth, I shared a platform with David Cameron. We issued a joint call for new legislation on climate change. The Conservative leader was passionate and knowledgeable. I believed then that he was sincere in advocating moves toward a greener future.

In 2008 the Climate Change Act was duly passed and it seemed that cross-party momentum for environmental action was unstoppable, no matter who was in power. On 14 May, a few days after the 2010 general election, David Cameron announced that he wanted the coalition to be the "greenest government ever". At that moment he also committed to reducing the government's own emissions by 10% within a year. That target was met and exceeded, but good news in progress towards the bolder aim has been very scarce.

Support for renewable energy has been reduced, the Sustainable Development Commission has been scrapped while the environment department suffered the deepest cuts in Whitehall. The natural environment white paper was good on words but short on actions and resources. The planning system and its decades-long process of honing finely tuned checks and balances that enable more sustainable development is under attack. As if to create the impression that these and other decisions not only demonstrate an indifference to environmental goals but outright hostility toward them, the Department for Transport is proposing to increase the motorway speed limit to 80 miles per hour.

At this rate, and with three and a half years to go, the coalition is not on course to be the greenest government ever. So why are we drifting so far off course, despite David Cameron's leadership signals? To whom must we look to take us in a better direction?

In recent months there has been a distinct 1980s feel to ministerial pronouncements on environmental goals, especially from George Osborne. His narrative that green policies are a drag on business and an alternative to economic recovery portrays a deep misunderstanding of where the debate is now at, including among business leaders. Many companies say they want clearer long-term frameworks from government, and know very well that environmental challenges could lead to greater economic risks in future. Many of them look to China, where the foundations are being laid for an eco-transformation that will deliver considerable competitive advantages, for example in renewable energy markets. Osborne's out-dated agenda has been bolstered by populist Daily Mail-style rhetoric from Eric Pickles.

There is also a question over the role of Nick Clegg. He is the senior figure with the strongest mandate in British politics to champion the green agenda, but has remained almost silent. His MPs know very well that a big proportion of their votes came from green-thinking people, who believed that among the main Westminster parties the Liberal Democrats had real passion and understanding.

Ed Miliband also needs to ask himself some questions. Where is the right focal point for the progressive left? Surely his narrative should be about how we can get the jobs and economic opportunities that lie in clean, renewable and more efficient technologies? He too says very little, provides no clear leadership or strong opposition policies.

It seems to me that several people need up their game (Clegg and Ed Miliband included), some need to be brought up to date with reality (Osborne and Pickles) while others who show leadership need to be given more space and support to do what is needed (for example Greg Barker and Chris Huhne in the Department for Energy and Climate Change). All of the above can be assisted through the delivery of clear leadership – and that needs to come from Cameron, assisted by key cabinet figures, especially Oliver Letwin. In order to connect a reinvigorated green agenda with the public, some high profile initiatives are needed, including on the global stage and on issues that people support. An ambitious intervention on rainforests would be good for that.

The world is getting into deep trouble. The symptoms are seen in rising greenhouse gas concentrations, deforestation, species extinction and the depletion of natural resources. As nature continues to decline, the collective human impact on the Earth only grows. This is not a good place to be. And while the economic crisis is serious, the prime minister, coalition and opposition must be reminded that nature does not do bailouts, and to behave as if they understand that basic reality.