Soon after I left my role as an adviser to the UK government in 2005, I was interrupted whilst speaking on the need for new climate-change policies. “If you advocated these things in government for four years, how come none of them happened?”

It was a question that deserves a substantive answer. I have been working to secure action on climate change for over ten years, since 2005 as director of Green Alliance. Much of it has been hugely enjoyable. There have been many successes along the way. But the stark truth is that we’re failing. The collective efforts of all those working on climate change have so far delivered far less than the crisis demands.

There is currently no real prospect of action at the necessary scale and speed. Resurgence readers will not need reminding that we must do far better – starting now.

To give ourselves a high probability of limiting average global temperature rise to 2 ºC, global emissions must peak and decline in the next ten years. Yet the most recent IPCC projections predict an increase in global emissions of 25-90% between 2000 and 2030. Climate change poses a profound threat to the wellbeing of our planet and humanity.

To succeed in the struggle against climate change, we must build a movement for change that our political leaders cannot ignore.

The current debate on why we are failing is essentially about allocating blame. Pressure groups blame politicians for not introducing the policies needed to reduce emissions. Politicians justify their inaction by citing the lack of public support for those policies. In the margins of this exchange, most businesses quietly blame both sides.

The power to avert runaway climate change is held first and foremost by governments. This is a collective problem that will only be solved with decisive action by governments, who can use tax, regulation and spending to give businesses and individuals the incentives and opportunities they need to act.

But climate change is also an issue of personal responsibility. Each of us chooses in our homes, at work and in the choice of our holidays whether to live in a way that is compatible with the climate crisis. Far too few people currently choose to do so. But it is high time we moved beyond this blame game. The attitudes and actions of politicians and the public are deeply interlinked. Governments shape personal action. They can opt for renewable energy, or to sustain the fossil-fuel economy. They can feed the car culture, or make public transport the cheap choice for us all.

But the public, ultimately, determines the paths our leaders choose. The most critical role for individuals is not their behaviour, but their influence on governments. The UN Summit in Copenhagen needs to be seen in that context. The media, politicians and campaigners all described it as the defining moment in the struggle against climate change. But don’t believe the hype.

An ambitious and effective global agreement will simply make success possible. The struggle to avert catastrophic climate change will be determined by the actions of national governments over the next five to ten years. The history of the Kyoto Protocol demonstrates that the real challenge is implementation, not negotiation.

There is much that our leaders could do right now, of course. Some, notably Ed Miliband, show a much greater willingness to act. But I know from my own experience that there are deep structural reasons why governments do not deliver. Climate change is perhaps the most complex policy challenge national governments have ever faced. It demands action across the silos of government, and at global, national, regional and local level. It must provide opportunities and incentives for action by businesses, communities and individuals. This action must be secured despite the lobbying of vested interests, and the inertia of government.

The commitment of presidents, prime ministers and their ministers of finance will be critical to this. But our leaders will not acquire this commitment or overcome these vested interests and inertia without far greater demand from below. Levels of public concern, behaviour and above all demand for political action are currently too weak to overcome these obstacles.

This is not a counsel of despair. For many years, climate change was an issue highlighted by environmental groups. But this has changed rapidly recently. There has been an explosion of concern and action over the past two years among faith leaders, development groups, trade unions and grassroots initiatives such as Transition towns.

But we still need a far broader and deeper movement for change. Climate change is not ‘just’ an environmental issue. It profoundly threatens many other causes that others hold dear, from security to poverty, from community cohesion to health. New initiatives are under way among groups concerned with all of these issues, to articulate these links and bring them to public attention. Initiatives like this are critical to the prospects for political action on climate change.

The ‘third sector’ holds the key to success in the struggle against climate change. It is made up of the community groups, national membership organisations, trade unions, faith communities, social enterprises and co-operatives that provide people with collective opportunities to act. The third sector can provide the leadership we need to transform the politics of climate change and make it the primary issue of public concern. It can and must do so in four ways:

First, by mobilising a huge diverse network of groups concerned with issues from development and security to housing and health. Secondly, community and local leadership will enable people to come together to change their lifestyles and demand political action, as Transition towns and low-carbon villages have done. Thirdly, led by the environmental movement, it can create a highly visible movement of people living low-carbon lifestyles and setting an example to others. This could be brought together by a voluntary national personal carbon-trading scheme. Finally, international mobilisation could persuade national leaders to act consistently and ambitiously, as pressure groups make consistent and compelling demands for national action.

Climate change is not a problem of science, technology or economics. It is above all a problem of politics. We need politicians with the vision and commitment to make the low-carbon economy and society a reality.

But in the eyes of many people and their governments, climate change is still characterised as a second-tier ‘environmental’ issue, of far less concern than core economic, social and security priorities. This view is profoundly mistaken. But we need to develop new strategies if we are to secure the political action we need. Together, we must create the pressure needed to persuade governments to use their power to full effect.

Stephen Hale is Director of Green Alliance. He is the author of The New Politics of Climate Change.