Ed Miliband, Secretary of State for Energy and Climate Change, writes that after the success of the London Summit, the target must now be the first truly global deal to stop climate change by the end of the year.

Momentum is the most precious commodity. When the G20 met in London it provided not just substantive commitments but a road to Copenhagen and a global deal.

Momentum came from a point of principle: even in a summit on the economy, the environment cannot be left out. This was made explicit in the communiqué, with building a green and sustainable economy made one of the six core commitments of economic recovery. Countries agreed to 'make the best possible use of investment funded by fiscal stimulus programmes towards the goal of building a resilient, sustainable and green recovery.'

Momentum came, too, from the recognition that a low carbon recovery is not just a way of preventing disaster ten or 20 years in the future; it is also an opportunity now. It is not a gospel of austerity, but prosperity. The move towards a low carbon economy can both boost demand and create jobs. Win-win options like improving energy efficiency can save families and businesses money at a time when budgets are increasingly tight. To help live up to that not just in the G20 countries but elsewhere as well, they asked the multilateral development banks to support developing countries as they move towards lower carbon economies.  

But above all there was an explicit commitment, and the first collective commitment from all the major countries, to find a deal. The world meets in Copenhagen this December to find a replacement to the Kyoto Treaty. With the US now firmly committed to getting a deal, we can feel for the first time that a strong deal is possible. The US has re-formed a dedicated group, the Major Economies Forum on Energy and Climate, and the sense of build-up for Copenhagen is palpable.

Outside the London Summit conference centre, the Prince of Wales hosted an event on forestry with Presidents, Foreign Ministers including Hilary Clinton, and others. It recognised how important forests are for the future of the planet, and how important it is to act early.

Outside the elites, the weekend before the conference, tens of thousands of peaceful demonstrators travelled to London to show they believed in urgent action on climate change. I met leaders from faith groups, development groups and unions, forming a coalition that shows no one can now claim green is a fringe issue.

There are big issues we still need to resolve. Agreeing how money should flow from one nation to another, and for the whole shape of economies to be reformed, is a lot harder than agreeing that climate change needs action. Actually getting those economies to move towards low carbon, with all the investment and new rules that will be needed, is a harder task still. Britain has legally committed itself to an 80 per cent cut in emissions by 2050, and is introducing binding 'carbon budgets' to get us there; but the hard work takes place beneath that, as we improve our renewable energy supply, or undertake a Great British Refurb to stem the energy leakage from our homes.

There are big issues, but the last ten days brought the deal closer. If governments will it and citizens demand it, increasing the focus in the months from now to December, the first truly global deal to stop climate change can be found this year.