Representatives of virtually every country in the world are meeting on the Indonesian island of Bali for two weeks of negotiations on a vital challenge that is starting to affect us all: climate change. The European Union will be exercising its global leadership role to press for strong action. The UN climate conference in Bali is crucial because time is rapidly running out to prevent global warming from reaching dangerous levels that could redraw the face of the planet and devastate our economies in the coming decades. The alarming scientific assessment completed in mid-November by the UN's Intergovernmental Panel on Climate Change (IPCC) concludes that climate change is "unequivocal" and accelerating. All its scenarios project a further rise in temperatures this century that would take us into the danger zone where the risk of irreversible and potentially catastrophic changes in the global environment greatly increases. It is our generation's historic responsibility to prevent this from happening. I believe this is also the clear message the Nobel committee wanted to give in awarding this year's Peace Prize to the IPCC and former US vice-president Al Gore. Yet as things stand today, the current targets for industrialized countries to reduce their emissions of greenhouse gases, established under the Kyoto Protocol, will expire at the end of 2012 with nothing to follow them. The international community has to move urgently to plug this gap. That is why the European Union is adamant that the Bali conference must decide to launch negotiations on a comprehensive and ambitious global climate agreement for the post-2012 era. We need to set a deadline for completing these negotiations by the end of 2009 so there is enough time to ratify the agreement and bring it into force before the end of 2012. And we must define a "Bali Road map" for the negotiations that sets out the level of ambition we are aiming for and the main components of the future agreement. FOR THE EU there is no question that the ambition must be to limit global warming to no more than 2Â°C (3.6Â°F) above the pre-industrial temperature. This is the level beyond which the scientists warn us that climate change would become very dangerous. Keeping within this limit means that global emissions will have to peak within the next 10 to 15 years and then be cut by at least 50% of 1990 levels by 2050. Achieving these reductions is without doubt a huge challenge, but the IPCC supports the European Commission's analysis that it is both technologically feasible and economically affordable if we act fast. The move to a low-carbon global economy also opens up enormous opportunities for innovation that can boost economic growth and job creation. One of the key components of a future climate agreement has to be deep, mandatory emissions reductions by developed countries. The European Union is proposing that developed countries commit to cut their collective emissions 30% by 2020, compared with 1990 levels, and 60 to 80% by 2050. Europe is ready to give this commitment provided that other developed countries agree to make comparable efforts during the forthcoming negotiations. In the meantime the European Union has already given an independent commitment to cut its emissions by at least 20% of 1990 levels by 2020, whatever others do. It is clear that the developed countries have the moral duty to lead the way in cutting emissions. But if we are to succeed in keeping global warming below 2Â°C, it will also be essential for other nations - and particularly the rapidly emerging economies - to contribute to the global effort. We have to find ways to help them limit the emissions intensity of their economic growth through a broad set of approaches including incentives and technology cooperation. The Bali conference will be a crucial test of the international community's political will to translate our new scientific knowledge from the IPCC's assessment into policy action. I am pleased to say there are some encouraging signs. Considerable political momentum has been built up this year through events such as the G8 summit and Ban Ki-moon's high-level meeting on climate change in September. The United States has said it no longer opposes starting negotiations. Australia's new prime minister pledged that his government would make the fight against climate change a priority and ratify the Kyoto Protocol. I very much welcome his constructive new approach. None of this means Bali will be an easy meeting, but I am cautiously optimistic that we will soon be able to start negotiating a new global climate agreement. That is when the real work will start. We face two very busy years ahead. The European Union will be doing all in its power to ensure global action after 2012 is ambitious enough to bring climate change under control before it is too late. The writer is the European Commissioner for Environment.