Today more than 50 newspapers in over 40 countries are taking the unprecedented step of speaking with one voice through a common editorial. We do so because humanity faces a profound emergency. Unless we combine to take decisive action, climate change will ravage our planet, and with it our prosperity and security. The dangers have been becoming apparent for a generation. Now the facts have started to speak: 11 of the past 14 years have been the warmest on record, the Arctic icecap is melting and last year’s inflamed oil and food prices provide a foretaste of future havoc. In scientific journals, the question is no longer whether humans are to blame but how little time we have left to limit the damage. Yet so far the world’s response has been feeble and half-hearted. Climate change has been caused over centuries, has consequences that will endure for all time and the fight against it has come down to the next 14 days. We call on the representatives of the 192 countries gathered in Copenhagen not to hesitate, not to fall into dispute, not to blame each other but to seize opportunity from the greatest modern failure of politics. This should not be a fight between the rich world and the poor world or between East and West. Climate change affects everyone and must be solved by everyone. Our leaders must signal to citizens that our way of life needs to change, and ensure this happens. The science is complex but the facts are clear. The world needs to take steps to limit temperature rises to 2C by 2100, an aim that science suggests will require global emissions to peak and begin falling within the next 5-10 years. A bigger rise of 3-4C – the smallest increase we can prudently expect to follow inaction – would dry continents, turning farmland into desert. Half of all species could become extinct, untold millions of people would be displaced, whole nations drowned by the sea. No one believes that Copenhagen can any longer produce a fully polished treaty. Real progress toward one could only begin with the arrival of President Obama in the White House and the reversal of years of US obstructionism. Even now the world finds itself at the mercy of US domestic politics, for the president cannot fully commit to the action required until the US Congress has done so. But the politicians in Copenhagen can and must agree upon the essential elements of a fair and effective deal. At its heart must be a settlement between the rich world and the developing world of how the burden of fighting climate change will be divided – and how we will share a newly precious resource: the trillion or so tons of carbon that we can emit before the mercury rises to dangerous levels. Rich nations like to point to the arithmetic truth that there can be no solution until developing giants, such as China, make more radical steps than those they have taken so far. But the rich world is responsible for most of the accumulated carbon burden – three-quarters of all carbon dioxide emitted since 1850. It must now take a lead and every developed country must commit to specific and significant cuts that together will reduce rich world emissions within a decade to 25 percent less than their 1990 level. Developing countries can point out they did not cause the bulk of the problem, and also that the poorest regions of the world will be hardest hit. But they must accept that in the future they will increasingly contribute to warming and thus pledge meaningful and quantifiable action of their own. Though both fell short of what some had hoped for, the recent commitments to emissions targets by the world’s biggest polluters, the United States and China, were important steps in the right direction. Social justice also demands that the industrialized world will need to dig deep into its pockets and pledge additional development assistance – in the form of technology as well as cash – to help poorer countries clean up their economies and adapt to climate change. The architecture of a future treaty must also be pinned down – with rigorous multilateral monitoring, fair rewards for protecting forests and the credible assessment of «exported emissions» so that the burden can eventually be more fairly shared between those who produce polluting products and those who consume them. Although no European state expects a free ride, newer EU members, often much poorer than «old Europe,» must not suffer more than their richer partners. The transformation will be costly but many times less than the bill for bailing out global finance – and far less costly than the consequences of doing nothing. Many of us, particularly in the developed world, will have to change our lifestyles. The era of flights that cost less than the taxi ride to the airport is drawing to a close. We will have to shop, eat and travel more intelligently. We will have to pay more for our energy and use less of it. But the shift to a low-carbon society holds out the prospect of more opportunity than sacrifice. Already some countries have recognized that embracing the transformation can bring growth, jobs and better-quality lives. The flow of capital tells its own story: Last year for the first time more was invested in renewable forms of energy than producing electricity from fossil fuels. Kicking our carbon habit within a few short decades will require a feat of engineering and innovation to match anything in our history. But whereas putting a man on the moon or splitting the atom were born of conflict and competition, the coming carbon race must be driven by a collaborative effort to achieve collective salvation. Overcoming climate change will take a triumph of optimism over pessimism, of vision over short-sightedness, of what Abraham Lincoln called «the better angels of our nature.» It is in that spirit that so many newspapers from around the world have united behind this editorial. If we, with such different national and political perspectives, can agree on what must be done, then surely our leaders can, too. The politicians in Copenhagen have the power to shape history’s judgement on this generation: one that saw a challenge and rose to it or one so stupid that we saw calamity coming but did nothing to avert it. We implore them to make the right choice.