If crucial climate negotiations later this year in Copenhagen are to have any chance of success, the US must take the lead, write Michael Northrop and David Sassoon from Yale Environment 360 , part of the Guardian Environment Network

President Obama will face one of the most important moments of his presidency this year on Dec. 18, and he needs his entire cabinet to help him prepare for it over the next 11 months. Dec. 18 is the final day of the global climate meetings in Copenhagen, a day that will signify whether the world community has finally mustered the will to rein in soaring greenhouse gas emissions. That fixed date, combined with escalating scientific urgency and unparalleled political opportunity, make 2009 the do-or-die year for comprehensive federal climate action.

Rajendra Pachauri, chairman of the Nobel Prize-winning Intergovernmental Panel on Climate Change, says that emissions must be stabilized by 2015 and in decline by 2020. Science, in its rightful place, can tolerate no further delay. For Obama, the political winds at his back are now as favorable as they will ever be. He is in a position to seize 2009 and do three things to meet the climate challenge: properly educate the American public about climate change and the need for immediate action; exercise the full might of his executive powers and regulatory discretion under the Clean Air Act to jump-start action; and spend freely from his enormous store of political capital to lead the government to enact comprehensive federal climate legislation. If he does, the United States will reclaim the mantle of global leadership when it takes its seat in Copenhagen.

After eight years of U.S. inaction on climate change, American leadership offers the only hope of success. Even if President Obama himself decides to attend the talks — and hopefully he will — his mission will fail unless he carries with him a year's worth of demonstrated results to lend weight and credibility to the promise he made in his inaugural address to "roll back the specter of a warming planet." In Copenhagen, his inspiring oratory alone will not be sufficient; he must demonstrate how science has been restored "to its rightful place" in America in strong climate regulation and law.

For almost a decade, Americans have been purposefully led astray about the reality of global warming and about the positive relationship that exists between sustainable economic prosperity and environmental stewardship. The new president must use the bully pulpit of his office to provide quick and remedial education.

Obama has well chosen his scientific team in John Holdren, the White House science adviser; Jane Lubchenco, the head of the National Oceanic and Atmospheric Administration; and Energy Secretary Steven Chu, and he should empower them and other government scientists to speak loudly, unequivocally, and frequently to the American public about the true science of climate change and the urgency of our present circumstances. The latest science only underscores the need for immediate action, given the acceleration of global ice melt, extreme weather events, dangerous feedback loops, and potentially irreversible changes.

The president must also instruct his cabinet to clarify the impact of global climate change on each of their respective portfolios. Global warming has been crammed into a "green" box for the sake of political expediency. Instead, it must be appreciated for its cross-cutting immensity — it is fundamental to national security, global commerce, economic recovery, energy security, public health and safety, agricultural policy, land-use planning, and environmental protection.

Obama must also make a prime-time, televised address to the nation about the climate crisis and the need for immediate action and U.S. global leadership. Such a speech would send a clear signal to the American public and the political establishment and prepare them to come together with the nations of the world in Copenhagen to meet this grave challenge.

Simultaneously, the president must travel to Copenhagen with real regulatory and legislative achievements. Signs are good that Obama genuinely means business. He is talking frequently about energy and climate change, and his economic recovery package makes important commitments toward green jobs, clean energy, and energy efficiency — $54 billion worth. This is more than a third of the $150 billion he promised over the next 10 years for clean energy investments, so if the package survives its passage through Congress, he will be ahead of schedule on that score. By itself, though, this investment inside a trillion dollar package merely colors the economic recovery with a pale green hue. It is not an energy and climate plan, and Obama will still face heavy regulatory and legislative lifting to turn promise into reality before Copenhagen.

Expectations are high that he will exercise the executive authority he already has under the Clean Air Act to achieve some quick victories and put pressure on Congress to act boldly. With former EPA chief Carol Browner heading up his climate team in the White House, Obama has tapped the talent he needs to implement a powerful regulatory strategy. As expected, the EPA's first order of climate business is already moving forward: granting a long-delayed waiver to California to allow the state to impose more stringent auto emissions rules, which 13 other states are poised to adopt as well. Manufacturers will soon have to deliver higher mileage vehicles on an accelerated schedule. By approving the waiver after a formal review process, EPA administrator Lisa Jackson will guarantee steep future emissions reductions from the transportation sector, and allow the thorny bailout of Detroit to proceed without any doubt as to where the industry must head, despite currently low fuel prices.

The boldness of Obama's regulatory strategy, however, really hinges upon the fate of coal-burning power plants under the Clean Air Act. Since the Supreme Court affirmed in Massachusetts v. EPA that carbon dioxide could be regulated as a pollutant under the law, it has become an open question as to how existing coal plants and permits for new ones will now fare under the act. The EPA plainly has the right to control CO2 emissions, and the real issue is how aggressively the law will be applied. In the short term, the question of coal rests largely in Obama's hands, and he has the authority to stop new dirty coal plants cold. He proved it his first week in office when the EPA revoked an air permit for the Big Stone II coal plant in South Dakota, pending further review.

If that first signal gets amplified, it will certainly change the tone of what happens with coal in Congress longer-term, where powerful lobbies have held science at bay. The president's executive action on coal will invigorate Copenhagen and bring seriousness to bilateral discussions with China, the world's coal juggernaut. At his direction, the Clean Air Act can jump-start climate action by speeding aggressive federal standards for building and appliance efficiency and placing limits on other carbon-intensive sources of pollution — steel mills, cement plants, other heavy industries, and shipping.

Coming to Copenhagen with the necessary legislative accomplishments — in addition to regulatory ones — will be harder still, but it is essential to Obama's success. The proposed economic recovery package has been disappointing to advocates of public transit, light rail, and smart growth, with sparse dollars allocated to those needs. But with the federal Transportation Bill up for reauthorization in 2009, Obama has another chance to redirect land use away from highway sprawl and in a low-carbon, mass-transit direction. The administration should also strengthen energy efficiency incentives and clean energy tax credits, adopt a mandatory federal renewable energy target, and increase investment in a clean energy grid.

To secure his crowning achievement, Obama must expend political capital in Congress and work with leaders there to complete passage of science-based federal legislation capping greenhouse gas emissions. The legislation must be signed into law this year, as delay into 2010 will wreck it on the shoals of mid-term elections, a time when political courage disappears. There will not be another political opportunity as ripe as now; nor will there be another financial context more sensitive to a strong new signal. As the global economy starts to rise from collapse, it must do so with a price on carbon as part of its cure.

There is considerable debate about the form which a cap and a price signal should take — in recent weeks a carbon tax has even been a topic of renewed discussion. None of the options is perfect, but one of them is rising as a preferred choice because it protects low-and middle-income families from rising energy prices. It's called "cap-and-dividend." Under this program, permits to pollute the air with greenhouse gases would be auctioned and the proceeds returned to citizens. The extra income, which should be targeted especially to the poor, will protect the most vulnerable American families from rising energy prices and will help build a long-term constituency for climate action. In the present economic crisis, the prospect of sending monthly dividend checks to families is a political winner. It makes a cap-and-dividend plan largely immune from criticism that it will be costly to the public, and it increases the chances of passage this year.

Many believe it may be necessary to reserve some portion of the auction revenues for investments in clean energy programs at home and in adaptation and technology transfers abroad. Whether the allocations should be shared and what the right ratios ought to be will be the subject of intense political negotiation on Capitol Hill.

Still, cap-and-dividend provides the best point of departure because it creates a fundamental break with business-as-usual. It establishes a new, winning, cognitive frame of reference: the democratic principle that an equal share of the sky belongs to each person. Indeed, Peter Barnes, who originally formulated this concept and has championed it tirelessly, began by asking a simple question: Who owns the sky?

Without a price signal, nobody does, and global warming pollution will proceed essentially unchecked. With cap-and-dividend, everybody owns the sky and the emissions cap then becomes universally comprehensible as it begins to turn us toward a low-carbon future.

This American accomplishment, brought by President Obama to Copenhagen along with other concrete actions, would set the stage for passage of a comprehensive international treaty to slow global warming. Now is the year for President Obama to act, while the window of opportunity is wide open.

• This article was shared by our content partner Yale Environment 360, part of the Guardian Environment Network