COPENHAGEN—Like all spellbinding human drama, the United Nations Climate Change Conference, which today entered its second and last week, represents the accumulated chapters of an urgent script.

But this time that script involves the fate of the planet.

Everybody in every corner of the world has a stake. Island nations, some of them starting to be swamped by rising seas, want huge cuts in climate warming gases to save increasingly fragile economies and cultures. Arid nations already challenged by deeper and longer droughts—from the Sahel of Africa to Australia—see action on the climate as essential to preserving their ability to produce enough food.

Rich nations see the advantage of a new clean energy economy that produces technology and jobs to achieve reductions in climate-changing emissions. And the small group of senators and representatives with outsize fury, expected to arrive here this week from the United States to contend there is no climate change at all, have staked their reputations on disrupting the momentum for meaningful action that is building here.

Still, seven days into the Copenhagen conference and with just five days to go, there is no clear consensus among negotiators or activists with NGO organizations about how this momentous drama will end.

The big narratives that are converging here break down like this. Developing nations seek large cuts in carbon emissions—30 to 45 percent from 1990 levels by 2020—and big investments by rich nations to finance their low carbon economies. The European Union has pledged somewhat smaller reductions in emissions targets by 2020: 20 percent below 1990 levels, and 30 percent if other wealthy nations reach agreement. The EU has indicated publicly that it is willing to spend $3 billion to $4 billion annually over the next few years to help developing nations, but it is unclear whether this is new money or simply redirected development aid.

Japan's new Prime Minister Yukio Hatoyama said earlier this year that his country's emission reduction target is 25 percent below 1990 levels and the country is willing to invest substantially in a global fund for developing nations.

But arguably the biggest story is what the rest of the world will do here with the clear positions made public by the United States.

Targets and Audiences
There are just two U.S. numbers that really make a difference.

The first is "in the range of 17 percent" below 2005 levels, which is how much carbon the Obama administration says it will agree to remove from U.S. emissions by 2020. The second is $1.4 billion annually, which is how much the United States indicates it is willing to contribute over the next few years to a global climate change fund for developing nations.

The president and his lead negotiators in Copenhagen, Todd Stern and Jonathan Pershing, have made clear there is not much room to move either number up. In order for the U.S. to stay in the final agreement, the climate pact must incorporate emissions and finance targets close to what the U.S. says it will accept.

Or is there wriggle room? This week the Energy Information Administration, a unit of the Department of the Energy is expected to announce that U.S. emissions dropped eight percent last year. Last week Environment America published a report that found state climate change policies alone will reduce greenhouse gas emissions by 536 million metric tons by 2020, about seven percent of United States 2007 emissions. The two studies could put pressure on the administration to increase its emissions pledge.

Though many nations and writers disagree, from the perspective of a journalist who's written extensively for years about environmental politics and economics, the American commitment to rolling back carbon emissions represents a momentous political achievement for the administration. If it happens here, and there is still no assurance that it will, it nevertheless would be the start of the U.S. transformation to a clean energy economy and a renewal of the country's traditional role at the head of the class as a leader in responding to a global environmental threat

Still, the U.S. commitment to reducing carbon "in the range of 17 percent" is nowhere close to what needs to be done, according to the science of warming. It's a start. And because of that, the pressure from developing nations may prompt the U.S. to commit to a bit larger target—say, 20 percent reductions below 2005 levels, the same target contained in a climate and clean energy proposal under consideration in the Senate. Or the United States can commit more money. But Obama aides have made clear the increases will not be much more.

On long-term targets, the proposed U.S. cut in emissions are 80 percent by 2050, which is consistent with what scientists say is necessary over the long run to keep global average temperatures below two degree Celsius.

The largely peaceful march on Saturday, attended by 60,000 to 100,000 people according to several estimates, is one more piece of the cultural and political saga that has unfolded here. While the global mainstream media focused on the 968 people who were detained by police, and barely noted that just 19 were held for investigation, the message of the march was received loud and clear inside the Bella Center. The world is calling for more aggressive action than the United States is close to considering.

There are other players in this drama that could alter how the U.S. approaches the conference's final day. While most of the attention here is focused on the emissions pledges of large developed countries, developing countries have pledged their own actions to reduce carbon. The Obama administration must be able to demonstrate to its domestic political opponents that U.S. climate action here will not put American industry at an economic disadvantage with the large emerging economies—most notably China.

So here is what the climactic moment is shaping up to be at the Copenhagen conference: whether the world will accept the U.S. targets. If the world insists that Obama bring more ambitious targets and greater financing, the U.S. has given every indication that it would not be able to accept this new agreement.

Charm Offensive
Obama and his aides have launched a focused message campaign here to avoid that possibility.

The administration established a U.S. Center, which has hosted cabinet secretaries and other top aides to talk about all that the United States is doing to combat climate change and accelerate the clean energy economy. Energy Secretary Steven Chu will be at the center on Monday. The Obama administration also is making it plain here in public and private conversations that the president is fighting a ferocious counterattack from the fossil fuel industry and the allies it has funded in the Senate and House.

The aim of the charm offensive is to help delegates and NGO staffers absorb the lessons from what President Obama has achieved this year—from enacting a recovery bill in February that contains $110 billion for clean energy practices and technology, to deciding this month to regulate carbon dioxide as a threat to health under the Clean Air Act.

If Obama is successful in making this case and leveraging his ample storehouse of global goodwill, the last chapter of the UN Climate Change Conference could also be the first scene of a new era in diplomacy, science and economics. The final chapter here could produce an international agreement that includes the United States and contains clear steps and a finance plan to cool the planet and heat up the global economy.