"The decisions you take today will determine whether Europe remains a world leader," Martin Schulz, president of the European Parliament, declared before the European Council as it decided how ambitious the continent should be in tackling the climate crisis.
With just over a year left for governments to reach a meaningful climate treaty, leadership is indeed up for grabs.
And Europe right now may have a greater right to the mantle of climate leadership than any other claimant.
Early on Friday, its heads of state, meeting in Brussels, unanimously endorsed a deal that includes a binding cut of at least 40 percent in greenhouse gas reductions by 2030, compared to 1990, along with somewhat less dramatic and non-binding goals for increasing energy efficiency and renewables.
But in light of the intricacies of Europe's convoluted governance that make any such agreement hard to strike, the broader import of this step was that it offers a glimmer of hope that a global carbon deal might not be such a farfetched idea.
To be sure, some wanted the targets to be made even more ambitious. Critics caution that because of the glut of carbon credits on the European market the 40 percent carbon cut goal is too easy to meet. They say more ambitious targets would more effectively cure Europe's addiction to natural gas imports, and would spur more job creation in the green energy sectors.
Samantha Smith, leader of the World Wildlife Fund's global climate initiative, said on twitter that the deal was "not ambitious, not climate leadership, not what we needed as the world warms."
But Europe's climate apparatchiks pronounced themselves satisfied.
"The agreement today keeps Europe firmly in the driving seat in the international climate talks ahead of the Paris Summit next year and the very close meeting in Lima [in December 2014]," said Jose Manuel Barroso, president of the EU Commission, which almost a year ago set forth the outlines of the arrangement the Council endorsed.
As Europe's representative at the United Nations climate summit in September, he said, "I can tell you how much this leadership by the European Union was awaited."
It is a sign of the times that few Americans, even among those who marched through Manhattan last month to demand climate action, are paying that much attention to what the Europeans decide.
But for anyone here who wants to see the climate problems solved, it's a good idea to tune in.
Whatever might be said about American exceptionalism, it is not an approach that has ever produced unambiguous climate leadership on this side of the Atlantic. And whatever China's ambitions, its ponderous turn away from coal-stoked growth hardly signals the arrival of a new great helmsman.
So it seems to be up to Europe. And as the continent's leaders assembled this week, there was some question whether they were all willing to have real leadership thrust upon them.
Getting major nations to lead with big commitments is crucial at the moment because of the way the impending climate treaty talks are structured. A draft treaty is supposed to be presented in Lima this year, and the U.S., among others—including Europe's heavyweights—is on board for an approach that will let each country declare what cuts it will make and how it will make them, and not set binding emissions limits. Those national declarations are due in the first few months of 2015. They have to be credible if they are going to attract broad support. And at the moment, only Europe is in a position to make firm, credible commitments promising major reductions—promises that will carry that much more weight because of the formal endorsement of the European Council.
Otherwise, the world could drift on with weak conditional pledges like those that emerged from the Copenhagen talks in 2009.
"We cannot afford another embarrassing failure like the one we experienced in Copenhagen," Schulz said, as if his audience needed to be reminded of the tepid results that emerged from that city, whose name now carries a Munich-like stigma of appeasement in some climate policy circles.
Subsequent negotiations in Durban and Cancun, and more recently the successful New York meeting of heads of state at the UN in September, at least opened the door of opportunity. But it is important to keep the momentum going, Schultz said, and that meant not backing down in Brussels from aggressive targets.
"It is not only the conferences in Lima and Paris which are important, but also the signals which emerge from this European Council," he said.
"The decisions which you take today on climate and energy policy will send a message to the rest of the world," he went on. "Only if we speak with one voice and continue to play a pioneering role in the sphere of climate protection will we be able to set a credible example to others."
Connie Hedegaard, the EU climate action commissioner, said she was proud that the 28 EU leaders "were able to get their act together."
"We have sent a strong signal to other big economies and all other countries: we have done our homework, now we urge you to follow Europe's example," she said.
Of course, the United States has always tried to position itself as a global leader on climate change, even when its actions faltered.
"Make no mistake—the world still looks to America to lead," President Obama said in his landmark climate speech at Georgetown University last year. "We will continue to lead by the power of our example, because that's what the United States of America has always done."
At the UN, he reminded China that "as the two largest economies and emitters in the world, we have a special responsibility to lead. That's what big nations have to do."
But without Congress on board, words like those can ring hollow.
The most vociferous climate obstructionists in the Senate, where opposition to a strong climate treaty runs deep, scoff at Obama's claim that his climate action plan and coal-power regulations will exert global influence.
On the day that Obama spoke to the UN, Senator James Inhofe wrote in The Hill:
"It is my hope that Obama will drop his counterproductive green dream that has already been lost and instead re-establish our nation's rightful leadership position on the world scene, where we aggressively promote freedom, economic innovation and the defense of our homeland and allies."
That world view is a reminder that after the summit in New York in September and before the big meeting in Lima in December, there comes an event in the United States in November—an election that may constrain how much leadership the U.S. can provide, and makes Europe's role all the more significant.