On Tuesday, June 3, Barack Obama didn’t land in Europe empty-handed. In fact, the day before the American president took on an initiative without precedent in the fight against global warming: He made public his regulation project, which would reduce the carbon dioxide emissions of American power plants by 30 percent by 2030, from their 2005 levels.

Getting louder in the face of the powerful coal industry, Mr. Obama decided to act using decrees and directives: in other words, by going the administrative route. He intends to go around Congress — especially the Senate, where the project for a law against global warming has been stalling for four years — at the risk of triggering the squawking of the Republicans, who decry this abuse of power.

Burned at the 2009 Copenhagen conference, where Mr. Obama turned his back on them to unite with China and India and push back an international treaty, the Europeans had waited for this move for a long time.

'Leadership by Example'

But the 2012 presidential election — along with signs of the American economy getting back on its feet — first had to take place before the U.S. president dared recommit himself to the climate issue. With his second nomination speech, he linked the question of climate change to the national American interest, and in his West Point speech on May 28, he made it a component of the "leadership by example" that he intends to develop.

Political will thus seems to actually be present this time. It's true, the circumstances have changed. The energy revolution is pushing the United States to free itself of coal, the main pollutant. Also, in five years, the U.S. reduced its dependence on energy thanks to hydraulic fracturing and the use of shale gas.

Simultaneously, the increase in extreme climate events — droughts, fires, hurricanes — made Americans aware of the danger of climate unpredictability bearing on their economy. The United States saw absolute record heat in 2012, which, according to the White House, cost the economy $100 billion.

The Europeans do, however, have some reason to be wary. The standards anticipated by the Environmental Protection Agency will not be finalized for another year and are giving a good deal to states’ local initiative. It will therefore be necessary to analyze, in detail, whether these standards will indeed allow the U.S. to meet its immediate goal of reducing greenhouse emissions by 17 percent by 2020.

In addition, while Mr. Obama’s initiative marks a significant step, it does not make the U.S. into a climate negotiation hero. There is still a long road ahead before the second most polluting country on the planet — after China — steps up to its responsibility in the current warming. The other countries will not stumble on that when signing — or not — the first global agreement regarding the climate, in Paris, in December 2015.