President Barack Obama has laid years of groundwork in order to be able to say these words in front of 150 world leaders at the COP21 Paris climate conference: “I’ve come here personally, as the leader of the world’s largest economy and the second-largest emitter, to say that the United States of America not only recognizes our role in creating this problem, we embrace our responsibility to do something about it.”

That might not sound like much, and his short speech at the opening of the summit certainly didn’t include anything that we haven’t heard from him before. In context, though, his address in Paris is remarkable compared to his address to the climate conference in Copenhagen in 2009. Obama was there on the last day of that conference to salvage what was left of a deal. And the remarks he gave were too little, too late.

At Copenhagen, Obama didn’t say much that signaled what his administration would do on climate change, especially important given the U.S.’s historic role as the world’s biggest polluter. His words—“America has made our choice. We have charted our course. We have made our commitments. We will do what we say”—rang false and empty. The entirety of his eight-minute speech echoed the same problems that have plagued global climate action for over two decades. “I have to be honest, as the world watches us today, I think our ability to take collective action is in doubt right now,” he said. “We know the fault lines because we’ve been imprisoned by them for years. These international discussions have essentially taken place now for almost two decades, and we have very little to show for it other than an increased acceleration of the climate change phenomenon.”

Now, six years later, the same fault lines remain. Paris has always been an uphill climb to overcome the same disagreements that derailed Copenhagen. One particular sticking point, which Obama addressed on Monday, was the need to adequately finance poorer nations who are stuck with the worst of climate change’s impacts, yet caused little of the damage themselves. But unlike the last major conference, Obama could point to a body of domestic measures, like limiting carbon pollution from the power sector and saying no to “infrastructure that would pull high-carbon fossil fuels from the ground”—a likely reference to his recent decision to reject the Keystone XL pipeline—as proof that the world could trust America’s commitment.

Obama’s environmental critics can quibble with some of his claims to success and whether the U.S. has really come far enough to take this kind of victory lap on climate change. But they would probably agree that this is not the same Obama who addressed Copenhagen. In Paris, he has a vision for the agreement, one he laid out in broad strokes as increasing in ambition over time, requiring transparency, and committing to funding climate finance and investment in clean energy. 

This time, he even suggested there was hope. “Here in Paris, we can show the world what is possible when we come together, united in common effort and by a common purpose.”