This dispatch was filed from the ongoing U.N.-sponsored climate change talks in Bonn, Germany.

As expected, Sunday’s speech by Todd Stern at the U.N. climate talks in Bonn created quite a stir.

Sitting in the rear of the hall, it was hard not to think back to the last time U.S. statements in a plenary hall provoked such a strong reaction — when the U.S. delegation was loudly booed for blocking progress in Bali in 2007. This time the United States was cheered, and a wave of relief could be felt going through the room.

The first cheer came even before Stern had said a word. Perhaps it was a cheer of support, saying, “Ok, guy, don’t screw this up.” And for the most part, Stern delivered.

Within two sentences, the room seemed pleased. To applause, Stern remarked, “On behalf of President Obama and his entire team … we are very glad to be back, we want to make up for lost time, and we are seized with the urgency of the task before us.”

Next, in perhaps a preemptive signal to delegates around the room, Stern reassured delegates that there’s a new boss calling the shots and U.S. delegates are on board with the new mandate. He said, “You will not hear anyone on my team cast doubt upon or downplay the threat of global climate change. The science is clear, and the threat is real. The facts on the ground are outstripping the worst case scenarios. The costs of inaction — or inadequate actions — are unacceptable.”

Affirming a commitment to reach an ambitious agreement in Copenhagen, Stern then went on to outline his five principles key to such an agreement: a long-term vision guided by the science; recognition that the United States is the largest historical emitter of greenhouse gases (cheers again!) and must be a part of the global solution; the need for a global response; the need for significant funds to flow to developing countries to support their efforts to reduce global warming pollution and adapt to climate change that cannot be avoided; and the need for an agreement that can actually enter into force with all countries involved.

Sure, there are specifics to quibble with in his speech (including the reiterated target of returning U.S. emissions to roughly 15 percent below current levels by 2020, a target that must be strengthened to match the urgent calls of the science), but there will be a time and place for that (though soon, to be sure). For now, it was a day to savor the change in the air.