At the last round of climate talks in Barcelona, I had an interesting conversation with a former negotiator about what the global leaders might do here in Copenhagen. It wasn’t so much a betting game about what they would actually get done as a discussion about how the mere presence of actual decision makers could result in a political phase-change of sorts.

Negotiators are trained to negotiate, and environment ministers handle environmental issues. Typically these talks don’t get beyond environment ministers, but these officials don’t have much to say about things like money (which is one reason why global warming talks are so difficult). Both levels have mandates and tend to focus on the text, but leaders can do anything they want as long as they can sell it back home.

Which is what everybody wanted, but at the same time everybody seemed surprised when the US President Barack Obama emerged from a series of multilateral meetings with a completely new outline that pretty much ignored two years of negotiations. There was uproar and confusion when the deal came down in the Bella Center. Even seasoned diplomats had no idea what to make of it. Anger over the lack of ambition to reduce greenhouse gas emissions flared during the plenary, eventually leading to ugly Holocaust comparisons and one Venezuelan negotiator holding up a bloody hand to signify something that I didn’t quite catch). Nobody appeared to like it, including signatories.

Although to be fair, it must be said that virtually everybody ended up endorsing it as the best path forward. Or perhaps it would be more accurate to say that a bunch of sleep-deprived zombies with blood-shot eyes and two-day socks “took note of” the proposal. What does that mean? Let’s go to United Nations climate chief Yvo de Boer for the answer: “That is a way of recognizing something is there, without directly associating yourself with it.”

And so, we have a deal which the UN climate body has recognized and with which countries can associate themselves if they so choose. The initial deadline for registering pledges, which would presumably be those that are already on the table, is this February. We’ll see. Debate over the significance of the deal will continue for a long time to come (see the New York Times and the Guardian for a current sampling) but one thing is clear: the game has changed.

And with that I’ll sign off. Watch out for our coverage in next week’s issue, and beyond.