Two happy developments surrounded day one (yesterday) of COP15, the international climate summit taking place this week and next in Copenhagen. First, it was announced last Friday that President Obama has changed his schedule and will be swinging by the summit not on Dec 9th, as had been planned (he’ll already be in Scandinavia then to accept his Nobel), but rather on the final day of the summit, Dec 18th. Second, the EPA yesterday “formally determined that greenhouse gas pollution imperils the health and well-being of present and future generations, “as a press release from the Environmental Defense Action Fund put it. “This finding sets the stage for U.S. action,” said the release.

The EPA’s finding is a big deal because it gives our government the power to act on climate change, and potentially join a global treaty (which, after all, is what COP15 is designed to produce), even if legislation such as the Kerry-Boxer bill doesn’t get pushed through in time.

“The move empowers the agency to regulate these emissions and gives President Obama an important tool if Congress fails to pass legislation to reduce global warming emissions,” said a New York Times editorial.

As for Obama’s change of plans, they represent a much-strengthened commitment on his part to actually coming away from COP15 with a hard deal, a firm and defined role to play in a global climate treaty.

“Coming to Copenhagen at the climax of the talks, specifically to push negotiations ‘over the top,’ as the White House statement says, is a risky move for Obama,” writes Grist’s political reporter, David Roberts. “He’s got skin in the game now; he’ll look foolish if he rides in at the last minute and fails to broker an agreement. If he’s willing to stick his neck out like this, Obama must be pretty confident that he can get a deal.”

In more animated news: a cartoon mini-documentary protesting the Senate’s proposed cap-and-trade program was also released this week by The Story of Stuff Project, Climate Justice Now, and the Durban Group for Climate Justice. Those still on the fence about a carbon market should look to it for a compelling – and adamant – argument against.

Counter that with Paul Krugman’s pro cap-and-trade NYT op-ed, “An Affordable Truth.”

Whoops, then counter that with NASA scientist and cap-and-trade detractor James Hansen’s NYT op-ed against: “Cap and Fade.”

Meanwhile, an unhappy, or at least disturbing COP15 announcement: Treehugger reports that a group of prostitutes in Copenhagen (the practice is legal in Denmark) have offered free sex to anyone who can produce a COP15 identity card and one of thousands of postcards distributed to local hotels by Copenhagen’s mayor, imploring summit participants to “Be sustainable – don’t buy sex.” Politicians are so bad for business! Whether this free trade exchange will make said sex workers feel they’ve had their revenge against the mayor remains to be seen.