Twelve years ago in Kyoto, the world was poised to act on a climate treaty but looked for a clear signal from the United States. Now, with the Copenhagen talks set to begin, the outcome once again hinges on what the U.S. is prepared to do.

President Obama took much of the drama out of the Copenhagen talks earlier this month when he and other world leaders announced that there’d be no treaty at the end — in essence, they said, we’ll wait for the U.S. Senate. Still, you can’t call off the party entirely, and so the planet’s climate scientists, bureaucrats, activists, skeptics and journalists will still descend on the Danish capital in a few days for a fortnight of meeting, marching, propounding, denying, and most of all spinning.

Almost all of what happens will be murky (and not just because Copenhagen in December averages 45 minutes of sunlight daily). Without the focus provided by the need to draw up a real document, much of the tension may go out of the proceedings — minus a deadline it’s hard to push to resolution on anything. And yet it’s the fate of the world being discussed: as British negotiator Ed Miliband put it, “Bretton Woods plus Yalta multiplied by Reykjavik.” We’ll see some kind of paper signed, but it won’t commit anyone to much of anything — the talks will lurch forward into next year. Most of what occurs in Denmark will be shadow boxing, feeling each other out.

And so here are a few of the places that bear watching, to see if some kind of consensus develops over the course of the proceedings:

• What’s the science really saying? For almost five years, the consensus position of those who cared about producing a treaty has been that we’re struggling to avoid a temperature rise greater than two degrees, and that to do that we’ll need to limit atmospheric concentrations of carbon dioxide to less than 450 parts per million. These sound like the kind of eye-glazing numbers that journalists try to avoid — but the vast and slow-moving bureaucracy of the climate negotiations process has adopted them as the goal, and most of the proposals on the table are geared to reaching (or plausibly approaching) those targets.

  The problem is, that’s not good science any more. After the rapid melt of Arctic sea ice in the summer of 2007, researchers recalibrated. A NASA team said that the right figure is 350 — that anything more is not compatible with “the planet on which civilization developed and to which life on earth is adapted.” That assertion has been backed up by no less than Rajendra Pachauri, the UN’s chief scientist, who has gotten grief for saying — most recently in an interview with Yale Environment 360 — that 350 is where we need to go. Ninety-two of the poorest nations on Earth have officially signed on to that target, and at the moment it’s still in the negotiating text, albeit in a preamble about a “shared vision” for the future.

  The problem, of course, is that meeting a 350 target goes far beyond anything the Obama administration, much less the Senate, or the Chinese, or many of the other big players, are currently contemplating. We now know that Obama will arrive on Dec. 9 en route to Oslo, and that he will offer roughly a 17 percent cut in 2005 emissions levels by 2020. That would be about a zero percent cut from 1990 levels; in other words, not very ambitious — the absolute minimum for saving face, but not enough to save the world.

  Going further would be fundamentally disruptive — it would mean not incremental change but a wartime footing. So the question of which science you embrace is really a proxy for how much you’re willing to do. And in this case “political realists” are the opposite of “scientific realists.” If you’re figuring the odds, there will more politicians than scientists on hand in Copenhagen.

• How tough will the developing countries be? Since Obama’s announcement that he will go to Copenhagen robbed journalists of their first cliffhanger, the next is likely to be whether the most vulnerable nations walk out on the proceedings. Here’s Mohammed Nasheed, president of the Maldives, whose country sets aside money in its budget each year in case it needs to buy a new homeland when its current one sinks beneath the waves, talking about what a 2 degree Celsius temperature increase would mean: “At two degrees we would lose the coral reefs. At 2 degrees we would melt Greenland. At 2 degrees my country would not survive.” He called the proposals from the big players a “suicide pact” and pledged to try and stop them. “As a president I cannot accept this. As a person I cannot accept this. I refuse to believe that it is too late, and that we cannot do anything about it.”

  Nasheed rallied a dozen of the most vulnerable nations earlier this month at a summit in his capital of Male. And virtually every poor nation is starting to realize how badly they’re going to be hit by climate change: The vulnerability of Andean glaciers, Asian monsoons, African rainfall patterns become clearer with each passing year. But the pressure from the rich nations — and indeed from some of the big environmental groups — not to be a skunk at the garden party will be intense. And it will come with sums of money attached — the kind of money that traditionally has been enough to buy off the anger of the poor world.

• Which leads to the next obvious question — just how much money will be on the table? The sums required are staggering. The World Bank recently estimated that keeping temperature rise to 2 degrees Celsius would mean spending $140 to $675 billion a year in the developing countries — which, after all, will only be developing if they keep figuring out how to acquire more energy. And adaptation — dealing with the effects of the climate change we can’t prevent — would run another $75 billion a year (an estimate that other research paints as extremely optimistic).

  Sums like that are not on offer. The Europeans have talked about a deal in the range of $100 billion a year, but that depends on the Americans ponying up, and so far the U.S. has been as coy about its willingness to pay as about its willingness to rein in emissions. Everyone outside the U.S. knows that this is — overwhelmingly — a problem we’ve caused; since the carbon molecule has a residence time of over a century in the atmosphere, it will be the decades before the Chinese, despite their vastly larger numbers, are as responsible for climate change as Americans. But if Obama puts a realistic number on the table, Senator James Inhofe (R-Armageddon) will be on hand to take it off. (Inhofe originally announced he was going to Denmark as a “one-man truth squad,” but then added John Barasso (R-WY) and “a secret person” to his delegation). In our poisonous politics, the idea of the U.S. meeting anything like its moral obligation seems small — and without that, the politics gets harder for everyone else in the world.

Against this backdrop, there’s a lot of important and less flashy stuff that has to move forward if we’re ever going to reach an agreement. Nations with large swaths of forest, for instance, seem willing to make a deal to stop their destruction. It’s cheap compared with the other steps we’ll need to take, so it will probably happen — though the devil is deeply in the details. The same with credits for farmers for keeping carbon in the soil — it could be a big help, or a loophole large enough to drive an endless fleet of combines through.

And then there are the plumbing questions. How do you monitor and then enforce any agreement? How do you draw something up that doesn’t require treaty approval by the U.S. Senate (no one thinks there are 67 votes for a real climate policy)? How do you give credit for actions already taken? How do you keep carbon trading from turning into one more Wall Street boondoggle?

One thing will surely be tested: whether civil society is capable of really pushing the process. Activists will be descending from all directions, but the deck is stacked against them: The conference center, where the media will be mostly cooped up, is miles from town. And the environmentalists themselves are deeply split. There are groups that, for all intents and purposes, are part of the negotiations — whose experts have spent careers working on one part of the treaty or another, and are deeply invested in its success. There are less formal groups — many of them veterans of the anti-globalization movement — determined to shut down the whole process. They won’t succeed, but it’s completely conceivable that tear gas will drift across the Radhuspladsen before the month is out. And there are thousands of young people, about to be disillusioned by their first exposure to big time power politics.

Having been to Kyoto (which at least took place in the daylight) there’s a sense of overwhelming déjà vu as I head toward Denmark. There, too, most of the world was lined up to do something, but waiting on a signal from the U.S., whose negotiators had been doing its best to weaken the treaty in hopes it might pass Senate muster. There was the same will-he-come anxiety, then centered on Al Gore, who flew in at the last minute to offer some small concessions and let the conference proceed. In those days China hadn’t yet emerged as a huge carbon source. In those days the Arctic hadn’t yet melted. But in those days, as in this one, everyone was waiting on the U.S.

This piece originally appeared on Yale Environment 360.

Image Credit: The Green Party via Flickr, Creative Commons License