At the end of his summit meeting on the climate crisis, UN Secretary General Ban Ki-moon put out a list of accomplishments festooned with 46 bullet points, some of them marking concrete new pledges, others diaphanous phrases.
Other announcements, such as promises by France and Germany that each would commit $1 billion to a fledgling fund to assist poorer nations, lent support to existing UN arrangements that have been slow to mature.
And there were also agreements that could help hold down emissions with or without a new treaty. These included pledges by dozens of big corporations to price the cost of carbon into their business decisions and force governments to follow suit; the formation of a compact among cities to track and reduce their own emissions; and new steps to make it easier for municipalities to borrow for projects like energy efficiency, a key to reducing their carbon footprints.
But would all of this really enhance the likelihood of a successful treaty negotiation?
The best Ban could offer was a glib claim that leaders at the summit "concurred" that the international treaty the UN is trying to negotiate in the next 15 months "should be effective, durable and comprehensive."
The real judgment on whether the meeting meant anything will have to wait until the world reaches three milestones on the path to a possible treaty.
The first is in Lima at the end of this year, when a draft treaty is to be presented at the annual conference of parties (or COP) to the UN Framework Convention on Climate Change. The second comes a few months later when individual countries are supposed to state what reductions in emissions they would be willing to make once the treaty takes effect in 2020. The third is the final negotiating session at the Paris COP in December 2015.
The September summit was never intended to be a negotiating session, so it has no real effect on the writing of the treaty's first draft. Participating leaders who spoke about what the treaty should look like stuck to their basic positions. China, for example, insisted that different states should have different obligations depending on their circumstances. The United States held that as circumstances change, so should the obligations of big polluters.
The summit's timing was originally intended to coincide with the second milestone, the moment when nations would come forward with specific pledges for emissions reductions. But at last year's Warsaw COP, the deadline for pledges was pushed off until next year—conveniently past the November 2014 elections in the United States. As Robert Stavins of Harvard University observed, the summit lost one raison d'etre and will have no effect on negotiating positions or reduction pledges.
And while everybody who spoke agreed that the third milestone, a Paris treaty, is an urgent imperative—that time is running out for the world to avert the worst effects of climate change— it was a bit of a stretch for Ban to declare that "a comprehensive global vision on climate change emerged" from the talks.
Major environmental and other non-governmental organizations that are heavily invested in the treaty process, such as the World Resources Institute, painted the events as a major success story.
"Leaders clearly demonstrated their understanding that the impacts of climate change are real and costly, and that they no longer have to choose between economic growth and climate action," nine WRI staff members wrote on the group's website.
Indeed, they called the UN meeting "a massive leap forward" for treaty momentum—fueled in large measure, they noted, by the demonstrations of public support for action in New York and other cities.
Just like the summit, though, any lasting effects of the demonstrations are hard to size up.
The green coalition that marched its legions in support of a treaty enlisted a Carnegie Mellon professor with a reasonably precise algorithm who estimated that three times the expected crowd were on the streets. But like promises from the UN's podium, no matter how soft or firm, a head count is not enough. Unless the environmental movement provides the power to overcome the political resistance that for decades has hobbled U.S. negotiators at climate treaty talks, the demonstrators who thronged 50 blocks of midtown Manhattan might as well have stretched their legs on 310,000 treadmills.
Still, it may turn out that something truly significant happened in New York in the past several days as the hottest summer humankind has ever recorded turned into autumn.
The turnout at what organizers billed as the People's Climate March was testimony to an extraordinary organizational effort by hundreds of seasoned activist groups and ad-hoc improvisers, not all of them previously linked in the fight for immediate action on climate change.
That organizational network did not disappear when the crowds melted away. There are still email lists and Twitter feeds and Facebook pages and telephone trees and committee chairs and block captains. And if some of them drop their leaves, others are likely to be evergreens.