What's it take to make an international climate accord? Sift heaping handfuls of patience. Whip the voices of opposition until stiff peaks form. Let rise for two weeks every year in a cavernous convention center someplace; it should smell warm, sweaty and stale by the end. Add a dash—not much!—of progress.
Almost 25 years ago United Nations delegates started cooking an international treaty to stabilize greenhouse gas emissions at a level that avoids dangerous climate change.
They began with a framework—the United Nations Framework Convention on Climate Change, or UNFCCC—that set no mandatory limits, carried no enforcement provisions and is non-binding.
Future updates, called "protocols," would set mandatory limits. The only one so far is the Kyoto Protocol, which became better known than the UNFCCC itself. Its first phase expired in 2012; a second expires in 2020.
Now the kitchen is primed for the next agreement, which maps cuts and financing required for 2020 and beyond. It might emerge in Paris in December.
Here's how we got there. Just don't forget to heat the oven from 350 ppm to 400: