Just tangentially, zborg's mention of The Gordian Knot reminds me of the tale of Alexander encountering The (original) Gordian Knot ...
When confronted with the fabulous improbability of untying said Knot, Alexander briefly considered the immense tangle, drew his sword and then cleaved The Gordian Knot in two.
The US should indeed lead, (via multilateral agreement), but our current Administration is clearly moving away from that position, don't you think?
Accept the "science," yes, but global politics remains the Gordian Knot for this planetary problem. Does it not? For "UN-insiders," this falls under the rubric of SDRs (Special and Differential Responsibilities). Briefly explained -- it's the devilish problem of how will all countries (both rich and poor) share FAIRLY the costs of mitigating GCC? That's the Gordian Knot inside the UN-system that has proven so difficult for the past 30 years.
P.S. -- I need to stay away from Elroch's "Evolution tread." They are ready to tar and feather me in that crazy thread. This GCC thread is (perhaps) a bit less nutty, don't you think?