When Bill McKibben — a visionary climate change leader,  an immensely prolific writer, and, by all accounts, as sober, earnest, and genuine a person as can be — says something like "This is the most important thing I've written in many years", you know that it is ABSOLUTELY a must-read.

Mr. McKibben's latest piece in Rolling Stone magazine is entitled "Global Warming's Terrifying New Math." It is Bill McKibben at his best, written in his unique, unmistakable style, paradoxically frank (many would say blunt) but hopeful, providing an impassioned and serious call to action even as he lays out how truly dire the climate crisis is. 

Mr. McKibben builds his essay around three numbers:

2 (degrees Celsius) — the generally agreed-upon ceiling for global temperature increase that has emerged from international climate negotiations, which McKibben calls "the official position of Planet Earth" and which we are very close to exceeding if swift action is not taken (The head economist of the International Energy, Fatih Birol, has been sounding the alarm for some time, saying that the continued build-out of fossil fuel infrastructure is locking us in to an emissions pathway that would exceed 2 degrees).

Also, though it is slightly dated, this backgrounder from the Yale Forum on Climate Change and the Media has a balanced perspective and lots of links and info on the scientific basis, history, and potential pitfalls of the 2 degrees target.

565-gigatons of CO2 that we have left to spend in a global carbon budget that gives us an 80% chance of staying below 2 degrees Celsius.

2,795-gigatons of C02 that would be emitted by burning the proven reserves of the world's biggest fossil fuel companies

Mr. McKibben methodically and mathematically lays out the case against oil, coal, and gas interests in a way that is by no means over-simplified: he notes multiple times that of course these numbers are not exact or written in stone, and he provides ample background and context to the studies and models from which these numbers were derived (Click here for the original Carbon Tracker Initiative report). Rather, he has taken an immensely complex topic- the global carbon budget- and made it elegantly accessible through the everyday analogies and metaphors that are so effective and so common in his writing. 

Taking these calculations even further, Mr. McKibben breaks even more new ground in this piece by emphasizing in excruciating detail just how many trillions of dollars these companies (and countries, in some cases) stand to lose in a transition to a low-carbon future, and how they will likely continue to fight that transition accordingly, tooth and nail.

Brad Johnson put together a beautiful infographic (seen above, originally posted here at Think Progress) a few months ago that helps illustrate both the global carbon budget and fossil fuel reserves numbers in one handy-dandy set of pies (the slight differences between Mr. Johnson's numbers and Mr. McKibben's are negligible).

There's so much more to say about this fantastic article, and you can bet there will be lots of reflection and analysis on it in climate circles in the weeks and months ahead. For now, I just wanted to provide Brad Johnson's chart (which was immensely helpful as I tried to wrap my mind around the McKibben piece), and to share that reflections on and analyses of this piece are exactly what Mr. McKibben and 350.org are looking for. According to Mr. McKibben's latest e-mail, he will be hosting a video chat next week to discuss "Global Warming's Terrifying New Math" as well as the continuing fight against the Keystone XL pipeline. You can RSVP for the video chat here

Additionally, Mr. McKibben explicitly asked for feedback from supporters and activists on the Rolling Stone essay, explaining that "The analysis -- the math -- that's in there is going to form the basis of a lot of our work going forward, and it would be useful to hear how it strikes you [the readers]." Those with comments and suggesitons on the content and framing of the piece should send them to thoughts@350.org