Update to Hansen et al 2016

Although I'm no longer employed as a climate professional, I still monitor the climate science news and cherry-pick the latest papers. In particular, I look for progress that would or would not confirm the primary hypothesis in Hansen et al 2016, "Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 ◦C global warming could be dangerous."

This is the paper that turned my professional life upside down. It took me three weeks to read it carefully, annotate it, and follow up on the primary literature cited therein. It's a very dense eighty-some pages. But I had a feeling then and still do that I was witnessing the emergence of the best prediction for the fate of the earth, and its consequences, all in real time, and that nearly everything I had done as an environmental activist, scholar, and teacher would become moot as a result.

Seems like the kind of thing you would want to keep track of. Especially if you have a six year old daughter.

In the years after Hansen and his colleagues published this tome, I tried to teach it. I was responsible for general education classes that included a climate change module, as well as a senior-level climate science class that taught the general science and the basics of climate modeling. It seemed my responsibility to give them this paper. But I failed badly in the attempt to teach it. 

It's just too complex a proposition. 

Not "if a then b," which is what most undergraduates can handle in terms of logic problem, essentially linear cause and effect, but "if a and b and c, then d might happen and e will perhaps ensue and then f is a distinct possibility if we cross threshold g and reach set point h, and hypothetical feedbacks i, j and k set in, and we have evidence of varying quality for a, b, c, d, e, f, g, h, i, j, and k, and if we get to f then a total catastrophe will drown all major cities within seventy years and set off storms that can flatten Florida, but you have to be an expert to understand the evidence and by the way, even you, the professor, is probably too stupid to understand any of this."

I have to admit I took a certain morbid and masochistic satisfaction trying to teach it. I could spend a lifetime just learning to teach this one paper. But this is what science is about for me: struggling with logic and reason and consequences.

Anyway. Updates, right? They have been fairly scarce and not written for the lay person.

Dr. Hansen has finally published an informal update of sorts here. It is intended to be a foreword to a book, but looks to me more like an attempt to put forming thoughts about updating H2016 on paper.

As such, I would expect it to either disappear or appear later in some other format. But for now it's very interesting. I plan to follow up on the literature as soon as I can get a draft copy of Chapter 48 of his new book, which is where he says to go next.