(His alternate career, if it hadn't been for Venus.)
My non-scientist thoughts on Hansen's latest:
* We're not doing enough about climate change now, and the appropriate policy option is to do more. Hansen provides more reason to do more, but that doesn't change the right policy option from what we should already be pushing for. So it's another thing to communicate about as to why climate change requires us to get going.
Some exceptions to the above where Hansen makes a policy difference: some things that may have a relatively minor climate benefit might be worth the societal cost if Hansen is right and not if not. Also it might change the priority that climate has among people who acknowledge reality but are not primarily climate activists.
* My expectation is that in 2-5 years, there will be a much better idea than there is now as to what extent Hansen is correct. I'd only expect that to be too short if testing Hansen requires obtaining new data from Greenland and Antarctica. Curious whether scientists agree.
As a non-scientist, my conclusion from above is that I don't need to spend time, for now, really trying to understand Hansen. Smart people will tell me soon if I need to.
* To the extent non-scientists do want to understand his perspective (some of it), Hansen's 15-minute Youtube was very helpful, the second time I watched it. Unfortunate that it's only had 60k views, I naively expected much more.
* I'm a non-scientist but do know something about responding to sea level rise. Adapting to one meter in 50 years is unfortunate and very expensive, but doable in priority economic areas of developed countries, with exceptions like Miami. Two meters in 60 years as Hansen speculates, OTOH, that's a different kettle of fish. There will be urban sacrifice zones. And poor countries are just screwed.
Having said that, 50 years is about how far you usually look ahead in construction, so I'm not sure what changes now in terms of responding to SLR if Hansen's right.
* Hansen does seem to change the priority in determining just how feasible it is to get substantial negative emissions. If negative emissions are too difficult to do, then we need to drop to zero much sooner.