James Hansen, former head of NASA’s GISS and long-time climate activist, finally got his paper published in the journal Atmospheric Chemistry and Physics. Titled “Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming could be dangerous“, the paper was put online some months ago in draft format and it has received a lot of critical commentary. Perhaps surprisingly, much of the criticism has come from his own ‘side’ of the fence–from the climate orthodoxy, including practicing climate scientists.
As I understand it after a cursory reading, Hansen’s paper is advancing a hypothesis–a ‘what if’ scenario that involves melted water from glaciers and the great ice caps of Greenland and Antarctica, resulting in a cascade of unfortunate events leading to… increased melting from glaciers and the great ice caps.
It doesn’t seem like a normal scientific paper, although it reports on the results of a model run from a climate model. It seems more like a tract, almost philosophical in nature rather than a paper in Nature.
I have little doubt that the various technical critcisms of the paper are well-grounded. And I don’t share Hansen’s fears about near term drastic sea level rise. But as a non-scientist I perhaps am not as concerned with some of the things that his critics have noted and am perhaps more sympathetic to the spirit driving Hansen on.
Critics of the paper started with the title and never quit. They got Hansen to change it from ‘is highly dangerous’ to ‘could be highly dangerous.’
Surprisingly, the best summary of all this back and forth is found at And Then There’s Physics, who reblogged Peter Thorne’s take on it all. Surprising because ATTP, who I have criticized roundly and frequently, is a staunch advocate of the trumped up exaggeration of the real consensus on climate change and he doesn’t suffer criticism of consensus icons lightly. ATTP should be congratulated on his matter-of-fact publishing of Thorne’s criticism–activists have long complained that if they admitted to any chink in the edifice of climate ‘dogma’ (too strong a word, but I can’t think of another), their opponents would rush into demanding more and more and use any admission as an excuse to attack the entire construct. So well done, ATTP.
And make no mistake, James Hansen is an icon. He led the activist fight for many years, finally retiring from GISS to move into an even more activist role. He’s taken flack recently, having been called a ‘denier’ by pseudo-scientist Naomi Oreskes, because Hansen frankly acknowledges that our emissions are unlikely to decline unless we take full advantage of nuclear power. But for 25 years before that, he received what amounted to hero worship for his dual role as scientist and policy activist.
For me, this paper amounts to a summary, perhaps a coda, of Hansen’s career. He is unapologetically scared of the possibility of dramatic impacts from climate change and is unapologetically convinced that humans are driving this change. Although there are many findings in science (many recent, many historical) that indicate Hansen’s case is unlikely (to say the least), Hansen has not been convinced, as this paper makes very clear.
Whether it’s a stake in the ground or a line in the sand, Hansen’s paper is a very clear attempt to make the case that as little as 2C in warming can have dramatic and unwelcome impacts on how we live on this planet. That I don’t think he succeeds doesn’t detract from my respect for what he has done for climate science.
He deserves a forum and a respectful audience. His paper also deserves the criticism it is receiving. To me, there is no conflict in having the two together.