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Comment by jfoutz | Hacker News Reader

Really, all we have is how well a model predicts the future. there's a fairly sucky model from the 80's, [1]. Maybe it's totally wrong. Maybe it's just overfitting. But it's got a good track record, if underpredictive. I'm all for the idea that co2 doesn't effect temperature. I just haven't seen any models that show that. Furthermore, i haven't seen anything with any sort of a track record. I'm pretty sure Hansen's paper is pretty much the root of all modern climate modeling. I'm totally willing to stipulate that the whole field is wildly off track, but there's no evidence of that. The only thing we have is 35 year old models that seem to work.

I mean, more specifically, aether was flat out wrong. it still had predictive power. Someday we'll have something more refined, or perhaps completely refuted.

[1] http://www.realclimate.org/index.php/archives/2012/04/evalua...

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Derailing the thread further, I don't understand why people say "aether was flat out wrong". Is it because they don't know it was just a name change, and we're now calling it "vacuum"? [1]

[1] https://en.wikipedia.org/wiki/Aether_theories

See for example,

The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. But we do not call it this because it is taboo.

Interesting.

Compare the chart in the linked article with Hansen's own assessment that he put out in 2005 (third page): http://www.columbia.edu/~jeh1/2005/Crichton_20050927.pdf

How do you reconcile those two? A lot seems to come down to centering decisions?

Scenario A I believe is closest to the emissions path we are on.

My guess is, the pink band is current (er, 2011 versions) of what the global average temperature was. Which makes the 60's even cooler (heh). As with all things, it depends on how you measure.

global mean global giss is here - http://data.giss.nasa.gov/gistemp/graphs_v3/

So anyway, i'd agree the centering of zero sure could change things, but it sure seems like predictive power in the rates of change. Like, temperature isn't stable, it's not going down, it's going up and it looks like it's going up at about that rate.

edit

but that sort of goes back to the original point, all we really have is models. you held up physics as an example, but if we look at something like the gravitational constant, things are really screwy. As far as i can tell, 3 really first rate teams came up with 3 different answers - not even overlapping in the error bands. big G is obviously helpful, but it must be more complicated than we understand right now.

I dunno. I kind of like the european model for chemical handling. Super toxic chemicals in tiny quantities aren't that big of a deal, maybe 50 people die, so it's not heavily regulated. Mildly toxic chemicals in large quantities, same deal. Maybe 50 people die. Large quantities of toxins are regulated in proportion to the risk. The point is, balancing the risk against the best current understanding really seems like the best that can be done.

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