What do you think of Broecker's global warming predictions 35 years ago?

[Dana1981]

35 years ago, Wally Broecker published a study in Science which was the first use of the term 'global warming' in the scientific literature. In the paper, despite the fact that the planet had been cooling slightly for several decades, Broecker predicted that a warming period would soon begin due to increasing atmospheric CO2.

Broecker predicted that by 2010, the atmospheric CO2 concentration would be 403 ppm. Not too far off - it's actually 392 ppm. He projected that between 1970 and 2010, the planet would warm 0.8°C. Considering that he overestimated the amount of CO2 in the atmosphere by 2010, that's not too far off either, as the planet actually warmed 0.55°C during that period, and the land surface (excluding oceans) warmed 0.7°C.

Broecker also estimated climate sensitivity at 2.2°C warming for a doubling of CO2, which isn't far off from today's most likely value of 3°C, and within the IPCC's range of possible values. He got a bit lucky in that his low climate sensitivity value somewhat compensated for the fact that he didn't include the thermal inertia of the oceans, which slowed the warming over the past 35 years. He also got lucky in that he purposefully omitted anthropogenic aerosol emissions (due to insufficient knowledge about them in 1975), but this was offset by anthropogenic non-CO2 greenhouse gas emissions.
http://www.realclimate.org/index.php/archives/2010/07/happy-35th-birthday-global-warming/

What do you think of Broecker's global warming predictions 35 years ago?
"So your case is that Broecker did a great job when he overestimated on all counts."

Wow, somebody didn't read either the question or the article. Either that, or read them with his denial-colored glasses on.

 

[Sachin]

May turn out to be true.

 

[Darwinist]

I've had a quick look and it seems he was pretty much spot on!

... though I expect there are some here who will say something like "with all those different theories back then, you would expect one of them to be right by chance!" and will not be as inpressed by this.

I'll try to have a better look at the link later and come back if I can add anything else.

 

[NoahH]

Predictions based on limited data tend to be limited in accuracy. We never know all the answers because so far at least we don't know all the science and we never have enough data. Still, there's a common sense component to this question of planet wide climate change based on any degree of retained solar energy caused by a CO2 induced 'greenhouse effect'. Basically the more observable, detectable, quantified and qualified greenhouse gases in a given volume of atmosphere the greater heat retention can be expected. Broecker's point here is that starting from an X standard in an X atmosphere, adding an X amount of CO2 and other gases to that atmosphere will always result in an X amount of additional heat retention. What's not to like?

 

[Darwinist]

I've had a quick look and it seems he was pretty much spot on!

... though I expect there are some here who will say something like "with all those different theories back then, you would expect one of them to be right by chance!" and will not be as inpressed by this.

I'll try to have a better look at the link later and come back if I can add anything else.

 

[karlhungus]

It's a depressing "happy birthday."

I think it's funny that this will be one of those "conveniently ignored" things the deniers push aside while they keep talking about Time magazine and global cooling...

Apparently, if the scientists are right, it's coincidence, but if they're (even slightly) wrong, climate science is pseudoscience.

 

[PaulB]

Prediction + observation + confirmation = validation

(Scientific method at its most effective. I think the Jason report a few years later came to very much the same conclusion independently)

 

[bumblebee1]

The big picture was correct. Some details have been improved (though with some luck, some of these things overlooked cancel each other out), but it is remarkable how long we've had a solid knowledge basis on this and yet so little political action.