Scarily accurate climate warming projections

Something interesting spotted on the website RealClimate, via Crikey.

Over 30 years ago, a neat paper by Hansen et al. on climate predictions was published in Science. Climate change, as an impending disaster, was not a big research drawcard, but the authors did graph predictions for warming trends for 2000 – 2100. Recently (as in, a couple of weeks ago), Geert Jan van Oldenborgh and Rein Haarsma revisited the data and presented their results on the RealClimate blog.

image from RealClimate

Given that we now have an additional 30 years’ observations from the dataset published in 1981, van Oldenborgh and Haarsma overlaid the new observations on the original predictive graph. You can see in the picture above: the fat pink line is the observations, versus the black line of the original prediction. They found a lovely congruence to the observations against the predictions – scarily accurate. As they say at the end of their analysis:

To conclude, a projection from 1981 for rising temperatures in a major science journal, at a time that the temperature rise was not yet obvious in the observations, has been found to agree well with the observations since then, underestimating the observed trend by about 30%, and easily beating naive predictions of no-change or a linear continuation of trends. It is also a nice example of a statement based on theory that could be falsified and up to now has withstood the test. The “global warming hypothesis” has been developed according to the principles of sound science.

I really like the last line. This research was done at a time when ‘climate change’ was not a buzzword. Now, it seems that we have a somewhat uncomfortable situation where researchers are hell-bent on adding ‘climate’, ‘climate change’, ‘climate impacts’ etc etc to research proposals in the hope of getting things funded. This usually results in projects being funded that have only a very tenuous link (if any at all) to actual climate change, and IMO potentially damages the climate change ‘brand’ (for want of a better word) when dodgy links to climate are made. Meanwhile, the politicians and the people with actual power to change the way humans go about their CO2-emitting business are more preoccupied with not actually doing anything, lest they get it wrong and climate change turns out to not be a big deal after all. Well, here’s some evidence that suggests that it is a big deal, and it’s coming our way.

Thanks to John, who brought my attention to this by posting the Crikey version on FB.


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