Another Climate Change Catastrophe from the Mail

It seems that no Sunday is now complete without another pile of nonsense about climate change from David Rose in the Mail on Sunday (see my previous post here for example) and this week was no exception.

Rose has found a graph which he claims contains

…irrefutable evidence that official predictions of global climate warming have been catastrophically flawed.
The graph on this page blows apart the ‘scientific basis’ for Britain reshaping its entire economy and spending billions in taxes and subsidies in order to cut emissions of greenhouse gases.

Typically for Rose the whole piece is riddled with inaccuracies and distortions – for example he completely misrepresents the views of climate scientist James Annan and repeats the easily debunked myth that scientists in the 1970s were just as concerned about global cooling as global warming. But the main problem with Rose’s argument is more fundamental. The graph that he shows in order to support his argument simply doesn’t show what he claims it does. His “smoking gun” is not only not smoking, it is not even warm. Here is the graph in question


The graph itself is genuine – it has been taken from the blog of climate scientist Ed Hawkins and shows projections of surface temperatures from climate models going back to the early 1950s and forwards to the mid 21st century with different certainty levels, and actual observations to date. Rose is wrong about the certainty levels they actually represent 50% and 90% but I’m betting that this is an innocent mistake because (as we will see) he just doesn’t understand statistical terminology very well.

We are told by Rose that this graph proves that predictions are “catastrophically flawed”, a “spectacular miscalculation”, that the scientific basis for action on climate change is “blown apart”, that the projections are wrong “to the point of falling out of the ‘95 per cent’ band completely”. Now usually at this point one would expect a detailed discussion of statistical methods, maybe exposing some clever sleight of hand, to explain why such claims are incorrect. However in this case all that is required to understand that the graph does not support Rose’s claims is the simple technique of just looking at it. The observed temperatures clearly follow the projections, spending much of the time in he narrower red band and during the whole 60 year period up to the present have fallen outside the 90% (or 95% as claimed by Rose) range just once, in the late 70s and then they quickly recovered.

Yes, we have had some relatively cool years recently (although 2010 was the warmest on record) and temperatures are currently touching the lower end of the 90% range, but then we have had a period of relatively low solar activity combined with repeated La Niña events, which have the effect of lowering global temperatures. This kind of natural variability means that over shorter periods observed temperatures can plateau or even fall while CO2 levels continue to rise so it is dangerous to draw conclusions from such short periods – this is nicely illustated here. But even so global temperatures still haven’t fallen outside the 90% range. Does this really look like a “spectacular miscalculation” that “blows apart” the scientific consensus?

Rose cites Met Office decadal projections of global temperatures which, he claims show that

the pause in warming will last until at least 2017. A glance at the graph will confirm that the world will be cooler than even the coolest scenario predicted.

So really Rose’s argument depends on what will happen in the future and he seems to place great faith in the Met Office’s forcasts, which is rather ironic since these are based on models and the whole point of Rose’s piece is to rubbish forecasts based on models. And in any case the forecasts show temperatures increasing over the next few years (it’s the dark blue line).

Rose further justifies his claims with this statement.

The graph confirms there has been no statistically significant increase in the world’s average temperature since January 1997

This statement is just bizarre as it is simply impossible to make that judgement based on the graph. There is no trend line (from 1997 or any other point) shown and even if there were it would be impossible to determine just by looking at it if it were statistically significant (ie it represents a genuine trend rather than just random variations in the data). One can only assume that Rose doesn’t actually understand the real meaning of this statement.

It is true to say that some scientists are now concluding that the higher end of the range of estimates for 21st century warming and climate sensitivity are looking unlikely. But then there was large uncertainty in such estimates anyway and the “most likely” ranges have not greatly changed and still give cause for concern. There are interesting and nuanced debates going on around this subject but Rose is not interested in them, and it is simply not true that scientists’ views have fundamentally changed or that Rose’s graph demonstrates that temperature projections have been vastly overstated.

We may or may not be heading for a climate change catastrophe but one certain thing is that the Mail’s coverage of the subject is truly catastrophic.

Update – Myles Allen, another scientist quoted by Rose in his abovementioned piece, also claims his views were misrepresented.

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