Archives for July 30, 2008

A new paper by Demetris Koutsoyiannis et al has been published, which demonstrates that climate models have no predictive value. The full paper entitled, ‘On the Credibility of Climate Predictions’ is published in the Journal of Hydrological Sciences, and is available for free download. 18 years of climate model predictions for temperature and precipitation at 8 locations worldwide were evaluated.

The Abstract states:

Geographically distributed predictions of future climate, obtained through climate models, are widely used in hydrology and many other disciplines, typically without assessing their reliability. Here we compare the output of various models to temperature and precipitation observations from eight stations with long (over 100 years) records from around the globe. The results show that models perform poorly, even at a climatic (30-year) scale. Thus local model projections cannot be credible, whereas a common argument that models can perform better at larger spatial scales is unsupported.

Hat tip to Climate Audit

I was interviewed by journalist John Stewart on ABC TV’s Lateline program tonight.

The segment was about global warming with a focus on blogging.

Mr Stewart made the claim that the only place where the science is still debated is on the internet amongst bloggers. In fact we were accused of still “attacking” the science of global warming.

Interestingly Andrew Bolt was not described as one a News Ltd columnist but rather as a skeptic and a blogger. He was shown making the point that there has been no increase in global temperatures for ten years.

I was also as described as a blogger and also shown making the point that over the last 10 years it hasn’t got any warmer.

If Mr Stewart had gone to the trouble of checking the internationally recognised sources of real world (as opposed to computer generated) data on global temperatures he would have been able to confirm that what Mr Bolt and I said was correct: there has been no warming over the last ten years.

Monthly globally averaged lower atmospheric temperature anomaly since 1979 as measured by NOAA and NASA satellites.
With the additional mark up from gorelied.blogspot.com, with thanks.

Even James Hansen’s GISS data shows that global temperatures have plateued, if not cooled over the last ten years.

NASA GISS Monthly Mean Surface Temperature Analysis since 1998

But instead of the news program confirming our pronouncements with reference to the data (as they might on a business program), I was accused of “spreading doubt about the world getting hotter”.

Graeme Pearman was then introduced, not as a warmaholic, but as a former CSIRO scientist, with Mr Stewart explaining that he believed the data from the Hadley Centre in the UK provided no evidence that the world is getting cooler. [So does this mean the world might not be getting warmer?]

Monthly near-surface from 1850, from the Hadley Centre

Direct comment from Dr Pearman then followed in which he appeared to avoid reference to global temperatures instead making comment about temperatures in Australia – but the average viewer probably thought he was referring to global temperatures.

I did get to make two final important points: 1. that Climate Change Minister, Penny Wong, should look at the global temperature data and, 2. that it was wrong for the Minister to suggest, as she did recently with the release of the green paper on emissions trading, that 12 of the last 13 years have been the warmest in history.

This is indeed an outrageous claim with the Minister ignoring much of geological history.

The Minister might have got away with saying that of the last 150 years, the last 13 have been relatively warm. But to suggest that 12 of the last 13 are the hottest ever is just plain wrong. Whatever happened to the medieval warm period, not to mention that planet earth is very old – in fact about 4,550 million years old.

Of course the earth’s climate has always changed and continents have moved, mountain ranges formed and when continents have pulled apart huge quantities of volcanic water, carbon dioxide and methane have been released into the atmosphere.

Don’t forget that just 120 million years ago Australia was at the South Pole but it wasn’t cold. Global sea levels were about 100 metres higher than at present and the sea surface temperature was 10-15C higher than now. Indeed parts of inland Australian were once covered in a shallow tropical sea.

The Lateline segment finished with John Stewart stating that we, the bloggers, aren’t going to go away. He has got that bit right.

I would have like to have made a couple of additional points, ten years is not a very long period of time, but there is now a breakdown in what was a close correlation for about 30 years between increasing levels of carbon dioxide and increasing global temperatures.

It may of course start warming again next year – but a recent paper in the journal Nature suggests global temperatures may now plateau until at least 2015 – that is there may be no more warming for a few years.

Of course it is worth remembering that there has been a general warming trend for the last 18,000 years and over this period sea levels have risen about 100 metres.

All in all I think John Stewart did a pretty good job with a difficult topic.

In fact, I’m hoping he will now become a regular reader of blogs and start checking the temperature data and pondering the difference between correlation and causation with us.

Cyclone Nargis – of course it’s easier to read a graph than a cyclone.

Update
A video clip of the segment is now here: http://www.abc.net.au/news/video/2008/07/29/2318074.htm