Mein Freund und Mitstreiter David Whitehouse hat einen Kommentar geschrieben, den ich heute auf CCNet veröffentlicht habe. Darin setzt er sich mit der Kritik an seinem heftig diskutierten Aufsatz auseinander, der jüngst im New Statesman erschien “Has global warming stopped?”:

My scientific training taught me to elevate data above all else. Whatever you might want the universe to do or to fit in with a cherished theory it is the data that tells you what the universe actually does. Huxley said, tongue in cheek, that it was the great tragedy of science that a beautiful hypothesis can be slain by an ugly fact. Data trumps everything…or does it.

Recently, I wrote an article pointing out that the global average temperature for the past 7 years was statistically flat – that is no analysis of that data could say anything about it other than it was a flat line. I didn’t think it was particularly controversial as I was merely stating what the data produced by the US National Climatic Data Center and the UK’s Met Office was saying. I wondered why the CO2 levels have gone up and the temperature had not. I discounted aerosols reflecting sunlight as there has been no big volcanic eruptions in over a decade and the IPCC says that the atmosphere’s aerosol load has declined, and doubted that decadal oceanic variations could do the trick either. You can read the article here:

http://www.newstatesman.com/200712190004

The article received a record 700 comments, mostly supportive. Several interesting points emerged (aside from the obvious fact that many who comment on such articles haven’t actually read them) that might be of interest to CCNet readers.

There are those who say the data does not exist and that I am lying! More puzzling are those who say that the data shows nothing of interest and that it is statistically irrelevant. Underneath this assertion is something very interesting. There is a vociferous body of opinion that says the data does not show the world hasn’t warmed and that in reality the upward temperature gradient of the years 1980 -1998 is still being maintained it’s just that the data does not show it! Some go on to say that in a 27 year temperature time series one would expect 7 flat years given the signal to noise ratio of the data.

To my mind this is seeing what you want to see and the maxim should be that the data shows what the data shows – if it shows the last 7 years is flat then that’s what mother nature says and no amount of arguing or statistical analysis is going to say it isn’t so. It seems to me these people deny the data to suit their own perspective. However, could we expect a 7 year standstill just by sampling errors alone even though the rising trend is still upward? It’s possible though highly unlikely, it is surely far more likely that the flat data represents flat data! Surely the important question here is: what would the data look like if the temperature has stopped rising. The answer is, of course, it would look exactly like what it does now. We should let Occam decide which explanation to choose.

Then there is the argument that 7 years is too short a timescale to prove anything. In a sense they are right, we do not know if the 7 flat years will continue or if the temperature will start to rise or fall afterwards. But many twist that question and use it to dismiss the 7 years of measured flat data as meaningless. This is not valid. The 7 years remains what it is – 7 years of measured flat data and it is not an insignificant fraction of the 18 years of warming we saw between 1080 – 1998. What’s more, the data set is not yet complete. It seems to me that many are judging those 7 flat years by different standards from that which they judge the 1980-1998 warming period and that is obviously unjustified.

The response to my article is here:

http://www.newstatesman.com/200801140011

It commits many of the sins I mention and more and even says my article will go down as the most controversial ever in that I claim that global warming has ‘stopped.’  It even denies that the period 2001-2007 has been measured as statistically flat and claims I made the elementary error of confusing long term average with year on year variability (seems that 18 years is a long term climatic effect but ten years is a year on year variability!) It says that although CO2 levels are rising year on year no one claimed that the temperature would do otherwise! Average things out and the trend is hotter. (no one denies that this decade is hotter than pervious ones so that is no response to my points). It cites as conclusive evidence a graph posted on the RealClimate website

http://www.realclimate.org/

that uses trend lines covering the recent post 1980 spell to prove that no recent standstill exists. The News Statesman response then makes some dodgy comments about the way science progresses.

The RealClimate graph is designed to prove what it wants to prove in that the statistical analysis chosen dilutes a 7 year flat spell at the end of a data series. It also includes no error bars on the annual temperature measurements and if it did the graph would tell a very different story and the trend lines would have a much greater degree of variation. The New Statesman reply says that similar 7 year standstills have occurred in the past so the current one is nothing special but it fails to add that those periods were statistically far more variable than the current 7 year standstill and that they were blips in an upward trend caused by El Chichon and Mt Pinatubo. There has been no similar event for the recent 7 years!

All things considered the New Statesman reply to my article fails to make any counter case when you look at the facts in detail and not in a shallow way with the eye of faith.

Finally, there is another aspect to the debate that worried me far more than an environmental ‘activist’ getting the science wrong. It is one of double standards and it has become rather predictable.

Provide any criticism, even mild or supportive, or even suggest that we might be wrong and that we don’t know everything and one’s integrity is attacked. I am accused of intentionally or otherwise of misleading the public and you will note the association made in the New Statesman reply between myself and those who posted comments who might have been paid to take a contrary position.

This idea that big energy companies are fuelling all so-called dissent has become a cliché and is often used reprehensibly by those who cannot respond scientifically to argument. One recent book about the catastrophe that is global warming even had a lengthy section about the tobacco industry denying lung cancer so as to set a parallel with the ‘climate change deniers’ camp.

On a recent TV debate that Benny Peiser and I took part in a representative from a well know environmental pressure group, who was obviously stressed and irritated by our comments, demanded that the question master make us swear we weren’t being funded by the oil lobby. Benny and I said we weren’t but thinking about it I should have demanded an apology for that slur before I decided whether to answer or not. We have reached a sad stage when such things happen. We should ensure that such debates are even handed and that both sides of any argument declare their vested interests, if any. Surely these big, campaigning groups have a stronger vested interest in global warming than most?

Finally this, another well know saying;

“Sit down before fact as a little child, be prepared to give up every preconceived notion, follow humbly wherever and to whatever abysses nature leads, or you shall learn nothing.”

David.