Not seeing the wood for the trees

This is a transcript of an email I sent to Paul Clark, the owner of the website Woodfortrees.org – from which graphs have appeared in presentations by numerous people who dispute the reality of anthropogenic climate disruption.

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Dear Paul,

RE: Your Comparison of HADCRUT3 and HADCRUT4 datasets

I have found my way to your website via a comment by Dan Olner on Peter Sinclair’s Climate Denial Crock of the Week.

I note that on your Home Page you say:

I have no particular axe to grind in the “Global Warming Debate” one way or the other. Indeed, as a life-long Green I think a shift to an efficient and sustainable way of life is a Good Thing whether or notCO₂ is a significant problem in and of itself.

Whilst I am not questioning your sincerity in making this statement, I am afraid I am bound to ask you two things:
1. What do you think the data tells us? and
2. Is it really appropriate to encourage non-experts to play around with it?

With regard to (1), my attention was drawn to your comparison of HADCRUT3 and HADCRUT4 and, yes, my first reaction was, “Why are they so different?” If I were David Rose, Christopher Monckton, or even Richard Lindzen, I would no doubt be very suspicious of the fact that HADCRUT4 anomalies are generally higher than those calculated for HADCRUT3. Therefore, I ask you, what purpose does it serve to present this comparison without a legitimate explanation as to why the two data sets are different? If you are in need of one, try this by Dana Nuccitelli on the Skeptical Science website.

With regard to (2), I am concerned about the frequency with which your website is used by climate change “skeptics” (such as those mentioned above) and therefore feel that, however good your motives are, you are merely encouraging unqualified people to bolster their unwarranted confidence in their unreasonable conclusions.

Returning to the comparison of HADCRUT3 and 4, I note that you have inserted a trendline for both over the last 1980-2010 (in addition to trendlines for the complete data sets). Have you considered inserting trendlines for both for the periods 1850-1910 and for 1910-1980? In fact, I suspect you don’t really need to do this: Just looking at these graphs, it is clear that there are three distinct changes:

– 1850-1910 – a downward trend of about 0.06/decade;
– 1910-1980 – an upward trend of about 0.08/decade;
– 1980-2010 – an upward trend of about 0.18/decade.

This is, therefore, yet another confirmation that the MBH98 ‘Hockey Stick’ cannot legitimately be dismissed as an artefact of statistical manipulation of data. In other words, it is signal not noise.

You call your website WoodForTrees but, with the greatest of respect, I think you are facilitating the denial of plain facts by people who don’t want to accept the nature of reality (mainly because of an underlying libertarian agenda). On your Home Page you may well pose all the right questions but, sadly, the vast majority of people who use or refer to your website appear to be coming to invalid conclusions.

Whereas a variety of natural factors contribute to global cooling – the Sun, ocean currents, and volcanic eruptions; only anthropogenic CO2 can explain the accelerating warming trend of the last 100 years.

I suspect you feel you are doing the right thing in encouraging everyone to play around with the data and satisfy themselves that they know what is happening. However, all the evidence suggests that your website is encouraging the unconsciously incompetent to play around with things they don’t really understand and reinforce the prejudicial insistence that we do not have a problem.

Irrespective of whether you respond to this email (I hope that you will), I am going to publish it on my blog at midnight tonight (British Summer Time [UTC+1]).

Kind regards,
etc.

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