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Sunday, October 6, 2013

Tony Brown's Cooling England

Sou | 4:45 PM 12 Comments - leave a comment

Speaking of credibility, I've noticed that Tony Brown is a bit of a darling at Judith Curry's blog.  His hobby is the surface temperature record for central England.  I admire him for his "profound" tenacity but not for his interpretative ability.  I've written about his WUWT ponderings before, when he was trying to argue that central England was a "good proxy" for global surface temperatures and drawing all sorts of oddball conclusions.  Today I noticed him popping up in the comments to the David Archibald article at WUWT (archived here), writing:

climatereason says (excerpt, my bold italics):
October 5, 2013 at 11:40 am
...here is CET to 1772. Temperatures have been dropping sharply for a decade. We are back to the climate of the 1730′s.
http://www.metoffice.gov.uk/hadobs/hadcet/
tonyb

Here's the chart to which Tony linked:


No, Tony Brown, Central England is not back to the climate of the 1730s


Tony has a case of confirmation bias.  He claims that "we are back to the climate of the 1730s".  To see if he's correct, we'll have to go to the longer record than the one to which he linked, which doesn't go back that far.  Let's first look at the long term decadal record for HadCET, which is better than annual temperature anomalies when considering climate change.  The trend becomes obvious:

Data Source: HadCET

The 1730s decade is the teeny orange bit wedged between all the blue columns at the left of the chart above. Now to look in closer, here are the temperature anomalies from 2001 to 2012 and the temperature anomalies from 1731 to 1742 - the anomaly is from the twentieth century average:


Year Anomaly Year Anomaly
1731
0.35
2001
0.43
1732
0.19
2002
1.10
1733
0.97
2003
1.00
1734
0.30
2004
0.98
1735
0.04
2005
0.94
1736
0.80
2006
1.32
1737
0.42
2007
0.98
1738
0.31
2008
0.46
1739
-0.30
2009
0.61
1740
-2.66
2010
-0.67
1741
-0.20
2011
1.20
1742
-1.14
2012
0.20
Average
-0.08
Average
0.71


Some years in the 1730s were quite warm compared to the century as a whole.  But the climate back then was nothing like what it's been like lately, as indicated by surface temperature.  Since 2001, the average temperature for central England was 0.71 degrees above the twentieth century average while the twelve year period since 1731 was 0.08 degrees below the twentieth century average.  The two periods are hardly comparable.


Have temperatures been "dropping sharply"?


Tony Brown writes that "Temperatures have been dropping sharply for a decade."  Let's see:

Data Source: HadCET
The above chart shows that 2010 was a cold year in Central England.  That year also happened to be the hottest year on record globally, equal to 2005.  On the other hand, the following year, 2011, was the second hottest year ever  in the 350 year record of central England temperatures, after 2006!

Here are the two periods compared in an animated chart, with the temperature scale held constant for easy comparison:

Data Source: HadCET

The only similarity I can see is that both periods can be measured as anomalies from the twentieth century mean in degree Celsius!  
Here is an animation of more periods for central England.  Look particularly at the first part of last century, to 1969, compared to the time since 1970:

Data Source: HadCET

Who is Tony Brown trying to kid?  I don't know if he really thinks the world is about to enter another ice age or not, but if he does he's deluded.  

Data Source: SkepticalScience.com

In regard to what will happen in central England, that's another matter.  At the macro level, here are the IPCC AR5 projections for temperature change under two emissions scenarios from the Summary for Policy Makers, page SPM-34 (click for larger version):

Source: IPCC AR5 WG1 page SPM-34

If the above is anything to go by, then England will get warmer if we keep burning fossil fuels.  Maybe not as much as some areas but more than others.  If we were to cut emissions and follow the RCP2.6 emissions pathway then temperatures in England might change very little from those of the period 1986-2005.  However the opportunity to do that is fading fast.

12 comments:

  1. Perhaps I will provide a comment that's as meaningless as Tonyb's. I am in York and it is unseasonably warm at the moment. Yesterday was t-shirt weather and I believe it's going to be something similar today. I am still waiting for it to get cold enough to wear a coat. York may not be central England but because it is just a little bit further north, I would have expected that it would be colder here by now and it's just not cold at all.

    ReplyDelete
  2. I've pointed out to Tony B several times that he should not be using the early part of the CET as prior to 1772 it is not considered sufficiently reliable. He tried to waffle his way around the insurmountable problem then resorted to insisting that his point was valid when it obviously is not. His continued repetition of this claim proves him to be dishonest.

    See Parker et al. (1992) here. Please note: it's *big* - a 10.8Mb pdf of a scan of the original:

    Manley (1953) published a time series of monthly mean temperatures representative of central England for 1698-1952, followed (Manley 1974) by an extended and revised series for 1659-1973. Up to 1814 his data are based mainly on overlapping sequences of observations from a variety of carefully chosen and documented locations. Up to 1722, available instrumental records fail to overlap and Manley needs to use non-instrumental series for Utrecht compiled by Labrijn (1945), in order to mate the monthly central England temperature (CET) series complete. Between 1723 and the 1760s there are no gaps in the composite instrumental record, but the observations generally were taken in unheated rooms rather than with a truly outdoor exposure. Manley (1952) used a few outdoor temperatures, observations of snow or sleet, and likely temperatures given the wind direction, to establish relationships between the unheated room and outdoor temperatures: these relationships were used to adjust the monthly unheated room data. Daily temperatures in unheated rooms are, however, not not reliably convertible to daily outdoor values, because of the slow thermal response of the rooms. For this reason, no daily series truly representative of CET can begin before about 1770. In this paper we present a daily CET series from 1772 to the present.



    ReplyDelete
    Replies
    1. Thanks, BBD. That's useful to know. Does the same proviso apply to monthly series as to daily do you know?

      The Met Office Hadley Centre provides daily from 1772 as you've indicated but they provide monthly from 1659. I figure that means they think the monthly is okay although I presume the earlier years would have larger uncertainties than the modern (recent) record.

      Delete
    2. Thanks, BBD. That's useful to know. Does the same proviso apply to monthly series as to daily do you know?

      I think it must. The various issues affect the raw data which is discontinuous, non-overlapping and in some cases non-instrumental and from the Netherlands, not CE. Nothing prior to the start of the continuous daily record in 1772 can be considered robust - and I'd be caution about the first ~100y of that too.

      The other irritant here is that the CET is a regional series - it doesn't represent England, let alone the UK. Here's the Met Office data for the whole UK - annual means to 2012.

      Not much like Tony's pet graph, is it? He's just cherry-picking at the bottom of the regional barrel and he's been told, so he's now being dishonest.

      Delete
    3. i didn't know that, BBD. a fascinating read, thanks! :-)

      Delete
  3. At least it's about Central England. Usually everything in the UK is about London.

    Thanks BBD; the take-away message appears to be that we're not dealing with raw data here. On the positive side, at least none of the sites involved before the 20thCE were at airports, so maybe Watts gives it a pass for that.

    One thing you can say for deniers, they've evaded the hobgoblin of foolish consistency.

    ReplyDelete
  4. For all its potential inconsistencies, the good thing about the CET record is that it goes back all the way to 1659, and there's no better instrumental record which is as old as that.

    As far as the 1730's are concerned (and I was surprised to see that you think they now include 1740, the coldest year in the whole 350 year record), the average CET for the 120 months was 9.86 C.

    The average for the most recent 120 months to October 2013 is 10.09 C, so not all that different. The average for the most recent 60 months is 9.70 C, even colder than the 1730's. Maybe 5 years is a bit too short to talk about "climate" but you can understand what prompted his original comment.

    ReplyDelete
    Replies
    1. Tony's comment was flat out wrong on two counts. CET temperatures haven't been "dropping sharply for a decade". The latest ten years includes the two hottest years in the entire record.

      And central England shows no sign at present of returning to anything like the climate of the early 1700s.

      The only way I could understand what prompted Tony's comment would be if he were either an 8% dismissive or a disinformer.

      Delete
    2. For all its potential inconsistencies, the good thing about the CET record is that it goes back all the way to 1659, and there's no better instrumental record which is as old as that.

      The CET is not an instrumental record extending back to 1659. Nor can the CET prior to 1772 be treated as reliable. Attempting to calculate averages for 120 month periods is absurd.

      Please read thread before posting further rubbish on it.

      Delete
    3. It's amazing how a public record like the CET, with its freely available supporting literature, is taken to be something it is not. Anyone who has read Manley and Parker on the assembly of the data will know that the first century and a half of it is more interesting for its history than its accuracy. The error margins are huge, and claims about relative properties of individual years and decades are useless.

      Delete
    4. The CET is not an instrumental record extending back to 1659. Nor can the CET prior to 1772 be treated as reliable. Attempting to calculate averages for 120 month periods is absurd.

      You should address that to the owner of the blog. She was the one who wrote an article discussing the temperatures of the 1730's, which contain exactly 120 months

      Delete
    5. No, I am addressing my comment to you, and peripherally, to TonyB. You are both guilty of error. You have both now been corrected and neither of you are capable of admitting your errors.

      Sou simply demonstrated that TonyB's claims about the CET are incorrect. I point out that his *use* of it is meaningless.

      Delete

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