date: Thu, 20 Dec 2007 16:39:06 -0000
from: "Robert Matthews" <robert.matthews14@btinternet.com>
subject: Re: BBC Focus magazine
to: "Phil Jones" <p.jones@uea.ac.uk>

   Great - thanks ! I see the story has been picked up on CC-NET; perhaps you should post this
   really handy rebuttal on there, before this story "gets legs" and is picked up by all the
   usual suspects (It's the Christmas silly season, and the papers are desperate for
   stories.....).



   Robert







   ----- Original Message -----

   From: [1]Phil Jones

   To: [2]Robert Matthews

   Sent: Thursday, December 20, 2007 4:32 PM

   Subject: Re: BBC Focus magazine

      Robert,
          This story has been doing the rounds for the last 18 months. There is nothing new
      in it. It's been wrong every time it's been used. It comes from people who have
      no comprehension of the climate system. I was surprised this time, as I thought
      this writer ought to have know better.
         Just look at the global temperature series that you now have the associated errors
      for. There is a lot of variability on the annual timescale.  A lot of this is just
      natural variability of the climate system. The trend is upwards. Some of the
      variability of the global temperatures is caused by El Nino/La Nina events. El Nino
      tends to make the world warmer and La Nina cooler. A measure of El Ninos is
      the Southern Oscillation Index (the difference in pressure between Darwin
      and Tahiti). When you regress this against global temperature you can explain
      quite a bit of the high-frequency variance due to the major El Ninos and La Ninas
      that have occurred since the mid-19th century.  I wrote about how to do this in
      1990 (see the pdf).
           The upshot of this is that 1998 is about 0.15 deg C too warm because of the
     1997/98
      El Nino influence - this El Nino being the biggest of the 20th century.
          So 1998 could be considered the problem, not the later years. There hasn't
      been much of an influence either way for the last 6-7 years.
          So if 1998 is reduced by 0.15, we would have all 7 warmest years as the warmest 7.
          Another way of looking at this is that all 7 years (2001-7) have a global
     temperature
      anomaly above 0.4 deg C.  The only year before this with a value above 0.4 is 1998
      (with 0.52).  The last 7 years contain the second through eight warmest years in
      the series.
          Finally, as a climatologist, I wouldn't look at a temperature trend over such a
     short
      period as 10 years. I know, as you now do, that the global temperature series
      has error estimates. Given these errors, it would be impossible to get a statistically
     significant
      trend for any 10 year set of global temperature data chosen from any period in the
      global temperature record. It is likely that you will get a few periods that might be
     significant,
      but then you have to consider that you'd expect about 5% of samples significant.
         So, knowing this, put the global T numbers for 1998 to 2007 into an excel
     spreadsheet
      and calculate the trend. It isn't significant - it definitely isn't allowing for the
     errors.
      Despite this the trend is POSITIVE. So despite starting with the warmest year, a linear
      trend fit through the 10 years from 1998 to 2007 gives a POSITIVE trend.
          So the world is warming....
       It will continue to, it just won't be a monotonic increase. It hasn't been like this
     in
      the past, and it won't be like that in the future. There is a case for the temps to
      have risen in a series of steps  --- well to my eye anyway.
        The 1998 record will get broken - we just need the next reasonable sized El Nino.
      Cheers
      Phil

     At 16:07 20/12/2007, you wrote:

     Hi Phil

     Thanks again for your help with the global warming figures. As it happens, the New
     Statesman has just published a piece about whether global warming is still continuing
     (it's here: [3]http://www.newstatesman.com/200712190004 ). I'd very much welcome your
     views on it.
     Best wishes
     Robert

          ----- Original Message -----
          From: [4]Phil Jones
          To: [5]Robert Matthews
          Sent: Tuesday, December 18, 2007 10:07 AM
          Subject: Re: BBC Focus magazine
           Robert,
             The attachment has the information you are after. This also has the full press
           release - all the background information that journalists could have asked for on
           Dec 13. This should have gone out from the World Met Organization from
           Geneva on Dec 13 as well.
             The error ranges are shown in 2 different ways.
          1 . Figure 1 (95% confidence values - so 'true' value will be in the range
           19 times out of 20) with the global T values ranked from highest to lowest.
           2. Figure 2  (top panel for the Globe, but also with the NH and SH there as well).
           These are the same values (and ranges) as in Figure 1 but plotted as a
           time series (the usual way).
            You'll see the errors are larger further back in time - especially in the 19th
           century. This is because there are fewer obs and the coverage gets sparser
           as regions drop out.  2007 has slightly wider error bars as we've estimated
           December.
            There are plots for smaller regions - the tropics, extratropics (30-90degrees N or
          S),
           arctic and antarctic sea ice areas, and some more local series for the UK.
           Cheers
           Phil
          At 18:24 17/12/2007, you wrote:

          Dear Professor

          I'm putting together a piece about the current rate of global warming, and was very
          interested in the data presented at Bali as summarised by the BBC News website here:
          [6]http://news.bbc.co.uk/1/hi/sci/tech/7142694.stm

          As the values are point-estimates extracted from a large number of measurements,
          presumably they should have some kind of standard deviation error bars associated
          with them. I wondered if you either knew the approximate size of these error bars
          (or even a graph showing them)?
          Thanks so much for your help with this.
          Best wishes
          Robert


          ------------------------------------------------------------------------------
           Robert Matthews
           Science Consultant, BBC Focus Magazine
           47 Victoria Road, Oxford, OX2 7QF UK
           Email: [7]rajm@physics.org
            [8]www.focusmag.co.uk
           Tel: (+44)(0)1865 514 004 / Mob: 0790-651 9126
           -----------------------------------------------------------------------------

          Prof. Phil Jones
          Climatic Research Unit        Telephone +44 (0) 1603 592090
          School of Environmental Sciences    Fax +44 (0) 1603 507784
          University of East Anglia
          Norwich                          Email    p.jones@uea.ac.uk
          NR4 7TJ
          UK
          ----------------------------------------------------------------------------

          __________ NOD32 2729 (20071218) Information __________
          This message was checked by NOD32 antivirus system.
          [9]http://www.eset.com

     Prof. Phil Jones
     Climatic Research Unit        Telephone +44 (0) 1603 592090
     School of Environmental Sciences    Fax +44 (0) 1603 507784
     University of East Anglia
     Norwich                          Email    p.jones@uea.ac.uk
     NR4 7TJ
     UK
     ----------------------------------------------------------------------------

     __________ NOD32 2738 (20071220) Information __________
     This message was checked by NOD32 antivirus system.
     [10]http://www.eset.com

