Dr Phil Jones back in drivers seat with CRUTem4 updated land only global temperature data – warms more than the UKMO CRUTem3 and with remarkable early outliers from Rio

CRUTem4 is just released and shows more warming than the UK Met Office dominated CRUTem3. Before I get on to CRUTem4 – a quick reprise of my Jan 2007 post commenting on CRUTem3 compared to our old friend of many years CRUTem2 (which ended in 2005). “Huge variations now between the 3 main global T datasets – January 31st, 2007″. I argued the view the that one reason for UKMO getting involved in CRUTem3 was they wanted to reduce excess warming in CRUTem2 northern high latitudes – more on that in another post where I will explore where CRUTem4 finds the extra warming.

I downloaded global and hemispheric trends from the official CRU website, CRUTem2 and CRUTem3 and 4.
CRUTem2 is from 1856-2005 while CRUTem3 and 4 run 1850-2010.
So I ran the MS Excel linest function for the 1856-2005 period for all 3 series, global, northern & southern hemispheres.

And for 1850-2010 for CRUTem3 and 4. Results summarized in this matrix – all trends are degrees C per decade.

The global differences chart shows the effect of the warming adjustments in CRUTem4 in the last 20 years – and cooling adjustments in CRUTem4 from ~mid 1850’s to 1890. (obviously cooling those years warms the overall trend). Note that from 1895 to the mid 1980’s the CRUTem4 minus CRUTem3 differences are small. The warmth in 1852 will be discussed later but stems from Rio de Janeiro data.

The northern hemisphere differences chart shows the effect of the warming adjustments in CRUTem4 in the last 20 years – and cooling adjustments in CRUTem4 from 1850’s to mid 1870’s. Note again that from the mid 1870’s to the ~1990 the CRUTem4 minus CRUTem3 differences are small.

The southern hemisphere differences chart shows the effect of the warming adjustments in CRUTem4 in the last 5 years – and cooling adjustments in CRUTem4 from the late 1850’s to ~1885 – much of which comes from adjustments to Australian grid boxes. (obviously cooling those years warms the overall trend). Note that from ~1895 to 2005 the CRUTem4 minus CRUTem3 differences are small. The outlier warmth in 1851-1852 stems from Rio de Janeiro data and we will investigate this in later articles.

Note that the Jones team already have some extra warmth built in for the CRUTem5 version – whenever that appears. They only have to adjust out the warm early years from Rio – and presto – there is a little more warming in the trend.
Added after comment #1.
Using the “Land” data from this University of Alabama at Huntsville site.
CRUTem3 warms much faster than the satellites and CRUTem4 faster still.

The period is to 2010 because CRUTem4 is not yet updated through 2011.
IMHO the CRU team consider themselves beyond effective scrutiny.

3 comments to Dr Phil Jones back in drivers seat with CRUTem4 updated land only global temperature data – warms more than the UKMO CRUTem3 and with remarkable early outliers from Rio

  • Beachgirl

    I have been pondering this and I can understand older data could carry more errors. But I have trouble understanding why errors should be found in new data and old data but few errors in the approx 100 years in between. Any ideas?
    Have you checked these trends against satellites?

  • Graeme Inkster

    How do they work out the Global average?

    From the figures quoted for CRUTem4 and UAH AMSU, I can only assume that the Southern Hemisphere is smaller than the Northern Hemisphere.

    It seems that the World has warmed 0.84 C, and the Northern Hemisphere by 1.05 C since 1979, at least in their own minds. No wonder they are parading around the streets in sandwich boards proclaiming “the end is nigh”.

  • Graeme Inkster

    From JoNova Werner Brozek says:

    Crutem4 is now on woodfortrees, but there is a slight problem. It only goes to the end of 2010…. but for what it is worth, here is what I did. I took the slope of crutem3 from 2002 to December 2010 and found it to be -0.00200314. Then I found the slope from 2002 to January 2012, its latest value, and found it to be -.00793462. The drop for the additional 13 months was 0.00593. The slope of crutem4 from 2002 to December 2010 was 0.00585. So if I am allowed to make the assumption that when crutem4 is completely updated, that there would be a similar drop, THERE WILL BE NO TEMPERATURE CHANGE in land FOR THE PAST DECADE.
    www.woodfortrees.org/plot/crutem4vgl/from:2000/plot/crutem4vgl/from:2002/trend/plot/crutem3vgl/from:2000/plot/crutem3vgl/from:2002/to:2011/trend/plot/crutem3vgl/from:2002/trend

    I think that when they update they will have to revise CRUTem3 retrospectively. But to quote John Wayne “a Climatologist has gotta do what a Climatologist has to do”.

    There is also some comment on Enguage Digitiser for extracting figures from these graphs.

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