Paul Homewood takes a look at NOAA's temperature adjustments for Nebraska and makes the point: "Nationally, over the last century, temperatures have risen at a rate of 0.14F/decade, so if the Nebraska “adjustments” are applied across the CONUS, two thirds of this increase would be accounted for by adjustments".
Cooling The Past In Nebraska:
www.ncdc.noaa.gov/cag/According to NOAA, July 2012, the hottest month in Nebraska in recent years was still not as hot as either July 1934 or 1936. Comparison with 1934, for instance shows:
Mean
July 1934 81.4F
July 2012 80.0F
However, the original State Climatological Report for Nebraska tells us that the mean temperature in July 1934 was 82.5F, so what is going on?
www1.ncdc.noaa.gov/pub/orders/IPS/IPS-6A84C3F3-F1B7-4012-88CB-C82793FF966F.pdfOf course, it is always possible that the mix of stations has changed, but this is easy to check. There are 34 USHCN stations in Nebraska, which have records for both years, and these are split into eight climatological divisions. [These are labelled 1-9, but for some reason Division 4 does not exist!]. Remember that USHCN stations are regarded as “high quality” ones.
Monthly temperature data for each station is available from the State Climatological Reports, for 1934 & 2012.
By averaging temperature data for the two years within each division, and then weighting the divisional results on the basis of area, we can overcome any issue concerning mix.
The results of this exercise are shown in the Appendices. But to summarise:
Per State Climatological Reports
Per NOAA
July 1934
82.2F
81.4F
July 2012
79.8F
80.0F
Difference
2.4F
1.4F
So, in relative terms, NOAA’s current version makes 2012 a full degree warmer, essentially by cooling the past. Remember too that, if anything, older temperatures should be adjusted UPWARDS to allow for UHI.
Of course, this does not simply apply to Nebraska. As previous exercises have shown, the same sort of cooling the past has taken place on a nationwide scale. I have challenged NOAA to tell me exactly how their current calculations for 1934 are arrived at, and why they are so different to the original figures. Other than giving me a bit of waffle, they were totally unable to.
There are two possible answers:
1) Their results are heavily skewed by unreliable urban/airport sites, which add a warming bias.
2) They have adjusted past temperatures downwards.
Nationally, over the last century, temperatures have risen at a rate of 0.14F/decade, so if the Nebraska “adjustments” are applied across the CONUS, two thirds of this increase would be accounted for by adjustments.
Link:
notalotofpeopleknowthat.wordpress.com/2014/03/25/cooling-the-past-in-nebraska/