Although the USHCN version used in Hansen’s 1999 press release seems to be expunged from official U.S. government records, it was fortunately preserved by John Daly. Jerry Brennan sent me a link to a version preserved by John Daly yesterday, from which I was able to replicate the version in the 1999 press release, as shown below.
Figure 1. USHCN Version from 2000. Left – From Contemporary Press Release; Right – from data archived by John Daly. Both are 1951-1980 anomalies in deg C.
Now here’s the fun part. Here’s a recent NOAA version of the same data. If you look carefully, you can see that the late 1990s are higher and the 1920s and 1930s are lower. Compare 1999 to earlier years.
The graph below shows the difference between the version archived in 2000 and the version downloaded from the table-making NOAA webpage. These are obviously not small adjustments – as the adjustment is approximately the same amount as the temperature increase being observed.
The effect of the adjustments since 2000 has been to bring the USHCN history more in line with the CRU version. One wonders exactly what adjustments have been performed by CRU and others and the recent admission by Brohan et al 2006 that original versions of many series have been lost (or never even collated by CRU in the first place) leaving only the adjusted versions at CRU (with the nature of some or all of the adjustments undocumented and unknown) is extremely disquieting.
Update: Jerry Brennan observed that the comparison above is between the 2000 GISS version and the 2007 NOAA version and that the more appropriate comparison was between GISS versions. I’ve done so below from the GISS data yielding the differences below: red – GISS2007 vs GISS 2000; blue – NOAA 2007-GISS 2000. So the effect exists with GISS adjustments as well. The proposed NOAA beta version looks like it’s going to increase the adjustments shown below even more (as noted above).