Steve McIntyre found an error in the GISS temperature data for the US. The GISTEMP page says:
USHCN station records up to 1999 were replaced by a version of USHCN data with further corrections after an adjustment computed by comparing the common 1990-1999 period of the two data sets. (We wish to thank Stephen McIntyre for bringing to our attention that such an adjustment is necessary to prevent creating an artificial jump in year 2000.)
How much difference did the adjustment make to the US temperature series? Well, it changed this:
Not much difference. The right hand end of the red curve has moved down a little bit, but this decade is still the warmest ever recorded in the US. The change to the global temperature series is imperceptible.
Of course, if you’re Steve McIntyre, you want to make this seem like a big deal. So what do you do?
Well, it’s hard to see from the graph, but 1998 went from being 0.01 degrees warmer than 1934 in the US, to being 0.02 degrees cooler, so he was able to present this as OMG! 1998 NO LONGER THE HOTTEST YEAR ON RECORD, NOW IT’S 1934. Right wing blogs started foaming at their mouths. Examples:
it suggests that a government agency is actually participating in a fraud against the American people by withholding information crucial to a major policy issue now facing the nation.
Fire [James Hansen]. Immediately.
The Ace (This is a different person from “Ace” — I think we should pop “Ace” and “The Ace” into Thunderdome.)
leftist hero James Hansen is behind this deliberate fraud. He should be frog-marched out of his office.
And the bottom line is, that 1998 is no longer — you can say NASA made a reporting error or did they make a reporting error? Did they do this on purpose? How long have they known that it was erroneous and haven’t corrected it? But the bottom line of this is that 1998 is no longer the hottest year on record. … Well, when 1934 was the hottest year on record, and NASA may know about it and doesn’t correct the data, and when a guy named James Hansen involved in all this, who is a political activist, then you have to figure there is a reason why they want 1998 continue to be reported as the warmest year on record.
I’ll let Nexus explain this one for Mr Limbaugh.
Also busy exaggerating is good old Roger Pielke Sr:
The hard work of of Steve McIntyre (Climate Audit) and Anthony Watts (www.surfacestations.org) has resulted in the identification of a significant error in the assessment of the rankings of what have been the warmest years in the United States as identified by GISS. The current warmest year is 1934.
1998 and 1934 went from being in a virtual tie, to being in a virtual tie. This is not a significant change. You would have hoped that Pielke Sr would have been aware of this, but I guess not.
Update: More from RealClimate.