All this was over a small
Y2K correction [oops, see correction below] that lowered a few years of data for the U.S. by about a tenth of a degree. And what about the correction for global warming? Well, it's in the chart above.
Can't see it? That's not surprising. James Hansen of NASA, who applied the corrections to both the U.S. and global data, writes:
The effect on global temperature (Figure 2) was of order one-thousandth of a degree, so the corrected and uncorrected curves are indistinguishable.More here. Bottom line: there's no there there. Global warming is still real, still climbing, and still not a hoax. Tell your friends.
UPDATE: It looks I might be guilty of passing along an urban legend here. It wasn't a Y2K bug that prompted the temperature corrections, it was a switch between two sources of US temperature data that happened to take place between 1999 and 2000. "There had been a faulty assumption that these two sources matched, but that turned out not to be the case," says Gavin Schmidt. More here.