NASA (National Air and Space Administration) has now silently released corrected figures [1], and the changes are truly astounding. The warmest year on record is now 1934. 1998 (long trumpeted by the media as record-breaking) moves to second place. 1921 takes third. In fact, 5 of the 10 warmest years on record now all occur before World War II. Anthony Watts has put the new data in chart form, along with a more detailed summary [2] of the events.
Via Flut terby [3], “Blogger Finds Y2K (2000 Anno Domini) Bug in NASA Climate Data [4]”
If the article isn't enough to show we still don't know enough about the weather to make dire predictions, then the scores of comments should be enough, with both sides debating the various arguments (“Greenland is melting!” “But it's also revealing large Viking settlements showing it was warmer a millenium ago!”).
[1] http://data.giss.nasa.gov/gistemp/graphs/Fig.D.txt
[2] http://www.norcalblogs.com/watts/2007/08/1998_no_longer_the_hottest_y
[3] http://www.flutterby.com/archives/comments/10324.html#artid_34701
[4] http://www.dailytech.com/Blogger+finds+Y2K+bug+in+NASA+Climate+Data/art