Currently 1998 is the hottest year on record. Two combined land and sea surface temperature records from Nasa's Goddard Institute for Space Studies (GISS) and the US National Climatic Data Centre (NCDC) both calculate that the first six months of 2010 were the hottest on record. According to GISS, four of the six months also individually showed record highs.
At the time the article was written, the first six months of 2010 were hotter than the corresponding months in 1998. Unfortunately that trend continued, and this year NOAA announced that 2010 had tied with 2005 for the hottest year on record. (2005 was hotter than 1998; the guardian got that fact wrong).
Nothing succeeds like excess. -- Oscar Wilde