HADCRUT4 V HADCRUT3: ‘The new version (of global temps) increases warming (or rather decreases cooling) since 1998 by 0.09C, a significant amount for a 13 year time span’
'Whilst the changes should not affect the trend in future years, they will affect the debate as to whether temperatures have increased in the last decade or so...We already know from UAH satellite data that the Antarctic has been cooling since 1980. It would therefore seem that HADCRUT4 has introduced a bias of its own, by increasing coverage of the warmer Arctic but not doing the same in the cooler Antarctic'
