OLE Humlum, Professor of Physical Geography, University of Oslo, Norway, puts out a regular monthly newsletter with the latest global climate statistics.
The latest update to January 2012 is here
This newsletter includes comment that following adjustments to temperature data held by the National Climate Data Centre (NCDC) early last year, and their subsequent incorporation by NASA’s Goddard Institute for Space Studies (GISS)…
The overall effect of the change introduced in the GISS record is towards lower temperatures in the early part of the record and higher in the latter part. The net result is therefore an enhancement of the overall global temperature rise since 1880. Various graphs are provided to illustrate the effect.