In a post on the WUWT(Watts Up With That) blog Dr Ed Thurstan reveals the deliberate changes being made to past temperature data which gives the impression of modern warming. In March 2012 the Hadley Climate Research Unit released the land temperature data set Crutem 4. This deliberate alteration to the Crutem 4 data set is skewing temperatures to appear colder in the past and warmer in the recent years than previously reported. Unwarranted changes will of course help those in the climate alarmist movement whose intentions are to deceive the public that the earth is warming, when in fact the opposite is the case, the earth is cooling with no global warming for 15 years. Crutem 3 and 4 are widely used as an authoritative global temperature history. The WUWT blog edited by Dr Anthony Watts has done climate honesty a great service in exposing this latest alarmist strategy.
About 286 temperature stations in the Crutem 3 data set are dropped from Crutem 4, while 738 stations are added to Crutem 4. The adjustments have been made with reference only to the earlier Crutem 3 data rather than the raw temperature data. For example for Adelaide the temperatures recorded in Crutem 4 for the 30 years from 1857 have been lowered each month! After this there are no adjustments until the year 2000 when a smattering of adjustments appear, mostly raising the temperature! The total effect of all the differences between Crutem 4 and Crutem 3 where there is corresponding data is to accentuate the warming trend by lowering pre 1995 temperatures by 0.1 to0.2 celsius and raising post 1995 temperatures by a similar amount.
As a result Crutem 4 is seriously flawed and should be immediately withdrawn. Between 70 and 400 stations have been warmed up by up to 0.2 celsius since about 1995. The temperatures differences, where there are corresponding data in each of the data sets works to promote the impression of a temperature surge in the 1990`s. Crutem 4 and Hadcrut 4 are seriously flawed. More information on data and processing programs used are available from the author at firstname.lastname@example.org