There is a continuum from corrections based on known problems (essential), to adjustments based on probable errors in the data (good practice as long as all assumptions are made clear), to adjustments done solely to make the data fit a hypothesis (distinctly dodgy). (newscientist.com)
Would you explain how your knowledge apparently exceeds the stated / acknowledged probable errors (which are generally presented, BTW as being symmetric and hence suggest that even the creators of HADCRUT (for example) believe their uncertainty is unbiased and symmetric — except when it comes to making a correction that is supposedly a part of that error)? (wattsupwiththat.com)
Despite stating that «the physical facts agree» that large effects of global climate change will be realized in 50 years and that a 2 % decrease in fossil fuel consumption would «considerably ease» the «immediate problem,» the committee still focuses on the «large probable error» of the data. (climatefiles.com)