I think you misunderstand that graph or maybe I do but these adjustments are algorithmic changes that adjust the various processes used to “sanitize and clean” the raw data from thermostats. These are not adjustments that arise say from a clock that is losing time.
Over the years the climate community has played with the algorithms for Time of day bias, homogenization and other algorithms that are meant to correct for what are thought to be errors in the instruments or lack of regional coverage of thermostats.
I fail to see how those adjustments would always be in one direction. It is as if the scientists were only looking for reasons or ways to up the temperature difference. Never thinking of anything that might do the opposite.
I have found the adjustments unbelievable for a number of reasons.
1) the reason shown here
2) the homogenization algorithm definitely seems to introduce a global warming boost and I’m not clear why
3) the raw data looks closer to the satellite data, balloon data and ocean data from ARGO than the adjusted data
4) there is no physical reason why land temperatures should climb more than atmospheric temperatures given the bulk of CO2 is in the atmosphere. If there is some anomalous warming of the surface relative to the bulk of the atmosphere it would indicate that the warming is NOT CO2 related but something else.
5) When I tried to use the adjusted data in my model I couldn’t get it to converge whereas the raw data converged nicely to a very low error indicating to me that either my model is wrong or there is something wrong with the adjustments.
6) The adjustments radically change the 1930s and 40s to being substantially colder than todays temperatures. I find this hard to believe. If you look at contemporaneous records in the temperature databases you will find the 30s and 40s produced a remarkable number of very hot days including many many records that stand today. Also, when you look for number of days over 90, over 100, duration of heat spells the 30s and 40s beat the current time, especially 1936 and one or two other years. The arctic also shows very strong evidence that it was warmer then than today. We have other evidence such as dust storms.
I just find it extremely hard to believe that history isn’t being rewritten by these adjustments. It seems unbelievable that the temps then were 1C colder than today and that temps stayed pretty much flat and then took off in the 80s. We know that from 1945–1965 the cooling was so pronounced that people thought we were going into another ice age. The temperature record after these adjustments looks completely unreal if you know the real history that people talked about.
I am very concerned that climate scientists are literally attempting to rewrite history. They are so zealous in pursuing this ideology they will trample all history and apparently don’t feel any need to give an explanation why all these things didn’t happen as people thought just a few years ago.