This peer-reviewed study tried to validate current surface temperature datasets managed by NASA, NOAA and the UK’s Met Office, all of which make adjustments to raw thermometer readings. Skeptics of man-made global warming have criticized the adjustments.
“You would think that when you make adjustments you’d sometimes get warming and sometimes get cooling. That’s almost never happened,” said D’Aleo, who co-authored the study with statistician James Wallace and Cato Institute climate scientist Craig Idso.
Their study found measurements “nearly always exhibited a steeper warming linear trend over its entire history,” which was “nearly always accomplished by systematically removing the previously existing cyclical temperature pattern.”
https://thsresearch.files.wordpress....ort-062717.pdf
From the study's summary and conclusion:
The conclusive findings of this research are that the three GAST data sets are not a valid representation of reality. In fact, the magnitude of their
historical data adjustments, that removed their cyclical temperature patterns, are totally inconsistent with published and credible U.S. and other temperature data . Thus, it is impossible to conclude from the three published GAST data sets that recent years have been the warmest ever – despite current claims of record setting warming.
Finally, since GAST data set validity is a necessary condition for EPA’s GHG/CO2 Endangerment Finding, it too is invalidated by these research findings.