Hansen’s 2001 paper exposed how NOAA and NASA massively corrupt the US temperature record. The image below shows the various steps of data tampering..
Before they start tampering with data, 47% of US rural stations cooled from 1900 to 1999, and 42% warmed. But after NOAA and NASA were done hacking the data, only 22% of stations were cooling and 69% were warming. They effectively contaminated rural stations with urban data.
Similar story for urban stations. After adjusting for UHI, the US apparently gets hotter. Note that after contaminating the rural data with urban data, both rural and urban stations appear nearly identical at 67-69% warming.
As awful as this 2001 data tempering was, they have continued to tamper with it since the 2001 paper was written. This graph shows the additional hockey stick of data tampering. Particularly note the spike after 1990, and hiding the warmth of the 1930s and 1940s.
Temperature graphs and press releases from NASA and NOAA grossly misrepresent the measured thermometer record, and in the case of the US actually reverse a long-term cooling trend into a warming trend.
Sensible adjustments would make urban stations look like rural, but NOAA/NASA do the exact opposite and make all stations look like the urban ones.