In 1999, NASA reported the US was in a 70 year cooling trend.
Whither U.S. Climate?
By James Hansen, Reto Ruedy, Jay Glascoe and Makiko Sato — August 1999
Empirical evidence does not lend much support to the notion that climate is headed precipitately toward more extreme heat and drought.
in the U.S. there has been little temperature change in the past 50 years, the time of rapidly increasing greenhouse gases — in fact, there was a slight cooling throughout much of the country (Figure 2)
That story wasn’t scary and wasn’t going to raise any money for NASA, so they massively altered the data to create a warming trend. The 2014 version adds 1.3C/century warming from 1976 to 1998, which didn’t exist 15 years ago.
The thermometer data which NASA uses to generate the temperatures, shows the US cooling over the past 90 years