Prior to the year 2000, NASA showed US temperatures cooling since the 1930′s, and 1934 much warmer than 1998.
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
NOAA and CRU also reported no warming in the US during the century prior to 1989.
February 04, 1989
Last week, scientists from the United States Commerce Department’s National Oceanic and Atmospheric Administration said that a study of temperature readings for the contiguous 48 states over the last century showed there had been no significant change in average temperature over that period. Dr. (Phil) Jones said in a telephone interview today that his own results for the 48 states agreed with those findings.
New York Times
Right after the year 2000, NASA and NOAA dramatically altered US climate history, making the past much colder and the present much warmer. The animation below shows how NASA cooled 1934 and warmed 1998, to make 1998 the hottest year in US history instead of 1934. This alteration turned a long term cooling trend since 1930 into a warming trend.