many surface measurements originally recorded in NOAA’s U.S. Historical Climatology Network (USHCN) have been replaced with temperatures “fabricated” from theoretical computer models.
In doing so, original recorded temperatures were subsequently lowered, thereby exaggerating warming in recent decades by comparison. Whereas the original records show that the U.S. has actually been cooling since the 1930s, the hottest decade on record,
http://www.newsmax.com/LarryBell/climate-global-warming-gore-co2/2015/02/16/id/624956/