In the November 1976 issue of National Geographic, they showed a Little Ice Age followed by a sharp warming spike to 1940, and then cooling back to 1880 levels.
This cooling back to 1880 levels was also shown by NCAR, and the National Academy of Sciences.
The warmth of the 1930s/40s and subsequent cooling was well documented.
This warmth of the 1930s and 1940s, turned rapidly into cooling and fears of a new ice age.
The post-1940 cooling ruined the global warming story, so NASA and other climate scientists erased it.
This strategy of hiding the warm past was openly discussed in Climategate E-mails.
But that was just the beginning. The removal of the post 1940’s cooling, paved the way for “Mikes nature trick” to “hide the decline“ in the proxy data – and erasure of the Medieval Warm Period and Little Ice Age.
Prior to erasure of the Medieval Warm Period by Michael Mann, NASA’s James Hansen in 1981 showed a Medieval Warm Period and Little Ice Age.
Global temperature trend is based on temperatures in central England, the tree limit in the White Mountains of California, and oxygen isotope measurements in the Greenland ice (W. Dansgaard of the Geophysical Isotope Laboratory, University of Copenhagen, pers. comm.), with the temperature scale set by the variations in the last 100 years
The 1990 IPCC Report showed a Medieval Warm Period and Little Ice Age.
But climate scientists plotted to erase the Medieval Warm Period, and that is exactly what they did.
By 2001, the Medieval Warm Period, Little Ice Age, and post-1940 cooling had been officially erased. Just as the climate scientists planned to do.
The Medieval Warm Period was well documented history. Greenland was much warmer a thousand years ago.
The pattern of climate scientists plotting to erase past warm (and cold periods) is well established, and completely fraudulent. NASA has doubled pre-2000 warming over the past 19 years.
And NOAA has turned a long-term US cooling trend into warming.
This fraud is being committed blatantly, right in front of everyone’s eyes.