In 1989, the head of NOAA’s National Climatic Data Center said that earth cooled from 1921 to 1979. Now they show lots of warming during that period.
Analysis of warming since 1881 shows most of the increase in global temperature happened before 1919 — before the more re-cent sharp rise in the amount of carbon dioxide in the atmosphere. said Thomas Karl, of the National Oceanic and Atmospheric Administration’s National Climatic Data Center in Asheville, N.C. While global climate warmed overall since 1881, it actually cooled from 1921 to 1979, Karl said
NOAA graphs now show a warming trend from 1921 to 1979.
In 1921, the Arctic was very warm and glaciers were rapidly disappearing.
In 1922, the ice between Alaska and the North Pole was thin, rotten new ice.
But in the 1970s, people were worried about global cooling and a new ice age.
The Northern Hemisphere had been cooling for 30 years.
This graph was published by the National Academy of Sciences in 1975, showing 0.5C cooling in the Northern Hemisphere after the 1940s.
That 30 year cooling trend has since turned into a warming trend.