In 1975, the National Academy Of Sciences published this graph, showing about 1°C warming in the Northern Hemisphere from 1885 to 1940, and that all 1900 to 1940 warming was lost by 1970.
GISS has since reduced the 1885 to 1940 warming by half, and reduced the 1940-1970 cooling by two thirds.
The animation below shows how they reduced both the pre-1940 warming, and the post-1940 cooling. Neither are explainable by global warming theory, so government experts made both largely disappear.
So which one is correct? In 1923, the Arctic was very warm and melting rapidly.
But in 1970, the Arctic was very cold, and ice was expanding rapidly.
The 1975 NAS graph makes sense. The Arctic melting when it is warm, and freezing when it is cold.
But what about the current GISS graph? It shows the Arctic melting when it is cold, and freezing when it is warm.
It is painfully obvious that the GISS temperatures are fraudulent, yet several prominent skeptics continue to enable this scam by pretending that the NASA/NOAA temperatures are somehow legitimate.