So what happened around 1940. My theory - most of the temperature gauges are out side of urban areas, which are heat islands. During the war, most of the rural temp. gauges were ignored. The local folks taking the measurements were in the military or had more important things to do, like not get killed. So the temperature gauges in the cities, where it was more convenient to get the temperatures, were oversampled. Hence, the large warming bias in data.
Similar data manipulation has been taking place for the last 17 years, or since the Environmental Activists have takien over the Universities, NOAA and the rest.
muleskinner :" Similar data manipulation has been taking place for the last 17 years,
or since the Environmental Activists have takien over the Universities, NOAA and the rest" You failed to mention "The Weather Channel", the cable media darling of "GlowBull Warming"
who gives names to storms and weather tracks.