The United States Historical Climatology Network (USHCN) takes records from 1,218 stations around the US, which show the country on a century long cooling trend – as seen in the blue line below. But they alter the data to create a sharp warming trend before they release it to the public – as seen in the red line below.
The animation below shows how they tamper with the data, to create a non-existent warming trend from thermometers which show a cooling trend.
The next graph shows the spectacular hockey stick of data tampering they are doing, which increase US temperatures at a rate of 3.3 degrees F per century since 1997.
This is bad enough, but it gets even worse. Thirty percent of the temperatures USHCN reports, are completely fabricated, i.e. there is no underlying thermometer data at that station for that month.
The map below shows stations which have reported temperatures in 2014. They are fairly evenly spaced, and cover the entire lower 48 states.
So how do we know that the US used to be hotter? Over the past century, the percentage of maximum temperature readings over 100 degrees has dropped precipitously.
They normally try to explain this away by claiming that time of observation bias (TOBS) causes double counting of past 100 degree temperatures. This is complete BS, as seen in the next graph – which can not be affected by TOBS issues and shows nearly the identical shape.
The bottom line is that the US is cooling, and NCDC is hiding the decline through massive data tampering. They are defrauding the public, legislators and scientists through unjustifiable and incorrect adjustments.
The next graph shows the 317 stations which took their readings either at morning or at night on July 15, 1936. These stations have a warming bias due to TOBS, and would need upwards adjustments in the past. Despite their warming bias, they do not show any warming.