I have shown a lot of data demonstrating that US and Northern Hemisphere temperature trends have been massively tampered with by NOAA and NASA. Their claimed goal was to make it line up better with southern hemisphere data, which supposedly has shown steady warming since the 19th century.
For example, CRU has been able to determine the southern hemisphere temperature to a precision of 0.001 degrees in August, 1850 – based on a single land thermometer in Tasmania.
1850 -0.897 -1.156 0.540 -0.577 -0.237 -0.072 -1.482 -1.182 0.000 0.513 -0.418 0.596 -0.364
http://www.cru.uea.ac.uk/cru/data/temperature/crutem3vsh.txt













