How to create a false rising temperature trend

This is the USHCN temperature measuring station in Orland, California. It has been in the same location for over 100 years






Here is what has happened when the raw data has been adjusted.







See what has happened? The Pre- 1940 raw data has been adjusted downward and the pre-1900 data removed altogether. This "old" raw data has now been removed from the public domain. We are just lucky that it has been preserved by folk who care about REAL data.

The effect is to create an apparent upward trend where none exists. This trick has been repeated all over the world to suggest an "unprecedented" late 20th century warming which is the basis of the AGW scare.

See the full article here

http://wattsupwiththat.com/2009/12/11/giss-raw-station-data-before-and-after/