One of the things we have learned about GISS is that they overwrite data in place. For example, there have been several radically different versions of the Reykjavik temperature data already this year. They have blocked access to data archiving engines like web archive, so you can’t find old GISS data there either.
On January 18, 2011 someone at GISS apparently tried to destroy this graph, which showed that Hansen used to believe that the 1930s was the hottest decade.
The corrupted version of the graph looked like this
It is very unlikely this happened by accident, but because I had archived an older version, I was able to report on the change. The original file was restored a few days later. The source data behind this graph has been deleted from the GISS file system.
If interested parties continuously archive as much GISS data as possible, we can track their endless alteration of the climate record. Too bad we can’t get back the disappeared data from the 1990s.