Global mean temperature 1850-2009
How has the global mean temperature evolved in the past. This was a simple question I had that I couldn’t find a straight answer to. So, I set out to calculate it for myself; it would also serve as a nice simple exercise in statistics.
I started out from some MATLAB code I found on a climate blog and modified it to my own needs. The data comes from the NOAA GHCN database http://www.ncdc.noaa.gov/oa/climate/ghcn-monthly/index.php.
The methodology behind the code below can be easily verified from http://stattrek.com/AP-Statistics-4/Margin-Of-Error.aspx or from http://en.wikipedia.org/wiki/Confidence_interval for example.