The RSS data is just since 1979 and is based on radiation given off by different levels of the atmosphere. There have been some adjustments to the data based on changes in the satellites' heights, but this is mostly non-controversial.

Download the data and run my script. It will be fun and "sciencey".

http://images.remss.com/msu/msu_time_series.html

https://en.wikipedia.org/wiki/Satellite_temperature_measurem...

[EDIT] I don't have to the mod points to downvote anyone :)