Global warming is partly caused by variation in the amount of sun light that Earth gets from the Sun. Acrimsat is the spacecraft that is currently measuring total solar irradiance. It launched in December, 1999, and it is continuing a data collection process that has been going on for 28 years. That is not a lot of time for the purpose of making long term forecasts, but it is now believed by the Project Scientist that as much as 25% of global warming is caused by an increase in total solar irradiance in recent years. Acrimsat is described at this web site.