The planet is not warming. We have been cooling for 6 years. Because Solar Activity has been weak. Brightness means visible light and we know that visible light varies in only a very small percentage over the solar cycle. It is the infrared, ultraviolet, CME's and solar wind that change significantly over the solar cycle. These clowns got just about everything wrong.
Space Weather has announced the end of the solar minimum with glee. I visit this site every few days. They have some spectacular movies of the sun, sunspots, and coronal mass ejections (one going on right now), and their sun-activity data are fascinating.
We're having a heat wave here (Ohio) right now.