a red herring, and a disgusting attempt to cover tracks
it is not the sun's apparent 'brightness' that has changed, it is the sun's increased output of cosmic rays that has warmed our solar system
how such morons ignore that the earth moved from frozen glacial cover to warm balmy hothouse repeatedly over the millennia, all without man's help or the invention of the suv, is pure comedy
call these clowns out at every opportunity, and shut them down now
scientists believe leeches key to good health
The galactic (not solar) cosmic rays that hit the earth may cause warming. The sun's role is that its weakining magnetic field may let more cosmic rays in. The same effect would not occur on Mars because there are no clouds to be enhanced by the cosmic rays.
And the orbit and tilt of the Earth over time hasn't been the same, either.