Another of my pet peeves, here. You do not prove theories with facts. An hypothesis must explain the facts, all of the facts, and predict future facts, before it can be considered a valid theory. The layman/Hollywood definition of theory is completely wrong. A scientific theory is about as close as you can get to explaining the real world.
I doubt that anyone outside of the media (and politicians, of course) are claiming that humanity is the sole cause of global warming. But the evidence does show that we are a significant contributor.Like humanity is the sole cuase of global warming when they still are not sure that we are.