The greenhouse effect is real. Whether or not it's causing global warming is arguable. Whether or not we can do anything about it is debatable.
Obviously the atmosphere retains heat. Beyond that, only global warming alarmists seem to give a fuck. And I've had enough of their TEOTWAWKI shit. People have been saying "It's the end of the world!" since the beginning of the world. If even one of them had been right, we wouldn't be here.