The Sun is midway through its stable hydrogen burning phase known as the main sequence. But when the Sun enters the red giant phase in around 5 billion years things are going to get a lot rougher in the Earth-Moon system.I don't see this as a problem in my lifetime, but it shows what we're in for.
During the red giant phase the Sun will swell until its distended atmosphere reaches out to envelop the Earth and Moon, which will both begin to be affected by gas drag-the space through which they orbit will contain more molecules.
Now, that other global warming... you know, the one that Big Al is espousing? Hell, a butterfly could fart in the Amazon and change the weather patterns next week. There is even a documented phenomenon known as the Gore Effect that seems to have a local effect on glowball warming, sending temperatures plummeting.
Still, that Red Giant thing is going to get a bit warm.
Hat tip to Say Uncle.