I think the moon is receding from the earth, not approaching it. The moon's orbit around the earth doesn't decay like a satellite's orbit because there's no atmosphere to make it happen at that distance. All satellites in closer earth orbit will eventually burn up in our atmosphere. Incidentally, the earth isn't following a smooth orbit around the sun - just as the moon orbits the earth, the earth is following a circle too...sort of like a mini orbit around the moon. It's hard to describe but imagine a man swinging his son around in big circles. The man also goes around in a smaller circle to balance his sons inertia. Similarly, the earth tries to sort of wobble it's way in tiny circles around the bigger circle of its orbit around the sun. The combination of the two means the earth actually wobbles from side to side and slows down and speeds up on its sun orbit. Jupiter's gravity is such that the sun wobbles around on an internal "orbit" too. The tidal effect of the earth on the moon long ago locked one side of the moon into facing us constantly. The moon is slowly doing the same to the earth - its slowing the earth's rotation on its axis and making the day longer. Eventually just one side of the earth will face the moon continually. But by then the earth and the moon may be much further away from each other. I think the earth must be moving very slowly out from the sun too. But long before that would make us any colder, we'll be fried when the sun changes into a red giant and engulfs us.