If the Sun is slowing down, how much? Solar Storms that are strong enough to penetrate the Ionisphere will destroy anything that is electronic(That's why I have an old VW in my driveway, no computer, no problem and cash in a safe at home). An large enough Asteroid is known as a Planet Killer(nothing will survive) even if it was small , the dust kicked up will result in a new Ice Age because the dust would block out the Sun. But with all the things that are happening now days, We may do ourselves in long before we should worry about outside of our control situations.
Just my 2 cents worth.