Global warming is only the latest in a very long line of anthropic eco-disasters predicted by people (read: wackos). Much like global cooling, vanishing ozone layer, and the old gem of a burning atmosphere will be forgotten in 20 years when the doom and gloom prediction does not come true, and a new one takes its place.
Also should sol stick to the plan it has roughly five billion years before it expands to a red giant.
Sorry guys the sun is not constantly expanding, going to explode, go super nova, collapse to a black hole, burn up the earth or any cool stuff. It could (if other stars are any indication) expand past the orbit of earth, but that might be an exaggeration, or it could not be, or the earth could be pushed away long before by the increasingly active sun, or all the above and the damn things gets sucked right back in to the sun as it expands anyway. Which would suck for all the people around, except they will have all burned up and died out because of an increasingly active sun. This will make the whole planet basically inhospitable in about a billion years or so (unless it decides to suddenly stop the 10% increase in activity per billion years it has evidenced.