I'm surprised this hasn't made the front pages of several pro-AGW newspapers and magazines yet. Perhaps it's the timescale that puts them off. Still, it could be amusing to see how they'd like us to respond and 'prevent' this one.
Say what? Well it's simple really, you see some of those wonderful chappies who live in cloistered and sometimes hallowed precincts in Universities, have calculated (or perhaps even modelled) how things will go downhill for us over the next few dozen millennia. The sun will get hotter and brighter as it ages, for a start, then the CO2 in the atmosphere will decrease, and the water will boil away. Now, the problem is this, the CO2 keeps some heat in and keeps the place habitable and temperate. It is also rather essential for plant life, and plants are essential for animal life.
So, in a billion or so years, the earth will have no living plants, animals or aquatic life. The oceans will have dried out, and any life left will be microbial. UV light will sterilise whatever is exposed to it and humanity will, of course be long gone. Quite possibly before most of the other larger mammals depart.
You can read all about it in the article Life On Earth to Die Out in One Billion Years.
Of course, if we are serious, we will do one of two things. We'll either find a way to get off the planet before then and find a new home, or we'll simply wait for the inevitable. With the current drive by NGOs trying to stop climate change and wasting billions on technologies that won't sustain our current civilisations, I'd say the latter choice is likely to be the outcome.
Fortunately, on a timescale as long as this one, I'd say we've a few years to sort something out. Even if it is a case of the more willing finding ways to head for the stars, and leaving the terminally green to face the decline with a pristine planet all to themselves - until the sun fries it.