First you need to define the term "uninhabitable planet"
Please don't try to sell us the bill of goods agrument that the Earth is headed for a "Venus-like" hot-spell that will wipe out all life on Earth.
Even if the Earth heated up 20 degrees Farenheit tommorrow, Human civilization would go on... So the Earth would still be "habitable" (admittedly in a much different way than it is today).