An article in Weekly World News describes a find by a Professor Lloyd Cunningdale of Salt Lake City who was excavating with his students at the site of the famous Donner party disaster of 1847. The latter were a group of settlers bound for California who became trapped by snow in the Sierra Nevada Mountains. Cunningdale and students have found a time capsule left by the settlers which contains many predictions for the future. They predict that nations will abandon traditional methods of conflict and resort to the use of biological warfare. In 2016, one such disease will spread and kill all of the humans on the planet.
My money is on 5 billion years from now. The sun will run out of hydrogen fuel and will expand, becoming a red giant. As a result, swallowing the Earth's orbit... or at the very least roasting it to a cinder crisp. It happens on Doctor Who, so that means it will happen unless it doesn't (because of the changes the Doctor made to the timeline). Either way, watch out for Daleks.