Concept: World's End
What would happen if the climate changed rapidly and reached the extinction point in 10 years? Changing faster then we, and our science, could adapt?
What would the world look like afterwards? Less snow and ice, less known landmasses, new viable land appearing after the thaw (Antartica).
Would humans migrate as far to the poles as possible? Live underground? Live in the depths (or shallows) of the oceans? Live in orbit? Colonize another nearby planet or moon?
Would we need to try and genetically engineer our offspring to better adapt to the new climate?
Would we abandon this world and seek out another habitable planet in another solar system?