Nuclear winter was to have been the worst-case scenario following a large-scale nuclear war. Nuclear winter would have meant the darkening of Earth's skies to the point where possibly all photosynthesis could terminate. This sounds very James Bond and it isn't going to happen.
The West Antarctic Peninsula is warming about four times faster than the global average. It is the biggest "canary in the coal mine," signaling one of the largest impacts of climate change for the entire world.