Jack Hall is a fictional character from the movie The Day After Tomorrow, which was released in 2004. He is a paleoclimatologist who studies climate patterns and their effects on the Earth. In the film, Jack becomes a central figure as he tries to save his son during a catastrophic climate event caused by global warming. Throughout the movie, Jack's expertise in climatology helps him understand the impending disaster. As extreme weather conditions unfold, he embarks on a dangerous journey to reach his son, showcasing themes of family, survival, and the impact of climate change on humanity.