With his signature bowtie, blue lab coat and irrepressible enthusiasm, Bill Nye became a hero for millions of children in the ’90s as the star of the PBS show “Bill Nye the Science Guy,” where he demonstrated astonishing properties behind everyday things. The show ended in 1998, but that didn’t diminish Nye’s fierce belief in scientific fact and the importance of education. With his field under increasing attack, he took on a new role: climate change activist and defender of evolution, education and science. Bill Nye: Science Guy chronicles Nye’s extraordinary life, including this new chapter, which has him traveling to Greenland to examine ice cores, debating prominent creationists and climate change deniers, speaking to college students and reflecting on his own childhood. Through it all, Nye comes back to something his dad instilled in him: to leave the world better than he found it.