Much is being said about climate change: is it real? Are we causing it? What can be done? I have recently come across three fascinating discussions of how human-caused increases in atmospheric carbon dioxide may relate to various natural cycles, and how, too, it provides an amazing object lesson in the fine-tuning of the Earth and solar system. Essential reading/listening.
How Ice Ages Happen: https://youtu.be/iA788usYNWA.
Geologist Dan Britt, Orbits and Ice Ages: the History of Climate (2012): https://www.youtube.com/watch?v=Yze1YAz_LYM&feature=youtu.be