The biosphere is an amazing place, serving as home for humans and many other species. The atmosphere provides the air we need to breathe, but the atmosphere also helps to protect us from the Sun’s radiation. The water, plants, and animals of the biosphere provide humans with many of the resources we need for survival. But as amazing the biosphere is in creating a “comfort zone” for humans, it can also be quite fragile, and from time to time has been subject to significant threats from various astronomical, geological, and biological forces. Changes in these forces can result in both mild and extreme impacts on the biosphere.