In "A Short History of Nearly Everything," Bill Bryson discusses the delicate balance of the natural biosphere and its role in mitigating the effects of human emissions. He highlights how our planet has the ability to absorb and buffer many of the impacts we create, but this system has its limits. When we exceed certain thresholds, the natural world can no longer help us and may actually exacerbate the effects of our actions.

Bryson emphasizes the importance of understanding these thresholds, as they signify a tipping point in environmental stability. Once the biosphere reaches such a point, the repercussions of human activity could become even more severe, leading to a cycle of damage that is difficult to reverse. This calls for greater awareness and action to prevent reaching that critical juncture.