Every living thing—plants, animals, microorganisms—shares an extraordinary history that stretches back 4 billion years to the origins of life on Earth. Although countless species have come and gone in that grand interval, today we share the planet with tens of millions of species, simultaneously shaping the Earth’s very form and function. Akin to the miracle of loaves and fishes, living things have turned, and continue to turn, stone into soil. The presence of life on Earth is so robust that it has markedly affected the composition of our atmosphere and continues to do so. Indeed, the atmospheric carbon dioxide concentration rises and falls in an annual rhythm tied to the seasons by biological activity—almost as if the planet itself was a living organism.
When I ...
