Abstract
The evolution of Earth’s atmosphere over the last 4.6 billion years has occurred in the face of an evolving and expanding biosphere, brightening sun, and cooling planet. The shift from a (weakly) reducing atmosphere to one with abundant free oxygen is a compelling signature of the co-evolution of life and geochemical systems on Earth’s surface. Since its advent, life has co-evolved with Earth’s surface and atmosphere through diverse cause-and-effect relationships and in tandem with fundamental solid-Earth processes including the silicate-carbonate weathering feedback, plate tectonics, and volcanic outgassing. Comparisons of Earth’s atmospheric evolution with Mars, Venus, and planets beyond our solar system can lead to deeper understanding of the biotic and abiotic forces and feedbacks that shape and maintain terrestrial planetary atmospheres and habitability.
Evan L. Sneed
he/him or they/them
Human searching for life far from home & improving habitability on Earth