Stanford Earth's Erik Sperling and Richard Stockey describe their research on the connection between rising oxygen levels and a previously unexplained slowdown in mass extinctions.

A sweeping analysis of marine fossils from most of the past half-billion years shows the usual rules of body size evolution change during mass extinctions and their recoveries. The discovery is an early step toward predicting how evolution will play out on the other side of the current extinction crisis.

A new Stanford University study shows rising oxygen levels may explain why global extinction rates slowed down over the past 541 million years. Below 40 percent of present atmospheric oxygen, ocean dead zones rapidly expand, and extinctions ramp up.

The geological sciences professor is among 59 fellows elected for outstanding achievements and contributions that push the frontiers of science – an honor that AGU has given to fewer than 0.1% of its members since 1962.