John Higgins is a professor of geosciences at Princeton University. His primary research interest is the evolution of the carbon cycle and the global climate system over the course of the Earth’s history. Higgins studies interactions between Earth’s climate, its lifeforms and the global geochemical cycles of carbon and oxygen on timescales of millennia to billions of years using chemical measurements in sedimentary rocks and bubbles of trapped air in polar ice cores.

On Twitter: @blueicehiggins