Polissar, an associate research professor at Lamont-Doherty Earth Observatory, will map vegetation history using molecular fossils to examine how climate shapes Earth’s ecosystems.
Polissar plans to compare recent vegetation histories with existing records of climate to illuminate the contributing factors to particular vegetation transitions. He will focus on the revolution in terrestrial ecosystems that occurred during the past 25 Ma when ancient and long-lived forests in North America, Africa, Asia, and Australia were replaced by the iconic modern grasslands of these regions.
The likely culprits for these defining events were a combination of changing temperature, atmospheric carbon dioxide levels, and the distribution of rainfall — all parameters being altered today due to greenhouse warming. Findings from the geologic past can therefore help map out how ecosystems and human food supplies may be affected in the near future.