Nathaniel Tarshish

Nathaniel is a climate scientist with broad interests in understanding historical and committed global warming.

Nathaniel received his Ph.D. in Earth and Planetary Science from UC Berkeley in 2024 and earned a B.Sc. in Mathematical Physics from Brown University.

His research has uncovered surprising insights into where global warming comes from and where it is going. His dissertation showed that the burning of fossil fuels is just now overtaking land-use change as the dominant source of global warming. For most of the 20th century, warming from fossil-fuel greenhouse gases was likely masked by cooling due to co-emitted aerosols. Regarding future warming, his thesis demonstrated that global temperatures substantially decline in the centuries after net-zero emissions. The committed warming that persists on multi-century timescales, however, is due almost entirely to fossil fuels.

These findings highlight how human activities can make differing contributions to transient versus committed warming. Nathaniel has also studied nuclear winter, modeling the extent to which city-scale fires could loft enough soot into the stratosphere to cause catastrophic cooling. His Ph.D. work in this area combined theory and simulations to bring the threat of nuclear winter into clearer focus.

In addition to his research, Nathaniel is invested in public outreach. As a founding member of Climate Up Close, he and several colleagues engage the public through tours and discussions about climate change (more information at climateupclose.org).

In his role as an Environmental Fellow, he will investigate the future of ocean heat uptake and re-examine the conceptual underpinnings of the carbon budget.

Faculty Host: Eli Tziperman, Faculty of Arts and Science