Christopher S. Bretherton

Christopher Stephen Bretherton is an American atmospheric scientist and professor emeritus at the University of Washington, where he held joint appointments in the Department of Atmospheric Sciences and the Department of Applied Mathematics. He has contributed to understanding cloud processes, climate modeling, and advancing the integration of machine learning into climate simulations. Bretherton was elected to the National Academy of Sciences in 2019 and is a recipient of the American Meteorological Society's Jule G. Charney Award. In 2019, he transitioned to industry, becoming Senior Director of Climate Modeling at Vulcan Inc. and later at the Allen Institute for Artificial Intelligence, where he led efforts to integrate machine learning into climate models.

Early life and education

He is the son of Francis Bretherton. Bretherton earned his Bachelor of Science degree in Applied Mathematics from the California Institute of Technology in 1980. He completed his Ph.D. in Mathematics at the Massachusetts Institute of Technology in 1984, where his doctoral thesis focused on modeling moist convection.

Bretherton joined the University of Washington in 1985 as an assistant professor. He became a full professor in 1996, holding joint appointments in atmospheric sciences and applied mathematics. From 2006 to 2011, he directed UW’s Program on Climate Change.
In 2019, he transitioned to industry, becoming Senior Director of Climate Modeling at Vulcan Inc. and later at the Allen Institute for Artificial Intelligence, where he led efforts to integrate machine learning into climate models.

Bretherton’s research focuses on cloud dynamics, turbulence, and their representation in climate models.

Developed parameterizations for subgrid-scale cloud processes used in major U.S. climate models, including the Community Earth System Model.
Investigated how marine stratocumulus clouds and tropical convection patterns influence climate sensitivity.
Used machine learning trained on high-resolution climate simulations to improve cloud representations in global models.
Led or contributed to projects such as the VOCALS-REx and ORACLES.

Bretherton, C.S., & Park, S.. "A new moist turbulence parameterization in the Community Atmosphere Model." *Journal of Climate*, 22, 3422–3448.
Bretherton, C.S., et al.. "Clouds and aerosols." In: *IPCC AR5 Working Group I Report*.
Bretherton, C.S., & Khairoutdinov, M.. "Convergence of aqua-planet simulations with explicit convection." *Journal of Advances in Modeling Earth Systems*, 7, 395–406.

Bretherton is married to Alison Cullen, a professor at UW’s Evans School of Public Policy and Governance. During a 2016–2017 sabbatical, he collaborated with institutions including MIT, National Center for Atmospheric Research, and the Max Planck Institute for Meteorology.