John Fasullo leads societally relevant research aimed at understanding and predicting Earth system variability. He is a member of CAS at NCAR and a Research Associate in the ATOC Department at the University of Colorado. Dr. Fasullo also has private-sector experience with environmental impact studies and expert witness testimony. He obtained his B.S. in App/Eng Physics from Cornell University and his Ph.D. from ATOC at the University of Colorado.

Research Topics

  • Earth System Processes
  • Earth System Prediction

Top Publications

Cheng et al. 2025: Record High Temperatures in the Ocean in 2024.
Fasullo et al. 2023: A multiyear tropical Pacific cooling response to recent Australian wildfires in CESM2.
Cheng et al. 2023: Another year of record heat for the oceans.
Fasullo and Richter 2023: Dependence of Strategic Solar Climate Intervention on Background Scenario and Model Physics.
Cheng et al. 2022: Past and future ocean warming.
PoChedley et al. 2022: Internal variability and forcing influence model-satellite differences in the rate of tropical tropospheric warming.
Cheng et al. 2022: Another Record: Ocean Warming Continues through 2021 despite La Niña Conditions.
Fasullo et al, 2022: Spurious Late Historical-Era Warming in CESM2 Driven by Prescribed Biomass Burning Emissions.
Fasullo et al, 2021: Coupled Climate Responses to Recent Australian Wildfire and COVID-19 Emissions Anomalies Estimated in CESM2.
Cheng et al. 2020: Record-Setting Ocean Warmth Continued in 2019.
Gettelman et al. 2019, High Climate Sensitivity in the Community Earth System Model version 2 (CESM2)
Herrera et al. 2018: Unprecedented 2013–2016 Caribbean drought intensified by climate change
Fasullo et al. 2018: ENSO Teleconnections to Temperature, Precipitation and Wildfire in a Warming Climate.
Fasullo and Nerem 2018: Altimeter-Era Emergence of the Patterns of Forced Sea Level Rise in Climate Models and Implications for the Future.
Fasullo et al. 2018: Persistent Polar Ocean Warming in a Strategically Geoengineered Climate.
Fasullo et al. 2017: The Amplifying Influence of Increased Ocean Stratification on A Future Year Without A Summer.
Nerem, et al. 2018: Climate-change driven accelerated sea-level rise detected in the altimeter era.
Cheng et al 2019: 2018 Continues Record Global Ocean Warming.

Selected Media

2023 CGD Seminar
9NEWS: The Climate Impacts of the 2019-20 Australian Bushfires

Publications

2025
Duffy, M. et al: Is the high ECS in CESM2 degrading transient climate change projections over the 21st century?, Journal of Advances in Modeling Earth Systems, accepted.
Perez-Carrasquilla, J, M J. Molina, K J. Mayer, K Dagon, J T. Fasullo, and I. R. Simpson, Observed and modeled amplification of the frequency, duration, and extreme heat impacts of the Pacific trough regime, Earth's Future, doi: 10.1029/2025EF007140.
Meehl, G.A., J. Fasullo, S. Glanville, A. Capotondi, J.M. Arblaster, A. Hu, and N. Rosenbloom, 2025: 2019-2020 Australian bushfire smoke, multi-year La Niña, and implications for the Interdecadal Pacific Oscillation (IPO), npj Climate and Atmospheric Science, https://doi.org/10.1038/s41612-025-01204-8.
Xing, S Stevenson, E Di Lorenzo, M Newman, A Capotondi, J Fasullo, N Maher, 2025: Apparent Changes in Pacific Decadal Variability Caused by Anthropogenically-Induced Mean State Modulations, Geophs. Res. Lett., doi: 10.1029/2025GL116499.
Xing, C., S. Stevenson, J. Fasullo, C. Harrison, C. Chen, J. Wan, J. Coupe, C. Pfleger, 2025: Subtropical Marine Cloud Brightening Suppresses The El Niño-Southern Oscillation, Earth's Future, doi:10.1029/2025EF006522.
Felikson, D., D. Rounce, J. T. Fasullo et al. 2025: Progress and outlook for constraining uncertainties in sea-level projections using observations, Nature Clim. Change, doi:10.1038/s41558-025-02437-4.
Maher, N., Phillips, A. S., Deser, C., Wills, R. C. J., Lehner, F., Fasullo, J., ... & Beyerle, U. 2025: The updated Multi-Model Large Ensemble Archive and the Climate Variability Diagnostics Package: New tools for the study of climate variability and change. Geo. Model Dev., doi:10.5194/gmd-18-6341-2025 .
Coats, S., P.R. Thompson, C.G. Piecuch, J.T. Fasullo, B.D. Hamlington, K.B. Karnauksas, R.S. Nerem, A.R. Rodriguez, J.M. Steinberg, J. Busecke, Understanding the role for internal variability in driving past and future ocean dynamic sea-level trends in CMIP6 simulations, J. Clim., doi: 10.1175/JCLI-D-24-0336.1.
Weathers, M. R., D. Rounce, J. T. Fasullo, F. Maussion, 2025, Evaluating the Role of Internal Climate Variability and Bias Adjustment Methods on Decadal Glacier Projections, Earth's Future, doi: 10.1029/2024EF005624.
Karnauskas, K. R. S. Nerem, J. T. Fasullo, P. Thompson, M. Merrifield, S. Coats, D. Chambers, B. Hamlington, 2025: Diagnosing Regional Sea Level Change Over the Altimeter Era, Journal of Geophysical Research, Oceans, doi: 10.1029/2024JC022100.
Little, C., S. Yeager, J. T. Fasullo, K. Karnauskas, R. S. Nerem, E. N. Slivia, 2025: Pan-pacific low frequency modes of sea level and climate variability, Science Advances, doi: 10.1126/sciadv.adw3661.
Trenberth, L. Cheng, Y. Pan, J. Fasullo, Michael Mayer, 2025: Distinctive pattern of global warming in ocean heat content, J. Clim., doi: 10.1175/JCLI-D-24-0609.1.
Buzzanga, B., B. Hamlington, J. Fasullo, F. Landerer, A. Peidou, 2025: Interdecadal variability of terrestrial water storage since 2003, Communications Earth and Environment, doi: 10.1038/s43247-025-02203-6.
Cheng, L., Abraham, J., Trenberth, K.E. et al. Record High Temperatures in the Ocean in 2024. Adv. Atmos. Sci. (2025). https://doi.org/10.1007/s00376-025-4541-3