Laboratory Fellow, Earth Scientist
Laboratory Fellow, Earth Scientist


Brian O’Neill is a chief scientist and Laboratory fellow at the Joint Global Change Research Institute, a collaboration between Pacific Northwest National Laboratory (PNNL) and the University of Maryland in College Park. His research interests are in human-Earth system interactions, in particular the human dimensions of global environmental change. Previously, he was a professor at the Josef Korbel School of International Studies at the University of Denver and also served as director of research at the Korbel School’s Pardee Center for International Futures. He led research groups on integrated assessment modeling and on climate and human systems at the U.S. National Center for Atmospheric Research and on population and climate change at the International Institute for Applied Systems Analysis. Early in his career, he was on the science staff of the Environmental Defense Fund in New York and was an assistant and associate professor (research) at Brown University's Watson Institute for International Studies. Brian is a convening lead author for the Intergovernmental Panel on Climate Change’s ongoing Sixth Assessment Report and was an author on the U.S. Fourth National Climate Assessment. He holds a PhD in Earth systems science and an MS in applied science, both from New York University.

Research Interest

  • Human-Earth system interactions, in particular the human dimensions of global environmental change
  • Development and use of scenarios for climate change analysis
  • Climate change risks
  • Integrated assessment modeling


  • New York University, Doctor of Philosophy, Earth Systems Science
  • New York University, Master of Science, Applied Science
  • University of Delaware, Bachelor of Arts, English

Affiliations and Professional Service

  • Member and co-chair of Analysis, Integration, and Modeling of the Earth System: Scientific Steering Committee and member of working group on Modeling Earth Systems and Human interactions (MESH)
  • Member of working group on Coupled Modeling, World Climate Research Program
  • Co-chair of Scenario Model Intercomparison Project (ScenarioMIP), an approved activity of the Coupled Model Intercomparison Project (CMIP)
  • Member of International Committee On New Integrated Climate Change Analysis Scenarios 

Awards and Recognitions

  • Highly Cited Researcher, Web of Science Group (2019–2021)
  • Integrated Assessment Modeling Consortium (IAMC) Award for Extraordinary Contributions to the Field of Integrated Assessment Modeling (2017)
  • Elected member of young scientists ("Junge Kurie") of the Austrian Academy of Science (2008–2016)



  • Simpson, N.P., K.J. Mach, A. Constable, J. Hess, R. Hogarth, M. Howden, J. Lawrence, R.J. Lempert, V. Maccione, B. Mackey, M.G. New, B.C. O’Neill, F. Otto, H.-O. Pörtner, A. Reisinger, D. Roberts, D.N. Schmidt, S. Seneviratne, S. Strongin, M. van Aalst, E. Totin, C.H. Trisos. 2021. “A framework for complex climate change risk assessment.” One Earth 4 (4): 489–501.
  • Dickerson, S., M. Cannon, and B.C. O’Neill. 2021. “Climate change risks to human development in sub-Saharan Africa: a review of the literature.” Climate and Development 1–19.
  • Gao, J. and B. O’Neill. 2021. “Different spatiotemporal patterns in global human population and built‐up land.” Earth’s Future 9 (8): p.e2020EF001920.
  • Melnikov, N.B., A.P. Gruzdev, M.G. Dalton, M. Weitzel, and B.C. O’Neill. 2021. “Parallel extended path method for solving perfect foresight models.” Computational Economics 58 (2): 517–534.
  • Bukovsky, M.S., J. Gao, L.O. Mearns, and B.C. O’Neill. 2021. “SSP‐Based Land‐Use Change Scenarios: A Critical Uncertainty in Future Regional Climate Change Projections.” Earth's Future 9 (3): p.e2020EF001782.


  • Tebaldi, C., K. Debeire, V. Eyring, E. Fischer, J. Fyfe, P. Friedlingstein, R. Knutti, J. Lowe, B.C. O'Neill, B. Sanderson, D. van Vuuren. 2020. “Climate model projections from the Scenario Model Intercomparison Project (ScenarioMIP) of CMIP6.” Earth System Dynamics 12 (1): 253–293.
  • O’Neill, B.C., T. Carter, K. Ebi, P. Harrison, E. Kemp-Benedict, K. Kok, E. Kriegler, B. Preston, K. Riahi, J. Sillmann, B. van Ruijven, D. van Vuuren, D. Carlisle, C. Conde, J. Fuglestvedt, C. Green, T. Hasegawa, J. Leininger, S. Monteith, and R. Pichs-Madruga. 2020. “Achievements and needs for the climate change scenario framework.” Nature Climate Change 1–11.
  • Zoraghein, H. and B.C. O’Neill. 2020. “A spatial population downscaling model for integrated human-environment analysis in the United States.” Demographic Research 43: 1563–1606.
  • Melnikov, N., A. Gruzdev, M. Dalton, M. Weitzel, and B.C. O'Neill. 2020. “Parallel extended path method for solving perfect foresight models.” Computational Economics.  
  • Zommers, Z., A. Fischlin, Z. Ibrahim, P. Marbaix, S. Grant, A.K. Magnan, H.-O. Poertner, M. Howden, K. Calvin, K. Warner, W. Thiery, Z. Sebesvari, E.L. Davin, J.P. Evans, C. Rosenzweig, B.C. O’Neill, A. Patwardhan, R. Warren, and M. van Aalst. 2020. “Burning Embers: Towards more transparent and robust climate change risk assessments.” Nature Reviews Earth and Environment.
  • Jiang, L., B.C. O’Neill, H. Zoraghein, and S. Dahlke. 2020. “Population scenarios for U.S. states consistent with Shared Socioeconomic Pathways.” Environmental Research Letters. 15 (9): 094097.
    • Model: Zoraghein, H., R. Nawrotzki, L. Jiang, and S. Dahlke. 2020. IMMM-SFA/statepop: v0.1.0 (Version v0.1.0). Zenodo.
    • Data: Jiang, L., S. Dahlke., H. Zoraghein, and B.C. O'Neill. 2020. Population scenarios for “U.S. states consistent with Shared Socioeconomic Pathways” (Version v0.1.0) [Data set]. Zenodo.
  • Sanderson, B. and B.C. O’Neill 2020. “Assessing the costs of historical inaction on climate change.” Nature Scientific Reports, 10: 9173.
  • Gao, J. and B.C. O’Neill. 2020. “Mapping global urban land expansion for 21st century using data science based simulations.” Nature Communications 11: 2302.
    • Data: Gao, J. 2020. "Global 1/8-Degree Urban Land Fraction Grids, SSP-Consistent Projections and Base Year, v1 (2000 - 2100)." Harvard Dataverse, V1.
  • Zoraghein, H. and B.C. O’Neill. 2020. “U.S. state-level projections of the spatial distribution of population consistent with Shared Socioeconomic Pathways.” Sustainability 12: 3374.
    • Data: Zoraghein, H. and B.C. O'Neill. 2020. Data Supplement: “U.S. state-level projections of the spatial distribution of population consistent with Shared Socioeconomic Pathways.” (Version v0.1.0) [Data set]. Zenodo.
  • O’Neill, B.C., L. Jiang, S. KC, R. Fuchs, S. Pachauri, E. Laidlaw, T. Zhang, and X. Ren. 2020. “The effect of education on determinants of climate change risks.” Nature Sustainability 3: 520–528.