About

Prof. Joellen L. Russell is an oceanographer, climate scientist, and University Distinguished Professor at the University of Arizona. Her research explores the role of the ocean in the global climate, with a focus on the Southern Ocean and the Southern Hemisphere westerly winds. She employs robot floats, supercomputers, and satellites to study the Southern Ocean and its influence on the transient global climate. Russell uses earth system models to simulate the climate and carbon cycle across past, present, and future scenarios, developing observationally-based metrics to evaluate these simulations. Her work on westerly winds led to a significant breakthrough in climate science, establishing that warmer climates produce stronger westerly winds, which helped resolve a long-standing climate paradox related to carbon transfer during glacial-interglacial cycles. Additionally, she and colleagues introduced the 'Zealandia Switch,' a mechanism explaining how changes in the Southern Hemisphere westerly winds can trigger rapid, global glacial retreat, accounting for synchronous ice sheet changes during the last ice age. Russell is the lead for the modeling theme of the Southern Ocean Carbon and Climate Observations and Modeling project (SOCCOM) and collaborates with NOAA’s GFDL. She is actively involved in international scientific organizations, serving as the US Executive Committee member of IAPSO. Russell holds an A.B. in Environmental Geoscience from Harvard and a Ph.D. in Oceanography from Scripps Institution of Oceanography, UC San Diego. She is also a cofounder of Science Moms, a group working to demystify climate change, and has contributed to legal and policy discussions on climate science. Growing up near the Arctic Circle, she has been passionate about climate issues since childhood and now holds joint appointments in multiple departments at the University of Arizona, including Lunar and Planetary Sciences, Hydrology and Atmospheric Sciences, and Mathematics. She has served on the UA Faculty Senate and is involved in various interdisciplinary programs and university committees, emphasizing her commitment to education, research, and community engagement in climate science.

Research topics

• Climatology
• Environmental science
• Geology
• Computer Science
• Oceanography
• Geography
• Ecology
• Physical geography
• Operating system
• Engineering
• Systems engineering
• Paleontology

Selected publications

• Circulation Dynamics and Climate Change Impacts on Lake Tanganyika: Insights from Modeling and Sediment Core Analysis

  Abstracts with programs - Geological Society of America · 2025-01-01

  articleSenior author
  PublisherDOI

• Rapid thinning of the Cordillera Darwin Icefield at the onset of Termination I

  Quaternary Science Reviews · 2025-12-15

  article
  PublisherDOI

• ESMValTool

  Open MIND · 2025-01-01

  softwareOpen access

  ESMValTool: A community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP.

  Publisher

• ESMValTool

  Open MIND · 2025-01-01

  softwareOpen access

  ESMValTool: A community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP.

  Publisher

• Seasonal Stratospheric Cooling Increases Southern Ocean Overturning & Ice Melt

  Research Square · 2025-11-06

  preprintOpen access1st authorCorresponding
  PublisherOA PDFDOI

• Evolution of simulated seasonal and interannual ocean carbon budgets for the global ocean and exclusive economic zones in CMIP6 earth system models: Benchmarking for better prediction

  2025-03-26

  preprintOpen access1st authorCorresponding

  Climate and Earth System Models still struggle with the seasonal evolution of ocean carbon exchange and budgets. With the advent of new near-real-time ocean biogeochemical data from argo floats and global biogeochemical data assimilation in the ocean, we should be able to benchmark and evaluate the earth system model simulations of seasonal and interannual net fluxes of carbon into the global ocean as well as regional and exclusive economic zone carbon budgets. We present results using metrics suitable for ESMValTool deployment to quantify and benchmark the carbon budgets in the CMIP6 simulations for the end of the historical period. We compare these results to the new BGOSE assimilation (global at 1/3°) as well as the observationally-derived carbon surface carbon data products.

  PublisherDOI

• Understanding the 3D Hydrodynamics of Lake Tanganyika: Insights From Modeling Circulation Patterns Using a 3D ROMS Model

  Geophysical Research Letters · 2025-08-02 · 2 citations

  articleOpen access

  Abstract This study simulates circulation patterns in Lake Tanganyika, an economically vital lake in East and Central Africa that has experienced significant warming, and reduced fishery yields in recent decades. We use Regional Ocean Modeling System to analyze thermal stratification, wind‐driven processes, and circulation dynamics within the lake. Our findings show surface temperatures ranging from ∼25.8°C to ∼27.8°C seasonally, with a notable increase of up to 0.4°C below 150 m depth between 2001 and 2020. Primary upwelling occurs in the southern region from May to August, while secondary upwelling is observed in the north from November to February. Bathymetric variations influence upwelling and downwelling processes. Our results emphasize that the interaction between atmospheric and hydrodynamic factors regulates the nutrient distribution, which is crucial for fisheries and biodiversity. We also highlight the importance of modeling in understanding the warming trends and ecological responses of Lake Tanganyika to climate change.

  PublisherOA PDFDOI

• ESMValTool

  Zenodo (CERN European Organization for Nuclear Research) · 2025-03-05

  otherOpen access

  ESMValTool: A community diagnostic and performance metrics tool for routine evaluation of Earth system models in CMIP.

  PublisherDOI

• What is Endangered now? Climate Science at the Crossroads

  2025-07-31

  preprintOpen access

  The greenhouse gas “endangerment finding” of the U.S. Environmental Protection Agency (EPA), established in 2009 after a 2006 U.S. Supreme Court case (Massachusetts vs EPA) in which we participated as amicus curiae (friends of the court) , has become the basis for U.S. regulation of greenhouse gases in the years since. The current Administration of President Donald Trump is now seeking its repeal. Here, we review the role climate science played in that 2006 case, and how the scientific evidence that undergirds the endangerment finding has gotten stronger in the 16 years since. Finally, we consider what will be the fate of the endangerment finding – and indeed that of role of science in contributing to policy – in light of the current challenging environment for science in the U.S.

  PublisherOA PDFDOI

• Uncovering the Seasonality of Storm-Driven Southern Ocean Heat and Carbon Uptake

  Journal of Climate · 2025-07-23 · 1 citations

  article

  Abstract The Southern Ocean is an important region for both heat and carbon uptake, due in large part to wind-driven circulation. This region also continually experiences strong winds associated with the passage of synoptic storms, which influence the upper ocean through strong fluxes of momentum, heat, freshwater, and gases. While studies have found that storms can induce strong carbon outgassing, their role in the combined uptake of heat and carbon remains unknown. In this work, we explore the climatological impact of storms on the Southern Ocean combined heat and carbon uptake through two preindustrial coupled climate model runs with contrasting seasonal carbon fluxes. We use a feature tracking system to identify storms and create composites for storm-following and poststorm anomalous fluxes of heat and carbon. Storms induce a net anomalous release of heat and carbon from the ocean throughout the year, with clear seasonality in the magnitude of the fluxes that coincide with the background seasonal cycles. We find a strong model dependency for the storm-driven anomalous carbon fluxes, in terms of both the seasonal range and timing of maximum outgassing. Storm-induced anomalous fluxes are dampened on the order of days after the storm passes, with a small continued release of heat that is most persistent in the winter. Our study underlines the high uncertainty about the seasonal nature of storm impacts on the ocean and suggests that evolving atmospheric and oceanic conditions could impose opposing shifts in the future seasonality of storm impacts. Significance Statement Strong winds within storms can enhance heat and carbon exchange between the atmosphere and ocean, which plays an important role in setting Earth’s climate. In this study, we identify storms in two climate models to isolate their impacts on heat and carbon exchange in the Southern Ocean. We find that Southern Ocean storms release both heat and carbon into the atmosphere. The magnitude of this release varies across seasons, with summer storms releasing most heat and summer and autumn storms releasing more carbon. Our work shows the importance of seasonal timing for storm activity, which can have important implications for heat and carbon cycling as the atmosphere and ocean continue to evolve within our warming climate.

  PublisherDOI

Recent grants

• The Southern Ocean in a Warming World: Winds, Carbon and Heat

  NSF · $323k · 2013–2017

• IPG: Collaborative Research: A high-resolution analysis of unique paleoenvironmental data from key hominin sites in East Africa

  NSF · $71k · 2012–2016

Frequent coauthors

• P. J. Goodman

  University of Arizona

  34 shared

• Ronald J. Stouffer

  University of Arizona

  34 shared

• Matthew R. Mazloff

  University of California, San Diego

  26 shared

• Lynne D. Talley

  Scripps Institution of Oceanography

  26 shared

• David A. Feary

  21 shared

• Kenneth S. Johnson

  Monterey Bay Aquarium Research Institute

  19 shared

• Nancy L. Williams

  18 shared

• Hideaki Machiyama

  Japan Agency for Marine-Earth Science and Technology

  16 shared

Labs

• Biogeochemical Dynamics LaboratoryPI

Awards & honors

• University Distinguished Professor, Biogeochemical Dynamics