Exploring the Potential for Regionally Cooling the Earth by Seeding Wintertime Mixed-Phase Clouds

  • Awardees
  • Jasper Kok, Ph.D. University of California, Los Angeles
  • Sarah Aarons, Ph.D. University of California, San Diego
  • Zachary Cue, Ph.D. University of California, Los Angeles
  • Ian Eisenman, Ph.D. University of California, San Diego
  • Amato Evans, Ph.D. University of California, San Diego
  • Lauren Zamora, Ph.D. NASA Goddard Space Flight Center
Year Awarded


Worldwide efforts to cut greenhouse gases emissions will likely be insufficient to meet the Paris agreement goal of limiting global warming to 1.5 degrees Celsius. There is therefore growing recognition that possible techniques for slowing down the planet’s warming need to be investigated. This project seeks to determine whether seeding wintertime polar mixed-phase clouds could counter the rapid warming of Earth’s sensitive polar regions. A major advantage of this recently proposed technique, termed mixed-phase cloud thinning (MCT), is that it might produce fewer undesirable side effects and face fewer governance challenges than more established techniques like stratospheric aerosol injection. This project will use observations from satellite instruments to estimate the cooling that could be generated with MCT. Modeling will then be used to determine the climate system’s response to this cooling and to assess the resulting positive and negative effects of MCT, including on Arctic communities. The project will engage with Arctic communities to integrate the concerns of local communities into the design of the research questions. The project will also engage high school students in a series of Next Generation Science Standards–aligned lessons investigating whether or not MCT should be used as an intervention to reduce the impacts of climate change on Arctic and other highly impacted communities.

Jasper Kok is a professor of Atmospheric and Oceanic Sciences at the University of California, Los Angeles (UCLA). He received a bachelor’s degree in physics at Leiden University in the Netherlands, his native country. He then obtained a master’s degree in applied physics from the University of Arizona and a Ph.D. in applied physics from the University of Michigan in 2009, for which he received a Distinguished Dissertation Award. He then received an Advanced Study Program postdoctoral fellowship at the National Center for Atmospheric Research and an NSF postdoctoral fellowship before starting at UCLA. His research focuses on the emission of atmospheric aerosols, in particular desert dust aerosols, and their impacts on radiation, clouds and climate. Kok was awarded an NSF CAREER award in 2016 and received the 2019 American Meteorological Society’s Henry Houghton Early Career award for “novel approaches to studying the physics of dust emissions into the atmosphere and the interactions of dust aerosols with Earth’s climate and beyond.”

Sarah Aarons is an assistant professor at Scripps Institution of Oceanography. She explores the relationship between climate and the Earth’s surface through the lens of geochemistry, with a strong emphasis on the cryosphere. She is also familiar with climate change impacts in Arctic communities, in particular the impacts upon Indigenous peoples and ways of life. Aarons received her B.S. in geological and environmental science from Stanford University and her Ph.D. in geology from the University of Michigan.

Zachary Cue is a former National Board-certified high school science teacher in Los Angeles and Memphis, Tennessee with over ten years of teaching experience in the Los Angeles Unified School District. He currently serves as a lecturer, faculty advisor and science coach for the University of California, Los Angeles (UCLA) Teacher Education Program and UCLA Science Project. Cue regularly presents at state and national educators’ conferences such as the California Association of Science Educators and the National Science Teachers Association. He is also an active developer of professional learning experiences aimed at opening up classroom conversations at the intersection between race and biology to explore culturally responsive science teaching and maintain an anti-racist stance.

Ian Eisenman is a professor of climate, atmospheric sciences and physical oceanography at the Scripps Institution of Oceanography, University of California, San Diego. He received a bachelor’s degree in philosophy and physics from Williams College, a master’s degree in physics from University of California, Santa Barbara, a master’s degree in applied mathematics from Harvard University and a Ph.D. in earth and planetary sciences from Harvard University, followed by a postdoctoral appointment jointly at the California Institute of Technology and University of Washington. His research focuses on climate dynamics, including sea ice, climate feedbacks, large-scale circulations of the atmosphere and ocean, icebergs and paleoclimate.

Amato Evans is a professor of climate and atmospheric science at the Scripps Institution of Oceanography, University of California, San Diego. Evan is an expert in the physics and chemistry of aeolian dust. He uses observations and models to study the dynamics of dust storms and how suspended dust alters Earth’s weather and climate. Much of his past work focused on dust storms from North Africa and their influence on tropical climate. His current areas of research include investigating small-scale processes controlling dust emission and transport, quantifying the effects of drying lakes on the global dust cycle and exploring the impact of dust on cloud properties.

Lauren Zamora is a researcher at the University of Maryland, College Park and also works as a contractor at NASA Goddard Space Flight Center. Her areas of expertise include both aerosol-cloud interactions and marine biogeochemistry. She earned her Ph.D. from the University of Miami in 2010. A significant portion of Zamora’s work is dedicated to the statistical analysis of extensive datasets from satellites, models and reanalysis products, as well as the examination of data from complementary field campaigns. Currently, she is participating in flight planning and leadership activities for the NASA ARCSIX aircraft campaign over Northern Greenland. This campaign aims to investigate the influence of clouds, aerosols and other factors on the melting of sea ice melt in this climatically critical area.

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