Parallel Session: Changes of Stratospheric Chemistry and Dynamics and its impacts as a result of climate change and stratospheric aerosol climate engineering

11:00 - 12:30

Stratospheric aerosol climate engineering and climate change are both expected to change stratospheric dynamics and chemistry. These changes may result in both an increase and decrease of column ozone depending on injection location, amount and timing, which impacts surface UV radiation. How large will these changes be and can we comprehensively assess these changes and aim to reduce them?



  • Amy Butler
    • Projected future change in stratospheric ozone
  • Mike Mills
    • Dynamical and chemical changes in the stratosphere due to geoengineering
  • Frank Keutsch
    • Stratospheric Solar Radiation Management Beyond Sulfate
  • Alkis Bais
    • Surface UV radiation in the 21st century: Environmental effects of changes in ozone and climate

Discussion points:

  • How uncertain is our understanding of change in ozone as a result of climate change and climate engineering?
  • Are there methods that could minimize the magnitude of changes, or even help reduce the super recovery of ozone?
  • How much do we know about the ecological and social implication based on existing uncertainties
  • How could uncertainty of potential changes in stratospheric ozone as a result of climate engineering be assessed and governed?
Convened by: 

Simone Tilmes

National Center for Atmospheric Research

Dr. Simone Tilmes is a Project Scientist II at National Center for Atmospheric Research (NCAR) and the liaison for the Community Earth System Model (CESM) chemistry-climate working group. Her scientific interests cover the understanding and evaluation of chemical, aerosol and dynamical processes in chemistry-climate models. She has investigated past, present and future evolution of the ozone hole in both hemispheres based on models and observations. Further research includes interactions in tropospheric chemistry, aerosols, air quality, long-range transport of pollutants, and tropospheric ozone. She also studies the impact of geoengineering on the Earth’s climate system, the hydrological cycle, and the impact of solar radiation management on dynamics and chemistry in both troposphere and stratosphere.

Rolf Müller

Forschungszentrum Jülich & Wuppertal University

Rolf Müller serves as a private lecturer at Wuppertal University and as a senior scientist at Forschungszentrum Jülich where he holds the position of deputy director at the Institute of Energy and Climate Research (Stratosphere). He is editor of Atmospheric chemistry and physics and was lead author of the WMO ozone assessments and the  IPCC special report on safeguarding the ozone layer and the global climate system. He is also reviewer of several journals, reports and funding agencies.
Müller habilitated at Wuppertal University in 2009 and holds a PhD in Meteorology from Freie Universität Berlin. His main topics of research are Stratosphere-Troposphere exchange, Transport pathways in the Asian Monsoon Anticyclone, Polar ozone loss and Polar stratospheric clouds and Stratospheric water vapour.


Michael Mills

National Center for Atmospheric Research (UCAR)

Dr. Mills is a project scientist at the National Center for Atmospheric Research in Boulder, Colorado. He serves as the community liaison for the Whole Atmosphere Community Climate Model (WACCM), a comprehensive numerical model spanning the range of altitude from the Earth's surface to the thermosphere. Dr. Mills received his S.B from M.I.T. in Earth, Atmospheric, and Planetary Sciences, and his Ph.D. work at the University of Colorado. His research has focused on stratospheric ozone, climate, aerosols, volcanic eruptions, geoengineering, and nuclear winter. He has participated in field measurement campaigns, which have taken him to Antarctica and above Arctic Circle. He has received the Marinus Smith Teaching Award from the University of Colorado Parents Association.

Amy Butler

Cooperative Institute for Research in Environmental Sciences & NOAA Earth System Research Laboratory

Dr. Amy H. Butler received her Bachelor's degree in Physics from University of Colorado-Boulder and her doctoral degree in Atmospheric Science from Colorado State University. She then worked at the NOAA Climate Prediction Center for four years before becoming a research scientist for the Cooperative Institute for Research in Environmental Sciences and the NOAA Earth System Research Laboratory.  Dr. Butler's research focuses on large-scale teleconnections and dynamics, seasonal prediction, stratosphere-troposphere coupling, and chemistry-climate interactions.

Frank Keutsch

Harvard University

Born in Tübingen, Germany, Frank Keutsch received his Diplom in chemistry from the Technische Universität München, Germany, under the supervision of Vladimir E. Bondybey in 1997. He received his Ph.D. in physical chemistry from the University of California at Berkeley in 2001. His graduate research was conducted under the direction of Richard J. Saykally and focused on vibration−rotation−tunneling spectroscopy and hydrogen-bond-breaking dynamics in water clusters. After working on stratospheric chemistry in the Department of Chemistry and Chemical Biology at Harvard University under the direction of James G. Anderson he started his independent academic career in 2005 at the University of Wisconsin-Madison. He then moved to his current position as Stonington Professor of Engineering and Atmospheric Science at Harvard University. His research combines laboratory and field experiments with instrument development to investigate fundamental mechanisms of anthropogenic influence on atmospheric composition within the context of impacts on climate, humans and the environment.

Alkiviadis Bais

Aristotle University of Thessaloniki