Skip Navigation

Stephen Schwartz

Adjunct Professor



- University of California

Research Topics:

Earth energy budget and climate change; Budget and lifetime of anthropogenic CO2; Role of tropospheric aerosols as shortwave forcing agents; Atmospheric radiation; Cloud chemistry and acid deposition


  • Bio/Research


    For much of my career my research has focused on the chemistry of Atmospheric Energy-Related pollutants (AER pollutants). The principal substances of concern have been sulfur and nitrogen oxides emitted into the troposphere as byproducts of fossil fuel combustion, and their oxidation products, i.e., sulfuric acid and nitric acid and the salts of these species. These substances are of concern from the perspective of human health, acid deposition, visibility reduction, and climate change. More recently my research interest has turned increasingly to understanding the response of Earth’s climate system to the increase of carbon dioxide (CO 2) and other so-called forcing agents, substances which change the radiation budget of the planet, specifically including also the influences of atmospheric aerosols (submicroscopic particles suspended in air).

    As these materials are introduced into the atmosphere largely in association with energy-related activities, the environmental consequences of these emissions are of immediate concern to the United States  Department of Energy, and much of the support for my research comes from the  Climate and Environmental Sciences Division (CESD) within the  Office of Biological and Environmental Research within that Department. Within CESD our research has been supported mainly by the Atmospheric Science Program (ASP) and the Atmospheric Radiation Measurement Program (ARM); in 2009 these two programs were merged into the  Atmospheric System Research (ASR) Program.

    From 2004 to 2009 I served as chief scientist of the Department of Energy’s Atmospheric Science Program. Much of the research of that program was (and in ASR continues to be) focused on the influences of aerosols on atmospheric radiation, clouds, and climate. An overview of the issues pertaining to the climate influences of atmospheric aerosols and approaches to understanding the processes governing the life cycle of these aerosols and representing them in models is presented in a  paper published in  The Bulletin of the American Meteorological Society in 2007. Research in the ARM Program focused on (and in ASR continues to focus on) understanding atmospheric radiation and the influences on this radiation, especially the influences of clouds. A description of the ARM program and its measurement approaches is given in a  paper published in  The Bulletin of the American Meteorological Society in 1994.

    The following narrative provides a rather general introduction to our recent research dealing with energy related emissions and their environmental consequences, focusing mainly on influences on climate and on climate system response, and places this work in the context of the larger climate change issue. Our research is represented in our publications. The links below are to the citations of the papers on my  publications page .

    I welcome inquiries of interest from any and all. Much of our work is conducted in collaboration with others at their institutions or as visiting scientists at Brookhaven National Laboratory. I particularly encourage inquiries from students; you are our future.

  • Publications


    Lifetime of Excess Atmospheric Carbon Dioxide: An Observationally Constrained Top-Down Determination. Schwartz, S. E., in review.

    Bounding global aerosol radiative forcing of climate change. Bellouin N., J. Quaas, E. Gryspeerdt, S. Kinne, P. Stier, D. Watson-Parris, O. Boucher, K.S. Carslaw, M. Christensen, A.-L. Daniau, J.-L. Dufresne, G. Feingold, S. Fiedler, P. Forster, 6 A. Gettelman, J. M. Haywood, U. Lohmann, F. Malavelle, T. Mauritsen, D.T. McCoy, G. Myhre, J. Muülmenstädt, D. Neubauer, A. Possner, M. Rugenstein, Y. Sato, M. Schulz, S. E. Schwartz, O. Sourdeva, T. Storelvmo, V. Toll, D. Winker, and B. Stevens. Accepted, Rev. Geophys.

    Resource Letter GECC-2: The Greenhouse Effect and Climate Change: The Intensified Greenhouse Effect, Schwartz, S. E. Amer. J. Phys., 86, 645-656 (2018).

    Resource Letter GECC-1: The Greenhouse Effect and Climate Change: Earth’s Natural Greenhouse Effect, Schwartz, S. E. Amer. J. Phys., 86, 565-576 (2018).

    Unrealized Global Temperature Increase: Implications of Current Uncertainties, Schwartz, S. E. J. Geophys. Res. , 2018, doi: 10.1002/2017JD028121.

    High-Resolution Photography of Clouds from the Surface: Retrieval of Optical Depth of Thin Clouds down to Centimeter Scales, Schwartz, S. E., Huang, D., and Vladutescu D. V., J. Geophys. Res. – Atmos., 2017. Paper #2016JD025384. This paper was featured as a Research Spotlight in Eos and as a “Nowcast” item in the Bulletin of the American Meteorological Society (July, 2017; page 1319).

    Earth’s Climate Sensitivity: Apparent Inconsistencies in Recent Assessments, Schwartz, S. E., Charlson, R. J., Kahn, R. and Rodhe, H., Earth’s Future (AGU), 2014. doi: 10.1002/2014EF000273

    Determination of a lower bound on Earth’s climate sensitivity. Bengtsson, L. and Schwartz, S. E., Tellus B 65, 21533 (2013). doi: 10.3402/tellusb.v65i0.21533

    Determination of Earth’s transient and equilibrium climate sensitivities from observations over the twentieth century: Strong dependence on assumed forcing. Schwartz S. E. Surveys Geophys. 33, 745-777 (2012). doi: 10.1007/s10712-012-9180-4 .

    Observing and Modeling Earth’s Energy Flows. Stevens B. and Schwartz S. E. Surveys Geophys. 33 779-816 (2012). doi: 10.1007/s10712-012-9184-0 .

    Reply to “Comments on ‘Why Hasn’t Earth Warmed as Much as Expected?'” Schwartz S. E., Charlson R. J., Kahn R. A., Ogren, J. A., and Rodhe H. J. Climate. 25, 2200-2204 (2012).

    Production Flux of Sea-Spray Aerosol. de Leeuw G., Andreas E. L, Anguelova M.D., Fairall C. W., Lewis E. R., O’Dowd C., Schulz M. and Schwartz S. E. Rev. Geophys 49, RG2001 (2011). doi: 10.1029/2010RG000349 .

    Feedback and sensitivity in an electrical circuit: An analog for climate models. Schwartz S. E. Climatic Change 106, 315-326 (2011). doi: 10.1007/s10584-010-9903-9.

    Reversible uptake of water on NaCl nanoparticles at relative humidity below deliquescence point observed by non-contact environmental AFM. Bruzewicz, D. A., Checco A., Ocko B. M., Lewis E. R., McGraw R. and Schwartz S. E. J. Chem. Phys. 134, 044702 (2011); doi: 10.1063/1.3524195.

    Why Hasn’t Earth Warmed as Much as Expected? Schwartz S. E., Charlson R. J., Kahn R. A., Ogren, J. A., and Rodhe H., J. Climate 23, 2453-2464 (2010); doi: 10.1175/2009JCLI3461.1.

    Additional publications

  • Links