AMS Climate Briefing: Nitrogen

The American Meteorological Society (AMS) and the University Corporation for Atmospheric Research (UCAR) present:

The Role of Nitrogen in Global Change: Science and Policy Implications

Friday, November 19, 2010

10:00 AM to 11:30 AM
Room SR-253 Russell Senate Office Building
United States Senate
Washington, DC

Register in advance (optional)

*This event is part of the AMS Climate Briefing Series, which is made possible, in part, by a grant from the National Science Foundation’s Paleoclimate Program*

Program Summary: Every year humans create and spread more biologically active nitrogen than all natural terrestrial sources combined. This has been critical for society’s success because nitrogen based fertilizers help feed our people. However, the additional nitrogen available to natural systems also has considerable downsides for society. Excess nitrogen both disrupts the flow of critical goods and services that biological systems provide and amplifies the risks of climate change. This briefing will describe the ongoing changes in nitrogen use, explore the possible consequences to society, and identify potential policy options.


Dr. James Galloway, Sidman P. Poole Professor of Environmental Sciences, and the Associate Dean for the Sciences in the College of Arts and Sciences, at the University of Virginia

Dr. Gordon Bonan, senior scientist and head of the Terrestrial Sciences Section in the Climate and Global Dynamics Division at the National Center for Atmospheric Research


Paul Higgins, Ph.D. Associate Director, American Meteorological Society Policy Program


Speaker: James Galloway

Title: The Nitrogen Dilemma:  How to Feed the World and Protect the Environment

Humans need food to survive. Nitrogen is required to grow food, but natural supplies of nitrogen to grow food have been inadequate since the beginning of the twentieth century.

The Haber-Bosch process, invented in the early 20th century, now provides a virtually inexhaustible supply of nitrogen fertilizer. This one invention is responsible for the existence of about half of the world’s population. That’s the good news. The other news is that most of this nitrogen (and additional amounts from fossil fuel combustion) is lost to the environment where it contributes to smog, ecosystem eutrophication, acid rain, climate change and loss of stratospheric ozone in a sequential manner—the Nitrogen Cascade.

This presentation will 1) illustrate how nitrogen is lost to the environment during food and energy production, 2) describe the resulting impacts on human and ecosystem health due to the loss, 3) show how the choices people make determine the magnitude of the loss, and 4) describe the opportunities for an integrated nitrogen management plan at the local and national level.

There are numerous challenges facing society to optimize the use of nitrogen to provide food for the world’s peoples, yet minimize the negative consequences on the environment.  A key challenge is how scientists communicate the issues concerning nitrogen to both the public and to policy makers.  The talk will conclude with some suggestions in this regard.

Speaker: Gordon Bonan

Title: Nitrogen and Climate

Nitrogen affects the physics, chemistry, and biology of Earth’s environmental systems and is a critical topic of climate research. Nitrogen deposited onto terrestrial ecosystems increases carbon storage, but the global carbon gain is small compared with other fluxes in the carbon cycle. Nitrogen’s influence on methane, nitrous oxide, ozone, and aerosols, all important determinants of Earth’s climate, must also be considered when devising strategies for global climate change mitigation. Synergism among nitrogen fertilization, carbon dioxide enrichment, and soil warming produces complex climate feedbacks. Climate simulations without these interactions overestimate the capacity for terrestrial ecosystems to store carbon and mitigate anthropogenic carbon emissions. How terrestrial ecosystems respond to climate change, and their capability for climate change abatement, depends not only on changes in physical climate but also on changes in nitrogen and other biogeochemical cycles.


Dr. James Galloway is the Sidman P. Poole Professor of Environmental Sciences, and the Associate Dean for the Sciences in the College of Arts and Sciences, at the University of Virginia.  Dr. Galloway received the B.A. degree in Chemistry and Biology from Whittier College in 1966.  In 1972 he received his Ph.D. degree in Chemistry from the University of California, San Diego.  Following two years as a professional potter in Lexington, Virginia, he accepted a postdoctoral appointment with Gene Likens at Cornell University.  In 1976, he accepted a position as Assistant Professor of Environmental Sciences at the University of Virginia and, from 1996 to 2001 served as chair of the department. He has been on the Board of Bermuda Institute of Ocean Sciences since 1983 and, from 1988 to 1995, served as President of the Board.  He was the founding chair of the International Nitrogen Initiative from 2003 to 2008, and was a member of the USA EPA Science Advisory Board from 2003 to 2009. He is currently a lead author in Working Group 1 of the 5th IPCC Assessment Report.

In 2002 he was elected a Fellow of the American Association for the Advancement of Science. In 2008 he was elected a Fellow of the American Geophysical Union and was awarded, with Harold Mooney, the Tyler Prize for Environmental Achievement.

His research on biogeochemistry includes the natural and anthropogenic controls on chemical cycles at the watershed, regional and global scales.  As part of this research he has investigated the impact of North America on the atmospheric and precipitation quality of Bermuda since 1979.  His current research focuses on beneficial and detrimental effects of reactive nitrogen as it cascades between the atmosphere, terrestrial ecosystems and freshwater and marine ecosystems.

Dr. Gordon Bonan is a senior scientist and head of the Terrestrial Sciences Section in the Climate and Global Dynamics Division at the National Center for Atmospheric Research.  Dr. Bonan received the B.A. degree in Environmental Sciences from the University of Virginia in 1982. He received the M.S. degree in Forest Resources from the University of Georgia in 1984. He returned to the University of Virginia for his doctoral study and received his Ph.D. degree in Environmental Sciences in 1988. He has been employed at the National Center for Atmospheric Research since 1989, following a one year postdoctoral appointment as a National Research Council research associate at NASA’s Goddard Space Flight Center.

Trained as an ecologist, Dr. Bonan studies the interactions of terrestrial ecosystems with climate. His research integrates ecological, hydrological, and atmospheric sciences to study terrestrial ecosystems, their responses to climate change, feedbacks that amplify or mitigate climate change, and human perturbations to ecosystems that alter climate. He specializes in the development of and experimentation with coupled ecosystem-climate models. He leads the development of NCAR’s Community Land Model, with a current emphasis on biogeochemistry.

Dr. Bonan is a past editor of the Journal of Climate (1998-2003) and has served on the editorial board of several atmospheric and ecological journals. He has served on national and international boards including the National Research Council’s Climate Research Committee (2001-2003) and the Integrated Land Ecosystem-Atmosphere Processes Study (iLEAPS) Scientific Steering Committee of the International Geosphere-Biosphere Programme (2010-2012).

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