Co-Chairs

• John Reilly, Massachusetts Institute of Technology

• Jeff Graham, US Department of Agriculture (through Sept. 1999)

Assessment Team

• David G. Abler, Pennsylvania State University
• Roy Darwin, US Department of Agriculture
• Steve Hollinger, University of Illinois
• Cesar Izaurralde, Pacific Northwest National Laboratory
• Shrinkant Jagtap, University of Florida - Gainesville
• James Jones, University of Florida - Gainesville
• John Kimble, US Department of Agriculture
• Bruce McCarl, Texas A+M University
• Linda Mearns, National Center for Atmospheric Research
• Dennis Ojima, Colorado State University
• Eldor A. Paul, Michigan State University
• Keith Paustian, Colorado State University
• Susan Riha, Cornell University
• Norman Rosenberg, Pacific Northwest National Laboratory
• Cynthia Rosenzweig, Goddard Institute for Space Studies
• Francesco Tubiello, Goddard Institute for Space Studies

This report was prepared for the US Federal Government as part of the National Assessment of Climate Variability and Change. The US Department of Agriculture provided the principal source of funding through the Global Change Program Office, Office of the Chief Economist. The US Department of Energy provided substantial funding for participation of the Pacific Northwest National Laboratory. The Farm Foundation and the Economic Research Service co-sponsored the initial stakeholder meeting.

Forward

Assessment efforts of this type offer an opportunity for researchers to apply their research tools and expertise to issues of National importance. We came into this effort hoping that the years spent analyzing, modeling, and studying will provide some measure of useful guidance to those who have commissioned the assessment. The efforts provide an opportunity to compare results among colleagues and to deepen one's understanding of the findings of other disciplines. I learned much from my colleagues who graciously and enthusiastically accepted the invitation to serve on the team. The funding available for the assessment was adequate to support specific modeling tasks and essential travel. Team members generously contributed time well beyond the tasks that were specifically funded. For this I am grateful. It is my hope that members found the experience rewarding and thus found participation worthwhile.

This report represents the combined efforts of the Agriculture Sector Assessment Team but I would be remiss if I failed to point out the substantial contributions of the individual team members. Francesco Tubiello coordinated the crop model scenarios produced by the suite of crop models run by GISS, the University of Florida, and the Natural Resource Ecology Laboratory at Colorado State. The protocols and site data developed at GISS by Cynthia Rosensweig for previous assessments were graciously made available to the teams of crop modelers. In addition, to Tubiello at GISS, Shrinkant Jagtap, Jim Jones, Keith Paustian, and Dennis Ojima composed the crop modeling teams that developed comprehensive and consistent scenarios for the 2 climate scenarios evaluated.

The PNNL team of Cesar Izaurralde and Norman Rosenberg and assisted by Robert Brown applied a model with more geographically comprehensive coverage for several crops for one climate scenario. This provided an opportunity to assess the differences that arose from methodological differences of this approach compared to the detailed site approach used by the other teams. Paustian and Ojima organised a crop modeling workshop to compare, in more depth, the performance of these models at selected sites to further understand the types of uncertainties that differing model structures could introduce. Linda Mearns contributed her crop modeling expertise as well as her expertise on variability and extreme events. A separate study she was leading, and funded by the National Science Foundation, provided critical coverage for cotton.

Bruce McCarl developed national yield changes based on the site results from the crop studies and simulated economic effects. He with several co-authors also investigated several other aspects of the problem including the dependence of pesticide expenditures on climate, economic effects of changes in El Niño, and he interacted with the Water Sector Assessment to assure that our water supply assumptions were consistent with their estimates. Roy Darwin provided results on impacts on trade based on recent analyses he has conducted with his global model. This large effort was possible within the short time-frame and restricted budget because of the tremendous expertise and experience of these team members.

In other aspects of the assessment, the analytical tools and approaches for conducting an integrated assessment have not been yet been fully developed. Here we relied on modeling case studies, creative evaluation of historic data, and judgement of experts. Steve Hollinger studied data on crop variability over the past 100 years to provide an historical perspective on adaptation. David Abler applied a newly developed model of the economics of water quality in the Chesapeake Bay Region and summarized potential environmental/agro/climatic interactions. Eldor Paul and John Kimble evaluated potential effects of climate change on soils. Susan Riha provided a summary of our current understanding of carbon dioxide effects on plant growth and the potential to develop new crop varieties as a response to climate change and increased ambient CO₂ levels. These efforts pushed into some new, but critical territories, lending perspectives we otherwise would not have.

I am also grateful for the time our Steering Committee took from their busy schedules to guide the effort. I know we have not answered all the questions they raised but hope that we have answered at least some of them. My thanks also to Jeff Graham for his help. He left USDA before the report was completed by left his mark on the effort. Finally, I am grateful to Margot Anderson, Director of the Global Change Program Office at USDA. She was our initial contact, secured funding, and did her best to keep us on track and responsive to the goals of the assessment.

John Reilly
January, 2000

Preface

This report contains the principal findings of the agricultural assessment. Detailed reports of results and methods are reported in the following working paper reports. All of these are available online.  If you are reading this in electronic form and are connected to the internet you can access these reports by clicking directly on them. Throughout the report we have provide direct hot links to WEB available sources.