Global warming may be net negative for US ag,
but carbon stewardship, wind power could help

Land-grant profs who gathered in Boston on September 29 say drought, flooding and pests will take greater tolls as weather extremes continue. Farm-based solutions include biodiesel and wind harvesting, along with carbon-building cropping systems that reduce carbon dioxide levels.

EDITOR'S NOTE: Click here for a streaming audio replay of the news event described in this article .

WASHINGTON, D.C. -- September 29, 2003: Falling crop production resulting from extreme weather events, diseases and pest infestations increasingly will be fueled by global warming and create an uncertain future for U.S. agricultural production and the nation's food supplies, according to leading experts gathered here today at a Harvard Medical School Center for Health and the Global Environment briefing, made possible by the Civil Society Institute, the Energy Foundation and the National Environmental Trust. A news media event was followed by a congressional staff briefing sponsored by Sen. Harkin (D-IA), Sen. Brownback (R-KS), Sen. Bill Nelson (D-NE) and Sen. Lugar (R-IN).



The Center for Health and the Global Environment ( at the Harvard Medical School was founded in 1996 to expand environmental education at medical schools and to further investigate and promote awareness of the human health consequences of global environmental change. The Center administers a course at Harvard Medical School entitled "Human Health and Global Environmental Change." The course is taught by scientific experts from around the world and is open to the public as well as students from Harvard Medical School, Harvard School of Public Health, and other university students in the Boston area. The course has also been taught at more than 20 percent of medical schools in the U.S. and three international medical schools via videotape and online videos. The Center also educates policy-makers by holding briefings and courses on human health and the global environment on Capital Hill, and directs two major projects for the United Nations—one looking at human health projections from climate change, with the participation and support of the Swiss Re Corporation, the other reporting on what is known about the contributions of biodiversity to human health.

Based in Newton, MA, the Civil Society Institute is a non-profit organization that focuses on five areas of critical need: kids and learning, health care reform, science policy and regenerative medicine, economic change and climate change and global security. Visit the Civil Society Institute on the Web at

Launched in 1991, The Energy Foundation is a partnership of major foundations interested in sustainable energy. The Energy Foundation awards grants and takes direct initiatives in six areas: Power, Buildings, Transportation, National Policy & Analysis, Climate Program and the The China Sustainable Energy Program. The foundation's geographic focus is the United States, with special emphasis on regional initiatives. Visit The Energy Foundation on the Web at

The National Environmental Trust is a non-profit, non-partisan membership group established in 1994 to inform citizens about environmental problems and how they affect our health and quality of life. Visit the National Environmental Trust on the Web at

For more information about this event, contact: Stephanie Kendall, for the Harvard Medical School’s Center for Health and the Global Environment, at (703) 276-3254 or

Not all the views from the experts were gloomy. Some noted that the impact of global warming can be lessened – and even turned into a boon for agricultural producers – if farmers take such steps as setting up wind farms, engaging in the production of "biodiesel" and ethanol fuels and participating in carbon sequestration programs.

Eric Chivian, director of the Center for Health and the Global Environment at Harvard Medical School said: "Since the 1970s, U.S. agricultural productivity has grown, but it has also experienced greater variability that has been, in part, climate-related. Extreme weather events (very high temperatures, torrential rains and flooding, and droughts) and crop diseases and pests have taken a heavy toll. Greenhouse warming is expected to lead in future years to even more intense and frequent extreme weather events, and to greater losses from diseases and from pests that may multiply more rapidly and expand their ranges."

William Easterling, professor of agronomy and director of the Institutes of the Environment at Penn State University said: "Climate variability continues to exert large year-to-year swings in U. S. crop yields and production in spite of technology-driven gains in crop productivity over the 20th century. Recent persistent drought conditions in the western Corn Belt states have particularly affected wheat production. While experiments persuasively demonstrate the positive effects of rising atmospheric CO2 concentrations on photosynthesis of major crops such as soybeans and wheat and on the drought-tolerance of all crops, these effects are not likely to fully offset the potential stresses of warmer temperatures and drier soils, especially as the warming progresses. Crop modeling results ... paint a consistent picture of crop yields being lower than today even in an environment with higher rainfall than now."

Among the big concerns for farmers when it comes to climate change: more pests and diseases. X.B. Yang, associate professor of plant pathology at Iowa State University said: "Climate change will greatly impact plant diseases and pests because climate dictates their occurrence. Literature in plant pathology has shown that pandemics of pests are associated with extreme weather events. Recently, increased large scale epidemics of new and old diseases have been recorded in our nation's major crops. Pandemics of wheat stripe rust occurred in The Great Plains during the 2001 and 2003 growing seasons. In 2002, U.S. soybean farmers experienced epidemics of soybean sudden death syndrome, and various viral diseases, costing them nearly 2 billion dollars. This summer, mass outbreaks of Asian aphids occurred in Iowa, Illinois, and Minnesota, the three largest soybean production states, after cool July weather suddenly turned into a record dry August. Farmers in the North Central Region, which includes our nation's Corn Belt and Soybean Belt, are experiencing increasing outbreaks of crop diseases and pests."

Yang added: "Before the mid-80s, no more than four major diseases affected soybean production. Now the number has more than doubled, with annual losses totaling almost two billion dollars. Range expansions northward of southern diseases or in the distribution of warm-temperature diseases have been attributed to these new disease problems. Recent warmer winters in northern production regions have increased winter pest survival and outbreaks of insect-borne viral diseases associated with them."

However, global warming also could work to the advantage of some farmers, according to Charles W. Rice, professor of soil microbiology at Kansas State University. He noted: "Agriculture can help solve [the CO2] problem [through participation in carbon sequestration programs]. Crops and other plants remove CO2 from the atmosphere and convert it into organic carbon. After harvest, the organic carbon in residues and roots is deposited in the soil, where portions can remain for long periods ... Benefits of carbon sequestration include increased soil fertility, reduced erosion, improved wildlife habitat and better soil and water quality. Recent estimates of the potential for U.S. agricultural soils to sequester carbon, using existing technologies, are on the order of ... 15 percent of carbon emissions in the U.S. This estimate does not include biomass production for renewable fuels nor advancement in soil and agricultural sciences. Economic analyses suggest that soil carbon sequestration is among the most beneficial and cost effective option available for reducing greenhouse gases, particularly over the next 30 years until alternative energy sources are developed and become economically feasible."

U.S. farms also could serve as a major source of alternative energy supplies, including wind farming and biodiesel production. American Corn Growers Foundation CEO Dan McGuire said: "Renewable energy, including wind, ethanol and biodiesel offers the means to improve the environment and make our country more energy independent and secure while enhancing the rural and national economy. The Wind Powering America program of the U.S. Dept. of Energy projects that wind power could displace 35 million tons of atmospheric carbon by year 2020. In May 2000, biodiesel became the only alternative fuel to successfully complete the Environmental Protection Agency's Tier I and Tier II testing under Section 211 (b) of the Clean Air Act. The Department of Energy and the U.S. Department of Agriculture have calculated carbon dioxide reductions of 78 percent for biodiesel when compared with petroleum diesel in a full life cycle analysis. Biodiesel also reduces air pollutants linked to cancer by 80-90 percent vs. petroleum diesel."

Recent news and research

[an error occurred while processing this directive]

Stay Up-to-Date –
Sign up for our Newsletter changes daily! Don't miss out on the latest interactive features, columns and news. Sign up now for our monthly e-newsletter and stay connected.


•Free the meat markets! End packer ownership and stop closed-door deals

• Support Saskatchewan farmers in efforts to block GM wheat

• Stop budget cuts to conservation programs--the one's that help you pay for environmentally sound farming practices!

Share Your Stories

Are you a farmer? A consumer? Whatever story you have to tell, let it be an inspiration to others.
Share it with us now...

T H E    N E W    F A R M – R E G E N E R A T I V E    A G R I C U L T U R E    W O R L D W I D E