Global agricultural expansion cut a wide swath through tropical forests during the 1980s and 1990s. More than half a million square miles of new farmland - an area roughly the size of Alaska - was created in the developing world between 1980 and 2000, of which over 80 percent was carved out of tropical forests, according to Stanford researcher Holly Gibbs.

"This has huge implications for global warming, if we continue to expand our farmland into tropical forests at that rate," said Gibbs, a postdoctoral researcher in the Department of Environmental Earth System Science and in the Program on Food Security and the Environment, who led the study.

Gibbs and colleagues at several other universities analyzed Landsat satellite data and images from the United Nations to reach their conclusions. Theirs is the first study to map and quantify what types of land have been replaced by the immense area of new farmland developed across the tropical forest belt during the 1980s and 1990s.

While this huge increase was happening within the tropics, agricultural land in the non-tropical countries actually decreased in area.

The study was published this week in the online Early Edition of the Proceedings of the National Academy of Sciences.

The United Nations Food and Agriculture Organization estimates that to keep pace with increasing demand, global agricultural production will have to keep increasing, possibly even doubling by 2050. That would likely lead to millions of additional acres of tropical forest being felled over the next 40 years.

Direct impact on carbon released into atmosphere

"Every million acres of forest that is cut releases the same amount of carbon into the atmosphere as 40 million cars do in a year," Gibbs said.

Most of the carbon released comes from burning the forests, but even if the trees are simply cast aside, the bulk of the carbon from the plants makes its way into the atmosphere during decomposition, she said.

Gibbs and her colleagues found that about 55 percent of the tropical forests that had been cut between 1980 and 2000 were intact forests and another 28 percent were forests that had experienced some degradation, such as some small-scale farming, logging or gathering of wood and brush for cooking or heating fuel.

"The tropical forests store more than 340 billion tons of carbon, which is 40 times the total current worldwide annual fossil fuel emissions," Gibbs said. "If we continue cutting down these forests, there is a huge potential to further contribute to climate change."

The increasing demand for agricultural production stems in part from the ever-growing number of people on the planet, who all want to eat. Additionally, members of the growing middle class in emerging economies such as China and India are showing interest in eating more meat, which further intensifies demand. And incentives to grow crops for biofuel production have increased.

But Gibbs and her colleagues also observed some encouraging signs. The patterns of change in the locations they analyzed made it clear that during the 1990s, less of the deforestation was done by small family farms than was the case in the 1980s and more was done by large, corporate-run farms. Big agribusiness tends to be more responsive to global economic signals as well as pressure campaigns from advocacy organizations and consumer groups than individual small farmers.

In Brazil, where a pattern had developed of expanding soy production by direct forest clearing and by pushing cattle ranching off pastureland and into forested areas, a campaign by Greenpeace and others resulted in agreements by key companies to rein in their expansion. Instead, they worked to increase production on land already in agricultural use.

'Seeing positive changes'

"These farmers effectively increased the yield of soy on existing lands and they have also increased the head of cattle per acre by a factor of five or six," Gibbs said. "It is exciting that we are starting to see how responsive industry can be to consumer demands. We really are seeing positive changes in this area."

Along with wiser use of land already cleared, Gibbs said, improvements in technology and advances in yield intensification also could slow the expansion of farming into the forests.

Other studies that analyzed land use changes between 2000 and 2007 have shown that the pace of cutting down the tropical forests has begun to slow in some regions.

But as long as the human population on the planet continues to grow, the pressure to put food on the table, feed in the barnyard and fuel in the gas tank will continue to grow, too.

"It is critical that we focus our efforts on reducing rates of deforestation while at the same time restoring degraded lands and improving land management across the tropics," Gibbs said. "The good news is that pressure from consumer groups and nongovernmental organizations combined with international climate agreements could provide a real opportunity to shift the tide in favor of forest conservation rather than farmland expansion."

In addition to her position at the Department of Environmental Earth System Science and the Program on Food Security and the Environment, Gibbs is affiliated with Stanford's Woods Institute for the Environment. Jon Foley, a professor of ecology, evolution and behavior, and director of the Institute on the Environment at the University of Minnesota, was Gibbs' PhD adviser when the research was begun. He is a coauthor of the paper.

Initial funding for the project was provided by NASA. Gibbs is currently funded by a David H. Smith Conservation Research Fellowship.

The grant will go toward supporting Rodrigo Pizarro's research on the impact of the world diffusion of conservation policy on biodiversity with special reference to Latin America.

Project Summary:

Pizarro draws from Institutional Theory to examine the accelerated adoption of conservation policies across the globe, particularly in Latin America. Although there is a remarkable convergence across countries in the ‘formal' policy of biodiversity conservation, through the establishment of protected areas, there exists a wide variety of experiences in implementation and outcomes. Pizarro seeks to understand what explains observed differences in practice by understanding the ‘structuration of the organizational field' - the exchange, interests and interplay of organizations - in selected countries. This approach can help explain why, despite having fairly similar formal policies, nations have a wide variety of implementation experiences. Further, he expect the results to provide insights to improve environmental policy implementation and thus provide guidelines for inter-governmental organizations or international non-government organizations in their support of developing countries' conservation programs.

Global meat production has tripled in the past three decades and could double its present level by 2050, according to a new report on the livestock industry by an international team of scientists and policy experts. The impact of this "livestock revolution" is likely to have significant consequences for human health, the environment and the global economy, the authors conclude.

"The livestock industry is massive and growing," said Harold A. Mooney, co-editor of the two-volume report, Livestock in a Changing Landscape (Island Press). Mooney is a professor of biology, senior fellow at the Woods Institute for the Environment and senior fellow at FSI, by courtesy.

"This is the first time that we've looked at the social, economic, health and environmental impacts of livestock in an integrated way and presented solutions for reducing the detrimental effects of the industry and enhancing its positive attributes," he said.

Among the key findings in the report are:

• More than 1.7 billion animals are used in livestock production worldwide and occupy more than one-fourth of the Earth's land.
• Production of animal feed consumes about one-third of total arable land.
• Livestock production accounts for approximately 40 percent of the global agricultural gross domestic product.
• The livestock sector, including feed production and transport, is responsible for about 18 percent of all greenhouse gas emissions worldwide. 

Although about 1 billion poor people worldwide derive at least some part of their livelihood from domesticated animals, the rapid growth of commercialized industrial livestock has reduced employment opportunities for many, according to the report. In developing countries, such as India and China, large-scale industrial production has displaced many small, rural producers, who are under additional pressure from health authorities to meet the food safety standards that a globalized marketplace requires.

Beef, poultry, pork and other meat products provide one-third of humanity's protein intake, but the impact on nutrition across the globe is highly variable, according to the report. "Too much animal-based protein is not good for human diets, while too little is a problem for those on a protein-starved diet, as happens in many developing countries," Mooney noted.

While overconsumption of animal-source foods - particularly meat, milk and eggs - has been linked to heart disease and other chronic conditions, these foods remain a vital source of protein and nutrient nutrition throughout the developing world, the report said. The authors cited a recent study of Kenyan children that found a positive association between meat intake and physical growth, cognitive function and school performance.

Human health also is affected by pathogens and harmful substances transmitted by livestock, the authors said. Emerging diseases, such as highly pathogenic avian influenza, are closely linked to changes in the livestock production but are more difficult to trace and combat in the newly globalized marketplace, they said.

Environmental impacts

The livestock sector is a major environmental polluter, the authors said, noting that much of the world's pastureland has been degraded by grazing or feed production, and that many forests have been clear-cut to make way for additional farmland. Feed production also requires intensive use of water, fertilizer, pesticides and fossil fuels, added co-editor Henning Steinfeld of the United Nations Food and Agriculture Organization (FAO).

Animal waste is another serious concern. "Because only a third of the nutrients fed to animals are absorbed, animal waste is a leading factor in the pollution of land and water resources, as observed in case studies in China, India, the United States and Denmark," the authors wrote. Total phosphorous excretions are estimated to be seven to nine times greater than that of humans, with detrimental effects on the environment.

The beef, pork and poultry industries also emit large amounts of carbon dioxide, methane and other greenhouse gases, Steinfeld said, adding that climate-change issues related to livestock remain largely unaddressed. "Without a change in current practices, the intensive increases in projected livestock production systems will double the current environmental burden and will contribute to large-scale ecosystem degradation unless appropriate measures are taken," he said.

Solutions

The report concludes with a review of various options for introducing more environmentally and socially sustainable practices to animal production systems.

"We want to protect those on the margins who are dependent on a handful of livestock for their livelihood," Mooney said. "On the other side, we want people engaged in the livestock industry to look closely at the report and determine what improvements they can make."

One solution is for countries to adopt policies that provide incentives for better management practices that focus on land conservation and more efficient water and fertilizer use, he said.

But calculating the true cost of meat production is a daunting task, Mooney added. Consider the piece of ham on your breakfast plate, and where it came from before landing on your grocery shelf. First, take into account the amount of land used to rear the pig. Then factor in all the land, water and fertilizer used to grow the grain to feed the pig and the associated pollution that results.

Finally, consider that while the ham may have come from Denmark, where there are twice as many pigs as people, the grain to feed the animal was likely grown in Brazil, where rainforests are constantly being cleared to grow more soybeans, a major source of pig feed.

"So much of the problem comes down to the individual consumer," said co-editor Fritz Schneider of the Swiss College of Agriculture (SHL). "People aren't going to stop eating meat, but I am always hopeful that as people learn more, they do change their behavior. If they are informed that they do have choices to help build a more sustainable and equitable world, they can make better choices."

Livestock in a Changing Landscape is a collaboration of the FAO, SHL, Woods Institute for the Environment, International Livestock Research Institute (ILRI), Scientific Committee for Problems of the Environment (SCOPE), Agricultural Research Center for International Development (CIRAD), and Livestock, Environment and Development Initiative (LEAD).

Other editors of the report are Laurie E. Neville (Stanford University), Pierre Gerber (FAO), Jeroen Dijkman (FAO), Shirley Tarawali (ILRI) and Cees de Haan (World Bank). Initial funding for the project was provided by a 2004 Environmental Venture Projects grant from the Woods Institute.

Editor's Note

To obtain a copy of Livestock in a Changing Landscape, contact Angela Osborn at Island Press: (202) 232-7933 (extension 35) or aosborn@islandpress.org.