All of humanity could likely be well fed in the future without having to convert any more of Earth's forests to croplands, but there is a catch according to new research: we would all have to become vegans.
While that scenario is unlikely, the research indicates how much could be gained if meat lovers the world over replaced their steaks, burgers and other carnivore selections with more eco-friendly vegan fare.
"First of all, area demand for agriculture would be drastically reduced, as well as the need to intensify agriculture and to achieve high yields," lead author Karl-Heinz Erb of Vienna's Institute of Social Ecology told Discovery News. "This could allow for reduced encroachments into natural ecosystems - including forests, savannas and natural grasslands."
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He added that a global transition to a vegan diet would also reduce biodiversity losses as well as pollution, such as by lowering carbon emissions resulting from land conversions.
For the study, published in the journal Nature Communications, Erb and his team explored the feasibility of feeding the world's population in the year 2050, when our species is projected to number 9.3 billion. They estimated per capita food demands based on data from the Food and Agriculture Organization of the United Nations, the USDA and other sources.
The scientists next modeled supply and demand tied to agriculture under 500 different future scenarios that varied according to changes in crop yields, area use, and human dietary choices. One hundred percent of all listed food sustainability and environmental goals could be achieved if the world's population became entirely vegan, the research found. This dropped a bit to 94 percent under vegetarianism. Only 15 percent of the goals were possible if everyone ate a meat-based, western-style diet.
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As it stands, human activities are responsible for reducing forests by one-third up to 50 percent, according to the researchers. Of this amount, two-thirds is due to converting forests to grazing lands, and one-third is due to conversion to croplands.
Cows, goats and certain other animals can graze on land that is not particularly fertile, but consumer demand for meat is often so high that such animals are moved to areas where crops could successfully be grown.
Currently, the percentage of people around the globe who are vegetarians is low. Another study, published in The American Journal of Clinical Nutrition, found that India tops the list with 35 percent of its population eating a mostly vegetarian diet. Italy, Great Britain and Germany tied for second, all having 9 percent of their populations being vegetarians. The Netherlands, U.S. and Canada all have 4 percent, Austria and Switzerland came in with 3 percent, and France rounded out the top 10 list with 2 percent.
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Another way to consider such data is to project what would happen if greater numbers of people decided to eat a meat-rich diet.
"Future deforestation would for sure massively affect biodiversity," Erb said, adding that the carbon emissions alone could drastically counter efforts to safeguard against climate change. Income poor regions might also suffer more if they become increasingly import-dependent, making them vulnerable to price fluctuations and food shortages.
While going vegan would help to solve many of these problems, the authors want to avoid taking an extreme position on this matter.
"We did not assess the vegan lifestyle as a suggestion for where we should aim, but rather to show how much would be possible if societies would go in such a direction," Erb said, mentioning that aiming for a "less meat" diet is more realistic for most.
Verena Seufert is a researcher at the University of British Columbia's Liu Institute for Global Issues and the Institute for Resources Environment & Sustainability.
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Seufert believes the new study "provides us important and interesting insights into the big question of how to feed the world into the future. The study addresses this question by exploring a wide range of different scenarios in a rigorous and systematic manner that I haven't seen before."
She told Discovery News that, based on the study, "business as usual does not seem to be an option" in meeting the human population's ever-growing food needs without destroying more forests, savannas and natural grasslands.
Seufert, however, thinks that there are other possible options for feeding people while altering less land in the future. Reduction of food waste could be an important strategy, she said. Still other researchers are studying ways of producing lab-grown meats and making high protein, sustainable and edible insects more popular and appealing to consumers.