Deforestation and Food Demand
June 26, 2012

Deforestation and Food Demand

Brett Smith for

Informed decisions on land use will be the key to not only carbon emissions control, but to keeping food affordable, a new MIT study said.

Using an “integrated global system model,” a team of researchers led by John Reilly analyzed the effects of deforestation and land-use choices on both agriculture and carbon capture.

“With a larger and wealthier population, both energy and food demand will grow,” said Reilly, the co-director of the MIT Joint Program on the Science and Policy of Global Change.

“Absent controls on greenhouse gases, we will see more emissions from fossil-fuel use and from land-use change. The resulting environmental change can reduce crop yields, and require even more land for crops. So this could become a vicious circle.”

The study, which was published in Environmental Science & Technology, explored several scenarios with the goal of keeping emissions down and the average global temperature from rising 2 degrees (Celsius), an international objective. The four main scenarios were: no policy, an energy-only policy, an energy-land policy, and a non-biofuels policy.

Without any international policy, the study expects that a growing population, an emerging third world, and increasing energy use will contribute to an average global temperature rise of 6 degrees. A lack of cohesive policy will also result in ballooning carbon dioxide levels and a net loss of land carbon into the atmosphere.

An aggressive international tax on energy emissions would not be enough to limit this warming to 2 degrees, but when the tax is applied to land-use emissions, or the emissions that result from deforestation, the global community could come much closer, with temperatures by the close of the century only rising 2.4 degrees above pre-industrial levels.

The most aggressive scenario laid out by the study involves not only taxing emissions, it also takes into account the production of biofuels, which could be a cleaner source of energy and would lessen the use of fossil fuels. The study´s models indicated that biofuels production could cut fossil-fuel use from 80 percent of energy without a tax to 40 percent with a tax. Researchers said this policy would further limit warming to bring the world just shy of the 2-degree target.

While taxing fossil fuels and carbon emissions are complex and politically sensitive as it is, the scenario involving the taxing of land use emissions becomes even thornier when considering the agricultural needs and markets around the world.

“The environmental change avoided by reducing greenhouse-gas emissions is substantial and actually means less land used for crops,” Reilly said. “The big tradeoff is that diverting this amount of land to carbon storage, and using land to produce biofuels, leads to substantial rises in food and forestry prices.”

The study said that higher food prices will occur over the next 90 years and while wealthier nations will be insulated by a growing GDP–developing and poor countries could see a disproportionate increase in food prices.

Unfortunately, tough choices will have to be made unless advancements in emission or agricultural technology allow for more efficient carbon capture and food production, according to Jonathan Foley, director of the University of Minnesota´s Institute on the Environment.

“In the last 20 years we´ve produced 28 percent more crops. But in the next 38 years, we need to double that growth,” Foley said. “We´re not going to grow our way out of the problem “¦ we must look at other possibilities.”