News

“We Must Take Action,” Easterling Asserts
in December 3, 2007 EarthTalks Colloquium

Agricultural adaptations from biotechnologies to new farming practices will not keep pace with climate change, so policy initiatives to reduce emissions also are necessary if the earth is to support its projected population of 10 billion, said Dr. Bill Easterling, Dean of the College of Earth and Mineral Sciences Monday (Dec. 3).

“Adaptation to climate change is not an option, but we also have to mitigate—we need to stop what we can,” said Easterling, the final speaker in the EarthTalks Fall Colloquium Series on policy options for global warming. “We must take action—we cannot do nothing.”

Easterling noted that warming temperatures will affect the yields of maize, wheat and rice—the three cereal crops which account for between 75 percent and 80 percent of the world’s food supply.

In high latitudes, warmer temperatures and higher CO 2 concentrations may increase crop yields. But in tropic areas which include most of the less developed countries, the yields of cereal crops will decline with even a warming of 1 degree C.

“When yields go down, prices will go up, and this will be a major stress on the people in the less developed world,” Easterling said. “Access to an adequate diet is a central entitlement of people.”

Easterling acknowledged that some of the impact of temperature warming may be offset by changing agricultural practices such as planting earlier to avoid summer heat, planting different cultivars, instituting moisture- and soil-conservation tillage practices and crop rotation. But these will not be sufficient in the long term.

Nor will genetically-modified crops. While 247 million acres were planted in 2006 with genetically modified crops, changing a crop’s genetic architecture to emphasize or suppress a particular trait can make it more vulnerable to pathogens or water shortages.

“Biotechnology is not a silver bullet,” Easterling said. “We are looking at a situation where despite adaptations, crop yields will go down everywhere in the 21 st century.”

Contrary to the public perception that adaptation involves radical change from the status quo, Easterling noted that adaptation is an ongoing and dynamic process. He described how after World War II, farmers in the Great Plains began drawing on the once vast Ogallala aquifer to irrigate crops which otherwise could not be grown in that area.

With that water table now declining and the cost of pumping water increasing, farmers are again adapting—this time, going back to dry-land farming practices, Easterling said.

Even though scientists don’t know with certainty all the effects of climate change, new policies are imperative now to be able to meet the world’s demands for food and fiber. Those policies must combine adaptation and mitigation because adaptation alone is not enough.

“We need to mitigate,” Easterling said. “And adaptation and mitigation need to complement each other.”