Thursday, December 16, 2010

Agriculture and Climate Change

Dr. Jerry Hatfield

Climate change patterns for Agriculture

(J)erry Hatfield, laboratory director and supervisory plant physiologist with the U.S. Department of Agriculture-Agricultural Research Service, discussed ongoing research efforts in studying current climate change patterns. He said farmers and ranchers should plan for more fluctuations of extreme dry to wet weather patterns in the future. "We will see an increase variance in precipitation in which we’re going to be experiencing longer periods of dry weather interspersed by longer periods of wet (weather)," he said. "It’s going to be a real challenge for agriculture on how to cope with this as we put together this puzzle."

Aside from increases in the amount of carbon dioxide released into the atmosphere and temperature changes, Hatfield said there also has been an increase in water vapor. "We’ve become much more humid and that's also affected temperatures," he said. He said nighttime temperatures have been overlooked when studying the changes in the atmosphere. "These increases in mean temperatures are due mostly to nighttime temperatures than daytime temperatures. In the last 20 years, increased nighttime temperatures changed very dramatically."

Another area that hasn't been addressed in examining the effects of climate change has been plant physiology and nighttime temperatures, he said. "It's one of the pieces of the puzzle that has been overlooked. We tend to look from a climatic view and not a plant physiological view." Higher nighttime temperatures will affect reproductive development "because of the sensitivity of pollen survival to temperature."

"Increases in nighttime temperatures will have a large impact on both vegetative and reproductive growth," he said. "Yields will be impacted because of shortened reproductive periods. Occurrences of higher temperatures will cause faster phenological development." Hatfield noted a few indirect impacts of climate change, which include more weed infestations. "Weeds love CO2 (carbon dioxide) even more and they are showing positive response to rising CO2 concentrations," he said. Insects and diseases also increase with more favorable environments over the winter and more humid conditions during the growing season, Hatfield said.

"Climate change will affect agriculture," he said. "Agriculture has adapted to climate change in the past and will again in response to long-term trends. These are some major challenges. These aren’t meant to scare you, it's how we adapt to these scenarios. We need to figure out how to build some resilience in our cropping systems to handle that."
(source: Colorado State University)

Kalpa's Note: See my previous post "Hot summer Nights" with maps.

The following is a map of the USDA's GRACEnet locations (starred) doing climate/mitigation research. The green areas are where row crops are grown.

GRACEnet (Greenhouse gas Reduction through Agricultural Carbon Enhancement network) is a research program that has been initiated by the USDA-ARS. The primary objective of GRACEnet is to identify and further develop agricultural practices that will enhance carbon sequestration in soils, promote sustainability and provide a sound scientific basis for carbon credits and trading programs. This program will generate information concerning carbon storage in agricultural systems that is needed by producers, program managers and policy makers. GRACEnet also addresses the other greenhouse gases, nitrous oxide and methane that may be emitted by agricultural practices. Agricultural lands to be studied by GRACEnet scientists include both grazing lands (range and pasture) and crop lands (irrigated and dryland). Coordinated multi-location field studies will follow standardized protocols to compare net GHG emissions (carbon dioxide, nitrous oxide, methane), carbon (C) sequestration, and broad environmental benefits under different management systems.