Original post by Jane Sooby, April 8, 2011
Organic Farming Research Foundation

To mark the release of a new report on agriculture and climate change, an overflow crowd gathered in Davis for the California Climate and Agriculture Summit on March 31.

The report, Ready … Or Not? An Assessment of California Agriculture’s Readiness for Climate Change, was prepared by the California Climate and Agriculture Network (CalCAN) who also organized the summit.

Main findings from the report are that, while California has progressed in understanding the impacts of climate change on agriculture, little work has been done to show how agriculture can reduce emissions or sequester carbon.

In addition, because of historic and ongoing cuts in Cooperative Extension and conservation programs, the state lacks capacity to provide farmers and ranchers with the technical assistance they need to manage anticipated changes.

Changes in agricultural conditions due to climate change that were reported at the summit include considerable reduction in chilling hours—an important factor for many fruit and nut crops—earlier peak stream flows, less snow and more rain, resulting in increased winter flooding and decreased reservoir levels in summer.

The authors of Ready or Not? set out to quantify the number of studies on climate change impacts on agriculture in California. They found only 39 research projects addressing the issue. Only four of these studies focused on organic agriculture.

At the same time, research indicates that organic farming and dairy production can play important roles in mitigating climate change. Chuck Benbrook, chief scientist at the Organic Center, presented data showing that, per unit of production, organic pasture-based dairy emits 77-80% of the methane emitted by conventional dairies.

Soil scientist Michel Cavigelli with USDA’s Agricultural Research Service reported on results of a long-term systems comparison trial at Beltsville, Maryland. Data from that study show that the global warming potential of organic systems in carbon dioxide equivalents is negative, meaning that organic farming is sequestering more carbon than the greenhouse gases it emits. No-till systems showed moderate global warming potential while conventional tillage showed about twice as much as no-till. The amount of soil carbon sequestered was the biggest source of difference between systems.

Karen Ross, the new Secretary of the California Dept. of Food and Agriculture, opened the summit by saying, “Research is key to everything we’re doing on climate change.”

Ross recounted that the agricultural and environmental communities in California were successful in working together to gain conservation programs in the last Farm Bill. She challenged both groups to cooperate again in making plans to address the impacts of climate change on agriculture.

CalCAN has released a new fact sheet outlining the potential role of organic agriculture in climate protection.

Organic farming systems use soil management practices that offer the best opportunities to reduce GHG emissions, build soil organic carbon (SOC) and sequester atmospheric carbon. Among the most promising are: reduction/elimination of synthetic nitrogen fertilizer applications; use of organic fertilizers and cover crops; and, conservation tillage. A 2008 study funded by the California Energy Commission found that these practices are particularly effective when used in combination.

In addition, organic practices reduce the reliance on fossil fuel based inputs, and organic and pasture-based livestock management practices minimize methane emissions and have the potential for increasing soil carbon sequestration.

The following is a summary of some of the data on carbon sequestration potential of organic farming:

•         In a twelve-year California study of organic farming practices, carbon sequestration was improved by 36 percent with the use of green manures and animal manures even though tillage was increased compared to conventional systems.

•         An eight-year California study found that SOC increased 19 percent in organic and low input systems, as compared with 10 percent in conventional soils with synthetic fertilizers.

•         After 23 years, organic management practices increased soil carbon by 15 to 28 percent and increased soil nitrogen by 8 to 15 percent.

•         A nine-year USDA study found that organic production sequestered more carbon than no-till systems at all soil depths up to 30 cm.

•        Studies comparing the energy inputs required for different livestock management systems suggest that conventional feedlot livestock require twice as much fossil fuel energy compared to grass-fed livestock due in large part to the use of synthetic fertilizers and pesticides used to produce the feed crops.