Iowa scientists: Farmers, policymakers key in reducing greenhouse emissions

Annual climate science statement signed by 187

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Iowa scientists are urging farmers to adopt climate-smart practices that reduce net greenhouse gas emissions while improving soil health, wildlife habitat and water quality.

They’re also urging policymakers to incentivize those practices.

“You can’t just say, ‘Do it when you want to or whenever you can.’ Policymakers need to provide incentives for beneficial action,” said Kamyar Enshayan, director of the Center for Energy and Environmental Education at the University of Northern Iowa and a contributor to the sixth annual climate science statement issued Wednesday.

Wider adoption of conservation practices would reduce net greenhouse gas emissions by pulling heat-trapping carbon dioxide from the atmosphere and rebuilding soil carbon, the statement said.

Converting marginal farmland to perennial vegetation and reducing crop land tillage, the statement said, are critical components of a U.S. Department of Agriculture program with the potential to reduce net carbon emissions and enhance storage of carbon in the soil by more than 120 million metric tons of carbon dioxide equivalent by 2025 — about 2 percent of economywide emissions.

Agriculture Secretary Tom Vilsack introduced USDA’s Building Blocks for Climate Smart Agriculture and Forestry last year and earlier this year announced a new $72.3 million investment to boost carbon storage in healthy soils.

The one-page statement, signed by 187 science faculty and researchers from 39 Iowa colleges and universities, did not mention the August and September extreme rainfall events in north-central and northeast Iowa that flooded farmland and communities along the Cedar, Wapsipinicon, Iowa, Maquoketa, Turkey and Upper Iowa rivers.

“We know the trend is toward more frequent downpours,” said Enshayan. “The statement is about how we are going to deal with that reality and reduce the size of our losses.”

In introductory remarks, David Courard-Hauri, director of the Environmental Science and Policy Program at Drake University, said, “Iowa’s record September rainfall and flooding reminds us that climate change is real and needs to be addressed on both the farm and in our communities.”

Jerry Schnoor, co-director of the University of Iowa Center for Global and Regional Environmental Research, responding to a news conference question, said climate change conclusions cannot be drawn from a single weather event.

“We can say that the frequency of extreme rainfall events is increasing in Iowa.” Schnoor said. “We see that trend clearly in the meteorological record going back 100 years. Total annual rainfall is increasing, and the severity of single-day events is increasing.”

Schnoor said agriculture contributes 27 percent of Iowa’s greenhouse gas emissions.

The prescription for climate-smart agriculture, intended to reduce those emissions, is nearly identical to the conservation practices identified in the Iowa Nutrient Reduction Strategy, intended primarily to reduce the runoff of nitrates and phosphorous from farm fields into the state’s surface waters.

They include no-till and reduced tillage, cover crops, replacement of annual row crops with perennial plants, conversion of marginal farmland to wetlands and better fertilizer management.

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