Greenhouse-gas emissions from U.K. agriculture fell 21 percent between 1990 and 2009 as the national cattle and sheep herds shrank, the government said.
Greenhouse-gas emissions dropped to the carbon dioxide equivalent of 49.5 million metric tons, the Department for Environment, Food and Rural Affairs said in a report today. Methane emissions slid 19 percent and nitrous oxide discharges dropped 23 percent, according to the report. Cattle, sheep, pigs and horses produce methane, and manure stored as a liquid for use as fertilizer produces the gas when decomposing.
Emissions fell as the number of dairy cows declined due to milk quotas and the beef-cow herd dwindled because of changes to subsidy schemes and a 2001 outbreak of foot-and-mouth disease, Defra said. The sheep herd also was hit by the illness, and the hog population declined on higher feed prices and disease issues, according to the report.
“Since 1990, the numbers of cattle and sheep in the U.K. have fallen significantly and this explains the majority of the fall in recorded” methane emissions, Defra said. “When manure is stored or treated as a liquid in a lagoon, pond or tank, it tends to decompose anaerobically and produce a significant quantity of” methane.
Agriculture generates about 37 percent of the country’s methane emissions and 79 percent of nitrous-oxide discharges, Defra said. It’s responsible for just 1 percent of carbon-dioxide emissions, according to the report.
Reduced U.K. greenhouse-gas emissions will be offset by increases in other countries from which importers purchase meat and milk, Defra said.
“While production has fallen in the U.K., which may result in lower total emissions, in the main domestic production, in particular meat and dairy products, has been replaced with imports,” Defra said. “Any reduction of emissions in the U.K. will have been at the expense of increases overseas.”
Growers may save money by adopting farming methods that reduce greenhouse gases, according to the report. Barriers to doing so include insufficient information, time and skills, the department said.
“Many farmers say they are aware of climate change and agree that something needs to be done to reduce greenhouse-gas emissions,” Defra said. “But there is a gap between this opinion and the level of farmer understanding of GHGs from agriculture and of mitigation measures they could adopt.”
Information will boost knowledge of practices associated with reducing greenhouse gases and may lead to more ways to cut down on methane and nitrous-oxide emissions, according to the report.
“Ensuring a greater understanding of GHG emissions is likely to be an important driver for change for some farmers,” Defra said. “A greater understanding of the issue may also lead to more innovative and cost-effective solutions for reducing agricultural GHGs.”