Article: Sucking Up Carbon

By GERARD WYNN

Soil and low-carbon pigs might be helpful in the climate fight.

JOHN Ibbett and pigs go back a long way. “The pig manager pushed me round in a pram,” recalls Ibbett, whose family have been farming on the same site since 1939. Now he’s proud that his family farm can turn muck into electricity.

His Bedfordia Group is one of only a handful of companies with farm-based biogas plants in Britain. Scientists complain that the world has so far failed to support agriculture in the fight against climate change, focusing instead on more visible emissions from factories and power plants.

Although his three-year-old venture is a rarity in Britain, more biogas plants are being established in Denmark, Germany and developing countries. That momentum could be a precursor of much bigger climate benefits, from changing farming methods to using the soil’s capacity to store vast amounts of carbon. Experts say this is an area so far almost entirely ignored by policy-makers.

Soils as well as trees can suck carbon out of the air, boosting what experts call terrestrial carbon. Farmers can nurture carbon underground as well as crops above by using longer rotations, not over-grazing pasture and ploughing less.

Livestock and stored manure account for half of the world’s methane emissions.

Ibbett’s plant, 90km north of London, traps methane emissions from food and farm waste in giant vats and then burns the powerful greenhouse gas to produce electricity, so preventing it from reaching the atmosphere.

Trying to sell part of the farm’s annual production of 23,000 pigs for bacon to supermarket group J. Sainsbury, Ian Smith estimates the Bedfordia pigs are one-third less carbon-emitting than others. First, the methane emissions from their manure is trapped and burned. Second, the electricity produced replaces high-carbon power. Third, the final product is a soil additive which replaces more energy-intensive nitrogen fertiliser.

Low-carbon pigs may not easily fly, but directly curbing greenhouse gas emissions from farming is important. Farming contributes as much to global warming as all the world’s planes, cars and trucks, and that will increase as the world tries to feed an extra three billion people by 2050.

Scientists also want more focus especially on the soil. In addition, academics have revived interest in a millenium-old technology to plough into the soil a carbon-rich type of charcoal made from heating plant, food or animal waste, called biochar.

The sticks and carrots policy-makers use to drive the climate fight have so far almost exclusively focused on energy. But soil could store as much as one-tenth of all the carbon that households and industry spew into the atmosphere, and so buy time in a gradual, global shift away from fossil fuels.

One reason the sector has not yet captured the public imagination may be that pig manure and soil are not the stuff of public relations dreams.

“Politicians can understand planting a tree and watching it grow ... that it removes the carbon dioxide from the atmosphere,” said Pete Smith, lead author for agriculture on the United Nations Intergovernmental Panel on Climate Change. “In agriculture, it’s not immediately visible.”

All plants, including trees and crops, draw carbon dioxide out of the air as they grow but trees, not soil, have been a focus for this.

“If you look across all the (economic) sectors together, farming has equivalent mitigation potential to the energy sector and to transport and industry,” added Smith. “We really need to get agriculture in there (the climate talks).”

Farming accounts for half of all man-made methane emissions worldwide – from ruminant livestock such as cows and sheep and from stored manure – and 60% of the world’s emissions of nitrous oxide, a greenhouse gas some 300 times more powerful than carbon dioxide derived from using nitrogen fertilisers.

Combined, curbing these greenhouse gases and using soil sinks could remove the equivalent of up to one billion tonnes of carbon emissions annually. Storing carbon in the soil would account for about 90% of that.

The idea of sucking greenhouse gases from the atmosphere, rather than just curbing emissions, is gaining credibility and support as scientists say they have underestimated the urgency of fighting global warming. – Reuters

This article was taken from: The Star Online: Lifestyle: Focus 14 April 2009