Cows absolved of causing global warming with nitrous oxide

In the past environmentalists, from Lord Stern to Sir Paul McCartney, have urged people to stop eating meat because the methane produced by cattle causes global warming. However a new study found that cattle grazed on the grasslands of China actually reduce another greenhouse gas, nitrous oxide. Klaus Butterbach-Bahl, of the Karlsruhe Institute of Technology in Germany, carried out the study in Inner Mongolia in China. He found that grassland produced more nitrous oxide during the spring thaw when sheep or cattle have not been grazing. This is because the greenhouse gas, also known as laughing gas, is released by microbes in the soil. When the grass is long snow settles keeping the microbes warm and providing water, however when the grass is cut short by animals the ground freezes and the microbes die. Dr Butterbach-Bahl said the study overturned assumptions about grazing goats and cattle. "It's been generally assumed that if you increase livestock numbers you get a rise in emissions of nitrous oxide. This is not the case," he said...more