Methane emissions on the rise

Emissions of methane -- a planet-warming gas several times more potent than carbon dioxide -- have risen by nine percent in a decade driven by mankind's insatiable hunger for energy and food, a major international study concluded Wednesday. Methane (CH4) has a warming potential 28 times greater than CO2 over a 100-year period and its concentration in the atmosphere has more than doubled since the Industrial Revolution. While there are a number of natural methane sources such as wetlands and lakes, the team behind the study concluded that 60 percent of CH4 emissions are now manmade.  The world now produces around 50 million additional tonnes of methane every year than it did between 2000-2006. Around 60 percent of manmade CH4 emissions were estimated to come from agriculture and waste, including as much as 30 percent from the digestive processes of cattle and sheep.  Twenty-two percent comes from the extraction and burning of oil and gas, while 11 percent leaks from the world's coal mines, the study found.