You thought burping is uncouth? Well, is quite "natural" actually! Scientists have found that at the start of every winter every year, the Arctic tundra burps methane- that explains the baffling mystery behind why atmospheric methane levels mysteriously shoot up at this time of the year.
According to a report in New Scientist, Torben Christensen at Lund University in Sweden and colleagues reckon the freezing of the ground squeezes the soil like a sponge so that it belches out huge amounts of methane gas.
The team measured the flow of methane coming from the ground in north-eastern Greenland at the onset of winter.
They found that levels of the gas rose at the highest rate ever recorded in the Arctic tundra.
Christensen said that tiny bubbles of methane, formed from the decay of plants and other organic material, are pumped out of the peaty soil.
He said that this is a surprise, because you would expect the methane bubbles to be locked away by the ice as the ground froze.
The explanation, according to the researchers, lies in the way the ice's expansion squeezes the soil.
As the frost descends from the surface, the ice expands, pushing the underlying soil against a solid layer of permafrost.
"This probably squeezes the methane out of the soil, which then escapes to the surface through plant roots that act like chimneys," said Christensen.
"The finding does not greatly increase estimates of greenhouse gas emissions from tundra regions," he added.