Warmer temperatures in the years ahead will dry up peatlands, release more carbon dioxide into the world's atmosphere and aggravate global warming, a study in Japan has found.

Peat is the accumulation of partially decayed vegetation in very wet places and it covers about two per cent of global land mass. Peatlands store large amounts of carbon owing to the low rates of carbon breakdown in cold, waterlogged soils.

Using computer modelling, scientists in Japan found that peatlands - concentrated in high latitude places like Canada, Russia and Alaska - look set to get dryer with increasingly warmer global temperatures.

A warming of four degrees Celsius causes a 40 per cent carbon loss from shallow peat and 86 per cent carbon loss from deep peat, according to the study, published in the latest issue of Nature Geoscience.

"This will cause carbon loss from the soil which means an increase in carbon dioxide concentration in the atmosphere, which will further worsen global warming," said Takeshi Ise from the Japan Agency for Marine-Earth Science and Technology.

"So we have to do something to mitigate global warming," he said.

Global warming is caused by an increase in atmospheric greenhouse gases such as water vapour, carbon dioxide, methane and ozone. The increase in carbon dioxide is mostly blamed on human activities such as burning of coal, oil and gas.