快猫短视频

METHANE bubbling up out of reservoirs accounts for about a fifth of all the
world鈥檚 emissions of the greenhouse gas. In the first calculation of their
鈥済reenhouse effect鈥�, Vincent St Louis from the University of Alberta in Canada
says reservoirs, particularly those in the tropics, could be responsible for 7
per cent of global warming鈥攎ore than aircraft emissions.

Globally, reservoirs cover an area six times the size of Britain. Many
contain little dissolved oxygen, so vegetation鈥攅ither flooded by the
reservoir or washed into it鈥攃reates methane when it decomposes. Methane is
20 times as potent a greenhouse gas as carbon dioxide, the product of rotting
vegetation in aerobic conditions. St Louis says that only recently have
experiments revealed the true extent of methane emissions from the depths of reservoirs
(快猫短视频, 3 June, p 4).

Only a third of the world鈥檚 reservoirs are in the tropics. But studies from
21 reservoirs worldwide reviewed by St Louis suggest that they produce more than
80 per cent of greenhouse gas emissions from all reservoirs. 鈥淲e suspect this is
because warmer temperatures in sediments promote faster, more anaerobic
decomposition, resulting in more methane,鈥� says co-author Carol Kelly.