Massive gas leak blamed for record drought in Chongqing

PUBLISHED : Wednesday, 23 August, 2006, 12:00am
UPDATED : Wednesday, 23 August, 2006, 12:00am

Chongqing's worst drought on record may have been intensified by a massive methane leak from a natural gas field outside the city owned by China National Petroleum Corp, an atmospheric scientist claimed yesterday.

Kuang Yaoqiu , a researcher at the Chinese Academy of Sciences' Guangzhou-based Institute of Geochemistry, said the remains of the leak in Kai county in Chongqing five months ago still hovered around the area and had contributed to a sharp decrease in rainfall.

Professor Kuang said methane raised air temperatures because high concentrations of it increased ground temperatures and reduced moisture in the atmosphere.

'At one point, methane was leaking into the atmosphere at several dozen cubic metres per second. You can imagine how much methane was emitted into the air and how big an impact it had,' Professor Kuang said.

He said the neighbouring province of Sichuan was a basin, making it more difficult for the gas to disperse.

'A bigger natural gas leak happened at the same place in December 2003 but gusts of cold air quickly blew the gas away,' he said. 'We have had no luck with cold air this year. The methane haunts the area, leading to a much longer dry season than usual.'

Southwest China has been in the grip of a heatwave over the past few weeks and the persistent hot weather pushed temperatures in Chongqing to a record 44.5 degrees Celsius last Wednesday. Chongqing had had no rain for more than 70 days until early this week, and two-thirds of its rivers have dried up

The Sichuan Bureau of Meteorology and Geophysics told the People's Daily that recent coastal typhoons were a main cause of the region's heatwave because they had pinned down a subtropical high hanging over southwest China and prevented it from moving on.

Professor Kuang said even if the leak was one of several factors contributing to the drought, authorities should still learn to prevent similar incidents caused by human error.

'Even if methane is not the only reason for the drought, it's definitely one of the main reasons,' he said.

Natural gas leaks have been frequent in the Luojia gas field around Kai county since the gas deposits were discovered in 1999 and drillers began tapping them.

A December 2003 explosion in the same place killed 243 people and required 41,000 to be evacuated, an incident described by mainland media as 'the worst of its kind in China's history'.

Last week local authorities dismissed a rumour on the internet that the drought was related to the Three Gorges Project as a 'story without any scientific basis'.