Petroleum's Other Emissions

[n2doc]

Climate Change: Scientists generate first-ever estimates of greenhouse gas emissions from oil development
Charles Schmidt

To make room for biofuel crops, farmers slash rainforests and other vegetation that absorbs carbon dioxide from the atmosphere. And that's a problem for the climate. But a new study points out that conventional oil development also requires changes to the land that destroy CO2 sinks and produce their own greenhouse gas emissions (Environ. Sci. Technol., DOI: 10.1021/es1013278).

Previous research has suggested that land use associated with biofuel production, such as clearing grasslands to plant corn for ethanol, could lead to producing more net CO2 than it saves from not burning fossil fuel.

"But no one had calculated the land-use emission from fossil fuels, so they weren't comparable on an apples-to-apples basis," says Sonia Yeh, a researcher at the Institute of Transportation Studies, at the University of California, Davis.

So Yeh and colleagues decided to quantify greenhouse gas emissions from two types of oil production: conventional development from oil fields in California and Alberta and development from oil sands in Canada, which contain the viscous petroleum mixture called bitumen. Engineers extract bitumen either by in-situ processes, in which they heat it with steam and then pump it to the surface, or by surface mining, in which they burn down arboreal forests and dig up overlying peat deposits to reach oil sands.

The researchers accounted for land-use emissions from several factors, such as greenhouse gases released when burning vegetation or the loss of natural CO2 sinks. One especially harmful consequence of surface mining is peat removal. Peat absorbs huge amounts of CO2 from the atmosphere, and when it's destroyed, its decomposition releases methane, a much more potent greenhouse gas than CO2.

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http://pubs.acs.org/cen/news/88/i44/8844news3.html