Sunday, November 27, 2011

Wood fires fuel climate change

Fiona Harvey in the Guardian (UK): There is little better on a winter's evening than curling up next to a wood fire, or the modern equivalent, a wood-fired boiler – unless it is the green warm glow you get from knowing that the fuel you are using is environmentally friendly and sustainable.

Except that it is not always. And nor is that two-year-old diesel car you bought because its fuel efficiency, compared with petrol models, makes it more green. As a United Nations report has just uncovered, wood burning and diesel vehicles are two of the biggest culprits in the developed world in generating the black carbon – soot – that is a major cause of climate change.

"It's nice to sit in front of a wood fire in the winter, but we should all be feeling pretty guilty," said Joseph Alcamo, chief scientist at the UN Environment Programme.

The most up-to-date, and expensive, models of wood-fired boilers do not produce black carbon. Pellets, for instance, are fine. But Markus Amann, of the International Institute of Applied Systems Analysis, in Austria, warned: "It's the cheap ones." Models that burn logs instead of pellets are particularly bad, as they are near impossible to retrofit with particle-catching technology that would render them harmless. Most diesel cars more than two years old are also likely to emit particulate matter that is big enough to cause air pollution – which causes the premature death of hundreds of thousands of people in Britain – and climate change....

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