Canada's abandonment of its progressive stance on the environment has grave implications for the whole planet, not just Canada. As Nasa climate scientist James Hansen said, should the proposed XL Keystone pipeline go ahead, it would be "game over" for the climate.
An estimated 170bn barrels of oil are recoverable from these tar sands alone. That is a problem in terms of greenhouse emissions. As Michael T Klare notes in The Race for What's Left, however, the extraction process itself burns up tremendous amounts of energy and carries multiple environmental risks. The most common form of production comes from open-pit mining, which requires cutting down vast forests of virgin pine and spruce. The tailings ponds are hazardous to wildlife – "in April 2009, some 500 migrating birds perished after alighting on one of these ponds", writes Klare.
Where the tar sands are too far below the surface, wells are dug, steam injected and the resulting liquefied bitumen pumped to the surface. This not only uses vast amounts of water but also natural gas to heat the water to make the steam. Carbon dioxide emissions from burning a barrel of oil made from tar sands are three times greater than burning a barrel of conventional oil. In addition, levelling the boreal forests for open-cut mining destroys the forests' capacity to act as a greenhouse gas sink.
Who will then regulate the oil industry if not national governments? As conventional oil supplies start their inexorable decline, oil companies are rushing in to mine unconventional deposits of oil. As well as tar sands, these include deep- and ultra-deep water, Arctic, shale oil and heavy oil. All carry massive environmental risks.
Who will clean up after an Arctic oil spill, for instance? How is it even done?
Jenny Goldie
Michelago, NSW, Australia
This item was originally published in the letters section of the Guardian Weekly & is reproduced here with permission of the author.
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