President Obama will be doing Canada a favor if he blocks the Keystone XL pipeline once and for all.
The most obvious reason is that tar sands production is one of the world’s most environmentally damaging activities. It wrecks vast areas of boreal forest through surface mining and subsurface production. It sucks up huge quantities of water from local rivers, turns it into toxic waste and dumps the contaminated water into tailing ponds that now cover nearly 70 square miles.
Also, bitumen is junk energy. A joule, or unit of energy, invested in extracting and processing bitumen returns only four to six joules in the form of crude oil. In contrast, conventional oil production in North America returns about 15 joules. Because almost all of the input energy in tar sands production comes from fossil fuels, the process generates significantly more carbon dioxide than conventional oil production.