"Many people I've met believe that plants are made up of soil-that the tree outside your house, for example, is mostly made from the soil in which it grew. That's a common mistake. That tree is mostly made up of one of the gases in our air (carbon dioxide) and water (hydrogen and oxygen). Trees are solidified air and sunlight."

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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.

— Thomas Homer-Dixon