Tar sands, oil sands, or bituminous sands are an unconventional source of petroleum that we are now more and more interested in extracting for energy production. The greatest concentration of tar sands in the world are located in east central Alberta Canada in the Athabasca, Peace River, and Cold Lake deposits. These deposits comprise the third largest proven crude oil deposit in the world, behind Saudi Arabia and Venezuela's large deposits. The video below by Greenpeace describes the controversy surrounding the tar sands in Canada, as well as the Keystone XL pipeline that is part of the overall Keystone pipeline network that delivers a vast amount of the United States foreign oil.
Oil sands are extremely viscous (thick) and have the consistency of molasses. Also, the crude oil is often mixed with sand, clay, water, and other naturally occurring sediments, minerals, or elements. Due to these properties, the unconventional crude oil source cannot be extracted or transported like the conventional oil wells that dominated over the past two centuries. In order to extract the crude bituminous sands, first the "overburden", an industry term, must be removed. This includes (in Alberta) the boreal forest system – its trees, water, and other biotic and abiotic systems. This is all scraped from the landscape in order to expose the tar sands for strip mining.
(Canada's Tar Sands: The most destructive project on Earth? – Truthloader)
Before the mined sand can be transported, it must be heavily processed with extreme quantities of water and chemicals, leading to tailings ponds (chemical waste water ponds) large enough to be seen in space that must be contained and maintained for decades or longer. Tailings ponds can leak into local groundwater systems or fail completely leading to large spills and widespread contamination.
Those concerned with the effects of climate change have taken an especially harsh and critical stance on tar sands, their pipelines, and their overall use. The crude bitumen according to a 2011 Stanford University study that was commissioned by the European Union (EU) found that these tar sand deposits were 22% more carbon intensive over their life cycles than other fuels. Extracting and burning this immense fuel source is dirtier than conventional fossil fuels of the past such as, oil, natural gas, and coal, and will have a greater impact on our environment and climate.
(CC Image of the Athabasca River tar sands mine and tailings pond courtesy of NASA)
(CC Image of Alberta's oil sands courtesy of Norman Einstein – May 10th, 2006)