Canada's oil sands are considered by many environmentalists as one of the largest sources of industrialized greenhouse gas emissions, and thus a big contributor to ongoing global warming phenomenon.
Main concerns connected with with oil sands are land damage, such as negative impact on land's ability to support forestry and farming, greenhouse gas emissions, and water use.
Latest studies have also showed that beside being responsible for emitting large amounts of greenhouse gases oil sands are also a constant source of low-level pollution to the nearby area's land, air and water.
Oil sands in Canada are huge source of PAC (polycyclic aromatic compounds) pollution. One recent study has even showed that that snow was contaminated with PACs for almost 50 kilometers around the oil sands complex in Alberta, Canada.
Oil sands have negative effect on the land when the bitumen is initially mined and with large deposits of toxic chemicals, the water during the separation process and through the drainage of rivers; the air due to the release of carbon dioxide and other emissions, and there is also a deforestation issue.
The process of oil sands extraction is generally considered to be more environmentally damaging than conventional crude oil extraction, for example, emissions are estimated to be about 1.3-1.7 times that of conventional crude.