Tar Sands:

• Tar sands consist of oil trapped in a complex mixture of sand, water and clay.
• The extraction and production of tar sands emits on average three times as much carbon dioxide as the extraction and production of conventional oil.
• Canada has proven tar sand reserves of 174 billion barrels of oil, second only to Saudi Arabia's conventional reserves.
• Canada has probable reserves of 315 billion barrels of oil, accessible using technology currently under development.
• Canada's ultimate reserves of tar sands are thought to be 1.7 trillion barrels of oil.
• Shell, ExxonMobil, ConocoPhillips, Total, and BP all have projects and expansion plans or planned developments in Canada's tar sands.
• Current production is in the region of 1.3 million barrels of oil per day.
• $125 billion has been earmarked for tar sand developments within the next few years. The industry is calling for this to be trebled to $379 billion by 2025.
• Production is  forecast to increase to between 3.5 million and 6.2 million barrels per day by 2020. Licenses have been granted to increase production to 7 million barrels per day.

Shale Oil:

• Shale oil consists of oil trapped in sedimentary rock, which is released when the rock is super-heated.
• Shale oil extraction emits up to eight times more carbon dioxide than conventional oil extraction.
• Shale oil exploitation is still at the research and development stage, but millions of dollars are being invested to make it viable.
• The US has estimated shale oil reserves of 1.5 trillion barrels of oil, probable accessible reserves are thought to be 800 billion barrels of oil.
• Shell, Chevron and ExxonMobil are all developing methods to exploit shale oil or have expressed an interest in doing so.

The exploitation of North America's probable 'Toxic Fuel' reserves would lead to an estimated increase in atmospheric carbon dioxide of between 49 and 65 parts per million, risking climate disaster and a new global extinction event.

For more detail, download our fully referenced report, 'Unconventional Oil: scraping the bottom of the barrel?, which we published in partnership with WWF-UK, in 2008.