Recent research indicates that the world needs to limit cumulative carbon dioxide emissions to approximately 1100 gigatons (with the IPCC suggesting a range of 870-1,240 Gt CO2) of carbon between 2011-2050 to have a 50% chance of keeping warming below 2°C from Pre-Industrial levels. However, as the authors of a new study in the journal Nature concluded, “the unabated use of all current fossil fuel reserves is incompatible with a warming limit of 2°C.” Indeed, the carbon dioxide that could be emitted by the current estimate of global fossil fuel reserves would exceed this critical threshold by three times (approximately 2900 Gt CO2). The study utilized a single integrated assessment model to assess the ramifications of the use of various fossil fuel resources in terms of their respective locations, type, and quantities. Its overall finding was that a third of global oil reserves, 50% of gas reserves, and over 80% of coal reserves need to stay in the ground to have a reasonable chance of avoiding passing the 2°C threshold.

Among the study’s other findings:

1. 82% of coal reserves would have to remain unburned under the study’s scenarios, with the United States and Former Soviet countries each pulling out less than 10% of their current reserves from the ground, leaving 200 billion tons unburned;
   1. Without CCS, bitumen production in Canada must cease by 2040;
   2. Even deployment of CCS within projected time frames and level of utilization does very little to change this number, permitting only 6% more to be utilized, and increasing oil and gas utilization by approximately 2%.
2. Gas plays an important role in displacing coal, including over 50 trillion cubic meters of unconventional gas production globally, half of which comes from North America. However, China, India, Africa and the Middle East would not fair so well, with over 80% unburnable by 2050;
3. None of the 100 billion barrels of oil and 35 trillion cubic meters of gas in fields within the Arctic Circle not being produced in 2010 can be produced in the 2°C scenario before 2050.

This would be an excellent student reading for any lecture that discusses solutions or efforts to establish priorities in terms of the future global energy mix. Its extensive coverage of the implications of CCS deployment would be helpful for coverage of that topic.

Among the possible questions for classroom discussion would be the following:

1. Would considerations of equity, including the principle of common but differentiated responsibilities suggest that the future mix should be re-jiggered some way?
2. What policy measures might be (practically) put in place to effectuate the prioritization of fossil fuel utilization outlined in the article?