Abby L. Harvey
GHG Monitor
1/9/2015
Even if carbon capture and storage technology is deployed by 2025, the United States would need to burn less than 10 percent of its known coal reserves if the world is to stay below the globally agreed upon two degree limit in global warming, according to a new study conducted by researchers at University College London and published this week in Nature. The study indicates that CCS’s ability to allow the United States to burn more of its coal reserves without negatively impacting the climate is fairly minimal. The study, which looks out to 2050, finds that in the United States, if CCS is not available by 2025, 95 percent of the nation’s coal reserves would need to remain unburned in order to avoid the two degree limit. With CCS available by 2025, 92 percent of coal in the U.S. is still unburnable. “Although there have previously been fears over the scarcity of fossil fuels, in a climate-constrained world this is no longer a relevant concern: large portions of the reserve base and an even greater proportion of the resource base should not be produced if the temperature rise is to remain below 2°C,” the report says.
The study, which aims to break down how each region would be affected by climate mitigation policies based on the 2 degree model, finds that while the United States is hit particularly hard by limits on coal use, the trend carries worldwide. According to the study, China and India are allowed greater exploitation of their coal reserves in the two scenarios but still must leave 66 percent unburned with CCS available or 77 percent without CCS. Globally, the study finds that with CCS 82 percent of the world’s coal reserves are unusable in the 2 degree model, only six percent less than the 88 percent if CCS is not available.
The study was conducted compiling known data about current estimated fossil fuel reserves and resources to determine what must be done to meet a carbon budget set by the Intergovernmental Panel on Climate Change. The IPCC “recently suggested that to have a better-than-even chance of avoiding more than a 2 [degree] temperature rise, the carbon budget between 2011 and 2050 is around 870–1,240 Gt CO2,” the study explains. The study looks at both fossil fuel “resources” which it defines as all oil, gas or coal that is recoverable with both current and future technologies and fossil fuel “reserves,” defined as only those resources recoverable under current economic conditions which “have a specific probability of being produced.” The study finds that the combustion of the world’s remaining fossil fuel resources would result in nearly 11,000 Gt CO2, much more than allotted in the IPCC carbon budget. Even the remaining “reserves” alone when combusted would result in nearly 2,900 GtCO2, still much higher than the IPCC budget. Considering in their research the location of the reserves, researchers were able to determine how much of a region’s fossil fuel resources would have to remain unburned to stay within the IPCC budget.
If CCS is not available, this will affect the potential use of other fossil fuel resources as well, but to a lesser extent, the study finds. “The utilization of current reserves is lower in nearly all regions for all of the fossil fuels when CCS is not available, although there is a slight increase in gas production in some regions to offset some of the larger drop in coal production. Nevertheless … the reserves of coal that can be burned are only six percentage points higher when CCS is allowed, with the utilization of gas and oil increasing by an even smaller fraction (around two percentage points). Because of the expense of CCS, its relatively late date of introduction (2025), and the assumed maximum rate at which it can be built, CCS has a relatively modest effect on the overall levels of fossil fuel that can be produced before 2050 in a 2 [degree] scenario,” the study finds.
