Table. Fossil-fuel reserves and resources by region and type, end-2011 (coal = 2010 data)
| Coal (billion tonnes) | Natural gas (tcm) | Oil (billion barrels) | ||||
| Proven reserves | Recoverable resources | Proven reserves | Recoverable resources | Proven reserves | Recoverable resources | |
| OECD | 427 | 10,657 | 28 | 193 | 244 | 2,345 |
| Non-OECD | 576 | 10,551 | 205 | 597 | 1,450 | 3,526 |
| Share of non-OECD | 57% | 50% | 88% | 76% | 86% | 60% |
| World | 1,004 | 21,208 | 232 | 790 | 1,694 | 5,871 |
| R/P ratio (years) | 132 | 2,780 | 71 | 241 | 55 | 189 |
WEO 2012 says we have plenty of fossil fuels currently: 132 years' supply of coal, 71 years' supply of natural gas, and 55 years' supply of oil, only from "proven" reserves.
Then, however, how much carbon dioxide can be released to the atmosphere if we consume (combustion) all the fossil fuel reserves or resources? Using the BP's suggested conversion factors, I got the following estimation.
Table. A rough estimation of possible CO2 emissions based on reserves or resources*
(unit: gigatonnes of CO2)
| Proven reserves | Recoverable resources | |
| Coal | 2,304 | 48,668 |
| Natural gas | 491 | 1,671 |
| Oil | 709 | 2,458 |
| Total | 3,504** | 52,797 |
** World Energy Outlook 2012 states the global carbon reserve is 2,860 gigatonnes of CO2 (p. 259). I think I used inaccurate emission factors, especially for coal.
That is, proven reserves alone can emit 3,504 (or 2,860) gigatonnes of carbon dioxide. A study published in Nature (Allen et al., 2009) stated that the total anthropogenic emissions could be 3.67 trillion tonnes of CO2 and about half of them had already been emitted since industrialization began. So at the time of the study's publication, about 1.8 trillion tonnes of CO2 were yet to be emitted. However, the new IEA estimation of reserves asserts there are still 3.5 (or 2.9) trillion tonnes of CO2 to emit.
So, technological advancement has significantly increased the possible future CO2 emissions. Do we have to be complacent because we have enough fossil fuels or is it a really sad news for our children? I hope that the world can somehow reach to an agreement soon and prevent the catastrophic climate change that could be realized if we burn all the fuels.
Emissions factors used in the emissions estimation:
| Coal | 3.96 ton CO2/toe | = | 2.294789 ton CO2/ton |
| Natural gas | 2.35 ton CO2/toe | = | 0.002115 ton CO2/cm |
| Oil | 3.07 ton CO2/toe | = | 0.418748 ton CO2/bbl |
References:
| Reserves/resources: | IEA. (2012). World Energy Outlook 2012. Paris, France: IEA Publications. http://www.worldenergyoutlook.org/ |
| Conversion factors modified from: | BP. (2012). BP Statistical Review of World Energy June 2012. London, UK: BP p.l.c. http://j.mp/BP_Review_2012 |
| Cited previous study: | Allen et al. (2009). Warming caused by cumulative carbon emissions towards the trillionth tonne. Nature, 458, 1163-1166. http://dx.doi.org/10.1038/nature08019 |
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