With world leaders meeting in Paris to formulate plans for tackling carbon emissions, it’s probably a good idea to reflect upon the source of those emissions. After all, if you are going to solve a problem, you better make sure you have a good understanding of the problem. Otherwise, as the great philosopher Yogi Berra might say, your solution to the problem won’t necessarily solve the problem.
In this column I want to cover the present and past geographical breakdown of carbon dioxide emissions, the breakdown by type of fossil fuel, and the breakdown of potential future emissions given the world’s current oil, gas, and coal resources.
The Current Geographical Emissions Profile
The world’s carbon dioxide emissions have historically come from the world’s developed countries (as defined by membership in the Organization for Economic Co-operation and Development), but since 2005 emissions in developing countries have outstripped those in developed countries. Of the 35.5 billion metric tons of carbon dioxide emitted in 2014, developing countries were responsible for 21.7 billion tons — 61% of the total:
Developing countries have seen their carbon dioxide emissions rise by 92% since 2000, and they now emit 58% more carbon dioxide than developed countries. In fact, the discrepancy is probably even greater, as China recently admitted that they have been underestimating the amount of coal they consume.
China was the world’s leading emitter in 2014 with 27.5% of the world’s total carbon dioxide emissions. The U.S. was second with 16.9% of the world’s total, and India was a distant third with 5.9% of the world’s total. However, India’s emissions have grown at a faster rate over the past 5 years than the U.S. and China’s combined.
Of course most of the carbon dioxide that has been dumped into the atmosphere since the beginning of the Industrial Revolution belongs to the developed countries. The BP Statistical Review of World Energy tabulates carbon dioxide emissions data back to 1965. Between 1965 and 2000, developed countries emitted 433 billion metric tons of carbon dioxide, which at that time was 60% of the total since 1965. But developing countries have been catching up. As of 2014 the total for developed countries had risen to 619 billion metric tons, but that had fallen to 54% of the total since 1965 because of the rapid emission growth in the developing world.
Emissions And Potential Emissions By Fossil Fuel Source
Here is the breakdown of emissions by fossil fuel source, which I calculated from consumption numbers available in the 2015 BP Statistical Review. Of the carbon dioxide emissions in 2014, 20.3% were from natural gas, 36.4% were from oil, and 43.3% from coal.
At the end of 2014, the world’s proved fossil fuel reserves consisted of 1.7 trillion barrels of oil, 6.6 quadrillion cubic feet of natural gas, and 891 billion metric tons of coal. Should we burn through those reserves, I calculate that it would produce an additional 2.8 trillion metric tons of carbon dioxide. To put that into perspective, the total amount of fossil fuel-derived carbon dioxide emitted into the atmosphere since 1965 is estimated to be 1.1 trillion metric tons. So the current proved reserves have the potential to emit nearly 3 times the amount of carbon dioxide that was emitted in the past 50 years. The breakdown of those potential emissions is 14% from natural gas, 25% from oil, and 61% from coal.
If we want to consider the entire fossil fuel resource (remember, proved reserves are a function of price and available technology and vastly understate the amount of fossil fuel in place), a 2012 paper by Neil C. Swart and Andrew J. Weaver from the University of Victoria is instructive. That paper shows the relative potential warming contributions of various fossil fuel resources.
Source: Neil C. Swart and Andrew J. Weaver, Nature Climate Change, 2, 2012
The warming potential estimates are based on modeling, but it illustrates that the potential carbon dioxide contribution from coal dwarfs that of every other resource.
As we seek to reduce carbon dioxide emissions, it seems to me that curtailing coal consumption in developing countries should be the highest priority. That doesn’t mean it’s the only thing we should work on, but we should recognize that this is the single biggest current and projected future contributor to global carbon dioxide emissions. In order to address the developing world’s coal consumption, it seems that the biggest priority should be in developing affordable, convenient alternatives with a low carbon footprint. Per capita demand in these countries is already very low, but is projected to grow as these countries continue to develop. So it seems to me that the supply side needs the greatest focus.
But we have to keep in mind that these countries are only going to use alternatives if they have a compelling reason to do so. Many have already indicated that they won’t restrict their development in order to utilize alternatives. This is definitely a variation of a tragedy of the commons scenario, but we have to recognize that countries will act in their own best interests. In order to mitigate acts that may be harmful to the rest of the world, developing countries have to view alternatives to coal as “better”, and by that I mean that consumers will prefer the alternatives over coal. Otherwise, the world will do a lot of hand-wringing, but we will continue to burn up all of our fossil fuel reserves.