To eliminate global greenhouse gas emissions requires a two-pronged policy approach. Much is made of reducing demand for greenhouse gases through the switch to renewables, regulations and carbon taxes. But, with respect to fossil fuels, the supply needs to be reduced and eventually ceased. Climate activists like valve-turner Micheal Foster recognize that to achieve the climate mitigation targets much of the potential supply of fossil fuels must be left in the ground. With respect to the valve-turners actions of October 16th 2016, whilst it is possible to look at the minuscule impact that on global oil supply and proven reserves of oil, it is more difficult to estimate the marginal impact on the overall greenhouse gas emissions of their broader objective of permanently shutting down Canadian oil production. That requires estimates of CO2 emissions per unit of oil, coal and gas. In searching for figures to make my own estimates I came across a letter to Nature. McGlade and Ekins 2015 (The geographical distribution of fossil fuels unused when limiting global warming to 2°C) estimate that the proven global reserves of oil, gas and coal would produce about 2900 GtCO2e. They further estimate that the “non-reserve resources” of fossil fuels represent a further 8000 GtCO2e of emissions.

There is no breakdown by country, so I input their values of CO2 per unit into the BP’s estimates of global reserves of oil, gas and coal, coming up with a similar 2800 GtCO2e. These represent roughly 50 years of oil and gas supply and 120 years of coal supply at current usage rates. This should be put into the context of the policy objectives. From the abstract.

It has been estimated that to have at least a 50 per cent chance of keeping warming below 2 °C throughout the twenty-first century, the cumulative carbon emissions between 2011 and 2050 need to be limited to around 1,100 gigatonnes of carbon dioxide (Gt CO₂).

This is similar to the IPCC’s central estimate of 1000 Gt CO2e from 2012 onwards. With just over 50 GtCO2e of GHG emissions per annum, from the beginning of 2018, the figure is around 700-800 GtCO2e. Taking into account other GHG emissions, to achieve the emissions target around 75% of proven reserves and 100% of any non-reserve sources or future discoveries must be left in the ground. I have produced a chart of the countries where these proven reserves lie, measured in terms of CO2 produced from burning.

These are very rough estimates, based upon assuming that the emissions per unit of each fossil fuel are the same as the McGlade and Ekins averages. This is clearly not the case. A better estimate for oil, for instance, would likely have higher potential emissions from Venezuela and Canada, and lower potential emissions from the Middle East, particularly Saudi Arabia. However, it is clear that if global emissions constraints are to be achieved, the UN must get binding agreements from USA, Russia, Iran, Venezuela, China, Saudi Arabia, India, Qatar – plus many other countries – to abandon these vital resources within a few years. This would need to be done fairly and equitably in the eyes of all parties. But in such matters, there are widely different perspectives on what is fair, with a lack of ability by the UN to impose a settlement. There are also considerable economic costs to those nations whose economies rely on the producing fossil fuels, with the compensation the that they might demand unimaginably high. Further, like any cartel, there are considerable economic advantages in reneging on such deals, whilst ensuring that rival countries are held to their part of the agreement.

The problem is even greater. McGlade and Ekins 2015 is likely to have underestimated the unproven reserves of fossil fuels, even though the 8000 GtCO2e is truly staggering. The short 2013 GWPF paper THE ABUNDANCE OF FOSSIL FUELS by Phillip Mueller estimates that unproven, but potential recoverable reserves of tar sands in Canada and Green River Basin Wyoming, heavy oil in Venezuela and shale oil in Saudi Arabia could each be similar to or exceed, the global proven reserves of oil. Combined these could produce the around the same CO2 emissions of all the proven reserves of oil, gas and coal combined.

Then there are methane hydrates, which could contain 500 to 5000+ GtCO2e of emissions if burnt. The very nature of the hydrates could mean that large amounts of methane being released directly into the atmosphere.  This US Geological survey graphic (from a 2014 BBC article) shows the very wide distribution of the hydrates, meaning many countries could have large deposits within their territorial waters. This is especially significant for African nations, most of whom have very low, or nil, proven fossil fuel resources.

Mueller does not explore the potential reserves of coal. Under the North Sea alone there is estimated to be 3 to 23 trillion tonnes of the stuff. (Searches reveal a number of other sources.) This compares to the BP estimate of 800 million tonnes of global proven reserves. 3 to 23 trillion tonnes of hard coal if burnt would represent 7000 to 55000 GtCO2e of emissions, compared to less than 1000 GtCO2e the IPCC claims sufficient to reach the 2C warming limit.

How many other vast fossil fuel reserves are out there? It may be just economic factors that stop fossil fuels reserves being proven and then exploited. What is clear is that whilst activists might be able to curtail or stop production of fossil fuels in Western countries, they are powerless to stop vast reserves being exploited in much of the rest of the World. The only significant consequence is to harm the economic futures of any country in which they gain successes and inadvertently work to benefit some pretty intolerant and oppressive regimes.

However, this does not leave climate activists impotent. They can work on better identifying when and where the catastrophic impacts of climate change will occur. But that would mean recognizing that previous prophesies of impending doom have been either totally false or massively exaggerated.

Kevin Marshall