by Hugh Richards
4 June 2022

In its 2022 report on mitigation of climate change, the Intergovernmental Panel on Climate Change (IPCC) says that “carbon capture and storage” (CCS) is going to be needed at vastly increased scale in coming decades if global warming is to be limited to 2°C, let alone 1.5°C. So why are so few climate activists campaigning for governments and companies to increase their efforts on CCS? This question was recently put to me in an email from a CCS specialist, and here I will attempt to respond.

Some traits climate activists (including myself) can be prone to may help answer the question; I can name binarism, tribalism, short-termism, risk aversion, pessimism, idealism, scepticism, cynicism and ignorance. Let’s start with ignorance, including ignorance of what CCS actually is or could be.

Perhaps one of the problems for CCS is that it is not a visually iconic technology (like wind energy) that is easily understood in terms of what it does. Worse, it has a fuzzy definition, and has been applied to a wide range of “carbon sequestration” methods, from increasing forest cover to increasing oil production by pumping CO2 into the ground. Also, the “S” can stand for “storage” (even though there is no intention to retrieve the “stored” CO2) or “sequestration” (a far from self-explanatory word). For now, let’s call it “geological carbon disposal”, meaning taking unwanted carbon that would otherwise end up in the atmosphere (or is already there) and putting it into a geologically stable form that we can be sure won’t end up back in the atmosphere for thousands of years at least. In the immediate future, geological carbon disposal will mostly be done by capturing CO2 from electricity generation and industrial processes that use fossil carbon, including chemicals, steel and cement manufacturing. The captured CO2 will then be compressed and injected into deep geological formations, such as depleted reservoirs that have previously held crude oil and/or natural gas for millions of years. In the longer term, the IPCC envisages that geological carbon disposal will have to be combined with biomass energy generation or direct air capture to remove CO2 from the atmosphere.

Already, warning lights may be going off in some readers’ minds; geological carbon disposal will be applied to large-scale industries that use fossil fuels, so it doesn’t sound very attractive. Here is one of the -isms in operation, namely binarism, in this case a widespread narrative that the only way to save the climate involves replacing fossil sources of energy with renewables (and, for some, nuclear). It’s a binary narrative: fossil energy bad, renewable energy good, with no middle ground. Binarism feeds tribalism. Like most people, I prefer to do things with people I feel comfortable with, or at least don’t want to fall out with, and trying to find middle ground between my tribe’s position and the enemy’s may lead to my loyalty to the cause being questioned.

Another problem for geological carbon disposal is that even its advocates admit that it can’t be scaled up rapidly enough in the short term to have a meaningful effect on global net CO2 emissions in the rest of this decade, when a reduction by about half is needed to hold global warming below 1.5°C without “overshoot”. Consideration of that drastic cut leads to some difficult questions:

• Is 1.5°C a safe level of global warming? Some would say no, it is too high. The logic of that stance is either that the world has already passed the point of no return from runaway climate change, or that CO2 removal from the atmosphere at almost unimaginable scale will be needed – which would involve geological carbon disposal as well as “nature-based solutions”.
• Is there really any possibility of the world achieving a drastic reduction in emissions in the next few years? If not, then again, massive CO2 removal from the atmosphere will be needed to deal with the overshoot and bring the warming back down below 1.5°C later this century (assuming that such reversal is possible).
• Is there a level of global warming above 1.5°C that must not be passed if runaway climate change is to be avoided? Is that what the Paris Agreement’s phrase “well below 2°C” means? Is 2°C itself a safe level for avoiding runaway climate change?

In response to these questions, there is a spectrum of scientific opinion on the overall quantity of future net emissions of CO2 that can still happen without triggering runaway climate change (i.e. the global carbon budget). These estimates range from effectively zero (assuming key tipping points have been or will be passed below 1.5°C) to about 1350 gigatonnes from the start of 2020 (based on 50% probability of staying at 2°C). That is a huge difference, but even 1350 gigatonnes would be exhausted by around 2050 at current emissions rates. Risk-adverse and/or pessimistic climate activists tend to emphasise the “effectively zero” position, while many commentators tend to emphasise the 500 gigatonnes figure associated with 50% probability of 1.5°C. Whatever is the case (and we can never have much certainty), the world needs to ensure that CO2 emissions start falling rapidly within the next few years and that geological carbon disposal becomes available, both to accelerate the fall in net emissions from unavoidable fossil carbon use and (quite likely) to start removing CO2 from the atmosphere.

The notion of unavoidable fossil carbon use can sit uncomfortably with idealistic climate activists, perhaps because it can sound like cover for business as usual. But if we are to take the UN Sustainable Development Goals seriously and acknowledge the global trend towards urbanisation, there will still be industrial processes for which alternative low-carbon energy and material sources (including limestone for cement) will not be available at a relevant scale any time soon. Geological carbon disposal is the only credible way of decarbonising such industries. These and other hard-to-replace demands for fossil carbon need to be borne in mind when considering the required future scale of geological carbon disposal. The notion that extraction and use of fossil carbon can be ended completely within the next three decades or so is not feasible.

Another problem for geological carbon disposal is that many climate activists have a deeply sceptical or even cynical view of it. They may believe that geological carbon disposal is unproven at scale, or that it has been found in trials to be too inefficient and/or expensive, or to be prone to leakage, or that it is something the fossil fuel industry likes to talk about without any intention of doing it at scale. There is some truth in some of that, but the fact that it does not yet exist at scale is down to governments failing to create regulatory requirements and incentives, not lack of confidence in the technology. The charge that it is prone to leakage is often overstated. These are facts of which I myself was not confident until relatively recently.

I am one of a small but growing number of people who think that attempts by individual governments to reduce demand for fossil carbon will not be enough, and that there is a need for some form of treaty to control the extraction of fossil carbon globally, and that it should create a body that oversees, verifies and accounts for geological carbon disposal as well as extraction. In this I am accused by some of naïve idealism, but I am not as idealistic as the larger number who advocate a fossil fuel control treaty that has no role for geological carbon disposal and that seeks to achieve “just transition” objectives in addition to the primary goal of minimising future extraction.

In the absence of such a treaty, individual governments could and should take control of their shares of the fossil carbon problem by issuing extraction companies that they license with a choice of “clean up or close down”*. For many, this suggestion prompts the question, “How can fossil fuel companies clean up their products?”. The answer could be for governments to impose on them a “carbon takeback obligation”. This would require the companies to fund geological carbon disposal at a scale that increases year on year until the annual amount of fossil carbon extracted is balanced by an equal amount of geological carbon disposal – thereby achieving what some are calling “geological net zero”. Governments would also impose carbon takeback obligations on companies importing fossil fuels, who would either have to fund the geological carbon disposal directly or source their imports from countries that are imposing equivalent obligations. Some governments might make the latter option a matter of policy. A virtuous circle should then develop in which carbon takeback obligations become the global norm for extraction of and trade in fossil fuels, and non-adopters would find themselves penalised by economic as well as political pressures.

Carbon takeback obligation is not a magic bullet; it will not of itself cause fossil carbon extraction to decrease as soon and as fast as necessary. Hence the need for an extraction control treaty, which could also accelerate roll-out of carbon takeback obligations by governments.

Both carbon takeback obligations and a treaty to control fossil carbon extraction are surely objectives that anyone who is concerned about climate change should support (in addition, of course, to the other means of limiting net greenhouse gas emissions that the IPCC envisages).

* I have noticed this phrase being used by some advocates of carbon takeback obligation.

Further reading:

IPPC 2022 Mitigation of Climate Change report (Summary for Policymakers): https://report.ipcc.ch/ar6wg3/pdf/IPCC_AR6_WGIII_SummaryForPolicymakers.pdf

US Clean Air Task Force article: M. Bright & T. Lockwood, What does the latest IPCC report say about carbon capture? 20 April 2022. https://www.catf.us/2022/04/what-does-latest-ipcc-report-say-about-carbon-capture/.

A generic case for a supply-side fossil fuel treaty: G.B. Asheim & others, The case for a supply-side climate treaty, Science Magazine, 26 July 2019 p 325-327. https://www.science.org/doi/abs/10.1126/science.aax5011.

The Fossil Fuel Non-Proliferation Treaty initiative: https://fossilfueltreaty.org/.

Ideas on a fossil fuel control treaty involving a role for geological carbon sequestration:
Sir Bernard Jenkin MP, A fossil fuel non-proliferation treaty: learning from other forms of international cooperation in the battle against climate change. In Conservative Environment Network “North Sea Transition” essay collection (August 2021). https://www.cen.uk.com/north-sea-transition.

Proposals for nationally-imposed carbon take-back obligations on producers and importers of fossil fuels: www.carbontakeback.org.

IPPC estimates of carbon budgets: Climate Change 2021: The Physical Science Basis: Summary for Policymakers. https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM.pdf

Article on climate tipping points and the possibility that there may be almost no carbon budget left. T.M. Lenton & others, Climate tipping points – Too risky to bet against. Nature, 27 November 2019 (corrected 9 April 2020). https://www.nature.com/articles/d41586-019-03595-0.

Article on why fears of leakage from geological carbon disposal sites are overstated: S. Flude & J. Alcade, Carbon capture and storage has stalled needlessly – three reasons why fears of CO₂ leakage are overblown. The Conversation, 4 March 2020. https://theconversation.com/carbon-capture-and-storage-has-stalled-needlessly-three-reasons-why-fears-of-co-leakage-are-overblown-130747

Geological study that showed leakage from a natural CO2 reservoir has been slower than needed for effective geological carbon disposal: J.M. Miocic & others, 420,000 year assessment of fault leakage rates shows geological carbon storage is secure. Nature Scientific Reports Volume 9, Article number: 769, January 2019. https://www.nature.com/articles/s41598-018-36974-0

Two geoscientists’ plea for bringing the concepts of a treaty and carbon take-back obligations together: Hugh Richards & Patrick Portolano, “Geological net zero” (Geological Carbon Neutrality) – How could we get there? 25 March 2022. https://www.researchgate.net/publication/358248129_Geological_Net_Zero_Geological_Carbon_Neutrality- How_could_we_get_there

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