Get serious about Net Zero

Myles Allen

How do we stop fossil fuels from causing global warming? 

It sounds like a simple question, but the answer has some profound implications, and highlights things that we are getting badly wrong in climate policy right now.

If you picked a person off the street, they would probably answer “well, fossil fuels cause global warming, so the only way to stop fossil fuels from causing global warming is to stop using fossil fuels.” Obvious, right? Sadly, wrong. 

If you take this approach, the only way to stop fossil fuels from causing global warming is to stop everyone using fossil fuels. A global ban, enforced with a massive fine (euphemistically known as a “carbon price”). That won’t work, and arguably shouldn’t work: what right have we, in 2020, to tell the citizens of developing and emerging economies in the 2060s not to touch their fossil fuels?

Global warming has reached 1.1°C, and is increasing at over 0.2°C per decade, overwhelmingly driven by carbon dioxide generated by fossil fuels. Which means we have 30-40 years to stop fossil fuels from causing global warming if we are to meet the goals of the Paris Climate Agreement and limit warming to “well below” 2°C, ideally closer to 1.5°C.

There are so many economically productive uses of fossil carbon, from aviation fuel to cement production, that it is both naïve and dangerous to assume that carbon-free alternatives will have been found to outcompete them all by mid-century. So, unless you subscribe to a ban, you have to accept we will collectively still be using fossil fuels well after 2050. 

So, to meet the goals of the Paris Climate Agreement, we have to stop global warming before we stop using fossil fuels. Keep repeating that, because it will change the way you think about the problem. The only way to stop fossil fuels from causing global warming, short of an outright ban, is to ensure that one tonne of carbon dioxide is safely and permanently disposed of, not dumped in the atmosphere, for every tonne generated by our continued fossil fuel use.

This is what Net Zero carbon dioxide emissions means: 100% permanent storage. And because of the millennial impact of carbon dioxide in the climate system, permanent has to mean storage timescales of 10,000 years or more. Planting trees to recapture carbon dioxide generated by fossil fuels, although massively popular, can only be a temporary solution to a small fraction of our emissions. Even the most optimistic estimates of “nature-based climate solutions” predict they could shave around 0.1°C off global temperatures by mid-century. Meanwhile, fossil fuel emissions are driving up global temperatures by 0.2°C per decade. And as the world warms, the risk increases that carbon stored in the biosphere will be released again back into the atmosphere.

The only large-scale permanent storage option available now is re-injecting carbon dioxide back underground, into the same kinds of rock formations that trapped the fossil fuels that it came from. Right now, globally, we are storing less than 0.1% of the carbon dioxide we generate in this way. In the UK, this fraction is zero. And we are aiming for Net Zero by 2050, so we have committed, as a matter of simple mathematics, to increase the stored fraction to 100% over the next 30 years. That’s an average of 3.3% per year. Current plans might get the UK to 2% by 2030 if we’re lucky. It’s not surprising politicians don’t want to talk about it.

So, what’s to be done? The first step towards achieving sustainable carbon neutrality, Net Zero CO2 emissions, 100% safe and permanent CO2 storage, is to acknowledge where we are now and start to measure our progress. Countries should publish, every year, the fraction of the carbon dioxide generated by the fossil carbon that they continue to import or extract that is safely and permanently disposed of. Companies should report, not just all the efforts they are making to reduce emissions, but how much of the carbon dioxide generated by their continued use of fossil fuels is being stored out of the atmosphere, and in what forms. 

Right now, these reports are easy: mostly lots of zeros. But there is no point in making a Net Zero commitment unless you’re prepared to measure and disclose your progress towards it. And we need to see this stored fraction in forward planning. A commitment to 10% permanent storage by 2030, which is about the lowest fraction consistent with 100% by 2050, should be part of the UK’s Nationally Determined Contribution to the UNFCCC.

Having acknowledged this is what we need to do, the next step is how we’re going to do it. This is where Carbon Takeback comes in. The only entities in the world with both the engineering capabilities, and the access to capital, to dispose of carbon dioxide on this kind of scale are the major oil and gas companies. But they aren’t going to do it on their own. By far the simplest way of increasing the stored fraction is to require anyone selling fossil fuels to store a small but steadily increasing fraction of the carbon dioxide associated with their production and use.  

It doesn’t need to be the same carbon dioxide, of course: initially, when the stored fraction is at a few percent, vendors would probably discharge the obligation by capturing and storing their own refinery emissions. Right now, these are covered by emission trading systems in many countries, but the price of permits is far too low to make it economic to capture them, so companies just vent the carbon dioxide and pay for the permits. How we integrate Carbon Takeback with emission trading will be a subject for a future post!

As the stored fraction rises, anyone who wants to sell fossil fuels would have to hunt around for carbon dioxide to dispose of. Point sources of carbon dioxide, like cement and ammonia plant chimneys, would become valuable assets, not liabilities. Of course, someone has to pay: but the cost is spread over all fossil fuel users, as it should be, because all benefit from depleting the remaining atmospheric carbon budget. A 10% stored fraction by 2030 would add less to the cost of fossil-fuel-based products than the current UK carbon floor price, or a few pence on a litre of petrol.

Boris Johnson’s commitment to a Green Recovery is of course very welcome. But as well as throwing even more money at offshore wind, a mature technology largely based on German and Danish engineering and Chinese materials, why not revolutionise global climate policy by inserting a commitment to 10% permanent storage of the carbon dioxide generated by our continued use of fossil fuels by 2030: and use COP26 to point out that any country not doing the same is clearly not serious about Net Zero. Delivered through a Carbon Takeback Obligation, it needn’t cost the taxpayer a penny. 

This isn’t a new idea: look at our resources page. But it is time more people started talking about it. Welcome to, and join the conversation.

You can hear Myles Allen plugging Carbon Takeback on TED’s Global Countdown event: 10.10.2020

See the programme and speakers:

Watch live on YouTube from 4pm BST:

Talks will be recorded and available after the event on the TED YouTube channel: 

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