The following is a trascript with slides of a talk that I gave at TED on June 15th 2022. The title for the TED event was “Is there a role for carbon credits in the transition to a fair, net-zero future?“
A recording of this session is available here – my talk begins at 25minutes.
It’s never easy to admit that you were wrong. It’s taken me years to accept that I‘ve been fundamentally misguided about our attempts to avoid dangerous climate change.
I thought that net zero was a sound science-based approach that represented a breakthrough in climate politics.
The reality is that net zero is being used to license a ‘burn now – pay later approach which has seen carbon emissions continue to soar.
Within just a few years, net zero has become the anchor concept to the world’s plans to avoid catastrophe. It sounds simple enough. Its premise is that the threats of climate change are the direct result of there being too much carbon dioxide in the atmosphere. So it follows that we must stop emitting more and even remove some of it. Hopefully by the middle of the century we should reach the point at which any residual carbon dioxide emissions are balanced by technologies that will remove them from the atmosphere.
But by including carbon removal in climate policies we have set a trap. Because it’s incredibly seductive to rely on carbon removals in the future, made possible by imagined technologies, instead of rapid decarbonization now. It gives the impression we are acting. So companies don’t need to change their models, and governments don’t need to propose bold action.
This means it’s now almost inevitable that we will enter a much warmer and more dangerous world.
How did this happen? How did the idea of net-zero become so compromised, so corrupted?
A critical moment for the development of net zero was the 2015 Paris Agreement.
The overall objective of this landmark climate treaty was that global warming should be limited to 1.5°C, to reduce the risks of devastating impacts.
Given that by 2015 we had already reached 1°C, how fast would we need to stop all carbon emissions to limit warming to no more than 1.5?
This fast.
The Paris Agreement represented a serious challenge to the academic community. Many scientists – including myself – were very skeptical that this was possible given the absence of radical proposals. But there was also a deep sense of responsibility to try to make the Paris Agreement a success.
None felt this more keenly than the international group of economists and scientists who develop Integrated Assessment Models. These are complex models which include representations of the global economy, along with land, energy, and climate systems. They soon discovered that they could not get their models to decarbonise as fast as 1.5 would require[2] – if one assumes continuous economic growth.
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The only way to make the models work was to include carbon dioxide removal. For example, aviation passenger numbers are expected to continue increasing. But there isn’t yet a viable alternative to burning kerosene in jet engines. However, if jet emissions were balanced with carbon removal, we could continue to have growth in aviation, along with other hard to decarbonize sectors such as cement production and steel making.
That carbon removal technologies didn’t actually exist, didn’t stop them from being included in Integrated Assessment Models.
Now there were a number of ideas about how large amounts of carbon could be removed from the atmosphere. Of those, BECCS – Bio Energy Carbon Capture & Storage soon came to be seen as the most promising climate savior technology.
BECCS works by burning biomass such as trees instead of coal in power stations, capturing the carbon dioxide before it leaves the chimneys and then storing it underground, hopefully forever. A promising approach, because the carbon released when burning the trees is the same absorbed by the trees when growing – and capturing and storing the carbon underground amounts to a flow of carbon out of the atmosphere.
Unfortunately, it has since been realised that large-scale BECCS in practice could have disastrous side effects. The planting of fast-growing trees over an area up to twice the size of India could impact biodiversity, threaten food and water security and displace people from their lands. Bioenergy is already contributing to deforestation. Today, we are cutting down ancient forests in North America to produce wood pellets to burn in European power stations.
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More recently, attention has turned to DAC – Direct Air Capture. This would separate out carbon dioxide molecules directly from the air, which would then be pumped to underground storage sites.
The technology is interesting. But plans to scale up DAC face two fundamental challenges. First, the process is energy intensive requiring large amounts of electricity and sometimes natural gas to run. Second, storing carbon dioxide – however it is captured – into safe geological deposits is not a trivial enterprise. Pilot carbon storage projects have repeatedly failed to meet targets. It is very likely that every carbon storage site will need to be carefully tailored to the specific geological circumstances.
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Such problems can sometimes be brushed aside by the sheer optimism that surrounds carbon removal. The assumption appears to be that carbon removal will work because it has to work. Even if we assume technologies will materialize at scale, we will probably need to spend significant sums of money running them – some studies estimate many trillions of dollars – for no evident economic benefit, since it’s about capturing carbon pollution and hiding it underground.
The time has come to voice our concerns about net zero policies. That begins by levelling with the public about the Paris Agreement. We’re currently desperately attempting to manage the narrative and adjusting the models in order to avoid acknowledging that the Paris Agreement is failing.
We are not going to limit warming to no more than 1.5°C.
The most optimistic scenario that the IPCC – the Intergovernmental Panel on Climate Change – can now offer is overshoot, a situation where temperatures will rise above 1.5, with large-scale carbon removal dragging them back down by the end of the century.
Net zero has gone from a way to offset hard to decarbonise sectors, to asking our descendants to offset decades of our delay.
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In private, IPCC scientists are highly skeptical about overshoot scenarios.
A survey conducted in 2021 by the science journal Nature found that the majority of IPCC climate scientists who responded thought we were heading towards a catastrophic 3°. Only 4% thought limiting warming to 1.5 was likely.
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So what can we do? I propose four ways we can make progress.
First, all carbon removal proposals must be based on robust science, engineering and economics. Once we have a credible total amount of carbon that can be removed by a proposed technology – which includes capture and it’s safe storage – then and only then can this be included in net zero policies and models.
Second, we must demand twin targets – all net zero plans should include a credible target for carbon removal, and a separate target for actual reductions in greenhouse gas emissions. We must stop hiding inaction behind promises of future removals.
Third, we need to acknowledge that net zero is becoming used to argue that nothing fundamental needs to change in our energy-intensive societies. Difficult truths need to be told.
And fourth, it is academics that need to be at the forefront of such truth telling. Most academics feel distinctly uncomfortable stepping over the invisible line that separates their day job from wider social and political concerns. There are genuine fears that to do so risks their objectivity. But we must be honest about our current situation, and where we are heading.
I want to be wrong. I want to believe that somehow my children will somehow come to possess miraculous carbon removing machines. But whenever I look there is an ever-increasing gap between the hype and reality.
This does not mean we are doomed. There are alternative, we can still avoid climate disaster. But I fear we won’t, if we don’t confront our wishful thinking about net-zero.
Thank you.