中文 | Español | Français

Guest post by Duncan McLaren, Lancaster University / 17 March 2020

Duncan McLaren is a Research Fellow with the ‘Assessing Mitigation Deterrence Effects of Greenhouse Gas Removal Technologies’ project at Lancaster University, funded by grant NE/P019838/1 from the Research Councils UK

[The views of guest post authors are their own. C2G does not necessarily endorse the opinions stated in guest posts. We do, however, encourage a constructive conversation involving multiple viewpoints and voices.]

Everyone seems to be talking about trees these days – and in particular, the prospects to remove carbon from the atmosphere by planting more of them.

Even President Trump and other US Republicans with histories of climate denial or skepticism have now endorsed tree-planting, in particular the Trillion Trees initiative. Airlines have made offsetting – including tree-planting – a central plank of their justifications for increased air travel. British minister Matt Hancock even claimed the airline industry had already decarbonised (in part because of its offsetting) in his defence of the public bail-out of Flybe.

Shell has started selling ‘drive-neutral’ offsets to motorists in Britain and the Netherlands based on tree-planting in Africa. BP’s plans to achieve net-zero by 2050 (despite growing rates of oil production) have not been detailed yet, but seem implausible without significant deployment of carbon removal, by trees and in other forms.

And in a very different sector, the UK National Farmers’ union has a plan for net-zero that sees continued methane emissions from livestock offset by future increases in carbon stored in agricultural soils (amongst other measures).

What ties all of these together is the problem of mitigation deterrence: the idea that promises of future carbon removal¹ might act as an excuse for avoiding the need to cut emissions today.

For the last two years our team at Lancaster has been investigating whether, and to what extent, promoting carbon removal might deter urgent mitigation action.

We convened deliberative workshops to discuss possible future scenarios of the development of carbon removal. Little did we expect that our hypothetical examples of mitigation deterrence would see so many similar promises transpire so soon in reality.

But our workshops also highlighted fears that such problems might lead to policy makers ‘throwing out the baby with the bath water’, and failing to support the development of carbon removal techniques for fear of undermining emissions reduction.

Because of the past success of denial and delay, it is already likely that to avert the worst impacts of climate change humanity will need to deploy carbon removal, possibly at a very large scale.

The key question we sought to answer therefore, is how to promote the development of carbon removal without deterring rapid emission reductions.

Technological imaginaries and fantasies (and the problems of modelling)

It might appear that rational policy makers would understand the need for both emissions reduction and carbon removal.

But there are many ways in which climate policy is not the product of objective science alone, and problems extend into the heart of climate modelling and technological innovation.

Climate models are full of imagined ways of drawing carbon from the atmosphere – particularly the idea of ‘bioenergy with carbon capture and storage’ – which make carbon budgets balance in the models even as emissions continue to grow in reality.

Such technological imaginaries are based on established science, but don’t (yet) function in practice at scale. For a technology to deliver climate impact it needs more than a technical concept; it needs commercial viability, public acceptability and appropriate governance – what science scholars call a ‘full socio-technical system’.

Sadly, commonplace modelling techniques that allow emissions overshoots, and heavily discount the costs of future action in comparison with current action, mean that integrated assessment models are predisposed to rely on future technological imaginaries.

Whenever modellers set parameters for such speculative future technologies, the models tend to deploy them preferentially instead of near-term emissions reduction with more established technologies.

This is because their speculative nature and associated uncertainties are hard to model, but their costs appear comparatively low, because of high discount rates.

Previously, for example, the models built in huge amounts of future carbon capture and storage (CCS) on coal fired power stations, but this technology now looks unlikely to ever be deployed at scale.

In the past climate skeptics have typically preached delay, arguing that we should wait for cheaper and more reliable low emission technologies – breakthroughs in CCS, or nuclear fusion, or new forms of renewable energy.

These are often not even specific technological concepts, but fantasies rooted in a generalised faith in technological progress. They appeal to politicians and others who hope for a ‘technological fix’ that would address climate change without behavioural, cultural or political change.

As carbon budgets approach exhaustion, however, technological fantasies based on cutting emissions in the future become unconvincing, even to political and business interests who want to be persuaded.

In today’s context the only technological fixes that still sound credible are those that promise not to cut future emissions, but instead to take carbon back out of the atmosphere – to act like a time machine for the climate.

So today skeptics are touting carbon removal, whether with real trees, or artificial ones (experimental technological devices that use chemicals and energy to strip carbon from the air).

How big is the problem?

How bad could it be if we slow down emissions reduction action (or fail to accelerate it) because of promises of carbon removal? There would surely be some benefits too, if we avoid premature scrapping of high-carbon infrastructure, or spread the benefits of high-carbon lifestyles to more people?

We’ve crunched the numbers, based on the models used by the Intergovernmental Panel on Climate Change (IPCC), to calculate that if we rely on future carbon removal which doesn’t materialise, the central risk is around an extra 0.7-0.8°C of warming (above a 1.5°C target).

In the worst case, we could face an extra 1.4°C warming, even if all the other things built into the models came to pass (McLaren, forthcoming, under review). And if we delay accelerating mitigation, all the potential economic and social benefits of a ‘Green New Deal’ would also be foregone.

To get to these numbers we considered how much carbon removal the models were promising, how much of it might trigger rebounds (such as more oil being produced as a result of carbon dioxide storage in oil fields – so called ‘enhanced oil recovery’), and how much remaining emissions reduction was likely to be delayed in the hope of replacement by cheaper carbon removal.

How should policy makers navigate the mitigation deterrence challenge?

What should we do if we want to develop CDR as a sensible insurance policy and a supplement to emissions reduction, but not allow it to deter rapid action to cut emissions? Our research, based on expert interviews and stakeholder deliberations, suggests three key measures.

1. Keep plans for carbon removal separate from those for emissions reduction

If we want to talk about ‘net-zero’, we need to be absolutely clear how much is to be achieved by emissions cuts, and how much offset by carbon removal. This is to avoid a vicious circle in which the former gets postponed longer as promises of the latter grow bigger. We suggest separate targets, separate accounting and separate incentives. Past experience with emerging technology – including renewables – says that direct incentives, or regulated standards, are more effective at supporting development, and more politically feasible, than generic carbon pricing or similar market mechanisms.

2. We need to constrain and strictly limit offsetting with carbon removal.

Offsetting is the easiest way in which carbon removal can end up compensating for emissions that could actually have been eliminated. There may be socially necessary emissions that cannot be mitigated yet, which should be offset by removal. We need to decide politically which those are, and not allow those profiting from emissions to consume the limited capacity for carbon removal in offsetting the emissions of wealthy consumers.

3. We need to raise our game on monitoring, reporting and verification (MRV), to minimise the risks of greenwashing and carbon fraud.

This is essential for techniques such as soil carbon storage, or enhanced rock weathering, or even tree planting where it’s very difficult to directly measure additional carbon stored. Improved MRV would also enhance mitigation, and reduce free-riding efforts by companies and countries.

Of course, to deliver such policies we need to recognize the problem, and understand that appeals to carbon removal may not all be good-faith engagement with climate change, but can also be a renewed effort to delay essential emissions reduction.

____________________

¹ NB: C2G uses the term Carbon Dioxide Removal

Related posts: