Carbon removal beyond net zero

We need carbon dioxide removal (CDR) at scale if we are to avoid the worst possible climate outcomes. This is indisputable to me, though many disagree.

When I first started on The Carbon Removal Show podcast, this was the loudest debate: whether or not we need CDR. We spoke about the bathtub analogy: that we need to turn the tap off (emissions reductions) and pull the plug (emissions removals) to keep water levels (atmospheric CO2) safe and inside the bath. We spoke about every scenario in the International Panel on Climate Change’s (IPCC) modelling requiring some level of CDR. We spoke about the potential moral hazard - that focusing on CDR might distract us from the emissions reductions that we need.

These arguments haven’t gone away. Now, at the end of my time on the podcast, I hear and see a little less on why, and a little more about how much carbon dioxide we are going to need to remove, and when, and how. I lose track of how many gigawatts by whatever year.

The discourse remains rooted in the coming decades. Dates beyond 2050 are rarely heard. CDR in support of net zero is all we talk about. I understand that, given the pressing-ness of the net zero challenge. But I think the most compelling CDR thoughts lie beyond.

Imagine the day when the Mauna Loa observatory reports for the first time that CO2 atmospheric concentrations are no longer rising. For this to happen, we would have needed to stop most emissions, and have the remainder balanced out by removals. With other greenhouse gas emissions also in check, global temperature averages stabilise - maybe 2 degrees Celsius above pre-industrial levels, if we’re lucky. I’m really pushing our luck now, but let’s say the year is 2050. What’s our plan now?

We could choose to stop there, keeping the remaining emissions in balance with removals. This means CDR doesn’t grow as an industry past 2050. Maybe we decide that CDR is not cost-effective, or socially acceptable, or adapting to our new climate is just easier now the changes in climate have been set in motion. After all, most earth systems will need significant time to recover - seas will keep rising, extreme weather will continue, who knows what positive feedback loops we may be grappling with.

We could aim for pre-industrial temperatures, and so set about removing a huge quantity of CO2 from the atmosphere. Maybe countries would adopt historical net zero targets, where they aim to remove all the CO2 they’ve ever emitted into the atmosphere. The CDR industry would have to get huge, at least to the size of the fossil fuel industry at its peak. It would be a multi-decadal, intergenerational project.

Or, maybe we aim somewhere in between. Decide 1 degree Celsius above pre-industrial temperatures suits us best, and expand the CDR industry accordingly.

The thorny thing is that we’ here is several countries and populations, and their preferences may differ. Canada may like the newfound accessibility of the Arctic Ocean, while India may want to solve its extreme heat problems. It seems likely that rich northern countries in the northern hemisphere may be in favour of the new normal, and what remains of equatorial regions or small island states will disagree. The international coordination needed now will be commensurate to that which was needed to stop emissions in the first place. I wouldn’t put it past a well-resourced, large country to go rogue, and set about removing CO2 towards their ideal temperature. These are not insurmountable problems (nor will they definitely materialise), just mountains and valleys to navigate. The point is that, from this point of net zero onwards, we will have unprecedented control over atmospheric CO2, and therefore our climate, and we will need to work out how we manage that.

Regardless of where we land, I can’t imagine a scenario where we don’t want to remove any further CO2 on top of what cancels out annual emissions. Most realistically, I can see the world set its sights on enough CDR to get us back to 1.5 degrees Celsius above pre-industrial levels. I’d like to see the CDR industry more explicitly guided by this mission - of achieving long-term climate safety - alongside the relative near-term challenge of net zero. Granted, the first steps of scaling the industry up probably look the same.

I feel there is great power in thinking about CDR beyond 2050, into the centuries which follow. As I gaze this far forward, I cannot escape the conclusion that CDR is our best route back to a safe climate, which can support a global human population and level of biodiversity anywhere near similar to that of today. Arguably, it is our only route back after net zero is achieved. The band-aid solutions (adaptation, solar radiation management) will have their place, especially in places where the effects of climate change are especially acute, or are locked in for several years. But they do not have the same magnitude or longevity of global impact as CDR over the long-term (especially the more permanent forms).

Thinking on this timescale, you might realise that the speed at which we deploy new CDR capacity over the coming decades matters. The sooner the climate is safe’, the sooner billions of people and thousands of species are safe’ again. It makes a difference whether the climate is safe’ again in 2076 or 2104 - 28 years of additional non-safety for billions of people and trillions of living things matters. Should we forget about net zero goals, and shoot for climate safety goals now? Is the real moral hazard of CDR that we pour too little into it now at the cost of future generations?

Today is the start of an industry which will take the Earth’s climate under our control, to bend it to what humans need, and eventually want. It’s the beginning of a sector almost as important as the energy sector to our civilisation, a project which will be handed from generation to generation. It’s time that we discuss CDR as if this is the case.

This piece is just some assorted thoughts which have attempted to see CDR through this wider time lens. I suspect there’s more significant principles, questions and conclusions to consider from this perspective. I suspect some could even affect how we think and what we do about CDR in the present day.

Imagine the day when we don’t need CDR anymore. How did we get there, and where is there?

June 4, 2024