This is the second in a series of bonus essays that accompany the documentary Overshoot: Navigating a world beyond 1.5°C
It’s 1992, a year of momentous agreements.
The Cold War is formally ended by Presidents Bush and Yeltsin. The Maastricht Treaty is signed, establishing the European Union. The English Premier League is founded.
And in June, in Rio de Janeiro, the world’s nations begin to sign a treaty to combat climate change, the first of its kind. It creates an international process that soon becomes familiar, particularly the annual ‘conference of the parties’ to the treaty, COP for short.
The central objective of the treaty is to:
“...prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.”
Imagine that, in the years after, the world comes to understand “dangerous” as meaning that climate change creates risks that threaten the very viability of societies.
In this conception, “dangerous” means that the collapse of the Atlantic Meridional Overturning Circulation (AMOC) can’t be ruled out, and so the loss of over half the growing area for wheat and maize also can’t be ruled out. “Dangerous” means that the chance of multiple breadbaskets being shocked at the same time could rise to a coin toss by the 2040s. “Dangerous” means that even at around 1.5°C, globalised economic systems could be destabilised.
In short, the shared understanding of “dangerous” is based on best practices in risk assessment, focusing on the worst that could happen and accounting for how climate shocks can have domino effects that can be far more severe than the initial impact.
So, imagine that the world goes for broke in response, ploughing vast resources into phasing out fossil fuels and deploying clean technology.
But it is soon realised that a back-up plan is still needed, just in case it’s discovered that the AMOC could be triggered at lower temperatures than originally thought or that the global temperature rise was playing out quicker than predicted.
The back-up plan
The back-up plan is eventually found, posited in a letter published in the august Science journal in the year 2001. The letter is titled ‘Managing Climate Risk’. Its co-authors include two up-and-coming researchers called Michael Obersteiner and Kenneth Möllersten.
They argue that, in the future:
“...technologies that can rapidly remove GHGs [greenhouse gases] from the atmosphere will play an important role, particularly if unforeseen catastrophic damages are expected…”
Their plan has two components. Firstly, begin expanding forests worldwide. Secondly, build a fleet of power plants that can burn the forest’s wood to make electricity and are fitted with devices to capture the subsequent emissions before they leave the smokestack.
The idea is that if the climate threat turns out to be greater than anticipated, this back-up plan can be executed. The power plants will make zero-carbon electricity, as the emissions are captured and stored. Meanwhile, each successive generation of trees will suck carbon from the atmosphere.
The letter’s authors think the system could become so effective that it leads to:
“...net removal of carbon from the atmosphere (negative emissions) before the end of this century.”
They call it bioenergy carbon capture and storage, or BECCS.
It’s such a good idea that some people say that this back-up plan should become the plan. But there’s a catch. It will take time to build the global BECCS system. There are also risks and trade-offs from switching so much land to forest. So, there’s no avoiding it: the world must go for broke on reducing emissions. There’s no other way to reduce the risk of a global catastrophe. As Kenneth Möllersten and colleagues later write:
“...this option should not be seen as an argument in favour of doing nothing about the climate change problem now and then switching on this technology if climate change turns out to be a significant problem. It’s not likely that BECCS can be initiated sufficiently rapidly at a sufficient scale to follow this path.”
The world takes heed and goes for broke on decarbonisation.
Then, a quarter of a century later, in the mid-2020s, our worst fears are being realised. The climate threat is escalating.
Advancements in science have confirmed that tipping points, like AMOC collapse, could be triggered even around 1.5°C of global heating. The temperature rise is seemingly accelerating. Societies and the globalised systems supporting them are proving fragile.
Global decarbonisation has been progressing apace, with peak emissions happening many years before. But it’s not enough.
Thankfully, the investments in the BECCS system are now paying off. Deforestation peaked many years ago. Old forests have been restored, while new, biodiverse forests have sprung up around the world, held in trust and managed by local people for their benefit. The BECCS power plants are beginning to provide low-carbon energy.
This is adding a much-needed boost to decarbonisation, while helping stabilise the damage to other natural systems, too.
It’s happening in the nick of time. As the years go by, scientists are becoming seriously worried that the stability of the entire Earth system is wavering.
But the proactive decarbonisation of the past few decades mixed with the BECCS back-up plan gives plausible grounds for hope that the world can avoid a temperature rise far beyond 1.5°C and minimise the risks of roiling instability and the triggering of catastrophic tipping points.
The other path
Unfortunately, in reality, something like the opposite happened.
That reality is covered in episode two of our podcast documentary series, Overshoot: Navigating a world beyond 1.5°C.
In it, we meet Kenneth and Michael and hear how, after their Science letter, the world didn’t go for broke on decarbonisation. At the same time, the idea of negative emissions - that the mess could be cleaned up later - was misinterpreted and manipulated, feeding a colossal complacency.
Key to that is how people interpret scientific modeling and how its findings influence the stories we tell about climate change. What happened in the years since Kenneth and Michael’s letter is shocking.
After it was published, lots of people noticed. One was a scientist called Detlef van Vuuren. He builds computer models of the global climate. These models are used to ask ‘what-if’ questions about different approaches to tackling climate change. As Detlef told me:
“So we can show what is needed to meet the Paris goals. How much the electricity system has to change and how fast. How fast we have to change the way that we produce food. How fast we would like the transport system to change to stay within the emission budget of the Paris agreement.”
In the mid-2000s, Detlef had a similar worry to Michael and Kenneth: what if climate change proved worse than we thought?
At the time, some governments were talking about limiting warming to 2°C. This is before the Paris Agreement signed the world up to the 1.5°C goal. So, Detlef decided to look at a situation in which the world erred on the side of caution and tried to stay far below 2°C.
He started to do a modelling experiment.
As with any model, Detlef and his team used a bunch of assumptions, including about how costly it was to reduce emissions, how much the economy would grow – and emissions with it – and how much people who use lots of energy might voluntarily reduce their overuse.
When they ran the experiment, the models told him something shocking.
Countries might not be able to decarbonise quick enough to stay well below 2°C. If something didn’t change, the world seemed destined to reach 2°C or more.
That’s when Kenneth and Michael’s back-up plan popped into Detlef’s head. What if emissions could also be sucked out of the atmosphere? No one was really talking about this at the time.
“When I entered the field, we only knew about positive emissions…So the idea is that you have a limited carbon budget and then if you want to reach a certain goal you simply have to limit the emissions within that budget in order to avoid the bathtub overflowing.”
So, Detlef plugged the BECCS back-up plan into the model. And it worked.
“And yes, we were able to go lower, because then all of a sudden there was an additional option in the model to go lower. And so in the discussion of that paper, we showed that it was possible to go to well below 2.”
But Detlef was clear: this had been done as a hypothetical exercise. It might make the models work, but whether it could be done in the real world - whether vast carbon sucking capabilities could and would be rolled out in the future - well, that was a completely different question.
That practical question was why - as with Kenneth and Michael - it was always a back-up plan.
But that soon started to be forgotten.
A key moment came in 2007. More people were interested in aiming for global temperature rises below 2°C. So, at a meeting of the world’s top modellers - in Noordwijkerhout in the Netherlands - the work of Detlef and the team took centre stage.
“...obviously thanks to that meeting in Noordwijkerhout, which was this IPCC meeting, it became a standard. And as a result, everybody that wanted to reproduce that particular scenario had to start thinking about negative emissions as well.”
As ever, Detlef and his colleagues stressed the caveats.
“I was a bit nervous at the time, simply because already the two degree scenario was the lowest of the scenarios and then all of a sudden this even lower scenario was selected, which relied on the technology, which wasn’t certain.”
But these concerns were often missed, with caveats buried deep in technical reports, reports that were presented to decision-makers who didn’t understand the complexities.
Misunderstanding and manipulation
This brings us back to the story we told in episode two.
After the 2007 IPCC meeting, two things happened. First, countries weren’t reducing their emissions fast enough. In fact, some were doing the opposite. Second, growing evidence showed that a global temperature rise above 1.5°C was more dangerous than originally thought, which was one of the factors that led to the 1.5°C being agreed in 2015.
Together, this meant that, as the 2020s arrived, the speed of decarbonisation needed to avoid 1.5°C overshoot was precipitous. Graphs began to appear that brutally illustrated the state of affairs, like this from Zeke Hausfather:
These rates of change might be physically possible, with a worldwide mobilisation akin to war or at least the Covid pandemic response. But it would be highly disruptive and therefore anathema to many. This of course includes the fossil fuel industry. Yet the scale and pace of change inferred by graphs like this are enough to spin the head of even the most pro-climate politician.
Just look at how steep the blue line is (and note that this would only give the world a 50% chance - a coin toss - of staying below 1.5°C). Compare it with the small dip in emissions on the black line above 2020, which is the Covid lockdowns.
And so this is where the idea that the mess could subsequently be cleaned up came back to haunt us. One way to make the graph far less steep is to assume that the slow pace of decarbonisation today is made up by sucking carbon back out of the atmosphere tomorrow.
Glen Peters, who we spoke to in episode one, brilliantly illustrated this with a gif a few years ago:
The more carbon sucking in the future - the green zone below the line - the slower you can (in theory) go today, and so the greater the possibility for prevarication.
The problem hasn’t been the existence of this idea in theory. It is the layers of misunderstanding, accreting through generations of analysis, policy positions, and storytelling, under which are buried the huge assumptions, caveats, and risks associated with the possibilities for any global-scale carbon sucking effort.
Whether we like it or not, that effort is now needed. But it has come about in the exact opposite way that the original progenitors of the idea wanted and intended.
A decent manner
Talking to Michael and Kenneth reminded me of an inscription I read on a war memorial in Whitehall in London, years ago when I worked in the UK parliament.
“The boldest measures are the safest.”
It’s a quote from Horatio Nelson, the British naval commander often valorised in Britain’s history. It’s featured in a letter to a fellow officer in which Nelson urged aggressive action against their opponents during the Battle of Copenhagen in 1801 (a painting of which is at the top of this article). He wrote that, “the measure may be thought bold, but I am of the opinion the boldest are the safest.”
In the original papers on the BECCS back-up plan, it comes across as a bold measure. Tied as it was to the risks of catastrophic climate outcomes, it was part of a wider strategy for taking the safest possible course.
I asked Kenneth and Michael how they would feel if we sent our conversation back in time, back to when they first met in the year 2000.
Here’s Kenneth’s answer:
“I think that my reaction would be that this was quite predictable…I have always thought that it’s very unfortunate, but we will not be prepared to do what it takes to deal with climate change until the impacts really bite, and when the impacts really bite, it’s pretty late to take action….We discovered something exciting in a way, but it wasn’t something to be very happy about. Because, I mean, the way I anticipated that it would…be used in the future…hearing this recording back then would confirm [my] perception of mankind.”
Then we came to Michael. I found what followed deeply affecting.
Michael: “I would not have predicted that we are standing here with so much PPMV in the atmosphere. I just looked it up, 422. I would never have imagined it. I would have said, ‘this is unacceptable’. I would not have forgiven myself sitting here now that we are actually there. And at that time, I truly believed that BECCs is here for risk management and that the climate overshoot discussion would be unnecessary. And at that time, I actually laughed at the climate overshoot presentations by colleagues, and I said, ‘Why are you considering this? This is out of mind. Who would want to do this’. But many times in my life I have been wrong for very naive reasons, but that’s probably my own nature.”
Kenneth: “You’re a very positive person.”
Michael: “Yeah. I cannot believe that people do this. I simply cannot believe.”
Kenneth: “You’re probably the most positive person that I have ever met in my whole life. I mean, you had a more positive interpretation of, prediction of the future than I had, probably.”
Michael: “Yeah, but I have grown into a pessimist now, and I don’t think we will really solve this in a decent manner. I think we will really go through trouble.”
Michael was talking about the scale of what’s now needed to avoid the very worst climate outcomes.
He went on to make an interesting interpretation about net zero. As we explained in episode two, this is the moment that - like with a bucket - the amount of carbon coming into the atmosphere is balanced with the amount being taken out by nature and by any human-engineered carbon sucking.
“...when you go around in the climate negotiations, you always hear ‘net zero, net zero’, and net zero stands for solving the climate problem. Net zero is the point where you have the highest concentration in the atmosphere, and then you have to go down. [But] this is actually the most dangerous point in human history, where, currently the narrative is, we solve the climate problem. So this is a major contradiction, and this is probably also partly our fault that we do not communicate that net zero is an interesting point in history, but it’s the most dangerous one, and later on, we have to go through this enormous effort to take CO2 out of the atmosphere.”
By this, Michael meant that the atmospheric bucket will be at its fullest when/if net zero is reached. And that means the climate system is also at its most disturbed.
So, far from being ‘mission accomplished’, net zero would only be one of a whole series of moments along a tightrope to avoiding the worst (albeit a cause for huge celebration).
Going for broke
Some of Michael’s work now focuses on the ‘net-negative carbon economy’. So, not just getting to a balance in the bucket, but draining it on a massive scale. This is the only way to hope to rule out risks like AMOC collapse.
The main point here is that the world now has to not only invent and rollout the carbon sucking needed to reach net zero - and therefore limit the temperature rise beyond 1.5°C, 2°C, or however high we go - but also to create a net-negative global society that sucks and stores carbon from the atmosphere for generations in order to ultimately get down below 1.5°C.
Otherwise, we live with the tipping points Sword of Damocles above our heads.
This carbon sucking capability will have to be sustained globally for many, many generations into the future, sucking and storing no matter what happens - financial crises, conflict, pandemics - in the meantime.
That’s a huge task, a whole dimension of climate action that is barely spoken about beyond a technical community.
And as we explored at the end of episode two, the carbon sucking burden can and must be reduced by going for broke on emissions reductions and finding more creative ways of doing so. This is imperative. There’s no hiding from it.
In particular, reductions in the use of energy and materials by those who consume the most - far more than they need for a fulfilling life - would hugely help. This seems far more realistic than cleaning up the mess afterwards.
Indeed, some scientists have long argued that, way back in the 2000s, more attention should have been paid to modelling scenarios in which governments began to disincentivise the huge increase in consumption by the very wealthiest that has occurred in recent decades. These scenarios would’ve helped highlight how there might have been a way to avoid climate chaos without vast carbon sucking (or at least as much as is now the case).
After all, the boldest measures are often the safest.
But, as the latest analysis of the government’s woeful carbon-cutting plans shows, the world is still not contemplating this.
Thank you to Kenneth, Michael, Detlef, and everyone else we spoke to for episode two. Thanks in particular to Leo Hickman and the Carbon Brief team for their 2016 article that mapped the early timeline of BECCS research, which inspired us to talk with Kenneth and Michael.
Just read that the lifecycle of plastics releases ca. twice the CO2 into the atmosphere than airplanes...That IS something we can do about.