Why the IPCC's upcoming 1.5°C report offers an unexpected glimpse of hope

We spoke to Heleen de Coninck, who is Coordinating Lead Author for Chapter 4 in the 1.5°C Special Report, about carbon dioxide removal and negative emissions technologies and why there is still hope for mitigating climate change.

A carbon capture and storage demonstration plant in Switzerland which sucks carbon dioxide from the air before it is resold. Photo: Climeworks / Julia Dunlop
Denise Young, Johannes Mengel

This is the third and final part of our series marking the 30th anniversary of the Intergovernmental Panel on Climate Change (IPCC).

Heleen de Coninck is Coordinating Lead Author (CLA) of the chapter on strengthening and implementing the global response to the threat of climate change in the 1.5°C Special Report. Previously, she was a Lead Author in the IPCC’s Fifth Assessment Report (AR5), Working Group 3 (WG3). Her expertise is climate change mitigation and policy analysis.

In a wide-ranging discussion, she highlighted what’s new and different in this report, challenges associated with the exponential increases in literature in each IPCC cycle, and clarifies some of the confusion whirling around the various carbon dioxide removal and negative emissions technologies.

WGIII Co-Chairs and authors consulting at IPCC-39 in Berlin, Germany in 2014. Photo by IISD.
WGIII Co-Chairs and authors consulting at IPCC-39 in Berlin, Germany in 2014. Photo by IISD.

What’s different about this Special Report on 1.5 C compared with the Fifth Assessment (AR5)?

De Coninck: From my perspective as an author, what really changed is the multidisciplinarity of the whole effort in the 1.5° C report. Previously, I was only involved in the Working Group 3 (WG3) report for AR5, which was mostly populated with engineers and economists. And that’s sort of been the history of WG3. This report is led by 3 Working Groups and 6 co-chairs, and all of them are involved which gives it huge breadth. I personally feel this is the first serious attempt by the IPCC to take into account social science.

As a natural scientist by background, but with a PhD which is probably closest to  political science, I’m a bit of a mix so I like the direction the IPCC is going in very much. I used to be an atmospheric chemist. My research today is social science but I still identify with the natural sciences.

When we’re assessing the literature, in particular the social science literature, we find that it’s so broad that it is really hard to tease out what we should include in the report. If something ends up in the Summary for Policymakers it has to be actionable, but it cannot be policy-prescriptive. It has to be policy-relevant and making that translation is very tough, more so from much of the social science literature than from the natural science literature, I find.

What has the IPCC done differently this time round on inclusion of social sciences? How is it working?

De Coninck: What it did this time is bring in a broader range of social scientists, not just economists, into the 1.5°C report. The AR5 WG3 was also very much focused around emission pathways that represent a very techno-economic view of the world that is based on the assumption that the economy is optimizing on abatement (or GHG reduction) costs. What we’re trying to change a little in this report is to assume that decision makers don’t only make decisions based on cost, that the real world doesn’t optimize in that way. The time schedule in the 1.5°C Special Report is too tight to take that into account in the emission pathways themselves, because if you want to quantify this, that’s really hard. The models need to be modified strongly to do that. But we are trying, for example, to look at the financial sector as an important actor — which is something that’s not in the models – and give an assessment adding on to what the models are saying about investment costs.

The way most Integrated Assessment Models (IAMs) work is that they optimize on cost. So they basically have an abatement cost, a mitigation cost that the model tries to minimize over time to achieve a certain emissions target. Which means you basically end up with the carbon price as the main determinant of costs. These models are very rich in technological detail, but they have limitations: they don’t include the financial sector. They rarely allow actors to show behaviour other than economically rational behaviour, and innovation is not represented very realistically. For instance, they didn’t predict the drop in costs of solar energy, or wind energy, that we’re seeing now. They have limitations on some real-world elements. And there are  elaborate models, so you can’t just change them overnight, or even over the course of a special report. I think we’ll see more progress on that in AR6.

What’s also new in the Special Report is that we have a chapter that looks at global responses, Chapter 4. In the approved outline, it has two key elements: a feasibility assessment of nuancing some of the technologies that models favour, and a discussion of enabling, systemic events, such as governance, finance and behaviour. We nuance the modelling outcomes in two ways: one being more hopeful – that you can do much more with innovation and lifestyle change than the models suggest – and the other more pessimistic – that the feasibility of negative emissions technologies, which play a prominent role in modelling of 1.5°C, from a social science perspective, might not be as viable as the models assume.


Delegates review text on Special Reports for AR6 at IPCC-43 in Nairobi, Kenya, 2016. Photo by IISD/ENB | Kiara Worth
Delegates review text on Special Reports for AR6 at IPCC-43 in Nairobi, Kenya, 2016. Photo by IISD/ENB | Kiara Worth

When the world’s governments called for a 1.5°C report at COP21, there were very few scenarios involving 1.5°C which had been assessed. Could you talk a bit about how the Special Report helps deliver on the ambition of the Paris Agreement?

De Coninck: What I really find interesting about this, and this is going to make me sound like a social scientist, is what’s happening at the science-policy interface. Because after AR5 all the modellers said is 2°C still feasible or possible? Not so sure. Some were saying yes we can, others said it’s out of reach, as that’s what the models were telling us. Then COP21 happened, and the world came up with a 1.5°C report! And suddenly everybody started modelling a 1.5°C limit while earlier many researchers were of the opinion that 2°C  was already a lost cause. So it’s not always researchers speaking truth to power, it’s actually a policymaker determining the research agenda.

Clearly, the request for this report has challenged researchers to think in different ways. This shows that the science-policy interface is far from a linear process of researchers giving information to policymakers. We see that policymakers are asking questions to researchers which they didn’t think they could answer. It is nice to see that the Parties in the Paris Agreement are challenging the researchers to come up with solutions.

Is the 1.5°C Special Report really the best use of the scientists’ time to get us to where we need to be by mid-century, and 2100?

De Coninck: My personal view is that you could say that aiming for 1.5°C is increasing your chance that global mean temperature rise is limited to 2°C. And that’s also a policy reality. It is not as though the scientists are going to give all the answers in terms of “this is what we need to do in order to stay below 2°C, or well below 2°C or below 1.5°C”. It is not the IPCC’s task or mandate to provide policymakers with a menu of options or a recipe. We’re supposed to outline what are the consequences of limiting temperature rise to 1.5°C, what are the feasibility constraints that the world is facing. What are the side benefits, and trade-offs? What sort of a world are you ending up in, in a 1.5°C world compared to a 2°C world? Both on the impacts and the mitigation side. I personally believe it’s a useful effort.

The 1.5°C Special Report is also a signal to the social science community to go beyond observations, beyond being a neutral observer, to saying: “this is what all these case studies are telling us about what policymakers could do.” My personal view is that in IPCC reports, behavioural change has never been given serious discussion. Innovation policy has never gotten the assessment it needed in order to make a change, and economically, developing countries have not been given an option that is a viable alternative to a transition to a high-carbon society.

Photo: Climeworks / Julia Dunlop
Photo: Climeworks / Julia Dunlop

There is quite a lot of confusion about the difference between CCS, BECCS and CDR and geo-engineering. In fact climate scientist Kevin Anderson recently described this menu of acronyms as an “alphabet soup of procrastination”. Could you explain briefly the difference between these things?

De Coninck: It is confusing as it has evolved over time. What’s interesting is that in AR3, the definition of geo-engineering included carbon capture and storage (CCS) as well as some very exotic solar radiation management options. Then during the development of AR4 there was a Special Report on CCS. After that, CCS was excluded from the geo-engineering group of options and was normalized into  mitigation options, and discussed as such in the AR4 and AR5.

Ah, so you’re saying in AR3, CCS was still weird?

De Coninck: Nobody wanted to talk about it back then, as the hope was that energy efficiency and renewables could by themselves prevent dangerous climate change. Now it’s almost completely normalized and legitimized. With AR4, CCS was part of the mitigation options. And then AR5 came and in order to enable the  models to limit temperature rise below 2°C, we needed negative emissions towards the end of the century, a category of options described as ‘carbon dioxide removal’ in the AR5. Bio-energy with carbon capture and storage (BECCS) is one of those options, and was from then on included in the category of mitigation, and not anymore in the category of geo-engineering.

I find “geo-engineering” a very confusing term. As we get closer to climate limits, fewer and fewer things are categorized as geo-engineering and are instead categorized as ‘normal’ in the mitigation space or in a separate category in the case of solar radiation management, which is neither mitigation nor adaptation. This is now the only measure left in geo-engineering.

CCS is part of the different scenarios now, even most NGOs accept it as part of the mix now. In my country, the Dutch government has provisionally proposed that CCS is going to be 40% of the additional mitigation effort. It’s not a minor option anymore.

As for definitions—CCS is carbon capture and geological storage from stationary  CO2 sources. These could be for instance coal-fired power plants, but also steel-producing plants, gas processing operations or bio-ethanol plants.

Bio-energy and CCS is a so-called negative emissions technology—carbon dioxide removal—because biomass is supposedly recently removed CO2 from the atmosphere. (This is by the way being debated because of the indirect land use associated with biomass and other sustainability concerns). If you combust this biomass, remove the resulting CO2 and put it in the deep underground, then you have a net removal of CO2 from the atmosphere. That makes it a negative emission, or carbon dioxide removal option.

CDR is carbon dioxide removal. BECCS is one of the CDR options. But there are others, for example large-scale afforestation and reforestation are also considered CDR options because they would also be net-removing. CCS or Carbon Capture and Utilisation is usually not a CDR option.

Let’s talk about scale and feasibility for all these mitigation options.

De Coninck: CCS is currently deployed at a rate of around 40 megatons of CO2 a year, according to the Global CCS Institute. Globally. There are 15 projects and they’re fairly large-scale. CCS is going beyond the demonstration phase, for sure. The problem is that it’s more expensive than not doing CCS. In many areas, legal frameworks are missing, and public resistance is an issue. So there’s a lot of barriers, a lot of problems. But technically, it’s seems pretty feasible.

Bio-energy and CCS is less mature. Of course the CO2 storage part is sort of the same as the CCS part. But current bio-energy plants are smaller scale. You need a different type of capture process, and so far there are no large-scale demonstrations of that. However there is no reason to believe it wouldn’t work technically; challenges include public perception and the supply chain of sustainable biomass.

In terms of maturity, CCS is moving beyond the demonstration phase, but is not at the scale where it ought to be for achieving the temperature goals. And it’s not going fast enough. And BECCS is at an even earlier stage, and potentially has greater challenges in terms of public perception. The hopeful message is that renewable energy options are going more rapidly.

Any advice to governments that will be asked to ratchet up their commitments?

De Coninck: IPCC authors are not supposed to give advice. The literature is clear and the 1.5°C report will not be any different—we will say that the NDCs are not sufficient. That’s completely uncontroversial, even parties in the UNFCCC are acknowledging it. So that implies that there will need to be a ratcheting up of ambition levels in the Talanoa Dialogue and in the global stocktake. That’s very clear.

What we’re doing in Chapter 4 is discussing responses in a number of categories—innovation and technology transfer, behaviour, governance, policy, institutional capacity (which is very important in developing countries) and finance. These are categories in which we discuss the literature and look at what’s worked and what hasn’t worked. I can’t really talk much about the content yet, as the report is still undergoing review and revision.

What’s the future of the IPCC? Do you have any thoughts on AR7?

De Coninck: AR7? We are only just thinking about AR6! In Chapter 4 alone, in the 1.5°C report, we are citing 1,700 papers. And we feel we are already highly selective. There is so much being published, it’s becoming mission impossible to make a complete assessment.

So I’d be tempted to say: Publish less please! Rather publish one good paper than three papers which are also publishable, perhaps in a better journal. My personal view is that the drive to publish or perish, quantity rather than quality, is getting out of hand. I’m not saying the IPCC assessments are the only purpose for these papers obviously. But it’s slowly becoming an impossible task to do an assessment by a small group of authors working on this report on a temporary basis.

We have only 17 authors in our Chapter 4, who all have jobs to do as well. We have to cover such a breadth of literature and it’s getting more extensive with each assessment.

Can you talk about the effects of this increase in the volume of literature you have to assess?

De Coninck: Presumably you gain more breadth. It’s good that we’re really taking the social sciences into account now. That’s a huge benefit. But the cost is that it’s a single author writing the behaviour change section, who needs to assess a thousand papers. And it’s a volunteer job.

I’m not saying that IPCC authors should be paid, but the world’s governments asked for this report. I don’t think we’ve asked them in return how the scientific community is supposed to respond to this constantly increasing workload on scientists who want to be policy-relevant.

We have almost less time to write the chapters than the reviewers have to review them. Between the lead author meeting and when all the authors gather and the deadline of the chapter draft there are just seven weeks. The Coordinating Lead Authors also have to collaborate on working on the Summary for Policymakers in parallel. It’s really a lot of work.

But this is an exceptionally fast report. Other special reports allow themselves more time. The land report is also being written now, it started early fall, and it has a different set of authors.

All these reports place a heavy workload on the co-chairs of the Working Groups. For the co-chairs, it has become a much harder job than in previous assessments.