The IPCC at 30: Is the 1.5°C Special Report a turning point?

This is the second of a three-part series that examines the history and the future of the IPCC.

To mark the 30th anniversary of the Intergovernmental Panel on Climate Change (IPCC), we talked to leading climate scientists in the IPCC about the upcoming special report on 1.5°C.

In 2015, the world’s governments assembled COP21 approved the Paris Agreement on climate change. Part of that agreement contained a request to the scientific community to prepare a special report on 1.5°C global warming. That report will be launched this October at the IPCC Plenary in South Korea. It is unique in many respects, not least because of the unprecedented workload scientists have had to cope with due to an usually tight set of timelines.

For this first article we spoke with:

Valérie Masson-Delmotte, who is currently co-chair of Working Group One of the IPCC, which looks at the physical science basis. She is a specialist in reconstructing past climate variability from ice cores, and leads Working Group One’s activities for the Sixth Assessment Report (AR6) cycle.

Heleen de Coninck, 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, Working Group 3. Her expertise is climate change mitigation and policy analysis.

What should we expect from the 1.5°C report? How will policy-makers be able to use it?

Masson-Delmotte: The report will be presented for approval at the IPCC Plenary in the Republic of Korea in the first week of October, I can’t speak about the conclusions, but the outline of the report is available.

Governments at COP21 requested this report to learn about the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways. The IPCC agreed to prepare this special report, and added the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. The interpretation of the invitation, during the scoping meeting to design the outline of this report, is that this remit also includes impacts avoided if climate is stabilized at 1.5°C compared to 2°C warming, or more, if relevant.

What’s new here is the multi-dimensional analysis of risks and response options, the fact that we’ve included the Sustainable Development Goals (SDGs) because some response options can provide benefits that help achieve goals, while other response options create trade-offs.

There’s a lot of new knowledge around comparison of impacts on changing risk between today’s 1°C global warming and 1.5°C global warming, and the difference between 1.5°C to 2°C, for instance in relationship with changing extreme events. The report is also assessing the different pathways related to either stabilization of global warming at 1.5°C or to temporary overshoot above 1.5°C, and the assessment of these pathways also requires looking at the various dimensions, for instance energy supply and energy demand, or land use change.

Governments within the framework of the UN Framework Convention on Climate Change, (UNFCCC) expect this report to provide the scientific input for the facilitated dialogue of the Paris Agreement, now called the Talanoa dialogue, which takes place from now until COP24 in Poland in December 2018. So this report will be carefully considered by climate negotiators at the international level.

De Coninck: The 1.5°C report will provide guidance on what the literature has to say about which pathways and actions will bring 1.5°C out of reach. There will also be a lot of novel work on social science, such as the inclusion of insights on innovation, behaviour, finance and governance. Not only does this add nuance to the quantitative techno-economic Integrated Assessment Model (IAM) results, it also gives a hopeful narrative for action.

There’s been debate in the scientific community about whether 1.5°C is a feasible temperature target and whether scientists should dedicate scarce time and resources towards contributing to this report. Could you say a few words about this?

Masson-Delmotte:This report is unprecedented because multiple scientific communities are providing new approaches and new knowledge, and because there is so much new literature. The first order draft of our report cites 3,000 papers, including 2,000 either published or submitted since the IPCC’s Fifth Assessment Report (AR5); the second order draft cites 5,000 papers.

On the relevance of the 1.5°C target, I can give a personal perspective. Given current trends in emissions,and the response of Earth’s surface temperature to changes in atmospheric greenhouse gas concentrations, we may reach 1.5°C warming (in a climate sense, averaged over several decades) quite soon, in the next 25-30 years.

There is thus value in exploring the near term associated risks. If emissions are quickly reduced, it would be possible for the surface temperature to stabilize a few decades later. If those efforts are insufficient, global warming will be above 1.5°C for a long time. On the question of feasibility, the position of the report is not to assess feasibility as such, but to look at the enabling conditions that have to be met, and compare them with the rate and scale of emission decreases for 2°C pathways.

At the start of the process I was anxious to see whether the scientific community would take up this challenge or not. In fact, there was unanimous support from all the co-chairs of the three working groups and of the panel to prepare the report. In the selection of authors and reviewers, we had to choose one out of seven applicants. So it’s clear that scientists are willing to contribute.

For the review process of the first order draft we received about 13,000 comments from more than 480 expert reviewers from 61 countries. This involvement of the scientific community in the review process is critical for its quality. For the second order draft, we have received more than 25,000 comments from expert and government reviewers. Addressing these review comments will be a major challenge for the author teams, given the stringent preparation timeline.

There has been a lot of discussion about negative emissions, and how certain assumptions about their role in the pathways have been misrepresented. Could you comment on this, and how it will be tackled in the 1.5°C report?

Masson-Delmotte: Negative emissions were included in pathways assessed in the last IPCC report, but not in a fully transparent way. Since then, there’s been a lot of new literature, and it was really important for the 1.5°C report to make the pathways available from the literature, accessible from a database of scenarios, and to make an assessment of the associated negative emissions.

De Coninck: What’s new in this report is that we’re trying to make more transparent what the assumptions are that drive the pathways. They used to be fairly techno-optimistic, optimization-based, with a carbon price as a main driver. This is changing as models are trying to do a better job at representing the real world, with real people, real economies and real decision-makers.

On the one hand there is increasing demand for special reports, as well as more regular updates between the big assessments, on the other hand decreasing resources. What does this mean for the future of the IPCC? How will the scientific community cope?

Masson-Delmotte: The IPCC reports have the value of being co-designed with governments, they are the ones who take the decision to prepare a report. We have this process of scoping, approval of outline, report, approval for Summary for Policy Makers (SPM) which creates endorsement of report on the government side in a co-designed process.

The fact that our reports are endorsed by governments helps to separate the assessment of knowledge on the one side (which is the purpose of IPCC reports) from the negotiations on the other side. If they were not IPCC reports, I’m afraid there would be a more partisan approach where individual scientists and studies might be instrumentalised in negotiations.

We have a hybrid approach in this cycle. Between now and 2022, we’ll have a methodological report on greehouse gas emission inventories, three Special Reports—in addition to 1.5°C, climate change and land (for 2019), there will be oceans and the cryosphere in a changing climate (also for 2019). Then the three AR 6 Working Group reports, in 2021, so that the synthesis report (2022) will be available for the global stocktake of the Paris Agreement, in 2023.

What’s really new in this cycle is preparing Special Reports across Working Groups and thus across disciplines. It avoids the usual silo’ed effect of clustering sciences in specific disciplines or fields.

The hybrid model is to have regular updates with a specific focus. We don’t know yet the value or risks associated with these frequent updates. There is a huge burden on the IPCC for its operations and a huge burden on the technical support units helping the co-chairs to prepare the reports, and on the secretariat. The key questions for the future are around expectations from governments, and needs of the UNFCCC.

The UNFCCC would like the IPCC to be in phase with the Paris Agreement 5-year stock take cycles.

There is tremendous pressure on the authors, and the reviewers. They aren’t paid for this work, it comes on top of their research and teaching duties, and the more reports you prepare in parallel, the more risks you have of inconsistencies, heterogeneity. We need to analyze lessons learned from the current cycle to think carefully about next steps.

Another question for the future is funding which is key to support the participation of authors from the global south to Lead Author meetings. Currently we are not restricted, we have received support from several supportive governments. But there are still question marks about the funding situation in the future.

The question of the US role in the Paris Agreement has been highly publicized, but less discussed is the question of the extent to which disproportionately US funding for climate science is critical for IPCC assessments? What would happen to the IPCC if there was a drastic decline in US funding for climate science?

Masson-Delmotte: I can’t answer directly, so I will just give a few elements of context. The IPCC received no contribution from the US government in 2017, and in the past the US government has provided about 40% of funding. This funding is crucial to cover travel expenses of authors from developing countries to participate in lead author meetings and for the organization of the sessions. We hope the US will contribute in 2018 and we have had support from the US government in the nomination process—in the circulation of the call for authors from the US communities, and in support for US authors to participate in the assessment report.

For instance on the special report on 1.5°C we have 14 authors from the US, that’s 16% of the total of authors. This reflects the strength of the US research community in the field of climate science and climate change.

Finally, whatever the US government is doing, the IPCC is working for all governments whether they provide funding or not and independently of their position in international climate policies. That’s our mandate, and the wish is to provide policy relevant, robust and objective information for all.

How are we going to solve the challenge of making these reports and assessments more user-centric in a fast-changing information environment. The IPCC’s production cycle is deliberately slow for a number of reasons. How can we get more decision makers to read the latest climate science more regularly?

Masson-Delmotte: The production of reports is slow because we have this co-design phase to identify the topics and to do the scoping of the reports, and because we have these critical review phases. I often describe the IPCC as super peer review process. It is quite striking for authors new to the IPCC to realize the amount of collective effort, it’s really unprecedented, and without analogue. When you write a chapter and receive comments from tens or hundreds of other scientists, it provides strength to the quality, rigour, exhaustiveness of the assessment and it makes it slow, at the same time.

We’re doing our best to improve communication, especially at the level of the Summary for Policymakers, and improve the relevance of IPCC reports.This is for instance the purpose of the IPCC Cities conference taking place in March 2018 in order to bridge between academics, city practitioners and policy-makers and stimulate the production of relevant and new knowledge that will strengthen the assessment of knowledge related to cities and climate change in IPCC assessment reports.

For the special report on 1.5°C, we launched an open consultation for the FAQs so that they are actually Frequently Asked Questions and not what we wish they would be. That was new in the process. The IPCC is also revising its website so you can have more user-friendly navigation across the chapters and reports.

There is also an important role to be played by other bodies—research bodies, science journalists and other mediators to help us share our report. The InterAcademy Partnership has recently published a statement to strengthen science education related to climate change, and use the IPCC reports as the basis for producing ‘Resources and Tools for Teachers’ in cooperation with local actors to make the necessary adaptations to the diversity of local situations.

If IPCC reports just stay in shelves in libraries, science centres or ministries I think we’ve lost. IPCC reports are heavily used for teaching in universities, but we want them to be used more to accelerate the sharing of the most recent state of knowledge, for instance for high school students.

Personally, as a scientist and not as an IPCC co-chair, I am very committed to sharing knowledge with younger generations.

De Coninck: Political decision cycles don’t follow scientific dynamics and vice versa. The question is: can policymakers find useable information at the moment that they need it? The timing of the Special Report on 1.5°C linked to the Talanoa Dialogue takes this into account, but national policy-making follows different cycles.

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