A Conversation with Valérie Masson-Delmotte: Part II, The IPCC and Public Outreach

Icebergs calving in Greenland. Source: Benoit Lecavalier, 2014.

Contributing editor Benoit Lecavalier recently conducted an extensive interview with Valérie Masson-Delmotte, one of the world's leading climate scientists and the lead coordinating author for Working Group One, the Physical Scientific Basis, in the next IPCC Assessment Report. To read Part I, on climate science, click here.​

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BL: As of now, what is one of the most challenging climate issues to communicate to the public?

VMD: There are many challenges in communication. Probably the most difficult thing to communicate is the notion of “commitment:" the fact that, with respect to accumulated greenhouse gas emissions in the atmosphere, there is "committed" warming. The climate response [to anthropogenic greenhouse gas emissions] will continue on the long term, same with the glacial response, ocean warming, and sea-level rise.

I understand that many believe that we have a global thermostat with our emissions. We have switched on the thermostat, and they understand it triggers warming, and they believe that if we decrease our emissions then we are safe. That’s wrong. Even if we decrease our emissions, we will only slowly stabilize the climate over generations to come. 

BL: Do you believe this is also one of the more important issues to communicate?

VMD: Yes, the climate system has thermal inertia and momentum. People need to clearly understand that the actions we are not taking now will have very long lasting consequences. It is simply not possible to go back to a pre-industrial climate, it really is not possible. We have learned this by looking at the past, by studying the response time of the system and of its different components. 

BL: How are climate scientists trying to improve their ability to communicate their research?

VMD: There was an IPCC workshop in Oslo, Norway, on communicating climate science with bloggers, social scientists, linguists, and the media. It is all accessible on YouTube. It covers all sorts of aspects, such as using language accessible to the public. I think that we must communicate crucial things like a physical understanding of the system, this is our work as physicists of the climate system. 

It is simply not possible to go back to a pre-industrial climate, it really is not possible. We have learned this by looking at the past.

BL: You’ve mentioned that the use of the terms “unprecedented” and “tipping point” are often used incorrectly in media reports about climate change. Does that reflect a lack of outreach by climate scientists to the media and public?

VMD: I think it can be a lack of background by the journalist on climate change issues, and the search for sensational issues which is the way the media works with the flow of information. It also has to do with the way we communicate science findings. You know there are high profile journals that search for new stories. We have these huge bodies of standard, high quality publications that do not get media coverage but consist of the main body of how science is producing new findings. It is easier to get media attention when you are outliers: either you are an outlier because you had a major breakthrough, or because you are covering a side story. I think there is an issue there.

BL: You mentioned making the language of climate science more accessible. How have you gone about achieving this?

VMD: There are many ways of going about this. I wrote books for children and I believe it helped significantly. If you manage to be clear with teenagers, then you can be clear with high level policy makers. Despite the difference in age, experience, and education level, they never had courses on climate science. So if you manage to be understandable to young people, then you are understandable to policy makers and the broader public. 

BL: Let's get back to the science. Climate scientists often return to drill the same ice sheet, ice caps, and glaciers. What is the importance of drilling additional ice cores? How is this justified to the public, and to funding agencies?

VMD: They don’t often go back to the exact same location. Some of the first ice cores were drilled in the 1960s. Since that time, updating the last 50 years all the way up to present is very important. That is the period where we have satellite measurements, and good knowledge of large scale atmospheric circulation. It is crucial to frame the old records with our present day context and understanding. 

Additionally, we have the oldest ice challenge everywhere, and then we have the challenge of extracting recent climatic variations where we have to drill in coastal places with high accumulation rates. Furthermore, as I already mentioned, there is the issue with the last interglacial ice and where to find it. There is just a lot we do not know, particularly in Antarctica where there is a lot to be done on the long term picture.

Finally, it’s not a matter of ‘empty’ polar regions, it is also a matter of inhabited regions where populations are affected by glaciers, either as risks or for water resources. Providing climate information at these non polar regions is really important. In high mountain areas, we have no direct measurements and no historical records. Yet they act as water towers for precipitation. They are critical for testing the suitability of climate models, especially when looking at hydrological aspects, and even with regards to atmospheric reanalysis. I think there is a need to raise the quantity of mountain ice cores worldwide, especially for the community that is working on regional climate modelling, so that they can make use of the complex and unique climate information these cores contain.

​Also, ice cores provide very precious information on atmospheric aerosol composition (dust, volcanic ash, pollution) for which we usually have very limited records prior to the 1980s. This data is extremely precious for atmospheric chemistry, which drives regional climate change.

It is easier to get media attention when you are outliers: either you are an outlier because you had a major breakthrough, or because you are covering a side story. I think there is an issue there.

BL: Aerosols created by human pollution end up in ice cores across the world. Shouldn't that unequivocally demonstrate to the public that humans have a global climate impact?

VMD: Certainly, it provides a background for understanding both how much we have and are affecting our environment, and also sometimes how policy measures can be efficient. If you look at the introduction of lead in fuel in the 1920s, for instance, you can see an atmospheric rise and then a decrease after regulations were put in place in the 1970s. The ice cores can monitor this change and demonstrate the positive effect of policy measures. There are two sides: having people aware [of the danger posed by anthropogenic climate change], but also showing past policy measure progress, which is important.

BL: What are you currently working on?

VMD: In the last year I’ve worked quite a lot on Greenland, especially the recent [climate] variations there. I've also looked at the fingerprint of the climatic cooling response to volcanic forcing. This is quite relevant and important because we will have large volcanic eruptions in the future, and we have to communicate to policy makers that this may happen. We do not know when an eruption will occur exactly and it has to be expressed to policy makers that adapting to climate change goes beyond adapting to a gradual warming. It is also about being prepared for these types of events. With 7 billion people today and 9 billion people in the future, we need to be ready because the more we depend on food security, the more we are vulnerable on these types of climate perturbations. That is one thing that has taken much of my attention recently.

My colleagues and I have also worked on Antarctic climate over the past two thousand years, and I think we are now providing quantitative information that is not just noise. I also have a new research project on the present Arctic water cycle to monitor water isotopes like those in ice cores and tree rings. Thanks to laser instruments, we can monitor the water isotopes continuously. We have instruments running in different sites: Svalbard, and a new one in Greenland. I believe by better understanding how the water isotope signal is produced at the weather scale we can better understand the ice core records. Water isotopes is an "integrated tracer." Using them, we can test climate models, and the ability of climate models to simulate the origin and transport of moisture. This is important on the climate feedbacks and impacts, so I would like to bridge this gap in knowledge. 

Finally, I have a new position with the IPCC that is currently ramping up, and decreases my ability to do my own personal research. I’m currently in the transition phase of my new role as co-chair of Working Group 1, the main scientific report of the IPCC. My responsibility in this new role is to facilitate the work of the authors, and uphold the principles of the IPCC, which are: transparency, rigour, and comprehensiveness. It is very important for me to have an open mind, so that our work really is comprehensive.

We require further understanding and confidence in our [climate] projections to lead to proper adaptation and mitigation.

BL: Where do you see the next IPCC report going after the Fifth Assessment Report (2013)?

VMD: There are many discussions on the future of the IPCC, which was decided for the upcoming Sixth Assessment Report [AR6]. It will be very similar in structure to AR5 with Working Group One, Two and Three, so the same basic organizations. I can say what I personally think but it all depends on decisions by the IPCC panel and scoping. 

One big issue is that we see that policy makers are interested in solutions. They acknowledge the climate problem now, and are interested in solutions which are framed through adaptation and mitigation. However, we have to be sharp and clear that we require further understanding and confidence in our [climate] projections to lead to proper adaptation and mitigation. Also, the AR4 and AR5 had very much the same structure, observations, processes, drivers, attributions, and projections, to keep things simple. That is not how people think or work. Usually people are interested in the processes, and then they look at timescales. 

So, I am in a consultation phase about what could be the structure of the next Working Group One [WG1] report, probably focusing on global to regional scale climate change. We are looking at further emphasizing the regional scale (since it is critical for policy makers); strengthening the discussion on natural variability (which overlaps with the human impact); and strengthening the process-based understanding. That is really all in the consultation phase.

I would very much like to produce a new, original document that would be a report that cuts across WG 1 and 2, a report that implements the regional results from WG1 into WG2 to investigate the impacts of variability and adaptation at regional scales.