Dr Hoesung Lee is a professor in the economics of climate change, energy and sustainable development at Korea University in Seoul, South Korea. He has been the vice chair of the Intergovernmental Panel on Climate Change since 2008 and is running as a candidate to succeed Rajendra Pachauri as the new chair of the IPCC in October.
On the burden on IPCC scientists: “I think the burden is quite high. However, at the same time…many of them take great pride in sharing this experience with fellow scientists.”
On how adaptation and mitigation complement each other: “The community would benefit more by recognising the complementing nature of the two approaches.”
On opening plenary sessions to the media: “One can improve the transparency of the process without opening the whole details of the deliberations process, I believe.”
On the limitations of economic modelling: “Right now the major stumbling block in the study of climate change economics is to have some reasonable understanding and estimates of climate damages.”
On a carbon tax: “If you ask me to choose the most important work in climate change issues, then I’ll choose carbon price. That’s because it is the driver to put us into the right track.”
On the “hiatus”: “I think that trying to read too much from 10-year temperature changes is more or less like trying to extract too much information from, should I say, daily fluctuations of stock prices.”
On a carbon budget for 2C: “Ideally, it should be very effective, but in reality I do not see carbon budgets having much impact on action.”
On the feasibility of 2C: “The IPCC report indicated that negative emissions are required to achieve a 2C goal and the technology to achieve that goal is not yet available.”
On the future of the IPCC: “Perhaps we may have reached a point where we have done enough of identifying problems and we may have time now to see the solutions.”
On climate skeptics: “The IPCC is certainly open to those who are skeptical of climate change and global warming to come into our arena and present their views.”
CB: The IPCC has confirmed there will be an AR6 [sixth assessment report], how do you think its scope or function might be different from AR5? Do you think there will be differences?
HL: Oh, I think there was a great deal of discussion about the future of the IPCC at the end of the last cycle of the IPCC and, overall, the consensus was that we would follow more or less a similar structure as we have adopted for the last reports. In terms of reports and the frequency of those outputs, we don’t generally expect much change from the previous cycle. I hope that there has to be some meaningful improvements in the way the IPCC outputs in the future.
CB: You mentioned the timing of the reports there, it has been decided to continue the big assessment reports every five or seven years or so. Would you have prefered to see smaller, maybe more frequent report on specific regions or topics?
HS: I think specific reports on specific regions will be very much in demand, but the constraint is whether the climate science community will be able to share that burden of many specific reports, in addition to the reports for the major assessments. So, the constraint is really on the potential contributors to the IPCC assessment cycle.
CB: At the moment, it is already quite an undertaking for climate scientists involved in the IPCC. Do you feel that the burden is already too high, or is it a fair task?
HL: I think the burden is quite high. However, at the same time, many of us recognise that the scientists fully understand the weight of this assessment process and also the importance of the process, and many of them take great pride in sharing this experience with fellow scientists. I think this is a very healthy sign for the institution as a whole.
CB: Talking of smaller reports, perhaps the favourite topic for the next special report is food security. Would that be your preference? Or is there something that you think is more urgently needed, for example, Monaco’s suggestion for a focus on the oceans, perhaps?
HL: I think those two areas for candidates for special reports have been very well recognised and I know that there is also a demand for special reports on climate change and desertification, I believe. There can be many other interesting topics to be considered for special reports. If I may add one more, it can be an integrated approach of adaptation, mitigation and sustainable development. But this is just one idea to have the benefit of the special report. Again, it depends on the availability of scientists and availability of financing sources.
CB: You mentioned adaptation and mitigation side by side there. Do you think that the way the reports are laid out at the moment strike the right balance with adaptation and mitigation? Do you think they’re clear enough that it’s not an either-or situation?
HL: At the beginning of the assessment process â?¦ the question of the relationship between adaptation and mitigation has always been on their relative contributions to climate stabilisation. Therefore, there were questions on whether those two are complementary or competitive elements as a measure to achieve climate stabilisation. And it is very obvious that those two are complementary. Every study indicates that the community would benefit more by recognising the complementing nature of the two approaches. Therefore, I don’t think the question is about striking the right balance between these two elements, but rather to have as much of each element as possible in the budget of our financial resources.
CB: The Summaries for Policymakers (SPMs) have been criticised as being a little bit too hard to read sometimes. What do you think of the suggestion to seek advice from science writers and graphic designers, for example, to make them a little bit more accessible?
HL: I’m not quite sure that will be the right approach, to handle the readability question of the SPMs. I think the problem may not be particularly with the readability of the SPMs. I have had a chance of observing the production of the SPMs for a number of years, right from the second assessment report when I was co-chair of working group three, right up to this last assessment report. Whenever those SPMs were released, I asked friends in the business community, for instance, all around the world, how much information they found useful for allocation of investment resources. Many of them said “not quite useful” for their decisions on allocation of financial resources. I asked the same question of policy makers around the world and they said it’s a good document, but the comment ended right there. So my assessment of the readability question was maybe the message contained in the SPM might not be of much interest to the policy makers, might not be of much interest to the decision makers. And my hypothesis is, it’s not the way the SPM was presented, but the content of the SPM presented to the decision makers. Maybe that is the crux of the matter that is known as the ‘readability’ of the SPM. That is just a hypothesis, but if this is the case then a science writer or a graphic designers, their contributions won’t work because the matter is really about the content of the SPM for decision makers who really need to take action.
CB: Separate from the SPMs then: do you think, looking back, more could have been done to make the IPCC’s findings as a whole more media friendly? How much of a priority would improving communication be if you got the role?
HL: I think media friendly IPCC reports is a very, very important role that the IPCC leadership must always keep in mind. And, in fact, the current and previous IPCC bureau members have always thought that media friendly IPCC outputs was very important. For the future, my point is not particularly on the way the IPCC products are conveyed to the general public, I would rather see the messages and contents in the IPCC reports: have we produced, have we conveyed messages from our report that are interesting and relevant to the policymakers, decision makers, for the decisions they are making in their daily lives, for instance, in their annual budget considerations. I think that is the key, that is the crux of the matter.
CB: How important do you think transparency is, and how do you think the IPCC process could be made more transparent? For example, do you think the SPM plenaries will ever be open to the media?
HL: Ever since the International IAC [InterAcademy Council] recommendations were adopted by the IPCC, the IPCC has made tremendous progress in making its process more open and transparent. And we’ll keep that process for the future, we need to keep that process for the future. Regarding the suggestion of making the plenaries open to the media, I believe that suggestion needs to be given further consideration. Because this is a vastly different way of approaching the transparency question of an IPCC product. One can improve the transparency of the process without opening the whole details of the deliberations process, I believe.
CB: Could you give an example? How might that be achieved?
HL: I think the current process of IPCC production of its output is exactly that example I’d like to emphasise. As you very well know, we do have a very laborious process starting with expert review and then we open up that the review process to the general interest readers and then finally we invite reviews from government policymakers. So, this review process is very, very open, without any restrictions. And it apparently helps our process to be more open and objective and more transparent. I think this has worked very well and, therefore, I think that we need to keep this process for the future.
CB: It’s sometimes been suggested that the three different working groups work a little bit too independently of each other. Do you think there’s truth in that and how would you go about making better connections between the working groups?
HL: I think each working group has different mandates and also consists of different expertise with different backgrounds. And, therefore, it is better that each working group has independent authority in pursuing its assessment duties. Judging from the current assessment experience, I do not see any incidents of problems arising from this independent approach by each working group. Now, the integration of the messages from each working group is very important because the IPCC, as a whole, must give a context to the general public about the crux of the climate change issues, and I believe that the chair must play that integrating role. And, I believe that the synthesis report will be the medium to integrate the major messages of each working group.
CB: So let’s talk about you a little bit. What is your own background and how do you think your experience makes you well-suited for the job of IPCC chair?
HL: I’m an economist with a speciality in climate change. Economics is a very wide area, as you know, and the study of externalities was always of a great deal of interest to me. And, so, I pursued my study in that area. Energy and climate change is an area that is full of externality problems and, so, I really swim in the river of that. I’m very much fond of that. I have built long-range, energy-planning models for Korea, when I was working for the government-affiliated research agency in charge of developing energy and climate policy. I also was in charge of directing a study about the economic consequences of climate change in Korea. I interacted with a variety of experts in the field of climate science, ecology and environmental economics and experts in the political economy. I do have other projects going on at this point. As you know, dealing with climate change issues requires an interdisciplinary contribution, so I interact with a number of scientists in this field. Once, in my early days of my professional life, I also worked for an energy company, an oil company, in the United States, for their corporate planning strategy development. In that time, I interacted with a number of geologists and scientists in chemistry, optimisation modellers, etc. I believe my experiences in government policy making, my experiences in research – and also I had a duty to perform as a teacher in environmental policy at the university of Korea, and also I have served a number of advisory functions to the government offices in Korea, as well as the international bodies – have very much enriched not only my own professional development, but I hope my services to those organisations will also be beneficial for them.
CB: Your background is in economics. Do you think economics can capture climate change, both the impacts and the benefits of mitigation versus business-as-usual? What are the limitations of looking at climate change from a purely monetary angle?
HL: Well, economics is a great discipline that integrates all aspects of human life. Climate change is really the outcome of the certain decisions by humanity and economics, let me just mention, deals with the cost and benefits. Right now the major stumbling block in the study of climate change economics is to have some reasonable understanding and estimates of climate damages. And that is a tough area. However, I believe that if we are patient and if we are willing to put in more research investment into this area, we will have much improvement in understanding the economic estimation of ecological services. Improvement and advancement in that knowledge frontier will help us in defining our understanding economic consequences of climate change. I hope that we move in the right direction.
CB: Some might argue that the most policy relevant areas of the IPCC are working groups two and three? Do we need working group one? How important do think working group one is?
HL: I think your question is hypothetical, really. We need the working group one science. For instance, if you look at chapter six of working group three in AR5, a great deal of inputs you can recognise from working group one. And also if you look at the regional chapters, not only the regional chapters of the working group two report, but many chapters in working group two utilises heavily the inputs from working group one. So really, working group one, two and three are inseparable in producing our objective and a meaningful assessment of our knowledge of climate change problems. So, working group one should be there.
CB: What areas of research excite you the most? Perhaps other than getting a handle on economic damages, what remaining questions would you like to see answered more than any others?
HL: Oh, I mentioned about the externality questions and I want to pursue the externality questionsâ?¦
CB: Can you just clarify what exactly you mean there by “externalities”?
HL: An externality? It is like the pollution cost. My action affects other persons’ welfare, but I do not pay for these disadvantages that I impose on other people’s welfare. Those are externalities. Climate change is a typical example of externalities and the way to correct the externality problem is to have a price on certain activities that cause those externalities. In our case, that is a price on carbon emissions – what you may call a carbon tax. Now, I think if you ask me to choose the most important work in climate change issues, then I’ll choose carbon price. That’s because it is the driver to put us into the right track. I would like to pursue, as much as possible, to increase our knowledge of carbon price and future emissions, and our knowledge on reducing the institutional barriers to adopting a carbon price system. And I think this is a tremendous challenge to the researchers around the world, but it’s a very exciting area.
CB: Are there any other aspect of climate change that didn’t get enough attention in the last report? Or just perhaps has moved on so much that there will be a lot of new thing in AR6?
HL: As you know, at the end of every chapter in each working group there’s one section indicating the areas for further study. And an aggregation of those suggestions can be a very good starting point for the next assessment. In addition to that, I think we may wish to go beyond that: identifying the areas for study by engaging scientists in the regions around the world to hear their voices about the AR5, and to hear their voices about what areas of further analysis, what areas of policy-relevant questions need to be expanded for the sixth assessment cycle. This sort of a regional workshop in scoping the AR6, I think, will be very, very beneficial. And I think that the, should I say, co-benefit of holding this regional dialogue, regional workshop, whatever you call [it], about the future assessment cycle is for us to find expertise residing in the region. We need to tap in[to] a number of experts in developing regions for the next assessment cycle. I think this way of holding a regional dialogue, regional workshops for the sixth assessment cycle would be a very valuable tool, not only to enrich the AR6 documents but also to invite and recruit scientists in developing regions in a meaningful way.
CB: One topic that’s getting quite a lot of attention at the moment is the suggestion from scientists that it’s looking very likely that 2015 will be the hottest year on record. What do you think is the significance of things like that? What do you think of the suggestion from parts of the media that it will signal the end of the so-called surface warming slowdown? Do you engage with those sorts of conversations?
HL: I follow, and I also tend to side with the scientists who have a very cautious view about reading too much from 10-year data points. And we are, in fact, dealing with a very long trend of world temperatures. I think that trying to read too much from 10-year temperature changes is more or less like trying to extract too much information from, should I say, daily fluctuations of stock prices. Therefore, we need to be cautious. Also, we need to be on more robust ground to say something definite about changes in the temperature trend. And I think that the IPCC scientists working in this area have been quite credible and reliable in dealing with this area.
CB: A question about carbon budgets. Carbon budgets were a new concept in the the last IPCC report. How effective do you think the concept is for communicating the challenge of staying within a particular temperature target – 2C, for example.
HL: Ideally, it should be very effective, but in reality I do not see carbon budgets having much impact on action. For example, I just mentioned that one should not read too much into daily fluctuations in the stock prices. When the carbon budget information was released – I believe that was September 2013 at the plenary of working group one – the next day, I looked at the stock market prices of major fossil-related companies and it showed not much of a reaction to that news. Obviously, one should not read too much into daily fluctuations, but I try to look at the stock price changes of those companies and their performance, and there’s not much relating to the news of carbon budgets. As you know, a carbon budget is a very serious message to the world energy industry and to have that common budget concept play a meaningful role in the decision-making process, we need something to connect carbon budgets to our decisions on daily life, our decisions on – if we are in the business community – daily decisions about allocation of investment resources. Now, we do not have that information at this time. We have a goal, a number. But many people ask: that’s great, so what? That’s the situation now.
CB: One implication of the carbon budget for 2C is that any pathway now available to us now relies heavily on BECCS (bioenergy with carbon capture and storage.) Is that risky?
HL: The IPCC report indicated that negative emissions are required to achieve a 2C goal and the technology to achieve that goal is not yet available. Therefore, there is a risk in expecting such a scenario to materialise. But at the same time, I must emphasise that we as analysts have a very poor report in projecting and understanding the way that technology develops in the future. We just simply do not know what sort of technology will be available for the future, in a set period of time. Therefore, we cannot really quantify, or we cannot really put a range on that risk regarding BECCS. But that is the state of our knowledge regarding BECCS.
CB: What’s your personal opinion: do you think 2C is still a feasible target?
HL: That depends on how the world will react to the IPCC messages of the 1,000 gigatonne carbon budget. The study indicates that if we act promptly and all countries participate in these reduction activities, and all technologies we think will be available are available at the right moment and deployed, then the cost of achieving 2C will be manageable. That’s the main message of the IPCC report. And you may have noticed that there are too many “ifs” in that statement, which means that we also need to be very wary about the risk of not achieving the 2C stabilisation. We do have an INDC [Intended nationally-determined contributions] system in operation now and many studies indicate that those preliminary [INDC’s] and judging from submissions from the Cancun pledges, many studies indicate that the aggregation of the pledges from the individual countries is very over the 2C stabilisation goal. Therefore, countries need to do some more to achieve that for the future, to achieve 2C.
CB: A lot of countries already affected by the effects of climate change are calling or 1.5C as a target to aim for. Given how ambitious 2C is and everything you’ve just explained, do you think we’ve missed our chance for 1.5C?
HL: Well, AR5 analysed 1,200 scenarios and virtually no scenario indicated the feasibility of 1.5C. Now, again, that is considering the state of our knowledge regarding the technology. At this point, that is the frontier of our understanding of 1.5C.
CB: So there’s momentum building ahead of the COP21 in Paris later this year. That momentum is coming from various different angles: you have the IPCC reports, the papal encyclical, the divestment movement, for example. How important do you think the international process still is? How much do you think we still need the UNFCCC COP process?
HL: Oh, I think we need it very much, the COP process. Because it is the arena in which both developing and developed countries share a common outlook, a common view of the importance of the 2C stabilisation. The problem of this large gathering of interested parties is mostly a problem related to the process, not a problem related to the goals or outcomes. For that reason, there are calls for having a parallel, separate forum to approach the problems of climate stabilisations. Maybe we already have those other forms of deliberations, so that’s the reality at this point. Everyone knows that the 75% of global emissions are coming from something close to 20 countries. And that’s the reality, too. However, the important point is that to have climate stabilisation, we need to have a very much meaningful coordination, cooperation between developing and developed countries. The developing countries have the population of five billion and still growing very rapidly, and they will need economic development, certainly. Then the developed regions have a population on one billion which is more or less stagnating. It’s very clear where the solution space lies for the 2C climate stabilisations, we need to have a very close, very strong cooperation between developed and developing regions.
CB: The IPCC was set up to feed into the UNFCCC process. Do you think there a way to align more with that? Do you think there’s more that can be done?
HL: The UNFCCC, ever since its inception, has been closely related to the IPCC. In fact, as you know, the IPCC’s first assessment report, which was requested by the UN general assembly, recommended the creation of a climate treaty. So, the IPCC was established in 1988 and a climate treaty was formed in 1990, on the basis of the major recommendations contained in the IPCC. So, it’s a very close relationship and the policymakers mentioned in the IPCC reports, in their communications, are really the policymakers in the UNFCCC. So, it’s very important that the IPCC understands what are the policy questions and the priority of those policy questions that the UNFCCC parties have. Those understandings of policy priorities need to be communicated very well to the IPCC scientists and IPCC leadership. More coordination will produce a better output for the IPCC, which will contribute much more to the adoption of [inaudible]
CB: The former chair, Rajendra Pachauri, suggested the IPCC should have, or could have, an annual role in assessing countries’ INDCs. Do you think that’s a good idea? Is that a good way forward for the IPCC?
HL: There are some who would like to have the IPCC involved in that process of evaluating the INDCs. However, I think that is not, should not be, the major function of the IPCC. I do not think, in reality, the IPCC has the capacity to do such an evaluation. There are other organisations who can handle such questions more efficiently and more effectively. I think the suggestion has the very good intention of helping policymakers to take appropriate action for climate stabilisation, but to analyse and evaluate INDCs will not be a major category of work for the IPCC.
CB: Many people will see the new IPCC chairmanship as an opportunity for a fresh start, a time for renewal or re-energising for the IPCC. What things do you think could mark the start of a new chapter? Or do you think there’s no need for a new chapter?
HL: I think the IPCC has done a very effective job of identifying problems. And perhaps we may have reached a point where we have done enough of identifying problems and we may have time now to see the solutions of these climate change issues, the opportunities they offer for the global community. In that sense, I think the IPCC has a great role to contribute. I believe the proper vehicle to convey that framework of message is the synthesis report. And not mostly on the identification of problems, not mostly on the reorganisation of messages from the different working groups, but a real synthesis in the context of providing a flavour for solutions, a flavour for opportunities for climate stabilisation, based upon each working group’s underlying report. I think for the global community to understand the climate change problems in a proper context, I think the new chair should play a very important role in identifying the climate issues, not necessarily only identifying the problems, but also the solutions and what opportunities the solutions may provide for the global society as a whole is very important.
CB: Do you envisage the synthesis report, then, as as an exploration of those solutions, or do you mean the IPCC could make recommendations of its own?
HL: The IPCC, as you know, is policy neutral – policy relevant, but not policy prescriptive. What I’m saying is that, based on the underlying reports, one could take an angle from the solution side rather than the problem side, an angle from the opportunity that the solution may provide, an opportunity for new kind of developments under this carbon-constrained world. We can find those messages. I’m quite sure we kind find those messages from our underlying reports. Therefore, it is not necessarily a recommendation but it’s a presentation of the key messages from the underlying reports. So it’s in line with the IPCC’s mantra of being policy-relevant but not policy prescriptive.
CB: What do you think Pachauri’s biggest achievements were in his 12-year stint as chair? And, equally, what lessons have been learned in that time?
HL: I think he has been a very enthusiastic supporter of the IPCC and many of us have benefitted greatly from his contribution. He made the IPCC leadership a cooperative entity, to produce these very important IPCC products. And his spirit of cooperation and collaboration is a very important principle, and I believe we have benefitted greatly from his service to the IPCC chair.
CB: Do you think the IPCC has done enough then to learn from previous mistakes? The ghost of Amazongate, for example, does still rear its head from time to time in the media. Do you think enough has been done, or is there still progress to be made on that front?
HL: I think we have done a good repair job from those incidents, unfortunate incidents. And we do have an error protocol in operation, and it those protocols been in operation in very successful ways. Therefore, we need to keep on that system as a way of handling errors for the future. So we are very confident about handling the future errors, although we want to minimise those errors in any way possible.
CB: Do you think the IPCC chair can be free to act and comment from a personal perspective, or would you see yourself as representing the IPCC at all times?
HL: I have been the head of an organisation for a number of years, and I know from my own personal experience that once you are the head of an organisation, you cannot have personal views no matter what you would like to say from your own personal perspective. So, any thinking of presenting a personal view while holding the hat of IPCC chair is out of the screen. So, there should not be any personal view from the IPCC chair. No matter what the IPCC chair says, everyone will interpret that as the view of the IPCC.
CB: Does that go for climate scientists in general? For example, can climate scientists be advocates? Or to put it another way, what role do you think a scientist plays in policy?
HL: Well, first of all a climate scientist has a role to play to advocate for the benefit of their profession. Now, that is the fundamental boundary for any scientist, any expert. There is one area that a scientist could not cross the boundary and that is if there is any personal agenda. When a scientists says something, whether it is a policy matter or a purely technical matter, one should not have any personal agenda related to the statement. So, it’s very much up to the integrity of the individual scientist. I, myself, as an economist, I always emphasise the importance of a carbon price: the need that the world must pursue, the policy of a carbon tax to have a meaningful result for climate stabilisation. I believe that as an economist, my advocacy, if you call it that, my advocacy of carbon price is an advocacy to my profession and also is an advocacy for the global benefit resulting from, supposed to be resulting from, climate stabilisations. So, that’s where advocacy without a personal agenda is very, very important.
CB: Why do you think there are no female candidates for the IPCC chair role? Do you think that sends a signal from the IPCC?
HL: I do not know the reason. But everyone is very much anxious of that phenomenon and I’m sure that in due course of time, we will have a good representation, a gender-balanced representation, of the IPCC leadership. I’m quite sure.
CB: It’s probably fair to say the IPCC is a much-hated institution among climate skeptics. How, if at all, would you address this as chair?
HL: Well, I don’t want to really address those people or organisations who hate the IPCC as an institution, or people who are associated with the IPCC. But I would welcome those doubters to come into the arena of scientific assessment, and present their views [with] a scientifically valid approach. It would be a great opportunity for both groups. The IPCC is certainly open to those who are skeptical of climate change and global warming to come into our arena and present their views.
CB: A question about social media. Do you use social media, Twitter or anything like that? Or if not, do you have any observations about how it is used by the IPCC or by climate scientists to communicate the IPCC’s work? Or just to talk about climate change more broadly?
HL: I do not use those social media, just because I don’t have much time to do that. Really not much time. There are people who are very much fond of using that medium and there must be some benefit of utilising such instruments. But, for myself, I do see not much of a net gain from using this medium of communication. I do have an account, but I rarely visit it.
CB: It just strikes me from what you just said about the IPCC being open to people asking questions, or discussing areas that perhaps they’re unsure of, or have doubts about it strikes me that social media is quite a good way to do that. It’s a very instant and accessible way to have a conversation with a scientist. Do you think there’s a role for it there?
HL: To a certain degree, yes. But I think the venue for serious and appropriate discussion is not social media. It’s the scientific arena that real debate can take place, that’s what I’m saying.
CB: What advice might you give to a young person beginning a career in climate science. If you could write a letter to you 18, 19 or 20-year old self, what advice might you give?
HL: Well, I think I’d tell them to focus on the basics, the fundamentals in whatever area they study and whatever area they find of interest. I always tell my students, “Do not come to my class if you think climate science is an area that will get you a good job after you get a degree. If that is the purpose, do not knock on my door.” My opinion, which I tell my students, is that knowing the fundamentals, knowing the basics – whatever area you work in, climate economics or ecological sciences – addressing and studying climate change problems requires an interdisciplinary approach and sooner or later that person who is very much well-versed in the fundamentals of his or her own choice of areas will see the avenue directing to the major issue of climate change or climate science. So, I always emphasise that knowing the fundamental, knowing the basics is important and one should not avoid that first step. That is my message first to my students and to all young scientists.
CB: Final question, which of the other candidates would get your vote?
HL: That is a difficult question and I think that the IPCC deserves a good field of strong candidates and this is the probably a rare moment in IPCC history that the community has really an opportunity for a good choice for their new chairmanship. It’s good for the institution, and not only the institution but also for the community as a whole.
Image: Film camera. © wellphoto/Shutterstock.com.
This interview was conducted by Roz Pidcock via Skype on 13 September 2015.
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