Expert briefing on 1.5C

Exclusive Briefing on IPCC Special Report on 1.5°C

Transcript has been edited for clarity

Moderator: Good evening from Incheon and good morning to all of you back in the U.S. I’m Bridgette Burkholder and I’ll be moderating the call today. This call is being recorded and an audio file will be available upon request.

Moderator: The IPCC special report on 1.5° was approved on Saturday after a week-long session where scientists addressed government comments on the Summary for Policymakers. The report will be released on Monday, October 8 at 10:00 am Korean time, that’s 9:00 pm Eastern time today [Sunday], for you folks in the States, about thirteen hours from right now. The report is embargoed until that time. On this call, we’ll hear from three authors of the report. Their comments are also embargoed until 9:00 pm Eastern time today, when the report is officially released. So, we have with us on the call Natalie Mahowald, lead author of Chapter One of the report and an author of the Summary for Policymakers. We have Kristie Ebi, lead author of Chapter Three and an author of the SPM. And we have Bill Solecki, coordinating lead author of Chapter One and an SPM author as well. Thank you all so much for joining us.

Moderator: There will be time for question and answer after the speaking lineup has concluded. If you’ve joined online, you can ask a question by clicking the Ask a Question button which should be at the top of your screen. That will put you in a queue and I will read your questions aloud to the panel. If you’ve joined on the phone, you’ll need to email your questions to Emma Stieglitz. Her email address is listed in the advisory that you received for this briefing. And I will reprompt for questions at the end of the speaking order.

Moderator: Without further ado, let’s hear from our panel. We’ll start with Natalie Mahowald. Natalie, over to you.

Natalie Mahowald: Great. Well I want to start with just some general statements from the report. The scientific evidence is clear that human activities have caused 1.0° Celsius of global warming since the late 1800s. The current trend suggests that if we keep warming at the same rate, we will pass 1.5° Celsius around 2040. Past emissions alone, however, are unlikely to cause 1.5° of warming. In other words, if we can cut net emissions quickly enough, we can keep temperatures below 1.5° Celsius warming, above pre-industrial.

Natalie Mahowald: Emissions reductions voluntarily agreed to by different countries as part of the Paris Agreement are not enough to keep the temperatures below 1.5°C, but rather suggest a global warming of perhaps 3°C. Ambitious mitigation will be required to keep climate change below 1.5°C global warming. This means conversion to sustainable energy, wind or solar for example, and sustainable agricultural practices, need to be done as quickly as possible.

Natalie Mahowald: Changes in behavior such as energy conservation or shifts in diet can make a huge difference in cutting emissions. In addition, development of new technologies or methods to remove carbon dioxide from the atmosphere may well be required to keep global warming below 1.5°C.

Natalie Mahowald: We are already seeing the result of climate change on extreme events, for example, an increase in the intensity of precipitation or increased heat waves and droughts. The climate impacts on 1.5° global warming are less than that from 2.0°C or higher temperatures. The lower we can keep the global warming, the less climate impacts there will be.

Natalie Mahowald: Adaptation to climate change at 1.5°C is much easier than at higher temperatures, but will still be required in cities, agricultural lands, and especially low lying regions. Poor and vulnerable will be much more able to adapt to a global warming of 1.5°C than higher warming levels. Ambitious cuts in emissions can be consistent with ensuring people around the world are healthy, prosperous, and have food, clean air, and water. Limiting warming to 1.5°C can go hand in hand with achieving other goals that we have.

Natalie Mahowald: While much more action needs to be undertaken, the good news is that there is the beginning of momentum in many of these areas to make these ambitious changes happen and save us from the worst impacts of climate change. Thank you.

Moderator: Thank you Natalie. And next we’ll hear from Kristie Ebi. Over to you, Kristie.

Kristie Ebi: Thank you, and thank you to Natalie for providing a comprehensive overview. I’d like to provide a few more details on what Natalie just said. As you heard, the earth’s temperature has already increased by 1°C, and with that warming we have seen impacts attributable to climate change in human and natural systems. In other words, the warming has already caused adverse consequences. As she said, as the earth continues to warm, for many human and natural systems, or ecosystems for biodiversity, for human health, the magnitude and pattern of those impacts are projected to increase.

Kristie Ebi: For most of them, the projected risks will continue to increase further to 2°C. It’s not true for all of the systems, but it’s true for most of them. The timing of when we hit these various temperature end points–hopefully they will be end points–the timing when we reach particular temperatures are critically important for understanding how big a challenge it will be to prepare for and manage the change and risk. If the earth warms to 1.5°C by 2030, that is a very rapid increase in temperature. It will be very difficult to be able to adapt fast enough. Similarly with 2°C.

Kristie Ebi: So the level of ambition for adaptation is intimately intertwined with the level of ambition for mitigation. And, as Natalie mentioned, there is many opportunities for both adaptation and mitigation. There are a wide range of options available. Some of them are being deployed, more are being developed, that can help countries and communities be better prepared and to reduce our greenhouse gas emissions.

Kristie Ebi: And these are tied with achieving the sustainable development goals and other aspirational goals that countries have agreed to. So the report ties together not just the scientific information on the impacts of 1.5°C and 2°C, but how these are interconnected with our economies, with our aspirational goals for moving into a world that is more sustainable and is more equitable, where we see a reduction in poverty and in disadvantage around the world. Thank you.

Moderator: Thank you Kris. Last we’ll hear from Bill Solecki. Bill?

Bill Solecki: Okay. Great, thanks. here are a few words. So I just assume my two colleagues have said much of the critical points, so I’ll just highlight some of these key messages–just to sort of burn them in a little bit–In some ways the report defines a benchmark of what we know with respect to the science of climate change, bringing forward results from previous assessments, but also bringing forward that most recent literature as well.

Bill Solecki: It’s clear that there’s a wide diversity of impacts ongoing already with respect to this 1°C of warming. In that context, it, it brings up that question about 1.5°C, and is that possible to respond. And I think what the report leads to is that there will be challenges, but as Kris and Natalie have mentioned, some of the technologies, the pieces of infrastructure, are present to potentially achieve that goal of 1.5°C.

Bill Solecki: Another key message coming from this tension between the 1.5°C and 2°C. Of course, Paris talks about below 2°C. The report contributes well to the argument that, there are clear benefits to sort of moving toward 1.5°C as opposed to 2°C. That kind of context is an important part of the discussion. To highlight one other point that Kris raised as well is this issue of synergies. One of the critical thematic elements that the report tries to reflect on is that of course the world’s economies, the world’s populations, the process of urbanization is such that these are sort of large-scale ongoing trends.

Bill Solecki: And the question is how to best connect with these trends to promote synergies to enable us to achieve some of the statements bound up in the assessment process. There’s an element of understanding the opportunity and some of the technical capacities for mitigation. This report also speaks at a significant level about the opportunities and needs for adaptation.

Bill Solecki: It also recognizes that, certainly there’s a global perspective to this, but there are regional processes, regional contexts that are critical and each of which need to be understood moving forward. It’s taking from the results and embedding that into potential practice.

Bill Solecki: The issue of equity is going to be critical not only in terms of context for response and adaptation, impacts of adaptation, and also the impacts of mitigation strategies as well. A lot of that in terms of this larger envelope question of feasibility and enabling conditions speaks to a broad set of social, cultural, and institutional approaches that need to be examined in the context of potentially, addressing the question of 1.5°C. Thank you.

Moderator: Thank you Bill. Now we’ll turn to question and answer. For the listeners, just click the Ask a Question button at the top of the screen if you’ve joined online. If you’re on the phone, you can email your questions to Emma Stieglitz, and her email address was in the media advisory that you received.

Moderator: We’ve already got a couple questions here. I would just like to again remind our panelists please introduce yourself when you answer so that folks know who you are on the phone. Our first question is from Seth Borenstein at AP. Seth asks, “Given how much warming there is already and how only a handful of the scenarios will limit warming to 1.5°C without overshoot, how feasible would you say it is to look at limiting warming to 1.5°C, or is this an academic exercise with little reality? And how much more, if any, does the Trump administration’s withdrawal from the Paris Agreement and pro-coal policies make it more unlikely to limit to 1.5°C. And if so, by how much?” That’s from Seth at AP. So, panelists, I will turn that over to you, and happy to repeat if necessary.

Natalie Mahowald: I can start by addressing the second question. This is a scientific report looking at compiling the science of what it would take to get to 1.5°C, and within the IPCC, we do not evaluate particular governments’ policies or discuss them. So that’s not really a question that the report addresses. On the first question, the report goes through quite a bit of effort to think about the different ways to think about the feasibility of this question and exactly what the different conditions are that would allow 1.5°C to be met. Bill in particular worked more on that section, so he would be in a better position to go through the details on that.

Bill Solecki: This is Bill. Uh, thanks Natalie. So the report obviously attempts to define a set of conditions of everything from the geophysical constraints in terms of how much carbon is already bound up in the environment, or greenhouse gas emission equivalents, all the way through institutional adjustments. Each of those six sets of enabling, or components of feasibility were evaluated and assessed, based on the literature. The outcome of that analysis is such that each of those feasibility components are defined elements through which they can be achieved.

Bill Solecki: Of course we’re not dictating or illustrating probabilities or capacities, but illustrating their presence. How that then is translated into action is a next part of a process.

Kristie Ebi: The other side of what Seth brought forward–and by the way, hello, Seth–is that there are models. These are models, they’re not reality, they’re models. There are models where it is possible to stay below 1.5°C. It doesn’t say that it’s easy, but it does say that it is possible. So there’s a clear message from the report that it is possible to keep global mean surface temperature from increasing above 1.5°C. That is now in the hands of the policymakers for their action, their decision. And that will certainly be discussed at the upcoming Conference of the Parties of the UNFCCC starting in December.

Moderator: Thank you panelists. Now I’m gonna go to a question on the phone. This is from Chris Mooney at the Washington Post, who asks, “Can you explain why the IPCC gave two separate budgets?”

Natalie Mahowald: Are we talking about the carbon budget? Is that what the question is?

Kristie Ebi: Yes, Bridgette.

Natalie Mahowald: So, I can speak a little bit to the carbon budgets. There are multiple ways to calculate the carbon budgets, and there’s always uncertainty in all of these. If you look carefully at them, and you compare them to what we would do if we were on a business-as-usual scenario, or, something where we’re not trying to cut emissions, they’re actually very, very similar and they give the same answer about what we have to do right now, which is everything we possibly can. We need very ambitious mitigation. So two slightly different budgets don’t at all change the big picture of what’s going on here.

Moderator: Thank you. Do any or our other panelists want to speak to that point?

Kristie Ebi: Natalie covered it well.

Bill Solecki: Agreed.

Moderator: Another question from, from Seth at the AP. Kristie, this is for you. “How is this a life-or-death issue for many people? Can you elaborate on that point?”

Kristie Ebi: People are already suffering and dying from climate change. There are detection and attribution studies showing that climate change is affecting human health and well-being. As temperatures rise, the projections are clear that the number of people will be much higher. At 2°C it’ll be even higher than that. There are concerns in particular about undernutrition, our food security could be affected with a- with additional climate change.

Kristie Ebi: And it’s not just the availability of cereal crops, which is what most of the world relies on. But it’s also the quality–the nutritional quality–of those crops. Higher carbon dioxide concentrations in the atmosphere are reducing the nutritional quality of rice and wheat. And hundreds of millions of people rely on those. This is not through a climate change pathway. This is a direct effect of carbon dioxide. So deep concerns about undernutrition. As you heard from Natalie, increases in the frequency, intensity, and duration of many extreme events, you can just look at what you’ve written over the last six months of the number of extreme events, the number of people who’ve been affected. There are concerns about vector-borne diseases, changing their range, projections for malaria and dengue fever, and along with dengue fever would be Zika, chikungunya, and possibly yellow fever, are likely to increase with the changing climate. There’s some other vector-borne diseases whose ranges could be smaller as places become too hot and too dry. There are also concerns about heat and both heat-related mortality and, as places become increasingly hot, of how it could affect overall worker productivity.

Kristie Ebi: There’s many potential impacts of a changing climate on human health and well-being that were not assessed in the report because there’s not literature that projects the differences in risk at 1.5°C and 2°C. So overall, I would estimate that what we said in the report is an underestimate. We do not give the full breadth and depth of the possible challenges.

Kristie Ebi: And I also should point out that the literature, the scientific literature, does not yet integrate as well as it needs to across different sectors. So for example: ozone. As ozone concentrations go up, there are impacts on human health. There are also impacts for crops. Those have not been integrated to understand how higher ozone could affect both our food and our nutrition in ways that would allow us to be more effective in preventing as much of those impacts as we could. There’s other issues that were not covered, again, in the report because we just didn’t have the literature.

Kristie Ebi: So there’s more work that needs to be done to understand what we’re going to have to adapt to if we can’t mitigate fast enough.

Moderator: Thank you. And Seth followed up to ask for maybe a one sentence sound bite of that answer, if you don’t mind.

Kristie Ebi: (laughs) Seth always asks really good questions. Human health is already being affected by climate change. It will be affected more in the future. Let’s not say will. The projections are that it will be affected more as temperatures continue to rise. How fast they rise will be very important for the level of adaptation ambition that will be required to protect and promote human health.

Moderator: Great, thank you. This is from Brain Kahn at Earther. And Brian asks, “What does considering ethics and equity look like in terms of implementing policies on the ground, and what institutions and frameworks are there to help ensure that they’re considered?”

Bill Solecki: Sure. So, obviously the question is referencing, that issues of ethics and equity need to be engaged with. It speaks to a couple of broad approaches. One, in terms of the notion that the impacts will be across the world and within the different regions, and recognition of the question of differential exposure and vulnerability.

Bill Solecki: But there’s a consideration, of a procedural element as well to ask questions about how and under what context responses, and capacity to respond to both mitigation and adaptation questions can engage across segments of society. The report speaks to those kinds of questions. It examines them in broad sectoral elements in terms of potential sort of transitions. It speaks to them regarding possibilities of integrating mitigation and adaptation to larger questions of sustainable development  across global concerns, but also within a range of difference in social scales, uh, going down even to, in some cases, discussion opportunities at the community scale.

Bill Solecki: But most of the approaches are looking at how the questions of equity and ethics are embedded in a process of feasibility. Responding to opportunities to create a 1.5°C world. And a lot of that goes into considerations of the social dimensions, institutional dimensions, and financing questions. Now of course, the latter part of the question is about what is present. Obviously the report process is attempting to assess conditions that are available and to review literature that speaks to other opportunities. It doesn’t provide a kind of a prescriptive statement on a set of steps per se.

Bill Solecki: But it recognizes that these sorts of engagements of equity and ethics are present in obviously in some cases in a lot of the discussion about sustainable development. And the, these are then highlighted as potential opportunities.

Kristie Ebi: And I would just add to that, saying the same thing slightly differently, that right now it’s the poor who are being affected. We see that particularly with extreme weather events. And typically, the poor produce the, the fewest amount of greenhouse gas emissions. So as temperatures increase, and if we his 1.5°C above pre-industrial within two decades, it’s a very rapid rise in temperature. They’ll be associated with that a very rapid rise in extreme events. And it will continue to be the poor who will be most affected.

Kristie Ebi: And so the report very clearly talks about these equity issues because, under the framework conventions you will know there’s common, differentiated responsibilities. And it looks at those squarely of what could be the consequences, and as Bill said, what are the opportunities to try and reduce those distributional impacts using a variety of different mitigation and adaptation options.

Moderator: Thank you both. We have a few more questions in the cue. I think some pieces of this have been answered already, but if there are any more that the panelists would like to highlight. Which impacts are much lower at 1.5°C  than 2°C?. Which do you think are the most important and least talked about? Can you elaborate on those?

Kristie Ebi: Almost all of the impacts are lower at 1.5°C than at 2°C. And looking across the report, which built very much on what was assessed in the fifth assessment report, we’re looking at a century that will face challenges with food and water security. Those challenges will be much larger at 1.5°C than they are today, and they’ll be even more difficult at 2°C. Of course, when you start talking about food and water security that intimately affects our health, so human health is part of that, it also is very intimately connected with energy, and how we produce and use our energy.

Kristie Ebi: So we’re looking at impacts across our economies in a variety of different ways. And we need to ensure that people have access to sufficient food and water. And without that, the consequences could be very difficult to manage.

Moderator: Bill or Natalie, would either of you like to come in on that question?

Natalie Mahowald: I could say a little bit about some of the new methodologies that have been developed actually since the last report in 2013 where, from a physical climate perspective, highlighted in this report, the new studies really show that we can tell the difference in the extremes between 1.5°C and 2°C degrees. That there is a statistical significance between those, and people will feel the difference between those. And that’s not only based on the previous studies, but new literature coming out.

Moderator: Thank you. We have a question from Chris Joyce at NPR who asks, for all the panelists, “Your comments seem rosier than the report. Emissions need to come down 40-50% by 2030 and carbon neutrality needs to be reached by 2050. This is a huge undertaking. The IPCC must have talked about the probability of reaching these goals. What’s your view on the probability rather than the possibility?”

Kristie Ebi: I will have a slightly flippant answer. One of the jokes going around here is, we were asked to do an impossible task to produce an IPCC report with 90 authors and review editors. They assessed 6,000 publications in a shorter time than any IPCC report has ever been produced. And if we can do this, the world governments should get onboard and do it too.

Natalie Mahowald: (laughs). I guess I would say that we have a monumental task in front of us, but it is not impossible.

Bill Solecki: Yes. And I would concur. I mean, again, the overarching statement of challenge, but potential is a huge theme in the report. And I think this is slightly outside the report, but embedded in, there is discussion of transitions, and transformations, and to Kris’ point about what is possible, we can examine how we’ve tried to, how societies have changed before, and transitions can happen. We don’t talk about probabilities in the context of the report. But certainly we lay out where some opportunities might lie.

Natalie Mahowald: The world years ago was really different then today. And, in 50 years it’s gonna be very different, you know, in the future also. So this is our change to decide what that world will look like. Some of the transitions that need to occur in order to keep temperatures below 1.5°C are very large. But a lot of these would occur anyway. You know, there’s so much going on. So it’s a question of deciding where we wanna go, and, and how to get there.

Bill Solecki: Could I jump in real quickly, I mean, to Kris’ point as well, you know, they’ll be multiple potential co-benefits in aggressively addressing this question. Obviously the issue of reducing impacts and enhancing opportunities for human life. But also potentially connecting with these other larger scale trends that press us. Things like sustainable development. Things like inequity, economic inequity. The rapid process, as I mentioned earlier of urbanization, can afford some clear opportunities for integrating some of these mitigation approaches. So I think that we need to recognize the challenge is clear, but the potential synergies lay in front of us as well–positive synergies.

Kristie Ebi: And I’d like to add to that, that some of these transitions are underway now. That when you look at certain countries–the number of electric vehicles has exploded in a very short period of time–that these transitions are underway. And so this calls for an acceleration of those transitions. The second part I’d like to add specifically, Bill, to what you had to say. There’s a growing literature base calculation the health co-benefits of mitigation policies and technologies that most of the mitigation policies have benefits for health, and they have benefits for health today. That as you reduce emissions of greenhouse gases for coal fired power plants, from tailpipes, that benefits our health now. And the estimates of those health co-benefits indicate, depends on the study specifically that you look at, but they are about the same order of magnitude as the cost of mitigation.

Kristie Ebi: So we should be mitigating to protect our health. We should get people out walking and biking because it helps reduce obesity, helps reduce blood pressure. And that’s good for people right now. And so there are opportunities within this report, as Bill said, of tying together a series of goals, and understanding that the transition we’re talking about in terms of adaptation and mitigation are important for achieving a whole range of goals. And they should be not separated from all the other goals our societies have.

Bill Solecki: I know we’re kind of piling on at this point, but I think that there’s an opportunity, there’s a chance. I mean, my quick thumbnail of this: you go around in the city subways of New York City, they were built by people who were born in the 19th century. We are “green” in New York because we have a great public transit system. We now have that opportunity. It’s a more compressed timeframe. You know, if we put forward a strategic set of responses there’s great opportunities for later in the century for enhanced sustainability.

Moderator: Thank you all for those great answers. Another question from Andrew Freedman at Axios. Andrew asks, “There are only a couple of emissions pathways that don’t involve large scale use of CCS and carbon removal. And they appear to show drops in fossil fuel use that would outpace even the most aggressive scenarios from all the major energy analysis groups. How would you characterize what would be needed so as to not rely on technology that is still in its infancy.”

Natalie Mahowald: Well, we do need to move to new sources of energy that aren’t as carbon intensive very quickly to avoid carbon dioxide removal methods. But I would argue, we probably should also be investing in research and development of carbon dioxide removal methods more. The only ones used in the report, well, um, some of the methods have clear co-benefits, just like the co-benefits of mitigation on the energy sector side. The co-benefits of allowing carbon uptake into soils is, you get more fertile soils. This is a great idea for agriculture. So that’s one method of carbon dioxide removal is just changing the way you manage your soils. Um, which again gives yue resilience in your agricultural system.

Natalie Mahowald: Maintaining forests is also a really great way to sequester more carbon, or stop the loss of carbon. And of course it allows for more biodiversity, for example. So those are methods for removing carbon dioxide from the atmosphere. But there are more methods that potentially could be developed, and more technologies that we could think about to make it so our economies aren’t emitting carbon dioxide, but rather sequestering carbon dioxide. So that’s an area that we probably should be thinking about also. The technologies that are in the report now may not be the ones that we would choose to use.

Natalie Mahowald: On the other hand, trying to scale up the energy systems to more sustainable as quickly as possible is hugely important. But some of the scenarios also point out changes in behavior or lifestyles that can make a huge difference to make it so we don’t have to rely on carbon dioxide removal. So there, there’s a lot of different ways that to achieve the goals we want and probably we should be doing everything we can. That’s the main thing about getting to 1.5°C, is just how aggressively we have to act in every different sector of our society.

Kristie Ebi: I’d like to say, underscore something Natalie just said is, there persists a perspective that somehow there’s one solution to climate change. And there’s not. There’s a million solutions. And when you look at each one of these, they can be relatively small. It’s when you put them together that they become large and powerful. And so the report lays out hundreds of different options that can be used to mitigate, and to adapt. And it’s not going to be a selection of one or two. We’re gonna need to do all of them. And we’ll need to do them in different combinations in different places. There’s different opportunities in the small island states than there are on the United States. And so it is putting forward these enormous baskets of possibilities. And you do need to do as much as you can of all of them, and what is going to happen in any one place will depend on their local context.

Kristie Ebi: But it is a very positive statement that there’s lots of tools in this toolkit. And people can start implementing now that they’re ready to implement, and think about what they need to do about their policies so they can pick up and implement more of these options and go forward.

Moderator: Great. Thank you. A question from Brian Conn at Earther. “An earlier draft of the Summary for Policymakers touched briefly on climate and conflict. The final doesn’t. Is there a reason it’s not in the final SPM?”

Kristie Ebi: The literature base on climate and conflict is incredibly limited, which means that statements about climate and conflict have low confidence. And we don’t put low confidence statements into the Summary for Policymakers.

Moderator: And so maybe just to follow up on that, can you clarify if they are addressed in the underlying report?

Kristie Ebi: Yes, they are addressed in the underlying report. So the very little literature that is available is in Chapter Three, and it was a decision from the authors on Chapter Three, because there’s low confidence, to not put that forward in subsequent versions of the Summary for Policymakers.

Moderator: Thank you. I don’t see any more questions now. I will give it a minute to see if anyone has last minute issues on their minds. All right. One more question coming in from Seth. “So is it fair to call this a life or death issue?”

Natalie Mahowald: That’s a tough question, Seth. It’s, it’s a critically important issue, and as we’ve emphasized throughout our answers, climate change is embedded in so many other decisions. And this report focuses, of course, on climate change. It does touch on the whole range of ambitions the world is trying to achieve. And you can’t actually pull climate change out separate from access to safe water, in terms of food security. There’s all enmeshed. It’s incredibly important. So, yes, it is incredibly important. I can’t answer whether it’s life or death.

Bill Solecki: No. I mean, for me, like getting out of bed is life or death, right? You know, it’s just like, everything is. But, in direct response, circling back to Natalie’s intro comments, the issue of extreme events, and also Kris’ point about declines in productivity in agriculture. These are potentially profound implications of what the science models and projections are presenting. We’ve already seen evidence of that over the last several years with, with extreme events that, you know, are they climate change? It’s hard to say, but are they listed under the conditions under which climate change could occur? You could probably say some of that. And that we see the impacts coming from those sorts of events as a sort of, um, a potential foreshadowing.

Bill Solecki: So, you know, getting to this question of life and death, there is a process, AR5 illustrated this and, and certainly this assessment and subsequent assessments, it’s a process underway of eating away at some levels of the economic infrastructure, the capacity for quality of life, the social reproduction of societies in various places, not to sound too academic. That will increase with projected shifts in temperature. Those will have significant implications for a variety of places, and for a variety of systems. Those that are more vulnerable, those that are more exposed will lack capacity to respond. And that will set off increasing sets of questions about how to address that at the local, regional and increasingly global scale.

Bill Solecki: This is not a question that goes away. It’s something that we, in this report, provide a benchmarking of what we know right now. The idea of looking at that and accepting that with clarity, but also with the notion that there are clear synergistic opportunities out there. So life and death is of course a heavy, heavy concept. I think certainly we could see that the everyday quality of life of individuals has already been affected, in many cases negatively, by climate change. And the prospects for more are in the future unless addressed.

Natalie Mahowald: I would answer the question maybe a little shorter. For some people this is a life or death situation, without a doubt.

Kristie Ebi: I’ll come back again to, you’re probably asking the wrong people in the sense that we’re scientists. And I would probably characterize all of us as worried optimists. If we didn’t have some optimism, we wouldn’t put the effort we put into, and as you well know, this is an unpaid activity. So I estimate I probably put in 2,000 volunteer hours on this. Those are nights, those are weekends. And I wouldn’t be willing to do that if there wasn’t some optimism that the human race could step up and face the challenge in front of us.

Kristie Ebi: If you wanna get a life or death question, you might go ask people who are the pure optimists. You might go ask people who are the pure pessimists. You’ll get a range of answers. But certainly for the authors of the report, we wouldn’t be willing to make the efforts that we have made if we didn’t think there’s a possibility.

Moderator: Thank you. One more question in the cue. This is from Akshat Rathi at Quartz who asks, “The report recommends the use of different technologies, but it doesn’t recommend economic tools. Why? Specifically, economists have shown that global carbon price would be the most effective way to act on climate. Would another IPCC report focus on that?”

Kristie Ebi: The short answer is, that will be done in the AR6. The mandate for this report was to look at the impacts of global warming at 1.5°C and 2°C. So that was outside the mandate of the report. And I will say, the mandate of the report was fairly large. But this is not a mini AR6, and the AR6 will assess that literature and come back with what they find looking across what’s been published since the AR5.

Moderator: Thank you. We have one follow up question on the carbon budgets from Chris Mooney at the Washington Post. The question is, “there were two sets of carbon budget numbers. One budget is calibrated against observations of just air temperatures versus the budget that is calibrated against observations of air temperatures and sea surface temperatures. Why did you do that?”

Natalie Mahowald: Well, I’m afraid, scientists are scientists, and we like to do our calculations every different way that could be done to make sure we’ve done them right. And the main point is, it doesn’t matter which way we do it, that carbon budget is really quite small, and we need to act ambitiously right now, and start mitigating. It doesn’t matter which budget you use. I would say that’s why we did it multiple ways is, we love to check ourselves.

Kristie Ebi: And I’ll add slightly to that is that, observations are based on measurements of temperature over the land. But we don’t actually have measurement systems over the ocean. And so the, how much the global surface temperature has changed is based on both these temperatures over land–you can also measure temperatures over ice–but sea surface temperature for the ocean. The climate models project temperature over land and over ocean. And there is a slight difference between them. It was important, as Natalie said, to calculate the carbon budget both ways to make sure that it didn’t make much difference. Because otherwise, the question would come back of, ‘if you calculated it that way, would we get a different answer?’ As Natalie said, ‘Nope. Didn’t really get a different answer.’ They both underscore the importance of mitigating quickly across economies.

Moderator: Thank you for that clarification. To each panelist, what impact do you expect the report to have on global policy making? Not what you’d like to see, but what you expect will happen.

Natalie Mahowald: I have to admit, I hadn’t thought that far. (laughter). We haven’t slept for a while, a year or so.

Kristie Ebi: The sleep was pretty amazing. And certainly this is going to, this is now in the hands of the governments. And they will start using this. And it was very clear, one of the reasons that we slept so little this week is, the world governments really care about what’s in this report. They wanted it clear. They wanted to make sure it reflected what was in the underlying chapters. That’s why we spent so much time going carefully through each line of this report. And this is a science policy interface. As scientists, we are now done. And it’s now in the hands of governments. And governments have signed off. There’s about 140 governments present, and they have signed off on every line, on every word in this report. And so this is now going back to each government for them to think about how they’re gonna reflect this in their policies. And of course, what I hope is that they will rapidly take this up. My expectation is that my hopes will be realized. We’ll find out. Natalie?

Natalie Mahowald: It’s actually in the remit was actually to think about the context of strengthening the global response. So actually the report itself is supposed to talk about how to strengthen the global response. So, whether the release of the report directly, or the use of the assessment in the report may also strengthen the global response. I expect it to help in moving governments and people in the direction that we need to go. I certainly hope so as well.

Bill Solecki: I think there are multiple facets to what might happen. Obviously some governments might carry it forward than others. But I think what’s also gonna be important, not only is how governments take it up, but all the other non-state actors, non- national level actors, certainly many, jurisdictional contacts within countries, states, provinces, cities, etc., are looking forward to what this report might have to say.

Bill Solecki: So I think there’s going to be an interesting interplay between all of those actors and the interpretation. It’s certainly the governments, and obviously that’s, that’s the “client” here. But I think there are multiple other perspectives and interests that will be addressed, and that will in turn create a larger discussion. That’s my hope. And I think that’s my expectation. That’s my expectation, my hope, of what this report will provide.

Moderator: I have no more questions in the cue, and we’re at the top of the hour. So with that I would just really like to thank all the panelists for joining. END CALL.