The Carbon Brief Interview: Dr Bill Hare

Dr Bill Hare is the co-founder and CEO of Climate Analytics, an international non-profit climate science and policy institute based in Germany. He is a physicist with three decades of experience in the science, impacts and policy responses to climate change and stratospheric ozone depletion. Hare was also a lead author of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report and has advised ministers from the Small Island Developing States and Least Developed Countries at the UNFCCC climate negotiations.

Carbon Brief: Let’s start with the 1.5C goal. Do you think the Donald Trump presidency has made limiting global warming to 1.5C basically impossible?

Bill Hare: No. Definitely not. I think that the actions by Trump are going to make the achievement of any climate target more difficult. There’s no doubt about that either, whether you’re talking about 2.5C let alone 1.5C, so I think it’s a problem. The question is, ultimately, how long does the US inaction go on for? So, in the next few years, the Trump Administration is not going to have a massive impact on global efforts. Apart from the direct emission impact, one of the problems that could happen with the US is if it really gets mobilised on pushing coal. That could become a big problem. If Trump manages to get a diplomatic profile going on carbon intensity of development, that could become a problem globally. But at this stage we haven’t seen any really big signs of that.

CB: In terms of the IPCC 1.5C special report coming out in October of 2018, is that coming too late to drive forward informed policy makers, or is that a vital document?

BH: It’s actually a vital document. I mean, it’s designed to be done in 2018 and to provide input to the facilitative dialogue, as it’s called [now called the Talanoa dialogue], which is actually a multilateral review of how countries are travelling toward the Paris Agreement that was agreed to be done in 2018. So the fact that there is an IPCC report on this issue is really quite fundamental, because the IPCC is going to show first where the impacts are huge. Many can be avoided at 1.5C that couldn’t be avoided at 2C, and that mitigation is possible, and not just possible, but will have large sustainable benefits. I am convinced that’s going to be very important in motivating countries to go further than they’ve already done or been able to do.

CB: In the new UN Environment emissions gap report, it only looks at a 50% chance of 1.5C, arguing that there were not enough models available to give it a viable path to 66%. In your mind, should the 1.5C target be interpreted as a 66% or 50% chance of avoiding warming?

BH: Well, that’s a good question. What the report has done is basically used what is in the literature. New scenarios have been submitted, and will be published, which actually achieve a goal of limiting warming throughout the 21st century to 1.5C with a decent probability, in some cases 66%. I think that from the point of view of the vulnerable countries, the 1.5C limit in the Paris Agreement was always seen as an upper limit. Of course, other countries have a different perspective and saw that the 1.5C limit could even be approached from above, but that’s very much constrained by what we agreed in the Paris Agreement. The “well below 2C” really means well below 2C, it doesn’t mean 1.8 or 1.9 or 1.7. So I think that’s a big constraint on policy.

At the time the 1.5C limit was adopted, I think the best pathways we had in the literature from complex integrated assessment models of energy and economy together were about a 50% probability, at best. But the new pathways take into account the massive drop in renewable energy prices, sort of all types, wind and so on. They’ve got to reveal that we could get to this limit faster and cheaper than we’d thought before.

CB: What in your view needs to happen by this time next year to keep the whole Paris Agreement on track in terms of 2018, and beyond that?

BH: At the international level, I think what’s kind of very important is that we maintain political momentum and political will to move forward, because that feeds into what governments are happy to do domestically, nationally. If we lost momentum internationally, if people began to think, well the Trump administration, for example, is going to go backwards and that means we’re all going to go backwards, that would not be a good outcome. But right now I don’t get a sense of that.

There is such a strong movement forward that I think we can maintain that through 2018 and I think the IPCC report is going to be very important for that. Then by the time we get to the end of next year we’ll see governments probably preparing to take further steps prior to 2020, which is the agreement the countries would put forward better, new proposals to get closer to the Paris Agreement limit by 2020.

Domestically, of course, important actors can send very important signals by moving forward. That means that, for example, the European Union discussions can be very important. If they are actually able to increase their level of ambition in the complex internal discussions underway now, and they do so by next year, that’s also going to send a strong signal. If China and India, particularly, keep moving forward in the direction they are going that’s going to overflow into a lot of positive benefits in other parts of the world. Because it will send a signal to countries like the Philippines, investing heavily in coal, or Turkey, or even some of the coal developments in Africa. This is simply not the way to go. It’s wrong, stop, go back, look at investing in renewables instead.

I think these multilateral processes moving forward in a positive way with a number of important actors nationally, continuing to move forward with purpose, vision, and real policies on the ground are going to have the biggest impact next year.

CB: As well as the 1.5C report next year, there is also a summit proposed in California and Macron in France has got one coming up later this year in December. What’s the importance of some of those events?

BH: Well, I think Macron’s summit in December is about maintaining momentum and confidence in the international system, so that’s good and it’s positive. I think the California Governor’s summit in September of 2018 is about bringing together the broader coalition of actors, cities, sub-national actors, as they call them. That is, states like California that are part of larger federations, and about bringing together businesses that are moving forward under one umbrella. I think the idea in California is to show that we can do it. That it’s got positive benefits, economic benefits, it can help save resources and money and provide really important employment opportunities for countries as well.

I think that is the whole idea is to maintain momentum. Of course, it occurs in a context where the Trump administration is going backwards on policy, so it will be a very important counterpoint to the Trump initiatives, to show that from a very American, Californian, can-do perspective that America is still moving forward and still playing a positive role in the world on this issue. I think the force of that can’t be underestimated.

CB: How important are the non-power sectors, such as transport, in meeting the Paris Agreement?

BH: Good question. The power sector and the transport sector need to be tightly coupled together, because the electrification of transport is the next big revolution coming. Not just cars, but trucks, buses, and so on. If you’re going to do that in a way that reduces emissions you have to make sure the power sector is prepared to go 100% clean and 100% renewable. So this is what is called an entire sector coupling. So these two sectors together are really fundamental.

Moving towards renewables in the power sector means coal being phased out very quickly, by the 2030s in developed countries, by 2050 at the latest in developing countries. It means oil demand will begin to be phased out quickly in an increasing number of countries as well. There you are going to remove very large fractions of the total carbon dioxide emissions quickly. So they are really fundamental.

The agriculture sector is more difficult. We don’t fully understand all of the options there. We know there are many different things that can be done, but every different agricultural context in each country is very different. Governments typically have a much harder time finding a way forward through the morass of different agricultural measures than they do in the energy sector. Now what that means is not to be pessimistic in the long term about our ability to reduce emissions from agriculture, just that it’s going to be slower and harder to actually achieve deep reductions in the sector over the next 50 or 100 years.

There are some scientists who have got some really good analysis about what we can do. Given the population growth and so on, a reasonably good outcome would be to hold emissions at present levels in the agriculture sector for the next decade or two until we are able to start reducing them.

CB: What is your opinion on negative emission technologies, such as BECCS?

BH: Well, it’s not really a matter of opinion. It’s a matter of physics, unfortunately. The prior question is do we need negative emissions, and if so, why? The problem is that because of the inaction to date, that is the amount of emissions that have been put into the atmosphere already due to lack of action in the last 10-15 years, and because of that fact there are sectors in which we see it difficult to reduce emissions, such as the one we just mentioned, agriculture, perhaps some industrial sectors. To meet a target like 2C and even more so for 1.5C, we’re going to have to take carbon dioxide out of the air.

Traditionally, we have focused on using forests, soils and so on to take up carbon and store it, and that surely is a significant part of the job. The problem is, it’s not enough. As a consequence, we are looking at technologies that will need to take carbon dioxide out of the air. They are often termed negative emission technologies. The technology of choice in the climate models, in the energy models, so far has been [BECCS, bioenergy with carbon capture and storage]. You grow biomass, which takes CO2 out of the air. You take the CO2 out of the power plant [inaudible 00:13:05]from the biomass, put it into the ground and repeat the cycle, and you’re essentially pumping CO2 out of the air and under ground.

I am not convinced that BECCS is likely to be the biggest future way of doing that. Everyone is aware of significant limitations on bioenergy for sustainable development, concerns and so on. It’s going to be a significant factor, but maybe not even the largest or the biggest. I think there are other technologies that can also take CO2 out of the air and I imagine there’s going to be a portfolio of different approaches.

CB: What would be another approach?

BH: Well, one that’s getting more interesting, principally because of the massive drop in the cost of photovoltaics, is carbon dioxide removal. Anyone of my generation involved in the energy business will tell you that this is horrendously expensive and will never happen. But the impending availability of large amounts of very cheap electricity from 100% renewable energy systems is meaning that the energy equation is changing. The technology and costs available to take CO2 directly from the air, carbon dioxide removal, through direct air capture is becoming more economically interesting, at scale in the future. That could also be, therefore, an option that many analysts, including myself, would have considered unreasonable, infeasible, too costly, just five years ago.

CB: What do you make of the SCoPEx geoengineering experiment being planned for next year in the US?

BH: I think, along with many physicists, or most physicists who have looked at this solar radiation management, it is a very dangerous technology. In many ways it would itself constitute dangerous interference with the climate system. I think these sort of experiments translated into policy are deeply unwise and deeply unhelpful. I think that there is very substantial uncertainties about the effects of solar radiation management technologies. We don’t understand their impacts at largescale on the monsoons, on precipitation, rainfall regimes. What we do understand about it tell us that we need to be profoundly concerned that these technologies could provoke really major damages in different regions.

What I’m also concerned about is the way in which this solar radiation management technology as a branch of geoengineering is being aggressively pushed now. It’s a real puzzle to me and a real shame, and a discredit to those pushing these, that they are at the very moment in which we are seeing fundamental changes beginning to happen in the energy system. Out there in their pamphlets, brochures, lectures and talks claiming that mitigation has failed, and, therefore, we need to look at these very dangerous technological approaches. I think that’s a serious mistake and error.

Some of the issues to do with solar radiation management include what is called the termination shock. That is, if you turn it off after some decades, then you will get a very rapid warming that will indeed be very shocking to human and natural systems. There are just some very fundamental issues that solar radiation management can’t deal with – ocean acidification, often forgotten and certainly overlooked by the solar radiation management advocates, is a very profound change to the Earth’s system. One which we just simply have to contain and reverse in the long term to maintain a habitable planet.

Solar radiation management, because it does not address carbon dioxide emissions, fails to deal with that issue completely. We won’t be able to run, we won’t be able to hide from that problem because it’s having a very profound effect on ocean ecosystems everywhere and will have very long lasting and damaging consequences unless we get that under control.

CB: Some of the people who talk about this say they need to do it for research purposes and say “we’re just at the research phase, that’s what we do”. What do you say in response to that? Should researchers be allowed to at least look at this?

BH: I think from a physics point of view there’s no case to oppose looking at some of the particular kinds of experiments. It’s a truth of this, though, that the people calling and doing these experiments are also promoting, in different ways, the use of solar radiation management and claiming that mitigation has failed. One is entitled to be frustrated and even angry about the inaction that has happened in recent years and continues to be a cause of concern in a number of countries.

On the other hand, it is also true that we are seeing a transformation taking hold in the world’s energy system. Coal emissions are dropping. That may continue. We’re seeing renewables come into countries where we never believed it possible, just from the point of view of the Climate Action Tracker where we are monitoring and calculating the effect of countries’ policies. We can scarcely keep up with some of the changes in some countries. It’s very hard to keep ahead of the curve in terms of what’s actually happening out there.

We’ve seen major reductions in our projections for Chinese emissions. Major reductions for India, perhaps more coming if they maintain momentum. These are very positive developments. They are going to have a much better outcome for people. If you look at the new from New Delhi on the massive air pollution episode there, solar radiation management isn’t going to help that. What is going to help that is a transition towards clean renewable energy systems with sustainable electric mobility. That’s going to have one of the most important ramifications will be improvements in human health and we shouldn’t overlook the very damaging effects of air pollution from coal and motor use is having on agricultural production in south Asia as well.

CB: Is 100% renewable, which is often painted as a vision, is that possible?

BH: It looks to be very possible. There’s not going to be a general answer to that everywhere [Clip 4: 2:23] but if you look at the scientific assessments that have been done of this, there are few technical obstacles to being able to run 100% renewable systems. There are important transitional challenges. They will vary very much by country and by region in order to get there. We are going to need, for example, as we move away from old coal-based systems to a fully renewable systems we will need, in many locations, to have natural gas come in to provide backup or provide peaking power for occasions when variable electricity and power from renewables isn’t available.

As storage systems become more widely available, and there’s a wide range, not just Tesla batteries of course, but there’s a wide range of storage systems that can be deployed over time, including pumped hydrostorage, gas storage, and so on. These technologies will slowly but surely replace even the need for natural gas peaking turbines. We can already see they are beginning to occur in some markets. Earlier this year, there was a competitive bid for power interests in Arizona, and interestingly photovoltaics and battery won that against what I would have guessed would have won, a peaking natural gas turbine.

We’re seeing several more cases like that happening as the costs of these technologies drops and as we importantly learn how to manage electricity grids. This is also something that people underestimate, is the important complexities in turning an old fossil fuel-based grid into a 100% renewable one. We’re talking about a digital transformation to a smart grid, which often requires changing the ways we think about electricity production and use. I think we’re seeing a lot of rapid learning in places, including the United Kingdom, or south Australia, and other places where we’re getting toward 50% renewables and electricity. Countries are learning how to manage that and finding there are actually great business opportunities in doing that.

CB: We often hear about natural gas being used as a bridging technology for the next 15 or 20 years, to buy us some time, with the priority being getting away from coal as fast as we can. You also hear about that we’re going to need nuclear for baseload. What are your view on those two issues?

BH: I think nuclear is too slow. You look at the modelling assessments of nuclear and most of them indicate that it’s too slow to be introduced, apart from all the safety and other issues, concerns about nuclear, to actually play a significant role in the 1.5C transition. Natural gas is a technology that will need to be deployed as part of a transitional framework, 10-15 years might be the timescale, actually. It might not have the same market potential as the natural gas industry hopes.

Typically, what we are seeing in the new generation of energy modelling is that we’re seeing the actual installed capacity, the potential power capacity of natural gas going up whilst the natural utilisation goes down. What that means is that natural gas is coming in the models and also in reality in order to meet single-event episodes where you need to turn on a gas turbine to replace a renewable system that might not be available at that time rather than running continuously and profitably over time.

As a consequence, you’re seeing governments begin to look at capacity markets or even buying and owning gas turbines so they can turn them on during a Christmas Day heatwave or whatever in order to keep the system running, but not in a fully commercial mode as we might have expected from experience over the last 20 years. It will be a very different environment for natural gas in a Paris Agreement pathway compared to what we have known in the last 20 years.

CB: What do you think are the key priorities for climate modellers in the decade ahead?

BH: Obviously, I’m concerned about what climate impacts we can avoid. I think one of the important issues is to be doing modelling of the climate system consequences of fully 1.5C pathways and maybe even more than that. To begin to understand how we prevent some of the major tipping point problems that we can already foresee coming even for 1.5C of warming. And to try and understand what it would take to protect and sustain important natural ecosystems, such as coral reefs, or to prevent ice sheet disintegration.

Apart from the normal progression of climate modelling to high resolution, better physics, having a smaller scale to give us better insights into all manner of temperature and weather extremes, which is very, very important and is ongoing and needs to be continued. I think in the strategic sense, it’s good to get a very good handle on just what we can actually avoid and what we can’t. That’s also going to provide a very important signal to mitigation policy. And a very important feedback on what governments are prepared to do.

One of the underdeveloped areas, including in IPCC assessment reports, is evaluating what are the avoidable impacts. It’s very hard to find a coherent survey of avoidable impacts in an IPCC assessment reports. I think we need to be getting at that so we can better inform policymakers about what the benefits are of taking some of the big transformational steps that whilst they might be economically beneficial are definitely going to cause political problems as incumbent power producers and others try and defend their turf.

CB: One of the issues that is often discussed within climate models is the value given for climate sensitivity. And it’s often something you see some climate sceptics talking about. In your view, what is the likely value for climate sensitivity for global warming from doubling of CO2?

BH: Good question. The first thing is that the climate sensitivity is an emergent property. It comes out of all the model components acting together. It’s been a long time since climate models assumed a climate sensitivity. I think it’s important to understand that the way in which our climate models encode our physical understanding of the system produces climate sensitivity or the response of the climate system to doubling of CO2, for example.

I personally think the evidence points towards climate sensitivity being at least on a 100-200 year timescale. The first steps of the changes are right around 3C. That’s just a personal opinion. I also think it’s fairly clear that the climate sensitivity increases with further warming; that it’s not a stable quantity. I grew up thinking that it was pretty much a stable quantity, but I think it’s been obvious from the science in the last 10 or 15 years that it’s actually not as likely to be increasing the further we warm the more sensitive the climate system will be. This is a feedback problem.

I think we are understanding that better. I don’t think the uncertainties about it are a fundamental obstacle to acting on climate change at all, as the sceptics claim. Some of the climate denialists are proposing climate sensitivities that are simply physically implausible, couldn’t be the case in reality at all, contradicting everything we know about the climate system.

CB: How low would that be? And for what reason?

BH: Some of them are talking about climate sensitivity at 1.2C, at 1.5C. I think this is completely implausible because the basic energetics of the climate system responding to the additional greenhouse gas emissions almost from simple physics, has to be at least 1.2C and possibly more before you begin to take into account any of the feedbacks in the system from water vapour in clouds and so on.

CB: The current assessment cycle of the IPCC is roughly 6-7 years, with occasional special reports in between. Is this the best way for it to be effective, in terms of the length of cycle, or are there better or other options?

BH: I personally think that the IPCC assessment cycle should be aligned with the [Paris Agreement’s] five-year global stocktake. I think that would involve restructuring somewhat the largescale assessments we do in the IPCC context. I believe in the value of these largescale assessments, but I think they could be reduced in volume and size and, perhaps, more targeted. I think the IPCC should seriously reflect on how to achieve that. There are moves from some countries to have 7- or even 12-year assessment cycles, but I think that takes you right outside of the original purpose of the IPCC.

The IPCC was established from an idea by Professor Bert Bolin from Sweden to actually provide accurate, scientifically agreed advice to government to deal with the foreseen problems from climate change. That advice, therefore, needs to be tailored to politically relevant timescales. I would say a 10-year timescale is not politically relevant. It is certainly not relevant to the timescales of mitigation adjustments within the Paris Agreement, which are five years. If the IPCC is to be true to its purpose, and doesn’t become an animal with its own agenda, in a sense, running off serving the needs of a scientific community disconnected from policy, then I think it’s very important it actually comes back and looks very hard at how it can manage a five-year cycle.

I think a consequence of that would also to be to take some of the volume of work off the scientists as well, because you’re starting to reduce the scope, you’re tailoring it more to the outcome of what’s needed. I think you could actually reduce the volume of work involved.

CB: Is there a risk that this might effectively mean that it is serving a political purpose with these five-year stocktake cycles, at the risk of politicising the process?

BH: You could always have said that from the very beginning about the IPCC. Because it was set up in order to provide scientific advice to governments on specific timeframes for specific issues. That could be a fundamental critique you could make of the IPCC from day one, essentially. I don’t think it’s valid. The IPCC is essentially an agreement between governments and the scientific community to come to a common understanding on what the science means. If you look at how the IPCC works then the summary for policymakers are negotiated line by line, comma by comma sometimes.

That reaches an agreed outcome between the world’s governments represented at the IPCC and the world’s scientific community who prepared the reports. That’s always been the case. That’s been the value of the IPCC, because then it means that a government can’t come and say we don’t believe this, because they’ve agreed to it. They’ve agreed on a common understanding about what the science means. You can say that process is political and at some level it is, but the integrity of the IPCC process has been that at the end of the day the IPCC check and say I don’t accept what governments are trying to force into our report. That’s how it’s worked historically. The scientific process is being defended by the integrity of its assessment exercises.

CB: You’ve been a scientific advisor for countries on the frontlines of climate change, including in a delegation. Why do you take on that role? What insights have you gained from it?

BH: I guess I got involved with this initially because of the awareness that there were countries that were much more vulnerable. Of course, in the late ’80s and early ’90s small [island] states were on the frontline of that. You can see that from the sea level rise projections and you can see that from of the other climate modelling assessments. I was very motivated to help with the alliances going on in the states. The more I’ve learned about the problems they confront, the more it’s been a motivation to remain involved and try to provide state-of-the-art scientific advice to them on defending their interests and advancing their agendas in the climate negotiations.

Of course, we now know that many other countries are very vulnerable, the least developed countries as well. I’ve also worked to help provide them with first-rate scientific advice. That’s also brought upon the observation, throughout my experience over all the years of these negotiations, that often it was the richer countries that had better scientific advice and better analysis and could effectively outmanoeuvre on important issues, smaller countries. So I thought it was a basic issue of fairness there. I felt that the scientific community could do a lot by mobilising really smart scientists to work to help advise countries in this position to actually overcome that gap. I think we’ve been very effective in doing so.

That doesn’t mean, of course, governments like to hear what scientists sometimes have to say. Like any scientists working in a policy environment, you will always come across situations where governments don’t want to hear what you have to say and you just have to accept that.

CB: You do have an almost unique experience of seeing how science is, to some degree, commissioned in the negotiating process. Can you think of any direct examples of how that goes about? How, as you say, some countries receive that advice from scientists and all the opportunities and problems along the way?

BH: I guess one clear example is 1.5C. I remember very clearly proudly presenting the IPCC assessment report to – which we’d just finished, of course – to the small island states in 2007 or 2008 and being confronted with a stunned silence. What was the problem? The problem was that the impacts we were showing, at the lowest emissions pathways we had then were 2C, were a bit hard to swallow for those countries. So then they started at us saying, “You know, that’s horrible. Can’t we do better than that?”

We said there really aren’t many other scenarios that go lower than this. We don’t really understand what we can avoid. We talked to other scientists and got together and did some analyses and then presented at another meeting. Well, actually, if we looked at this we could avoid a bit of this. They begin to say: “Well, OK, great. Come back with another review and we’ll think about it.”

My colleagues and I went to a meeting of the alliance of smaller states in Singapore at the end of 2008 armed with a bit more science that we’d done and said, “Well, maybe we could avoid some more impacts.” We went: “At 1.5C, we don’t know. We need to do some more science.” Then we had to leave the room because the parties were disgusted. A little while later we found out they adopted the 1.5C position, so we thought: “OK, that’s interesting. What can we do about that? From the scientific community, what can we do to look at this position that they are now talking about in terms of feasibility, about avoiding impacts, and so on.”

When we first started talking about it many scientists thought we were crazy. “Where did this come from? Did this come out of thin air? We already talked about 2C. How can we be told there is a difference?” We slowly worked on that. As you do in the scientific community, nothing ever happens quickly. We progressed the methodologies and so on. We’ve begun to get a clearer picture that actually you could say a lot more about a half-degree difference. We also realised what we’ve observed to date is actually about a half-degree of warming.

What we really know about half a degree we can see in the observational record, and for many it is not particularly good. We can already begin to draw conclusions about that, so putting the observation and modelling side together we begin to see you can do a lot more. And see a lot more avoided damages by limiting warming to a bit lower than 2C.

CB: In clear terms, in your view, what is the difference between 1.5C and 2C in terms of impact for a low-lying island state, for example?

BH: It could be the difference between survival and non-survival, depending upon what happens to the sea level rise equation. Some of the recent modelling would say that if you can limit warming to 1.5C, or ultimately lower, you’re going to be able to limit and reduce or even prevent massive ice sheet disintegration. Which means you’re still confronted with a possible sea level rise of half a metre or more in the longer term, but not with multi-metre sea level rise.

Whereas, if you’re going towards 2C then maybe you’ve tipped the Greenland ice sheet. Maybe you’ve caused enough heat to be moved south through the southern ocean to Antarctica and tipped parts of the Antarctic ice sheet. That’s a big risk that you could limit by staying to 1.5C. In terms of more mundane issues like fresh water availability, the new modelling is showing that you can avoid really substantial risks to freshwater by limiting warming to 1.5C in many of the regions, compared to 2C.

That’s one of the common denominators we are finding out of a lot of the research is that the risk escalates surprisingly rapidly with every half degree of warming. It’s not a linear rise. We’re seeing a nonlinear impact in many cases. Not all cases, but in many important cases we’re seeing a nonlinear increase risk with increasing global surface temperature.

CB: You’ve also had a role with NGOs like Greenpeace. What’s the difference between inputting science into an NGO versus inputting science into the negotiating process?

BH: From an NGO, or working within an NGO, like Greenpeace, the challenges for scientists are also there. You have people who want to advocate a certain position and they want science to justify it. That’s a common issue, even in government. As a scientist working in Greenpeace it was always a challenge to make sure that the science was honest and wasn’t just out there to support a particular position. That doesn’t make you friends all the time, but in the long scheme of things it was very important.

As an advocacy organisation, one is much freer to express views and speak truth to power. And free to act on one’s own judgement in making comments or interpretations about issues. Advising governments is very different because you are advising governments and governments can take, or not take the advice you’re offering and will want to frame that advice in the way that is best suited to their interests or understanding. You have to take much more of a backseat role in advising governments and understanding intimately what they’re interests are and how to provide policy-relevant scientific analysis for them that meets their needs when they need it. There are challenges there are well.

Sometimes you simply can’t do it. The science isn’t available or the science won’t justify what the government wants to see. As a scientist, you simply have to say that to government. “Well, that’s great, but you’re not going to get that support from the scientific community.”

CB: You also co-founded with climate scientists, Climate Analytics, 10 years ago. What did you aim to achieve and what, over that period, had been your notable successes?

BH: That was founded with Malte Meinshausen and myself. The idea was to provide science synthesis for small island state and least developed countries, and to fill the gap that we saw out there where we felt these countries were essentially being outmanoeuvred by larger countries simply because they didn’t have access to state-of-the-art science. It might have been arrogant to think we could provide state-of-the-art science, but I think we did ultimately do it. That was the original motivation.

Starting any organisation, it begins to grow and change and you begin to look at different things that become more interesting. We followed the climate change debate very closely with the 1.5C issue. First it was something that was given to us by the governments who said: “We don’t like 2C, we think 1.5C is better.” So we had a look at that and worked on it and many things we have done have followed from that, both on the impact side, mitigation, emission reduction, modelling, climate finance, a lot of the central organising principle has become about how to take the steps required to enable countries to deal sustainably with the challenges of meeting the 1.5C limit.

CB: Just a bit around public opinion and how to shift public opinion. If you ask people, “are you concerned?”, they go “yes”, but if you rank them in their list of concerns versus their day-to-day concerns – putting food on the table, etc – it drifts down that ranking. What, in your view, needs to happen to shift public opinion on climate change? And, therefore, give leverage to the politicians?

BH: The paradox of this is that if climate change was a top political issue for people, generally, it would be time to panic. The impacts would already be so visible and concerning that they would overtake the more short term issues of survival, economic, schools, kids, medicine, health. That would be a big concern, if we got to that point, somewhat unfortunately. It’s understandable that climate change is rarely the top issue for people. Many other issues that are very important to society are also not top issues either. That’s where we get down to the role of government, actually.

Government is meant to take account of all of these issues and develop ways and means and strategies for society to deal with them. I think that’s where there’s been a failure of government, in many places, to actually rise to the challenge of introducing policies. Even if it is issue number five, six, seven, eight, nine or 10, governments have the best available science often available to them. They know, in every meaningful sense of the word know, that this issue is a long-term problem that requires short-term action to avoid major problems in the future.

Governments wilfullyw ignoring that are actually undermining many of the principles that bring people to support government in general, and we’re seeing around the world a corrosion of the belief in the value of government, unfortunately. Some of it is misguided, but I also feel some of it is due to the fact that governments have failed to act on some important public policy issues. Climate change is one of those. You see governments essentially beholden to very much sectional and often commercial interests ahead of the interests of larger population.

The inaction on climate change is part of a pattern of behaviour of governments in the last decade that is giving rise to the political issues that we are seeing in different countries.

CB: We often hear about silver bullet solutions to climate change. One of which is let’s just put a price on carbon. What’s your view on that?

BH: I really believe we have to have a global carbon price, ultimately. I don’t think there’s any way of really avoiding that happening. On the other hand, do we have to have it now? Is it a prerequisite for successful policy to have it? Was the Paris Agreement a failure, as some said, because it didn’t adopt a global carbon price? No. We’re seeing a lot things happen out there without a carbon price due to technology price drops. These things would happen faster, maybe more efficiently, but not necessarily with a carbon price being introduced.

I’m seeing this gradually growing around the world. More and more countries are bringing in a carbon price. I think that will become the norm in 10 to 20 years, but in the meantime we’re going to have to get by in many places without a price. And there I think it is traditional approaches, technology based approaches that would work.

Another issue, which is actually quite practical for policy, is that carbon pricing systems are fundamentally short sighted. From the theoretical economic literature, you can see that you need both a price signal, which is politically mediated at any point in time, and a long-term technology perspective. Governments won’t be able to evade the need for long-term policy perspectives to produce the right outcome for the Paris Agreement. Imagine you’ve got a $20 or $30 a tonne or euro tonne carbon price now. In order to get into the right pathway you might have to assume that in 15 years you have $100 a tonne, but obviously hedge that it won’t happen.

They won’t necessarily make the optimal investments on that timeframe unless they are particularly far sighted. In order to guide investments you would need renewable energy goals. You would need motor vehicle standards. You would need many things like that in order to compliment the price signal. In that sense, the carbon price is not a magic bullet on its own. It needs to be, for effective policy, fully integrated with other instruments. Also, you have to see how to manage some of the distribution and social consequences of carbon pricing, which will mediate the actual nature of the price, what it’s put on, who is compensated or not over time as well. It will, therefore, be mixed up with other complex instruments as well, which redistribute income within a society to sectors and individuals, households, that need to be compensated for the relative price changes of energy elsewhere in the system.

CB: Another thing you often hear is that to tackle climate change we basically need to get India and China off coal as fast as possible. Is that a simplistic or broadly correct thing to say? Or is it way more complicated than that?

BH: In the first instance, it would be a good start, that’s for sure, but it turns out to be a lot more complicated than that because coal is important. If you get rid of coal, you’ve got to deal with the next thing and you’ve got to deal with oil and natural gas and so on. You’ve got to look at a number of different things simultaneously. Getting rid of coal in India and China in a socially and economically beneficial way is fundamental. We certainly can’t get into the Paris Agreement pathway unless we do that quickly. I might just say not India and China as well, but the European Union needs to get its act together. Australia, Canada, places like that, need to move faster and there we will get positive economic spillover effects.

If these countries move out of coal it will bring technology prices down on the clean side everywhere and have spillover benefits. But if that’s all you do, you wake up in 10 or 15 years time and think, “Oh, well, that was great but now we have motor vehicle emissions growing. We have not dealt with iron and steel. We don’t have agriculture emissions under control.” You will still bust through 2C or 2.5C easily.

CB: And then there’s also the CCS question. A lot of fossil fuels outfits say, “That’s OK, just move over to CCS.” Again, what is your view on this?

BH: I am astonished they have any credibility left because unless you’re suffering from amnesia one can remember the very heavy political efforts and claims that many in the fossil fuel industry made about carbon capture storage a decade ago. It was promised this. It was promised that. Billions were put into it and in the end the outcome has been rather sad. There has been very little actually really going in the power sector at all. Many who were once involved with the CCS move are disillusioned about that.

There are many reasons for that. I speculate that maybe in some ways some electricity firms are not very serious about that. It was a way of getting the issue off their case for a while and hope the governments went back to sleep on the problem, which actually happened in some cases. In other cases, it’s been technical difficulties, very expensive, hasn’t worked out the way people thought. I think this time has passed. I think anyone who looks at this in a very sober way now just looks at the costs, the engineering issues involved, would have to say that in the power sector, carbon capture storage has missed the boat. It’s gone. It sailed.

Carbon capture storage might be very relevant for some sectors. It could be relevant for iron and steel, maybe even cement, if we don’t find alternatives there. It could be relevant in some fossil fuel production sectors that might remain as well, but only on limited scale. The other issue is the question of what do you do with the carbon you take out of the air? Carbon dioxide removal technologies, direct air capture; because that means in the end you’re capturing carbon dioxide and you’ve got to store it somewhere. And this is an unfortunate platform that’s needed at scale. But if you look at the details of that, the capture storage facilities, transport facilities, would probably be different places than the fossil fuel carbon capture storage.

You probably wouldn’t want to go near carbon capture storage for fossil fuels at all. Instead look to see how you would begin to roll out capture storage transport facilities for carbon dioxide removal technologies in the next decade or two, to see how to do that in a much safer and environmentally sound way than what’s talked about in the fossil fuel CCS case.

CB: Finally, more of a personal reflection. You’ve obviously had a great and long experience of this whole climate change effort, from the science, negotiations, etc, and it’s been a roller coaster. You’ve had ups and downs. You have Copenhagen and Trump. And the costs of solar and the moments of the Paris Agreement where you get some positive outcome. Looking ahead for a generation ahead, are you optimistic or do you have increasing pessimism?

BH: You’re right. There’s been a roller coaster. You think of the Copenhagen experience and the pit that everyone was in at the end of Copenhagen and for some time afterwards. But in the background stuff was going on that made a big difference. There was a move to set up an international renewable energy agency, governments would putting into place renewable energy targets. At the multilateral level, we recovered from the Copenhagen shock. There was a full on effort by big emitters to completely destroy the multilateral system on climate change following Copenhagen.

I think the victory came from the small countries who fought back. I don’t just mean the small island states, or least developed countries, but the countries like Mexico. Middle-sized economies that really needed a multilateral rule-based system to survive. They fought back against the attempt to completely crash the system that followed Copenhagen. I think the Paris Agreement is a product of that renaissance in the belief of the international community to mobilise global action.

What’s made it optimistic are the very massive changes in the technologies that we’ve talked about. That’s driven by the economics of the technology as well as by the motivation and mobilisation of entrepreneurs globally. If you look around the engineering professions now, for example, you see many young people whose reason for living is to solve the climate change problem. People have been working for natural gas companies, people working for wind companies, for iron and steel and cement companies, younger engineers and scientists; they are really on the case. Their energy is revealing itself in the market. You’re seeing companies pushing and mobilising resources capital to take advantage of this transformation.

Of course, there are some dark spots out there. There’s no doubt about that. My own country, Australia, is a good case there politically. But even there the government is out on a limb. The vast majority of people want more energy action. I hardly know anyone outside the coal industry there who is not frustrated by the lack of action in Australia. You go to other countries where there are problems going on as well and you find that the economics are stacking up more and more in favour of clean alternatives and governments are having to invest political capital and excess economic resources in more coal. I think that’s not sustainable, ultimately.

I think the economics will turn against this industry, fundamentally, universally, in a decade or so. Looking 25, 20 years ahead I am quite optimistic. I remain quite optimistic. Of course, history tells that things can go badly wrong and they can go wrong quickly and we are living in a complex world now. We have lots of problems going on in the European Union. We have issues in the United States, in other countries and regions where at any moment you could see a serious setback to all of the trends I’m talking about. But I do remain optimistic that we are going to move it forward.

CB: Great. Thank you very much.