Bonus: Mark Howden AC — Climate Reality, Climate Hope

We couldn't fit all of Mark Howden's insights into our Local Environment Heroes conversation, so we're sharing his full Impact Hour talk as bonus content.

In this June Impact Hour session, Emeritus Professor Mark Howden AC takes a clear-eyed look at where we are heading on climate change — and where there are still genuine reasons for hope.

Drawing on almost 40 years working across climate science, policy, and sustainability, Mark explores current emissions trajectories and what they mean for Australia and the ACT. He also looks at the practical opportunities available to avoid the worst impacts of climate change, from renewable energy and electric vehicles to adaptation and emissions reduction. 

Mark discusses climate reality, without losing sight of climate hope or the paths for change that remain within reach.

Recorded at Dissent Cafe & Bar, Canberra, in June 2026.

Local Environment Heroes is a Canberra Environment Centre podcast celebrating the people working to create a healthier, more sustainable and connected community.

Find out more and get involved: canberraenvironment.org

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Thanks for listening; environmental change starts with people. 🌱

Transcript

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SPEAKER_00 0:02

Alright, I'll make a start. Um, good evening, everyone. I've got some long scripted notes that poor Jen, who normally stands up here and introduces people, was going to read out. She's unfortunately homesick, so I've got the notes, and so I am going to read a little bit from my screen. Uh so I'm Julie Bolton. It's important that she wrote that down for me. Um I'm the president of their Canberra Environment Centre. For those of you who don't know the CEC, we're amazing. Um we're one of three organizations behind this idea of Impact Hours. So alongside the wonderful Kathy over here from Sea Change and the Cons Council. And unfortunately, Simon is not able to attend tonight, but you need to look up all three organizations if you don't know us, because we're we all do incredible things for the environment and for our community in Canberra. Uh so um I'd like to begin by acknowledging the traditional custodians of the land on which we meet tonight, the Nunnawal and Nambri people, Canberra's first storytellers and nature protectors. I extend that respect to elders, past, present, and to any First Nations people who are joining us here tonight. Um, some brief notes before we begin. We're at Descent Bar, thank you so much to Dave and the team at Descent Bar for hosting us. Yay! Yes. Um please support Descent Bar by buying drinks, ordering pizzas. I'm about to order a pizza. It would be cool if I could do it while I'm talking. Um I haven't had one yet. Apparently, they're awesome, um, and there's gluten-free ones. Um, note that this is being recorded, so Dave's already hit record, uh, and what we'll do eventually is upload all of these onto Canberra Environment Centre's website, possibly also the other two websites. We also then record Mark tomorrow. We've got a special meeting with Mark Den and I tomorrow, where we're going to record further conversation with Mark about what he talks about tonight, and that'll be up on the CEC podcast channel shortly, um, which is awesome. The podcasts are there for we've done to our fourth season, and there's some amazing stories. We actually interviewed Mark three seasons ago. I think Mark might have been our number one interviewer back in the day with Ryan when CEC was at ANU. Um, it was a conversation that made me cry. So I'm hoping not to cry tonight. I might though, quite emotional. Um, and it was just such a joy to have Mark on the podcast. So I encourage you to go back and listen through all of our previous podcast episodes and then look forward to the one that we're going to record tomorrow. Though this wasn't on the notes, so I'm totally going over the notes already. Um, okay, so if anyone can think of questions while Mark is talking, that would be awesome because what we'll do is let Mark talk for about 30 minutes and then open it up for QA. Okay, this is our third impact hour of the year. Um, so thanks everyone for coming along and supporting this new initiative. These evenings are about bringing together people who help us better understand the challenges that we're facing. And importantly, the opportunities that we have to create a more sustainable future for Canberra and for our region and for Australia. And importantly, I'm just gonna add to her notes, that's why I should never have had her notes. Um, also about building community. This is really an opportunity to meet each other. So if you don't know the person sitting next to you, please make sure that you know them before the night is out because it's really important that we actually foster a sense of connection and community, and that's how we believe we're gonna build resilience and build connections and actually foster a new way of living, which is what we know we need to do. Uh, so um, I've now got a long introduction for Mark, Professor Mark Halden from Jen. I'm gonna summarise this really quickly. Um, many of you probably already know Mark through his extraordinary contribution to climate science and climate policy over nearly four decades. He's the vice chair of the Intergovernmental Panel on Climate Change, a role that takes up about half of his time, and he does this entirely pro bono. This mammoth job involves everything from late-night international meetings and reviewing major reports to helping navigate the complex global conversations that underpin climate action. Um, alongside that, he also continues to advise governments and organizations, speak at universities and conferences, and talk to us tonight at Impact Hour, brief policy makers and engage with the media and speak to people like us while remaining one of Australia's most trusted voices on climate change. But that's only part of the story. Uh, and I'm actually gonna let you talk about what the story is next, because Mark has recently semi-retired. And we were just having a conversation then about what semi-retirement means for someone who is so passionately and intimately involved in the climate conversation. Can you actually ever retire from that? No, I didn't think so. So it'd be interesting to hear what Mark is up to now. Um again, I have loads and loads of notes here, and I'm going to briefly summarise what Jen really wanted to say tonight. So Jen's Jen's a little bit sick, which is very sad. She actually chose Mark as tonight's speaker because she thinks Mark, as we all do, is just amazing. Um again, I'm ad libbing from, so don't tell Jen that I'm kind of making up bits of what she really wanted me to say. Um Jen has said that when she was a PhD student, studying journalism and writing, she spent a lot of her time hanging around the Chifley Library. And she started attending the all-day AU climate updates that Mark would run at the time. Mark didn't know this, he probably still doesn't know this, but those public events which brought together medical doctors, farmers, communications people, as well as climate scientists, let Jen see that everyone, regardless of their expertise, should and could come on board and talk about and address climate change. So it was that realization that gently nudged her towards a different career and helped her understand the climate challenge in a way that was rigorous, honest, and emerging. Ultimately, Jen says, Mark played a significant role in Jen's eventual move into the environment sector. And we are so pleased, again, I'm Ad Libing here. We are so pleased that Mark did that because Jen, for those of you who don't know, is our amazing director of the Climate Environment Centre and has been there for about a year and a half now and is doing extraordinary work. And we're so thankful that Jen is there. So thanks, Mark, to you for leading Jen down that pathway. Uh I'm gonna skin this really quickly. Okay, so tonight. Tonight, Mark will be speaking about climate reality, climate hope, and exploring both the sobering realities of where current emission trajectories are taking us and the very real reasons for optimism that still exist. So please join me in welcoming Emirates Professor Mark Howden AC.

SPEAKER_06 6:59

Thanks for that introduction, Julie. It's uh it's it's great, and uh and I and I always uh love hearing where I've actually impacted on someone in such a positive way as Jen related. And uh it's it's actually the ultimate compliment, actually, where where someone actually comes up and says, you know, to me, you you know, you may not know this, but 20 years ago I heard you on the radio or whatever, and it changed my life. And that that you know is the ultimate um, you know, for me the ultimate impact, and so so it's great to hear. Um so anyway, firstly, thanks very much to to to uh you Julie and to Kathy and Jen for getting me here. Uh it's always lovely to connect with people around the uh the area and uh and acknowledging my neighbour, um Shane, Shane Rattenbury, um, and my daughter, Marguerite, who's here tonight, um, uh who bought me my notes which I'd left behind, but maybe I won't need them. But um so so what I thought of doing here was um really just in two parts. With the first part was just acknowledging that the pace and issues associated with climate change are extraordinary and and which are often glossed over by the media, and and so we don't get a feel for the rate of change and the uh the impact that it's already having on our systems. And and so so there was a little bit of a reality check there. And and secondly, was just to emphasize that even though things may appear um somewhat dire, um there's always hope, and hope stems from action, and so it's about you know what are the actions that we can take uh to both reduce our greenhouse gas emissions and to adapt to climate change. So the to to the the kick off the first bit, the the grim bit, um, is that the reality is that within a year, maybe two years, um, we're actually going to cross the 1.5 degree threshold um on a trend basis. And um and so we haven't got a lot of time. If we look at our carbon budget that's consistent with 1.5 degrees, it tells the same story. We're probably going to chew that up in two, maybe three years. Um, and so at that point there is no alternative but to go further above 1.5 degrees. So the reality is the question is not whether we will actually exceed 1.5 degrees, but by how much we will and whether we can then bring that temperature back down. And and the way the world is going at the moment, I I have to admit that I have a bit of personal pessimism about whether we can actually do that. And and the basis for this is actually relatively straightforward is that when we look at our greenhouse gas emissions, uh, we're currently producing around about 60 billion tonnes a year of carbon dioxide equivalents. That's around you know just a bit less than 40 from fossil fuels, and then a series of it's carbon dioxide, and then a series of other greenhouse gases, uh, and then there's land clearing emissions as well. And and so when we add all of that up, it's a huge atmospheric load, which has already changed the atmosphere. So our carbon dioxide concentrations are now 50% higher than they were pre-industrially, our methane emissions are heading towards tripling pre-industrial concentrations, and we've known for 200 years, 201 years, um, that if we add those greenhouse gases to the atmosphere, we will warm the earth. So it's not surprising we're seeing the warming that we're already observing. And and so the momentum behind those greenhouse gas emissions remains incredibly strong. And so uh, you know, you even hear in the face of the Strait of Hormuz sort of disruption uh that there's political people here in Australia and elsewhere who are then rationalizing that um uh you know, because we actually haven't got enough oil or there's a concern about that, that we should actually increase extraction and increase uh combustion of these fossil fuels rather than actually doing the obvious thing, which is actually saying let's get off the addiction so that we don't have those vulnerabilities in the future. And so we see some extraordinary things, you know, things which are so illogical and yet they are framed in that way as though it makes sense, as though the only way we can get energy that we need for our our lifestyles is through fossil fuels. And yet there are viable alternatives, which we'll I'll cover in a few minutes. So, anyway, those temperatures which we're seeing are extraordinary. So 1.5 degrees may not sound like a lot, but if we look back in Earth's history, relatively recent history, back to the recent ice age, um, that ice age was around five degrees colder than our historical temperatures. So five degrees delivers us an ice age. Five degrees delivers us a world where there's two kilometres of ice over Europe and parts of North America and South America and glaciers in Australia, and uh and our sea levels were 120 meters below where they currently are. That's what five degrees does, you know. So um, you know, the Mediterranean was dry, we had, you know, um huge uh continental shelves such that you know people could walk from the mainland to Tasmania or from Papua New Guinea to the mainland or from Europe to England because the sea levels are that much lower. So we we know definitively that five degrees changes the face of the earth. So when we're looking at 1.5 degrees, which is what we've already done, that's like a third of an ice age, just under a third of an ice age's worth of change. That's extraordinary, you know. So that's that's you know, you can't do that and persist with it for the long term and not have fundamental impacts on the Earth's system. And where we're currently heading is around about three degrees of change. So our current trajectories and emissions, if we continue with those, it'll end up with a world 2.7 or 3 degrees warmer. So that's like two-thirds of an ice age's worth of change. Um, and you can't have that and not fundamentally change a lot of things that happen on Earth. So the prospects um are very straightforward. Like it's this is not rocket science. We've known about this for a long, long time. The oil companies have known about this for a long, long time. ExxonMobil had projections of greenhouse gas emissions and temperature change back in the 1970s, and they were right. They even had carbon budgets well before the science community had carbon budgets, and they were pretty much right. So we're not, you know, we're we're we're entering into this uh you know fundamentally changed world with the knowledge of what it actually means to us in a broad sense. So it we can't claim innocence, we can't claim that we were ignorant of the dangers. Um we have known for 20 years or more what climate change means for us and what we need to do to stop it, but we simply have not done what it takes. And that's because we have a whole stack of political vested interests and industry vested interests and even personal vested interests in the way things are rather than the way things could be. And that's why groups like Sea Change and others are really important, because they actually take us into the way things could be, and that's a really important pathway uh to a better world. Now, when we look at the the record of how climate change is impacting on us already, like it's it's extraordinary, and so I won't go into that in great detail, but but what we've seen is is extraordinary heat waves on the land in the ocean. Just a couple of years ago, three-quarters of the oceans of the world suffered a marine heat wave. Um, you know, this is just you know extraordinary. If we look at sea level rise, it's accelerating, so it's it's roughly about three times what it was on average last uh century, um, and it's getting faster and faster over time. That sea level rise has given us our first mammalian climate change extinction, and to our shame, that happened here in Australia. It happened on our watch. So this was a little critter, little rodent-like critter that lives on the or lived on the Torres Strait Islands in the low muddy islands in the Torres Strait. Um, sea level rise means that those islands no longer exist, which means that little animal no longer exists. So that was the first mammalian climate change extinction happened in Australia. We have nothing to be proud of. Um if we look at the the human cost, um every degree that we increase our temperatures, uh productivity, labour productivity goes down. Every degree that we increase our temperatures, health issues increase, including through air pollution. Every degree that our temperatures go up, domestic violence goes up here in Australia. Good studies on that. Um we look at the energy security, that's that's also um impacted by climate change. So when we get high temperatures, our energy supply capacity goes down, our energy demand goes up, and our ability to transmit reduces. And so these climate change uh factors are impacting already on everything that we value in a sense in the world. Um we've got someone here from MDBA, um uh we already see massive changes uh in our river systems due to climate change, with climate change plus other factors already reducing average flows in the Moray by around about 40%. If you're over in Western Australia, um climate change has already reduced the inflows to Perth Dams by 85%. These are not trivial changes, these are massive, massive changes which impact on the things that we value. So if we're if we have any sort of idea that um we've got time to waste and that this is not important, I'm just wanting to try to put that to bed right now. And it's not um just me saying this, the evidence base for this is extraordinary. Um there the last IPCC report um stated that the um the impact of humans on climate change is now unequivocal. In other words, there is no uncertainty left. There is no room to hide about the link between human activities and climate change. So I just wanted to um uh sort of make those points and then make the point about well, if you listen to governments, a lot of governments will say, oh yeah, we've got it under control, our policies are working and all that type of stuff. Um but when you actually ask the scientists, you get a very, very different point of view. And so The Guardian a couple of years ago did a survey of I think it was 450 scientists across uh the world, uh including me, and uh asked, where do you think we'll land in terms of temperatures? And uh and it was nearly 80% said we're going to be at least two and a half degrees, almost half said it was going to be at least three degrees, virtually none said it was going to stick to one and a half. So, so you know the scientific consensus is that we're in for a rough ride. And uh and we're simply uh you know not responding to that uh expert judgment in the way that we should. You know, uh um you know you get uh people like Donald Trump uh whose whose speculation about climate change uh or um uh you know deliberate misinformation or disinformation somehow weighs equally with the the incredible weight of scientific evidence that we have. And that's again an extraordinary thing that we need to recognise individually and try to address in our own lives. So against that, what's the good news? And so I did say I was going to talk about good news, and there is good news because change is happening, it's just not happening fast enough and and broadly enough. Um so when we we look at some of that good news, um uh a lot of it can be portrayed very um very well through what's happening in the ACT. And so we should feel proud that we actually live in a jurisdiction which is actually at the forefront of taking climate action, and and and a lot of that is credit to Shane and and the Labor Greens um coalition that we've had uh for a long time but have no longer here in the ACT. And so so there was you know many, many innovations which uh that's generated, which has put the ACT at the forefront of climate action. But even then there's a lot, lot more, which I would argue needs to be done. So if we look at part of that story, it's renewables, and we probably all know the story about renewables here in Australia, which is a massive rollout. Um we've got almost half of the grid uh being the East Coast grid being uh powered by renewables now, and at times it's way up into the 90% sort of range, and at times it's over 100%. Um so that's an extraordinary achievement. It was only a few years ago that people were saying you can't have more than 15% renewables in the grid, you know, like the grid just won't support it, you know, the engineering won't deal with it, etc. Um, you know, it was just bullshit then, and it's bullshit now, and we need to recognise it and call it out for what it is. And um and so so the sort of ability for individuals with their um panels on their roofs, which makes a big slab of our renewables in Australia, our investment now in batteries, you know, 400,000 new batteries under the uh cheaper home batteries program run by the feds is is extraordinary. That's that's got about 11, 11.5 gigawatt hours of storage in the batteries that have already gone in. That's like three or four power stations worth of power that's actually gone in in batteries. You know, this is incredibly big change. And that's projected to go up to about two million um batteries by 2030. And if you look at you know, anywhere else in the world, that sort of uh you know penetration of um home batteries uh is is nowhere near what we're seeing in Australia. So Australians buy into climate change. Australians broadly acknowledge and recognise that climate change is not a good thing for Australia and Australians, and they're prepared to put their own money on the table to get batteries, to get solar panels, and sure it earns a bit of money for them as well, but a lot of it is actually motivated by environmental concerns. And so we see renewables as a fantastic uh story, and uh the ACT, of course, being a leader globally in that with the reverse auction scheme, uh which is a policy innovation from here, um, is part of that. And so other countries and other jurisdictions have uh adopted that same approach of how to get the cheapest uh renewables into the system that we can. And maintain that cheapness using sensible policies. If we look at um uh wholesale prices for electricity, they're now coming down because of renewables, in spite of the rhetoric from some. Uh and um and it would be a lot more, except for the fact that in terms of our electricity bills, except for the fact that we pay extraordinary amounts out for the transmission and retail side of things, and so the wholesale signal gets a bit lost in that. Um, but nevertheless, uh our power prices are coming down. We've got a policy now coming out of the federal government, which is for um this what's called the solar share offer, which is three hours of free electricity every day in uh South East Queensland, New South Wales, and South Australia. Presumably that will include the ACT, but I'm not sure. And um, and that means if you've got a battery, you can actually top up that battery using that free electricity. You can charge your car, you can put the um dryer on, you can turn the air conditioner on to preheat your house or pre-cool your house in summer. Um, it's an incredible innovation and it happens because renewables are driving the prices so much down in the middle of the day that in many situations they're actually turning negative. So if you actually went back a decade and said to people, um, you're likely to be be paid to use energy in the future, most people would have laughed at you, and yet that's actually a reality here in Australia and elsewhere. And so um things are changing and they're changing incredibly quickly, and they're changing incredibly positively as well, because if you switch um you know to renewables, um, uh, you know, move away from gas in your in your home kitchen, you incre improve your air quality. You know, you don't have your particulates that your your gas cooktop generates um in indoors. Um, you know, when you move away from fossil fuel cars, you improve the air quality in your cities because you don't have the uh taupipe emissions that you'd had previously. So there's lots and lots of co-benefits there. Um just wanted to um talk briefly about um electric vehicles and uh so again the ACT leads Australia. Um it doesn't lead the world, but it leads Australia with electric vehicles. So in May, 34% of new cars were electric vehicles. Um and when you add in the hybrids and um uh sort of petrol hybrids, um, that's well over 50%. Uh and nationally it's 46.5%, is the is the non-uh fossil fuel only cars, and uh and nationally it's about 20% for um electric vehicles. So so you know the ACT is at 34, the rest of the nation's at 20 on average. And so so the ACT is doing more than its fair share of um taking on these new technologies. And and that's in part because we've got a you know highly educated and progressive population, um, but it's also because there's policies here in the ACT which support uh renewable uh both in the uh the new market and in the secondhand market. And we've got a long-standing uh program of uh charging stations and innovations and change uh such as putting uh uh recharging in in uh units, etc. Um, and then of course the ACT also has the um close down of the gas uh um fossil fuel gas um system as well, which uh closing out by 2045 and no gas in new houses, etc. So um, you know, pushing hard against those sort of fossil fuel uh dominant uh paradigms that um otherwise have uh existed uh in the past. And so there's a lot to be said, I think, for those sorts of policy changes. Having said that, um in Australia we're not making much progress on uh fugitive emissions, that's uh emissions from coal mines, like methane from coal mines and leakage from gas extraction. We're not making much headway on industrial emissions and not making much headway on agricultural emissions, and and collectively there are a bit over a third of the emissions profile. So, you know, there's areas where we're doing well and there's areas where we're not. Now I wanted to move um briefly to climate adaptation. So that's um essentially climate adaptation is responding to either the change in climate that we're seeing or that we expect to happen in the future. So mostly this is about improving climate risk management, but sometimes it's about how do we respond to opportunities that might arise from climate change, and so how can we be on the front foot to maximize the benefits from that? And uh in Australia we've pretty much dropped the ball on adaptation at a federal level. Uh, there's really no major program. There's a little bit of NESP funding, that's the uh sort of environmental research program funding on that. Um there's a little bit that comes out of the uh disaster risk funding, which is essentially disaster risk prevention. But apart from that, there's not a lot going. Um most of our attention is remains at a federal level on the emission reduction side of things, um, and yet climate change is costing us at the moment something like $38 billion a year. That's a number coming out of Deloitte's, and we're not actually figuring out that adaptation can take at least some of the sharp edge off that um huge cost. Um $38 billion, you know, if you actually think about that, that's basically one-tenth of an AUKUS program, and over a decade it's a whole AUKUS program. And so if you actually said, well, you know, like this is the cost of climate change, it's the cost of the you know, same sort of cost as the uh you know single biggest uh defence program we've ever had, um, you know, perhaps that might come onto the radar because at the moment it's not on the radar. And uh and so we do need to up our game a lot on climate adaptation because when we adapt well, we can often have lots of co-benefits. So, you know, when we build better houses like passive house-style houses, um, we can reduce our greenhouse gas emissions tremendously, 90% or thereabouts. We can improve air quality, so reduce um hospitalizations and uh reduction in quality of life, um, and we can make more livable suburbs out of uh having more effective housing and housing design and urban design. So um, whilst we're doing some of that here in the ACT and elsewhere, there's a lot more that we can do. And so, you know, we've only started to scratch the surface of adaptation and recognize the other co-benefits that that can have, including through emission reduction. And so when we look at a global scale, um the congruence between effective climate change adaptation and the sustainable development goals is almost a hundred percent. So almost any adaptation program that you look at, which is well designed and well implemented, will assist with multiple sustainable development goals. So that's actually improving the lives and livelihoods of people across the globe. So that's an example of the co-benefits that I'm talking about. So what's it's given that it's in a sense a no-brainer, um, you know, climate change adaptation, you know, what's stopping us from adapting more? And um, for one, I think part of it's a story about lack of leadership and and it's that lack of public commitment to dealing with climate change. Um, it's if you um commit to climate adaptation, what you're doing is acknowledging that your emission reduction programs are failing. Um, politicians don't like to admit failure, and so um so it's easier to just ignore that. And um, and so it's as part of that argument too, I think it's it's a lack of recognition that it's clearly in the national interest to take very rigorous and rapid action on climate change. And and so without that recognition of the multiple elements of climate change and the the uh you know the overall um uh you know no-brainer sort of element of being much more on the front foot means that we don't have that leadership that pushes for adaptation as an effective response as well as emission reduction. Um I think there's also um issues about resourcing, so we're in a resource-tight uh environment, but we always are, you know, like I don't think you could go to any year in the last 50 um and you'd have governments saying, Oh, yeah, we've got plenty of money, you know, we're not limited by money in terms of the policies that we're going to implement. So that's just normal, um, but we get it played against us so that we the argument is that we can't afford to take effective action. I think there's also um uh a real issue in uh when we're dealing with climate change that we only look at the costs, not at the benefits, and so we have a very asymmetrical view. And in any other human domain, if you only ever looked at the costs of doing something but not at the benefits, you'd never ever do anything. Um you wouldn't do it if it was uh you know buying a car. You know, your expectation is the benefits exceed the costs. You wouldn't do it if you went and got um some medical advice. Your expectation is always the benefits exceed the costs. And and so without, if if you if you don't include the benefits, you're only left with a cost. And if you're only left with a cost, you won't do it. And so so that simple framing about having a cost-only sort of approach to adaptation is a fundamental political barrier, in my view. And also, I think we we've got real big issues here in Australia and elsewhere in terms of misinformation and disinformation, which muddies the waters, which throws in uncertainty, uh, which disputes uh the evidence base, which um you know challenges the benefits coming out from climate adaptation. And that's something we can't afford. And the recent Senate inquiry showed a shone a light, I think, on the on the depth and breadth of misinformation and disinformation here in Australia. And the last thing I want to comment on is um that as well as the all of those sort of logical and rational sorts of things, we also have legal and moral imperatives to act on climate change. Um the legal imperative is essentially um uh framed in the International Court of Justice case, which basically said that uh you know not taking action on climate change was a fundamental problem uh by if by governments. Subsidizing fossil fuel extraction um was a wrongful act by governments, uh supporting in various ways fossil fuel exploration, etc., was a wrongful act. Um and so this is pretty uh firm stuff uh coming out of the ICJ, and so far that really doesn't seem to have seeped into the decision-making processes here in Australia. And the moral dimension is particularly around equity. Um when we look at climate change, it shines a light on how inequitable our systems are. So when we look at the evidence base, uh climate change impacts most on those people who are most disadvantaged. It impacts most on females, older people, younger people, it impacts on the next generations who haven't got a voice in terms of making decisions at this point, um, and it impacts most on developing countries rather than developed countries. And so we see um multiple dimensions of inequity associated with climate change, and so there's a fundamental moral dimension, and I'm not trying to be like Kevin Rudd here, um, but you know, like when you actually think about it, it's it's a real problem. And what uh various studies show is that um inequity is toxic in our systems, is that it it um uh it reduces trust, it increases transaction costs, it uh you know causes um you know ultimately violence in various ways, um, it generates lots and lots of bads in our system, which we really can't afford. And so so I I think we should be taking a lot more notice of the equity dimensions of climate change than we have in the past. So the last thing I'd say is, you know, if we look at that sort of more broadly, um what's in the national interest in terms of climate change? And and a few groups like the Investor Group on Climate Change and Deloitte's have done some numbers on this, so so they're probably pretty rubbery, but but nevertheless. And and their sort of assessment was is that if we don't act on climate change, both emission reductions and adaptation, that's likely to cost Australia between $3.4 and $6.8 trillion over the next several decades. Um whereas if we actually took action on climate change, that could actually boost the economy by about two-thirds of a trillion dollars and add another 250,000 jobs, whereas inaction costs almost a million jobs. So the sort of simple economics of this is showing that the best thing we can do is take action on climate change. The worst thing we can do is ignore it and not take action on climate change. And that doesn't take into account the intangibles, uh, you know, the non-economic values associated with equity and biodiversity loss and all those sorts of things. So my my sort of leaving message here is um yes, there is reason to be concerned. Um yes, there is reason to hope if we take action, um, and the logic of taking action is absolutely solid. And I'll just leave it there and happy to answer any questions.

SPEAKER_03 36:13

Is this working? Yes.

SPEAKER_02 36:14

Any questions?

SPEAKER_03 36:17

Thank you very, very much. Um something you just said at the end there, where you tagged on what you described as an intangible loss to do with, say, for example, biodiversity loss, um there's a great big rub, isn't there? So uh uh if money and and economics are the only um ways we have of speaking broadly about the the costs and the benefits of action or inaction, um surely there are some other metrics that are that are really applicable now to raise the esteem of biodiversity and well-being and those other things that break our hearts. Can you speak to that at all?

SPEAKER_06 36:58

Um a little. So there's lots of different dimensions to that. And so so the reason why I mentioned intangibles and non-economic um is there is because those uh sort of analyses typically run on economic models which don't include um much, if any, of that. And so um whereas if we actually approach this in a uh you know not necessarily an economic modelling framework, we can include those intangibles, so things like cultural loss and heritage loss and uh you know value of biodiversity loss, etc. Um and so so that that's the difference there. I think depending on how you want to aggregate or integrate that information, uh it gives you more or less sort of way of doing that. Now, in terms of the that broader thing about including uh the goods and the bads, um, so for a long time people have recognised that GDP as a metric is actually um you know lumps them together and and uh and it's a problematic metric. And so there's things like the genuine progress indicator, which take us on along a uh a pathway which is a a more fair um assessment of the uh costs and benefits of different um activities and and different development paths. And and to some extent, I I guess you know that sort of thinking leads the way to a more comprehensive approach like you're talking about.

SPEAKER_05 38:22

Well, okay, so it's very Paul Glazers. I just sort of raised an issue which is floating around the ACT at the moment. To actually get anywhere with any sort of government action, you need sort of two things. You need policy direction, but you also need competent implementation. And one of the things that's going on in the ACT is people focus on the international and the national and tend to neglect what's going on in the ACT itself, like to feel positive about the policies. But the reality in the ACT is we've got now a seriously dysfunctional, incompetent government, and that that's really blunting the effectiveness of implementation of policies. The one example I work, I live in a public housing complex, there could be a straightforward policy of putting in reverse cycle air conditioning. Instead, there's a complete shambles of like some people get it for medical reasons, some people get it as part of a changeover, some people are left with an electric panel on the wall, some people are left with nothing at all in terms of space heating in the transition from gas to electricity. So it just seems to me that like if people are concerned about climate change and action, they really, really do need to focus on possibly the difficult and dirty work of looking at what's going on in the ACT administration and really seeing just exactly why is this being done so stupidly? Why is this being delayed so long? Why do we have ministers who seem to be just profoundly incompetent and incapable of dealing with things? I mean, we've got that remarkable example of essential motion against a minister, the minister responsible for public housing, for being broadly incompetent over ten years. And I so I just sort of raise that as a shift of attention from the the international to the national to the equivalent of looking at what's happening with the plumbing and what's happening with the shifting of recycling. That's like a difficult work.

SPEAKER_06 40:28

I might take that as a comment, um, well outside my scientific expertise. Um I I th I think uh like not wanting to buy into that, is that the reality is as you go into the uh uh you know more and more granular sort of change, uh the thing has become much more complex and sticky. And and so I I think um uh it it's not unexpected that we we see uh you know challenges in terms of program implementation once we get down to that sort of household level. Um and uh and so it doesn't surprise me. Um I I think if if I had to make a comment is that if you put in place overarching policies uh such as putting an effective price on carbon, you know, price on greenhouse gas emissions, it it tends to push into systems in a much more comprehensive way, which doesn't then require that sort of more granular policy making because it sort of permeates decisions everywhere. And if we'd actually done that 20 or 30 years ago, we wouldn't have the legacy decisions, legacy housing and others that we we now have that uh we have to play catch-up on. And it's and it's pretty well recognised that it's you know that the next steps in terms of reducing emissions um are going to be much more difficult. The the easy step was doing the electrification and and to some extent the electric vehicles. The the really hard steps are you know waste, um, household heating and cooling, um, you know, hot water systems, you know, those sorts of things. So it doesn't surprise me that you're feeling uh aggravated, um, but uh I I suggest taking it up at the ballot box is the best solution there.

SPEAKER_02 42:18

Thank you very much for sharing your insights with us. Um when you talked about HOP and what should give us HOP, you mentioned renewables, you mentioned EVs. Um I wanted to ask you do you think there is too much reliance on that when we talk about climate change? Uh we know there is more and more need for energy across the world with big data centers. We know we need social license to put um wind farms. Um I come from Wollongong, um, and uh we the offshore wind farm is nowhere to be seen in the next 10 years. So I I guess um should we maybe change a little bit um the way we talk about climate change and maybe put um a little bit more, I guess, um, reliance on adaptation and good designs, good land use planning, but also talking about population growth.

SPEAKER_06 43:18

Yeah, so so if we if we look at uncertainties about future energy consumption, uh you've mentioned a few of those. So if we go full EV, um it's going to significantly boost electricity consumption. Um data centers are a big unknown, and uh both electricity and water are big uh consumables from those systems. Um population growth is is one of those things which uh uh you know talking about it for a long time has been taboo. Um and uh and and some people approach it from a very xenophobic sort of perspective, some people approach it from a uh sort of environmental perspective. I come from the latter. Um and from my perspective uh i it's a it's a no-brainer is that if we have rapid expansion of our population here in Australia, um as we've seen in the last few years, like you know, best part of a million people in a few years, um we're we're now at our population level that uh earlier projections didn't have us reaching under 2050. You know, that's the rapidity of our population uh growth. Um i i i uh uh uh it it it beggars belief that someone could um think we can have that level of population growth and not have implications for things like greenhouse gas emissions or water consumption. Um those things go hand in hand. And so um so we need to um have a mature conversation which includes those factors in terms of decision making. Um now when it uh it comes to um things like um wind farms off the coast and things like that. I mean I think uh an obvious thing is that you need to use common sense in terms of citing these things. You know, there was a one stage proposal to put wind farms on North Head in Sydney. Um, you know, like just it's not going to fly, it just makes no sense. You know, there's much, much better places to put that. Um but at the same time we need to um uh recognise that people's viewpoints uh about the desirability or otherwise of of solar farms and wind farms are very much influenced by the politics of the day and uh and you know which side of politics they align with. And uh and so and and oftentimes there's a lot of rubbish spoken about about this, and particularly from the right-hand side of the politics, I'm afraid to say. And so um, as one example of that, but going back into the Joe Hockey, Tony Abbott sort of era, um, I was driving past uh Lake George with the kids in the car, Marguerite being one of them, um, and we were going past the wind turbines across Lake George, and and I said to the kids, hey, hey, um look at the wind turbines, um, and then just give me in one or two words what you feel when you look at those wind turbines. And the answer came back, hope. And and so that's what people who aren't caught up with all of the p politics and stuff, that's what they see when they look. They they see that um wind turbines providing clean, renewable electricity, providing employment in local environment, um, all in a matter of perspective, but some people see wind turbines and they see something horrible, other people look at them and they see something incredibly beautiful, and so there's a uh you know a whole aesthetic element in there. Um but that's what my kids said, and um, and and I've always remembered that. It was a powerful moment. Um so I think we we need to uh you know, again, push back against misinformation. So at the moment, you know, we've got uh um lobbying against solar farms happening from you know a thousand kilometres away. Um you know, if if there's people going to protest, make it make it a local protest for local reasons. If people want to protest on a bigger scale, like you know, some sort of global rationale, um then you include that, but you separate those things out. Um so I think we need to um have much better and much more mature uh sort of processes recognising the real politic that we're in and that it's actually quite uh a contested space and one which can actually be decontested by appropriate institutional arrangements.

SPEAKER_01 47:35

Hi Mark. Oh, I've got the mic. Uh really liked your talk. Thank you very much. My question is about when you talked about misinformation and disinformation, obviously the evidence base for the effects of climate change is very, very strong. So, how do you talk to those people who aren't so convinced about the scientific facts and how do you approach that sort of conversation and trying to get them to change their mind?

SPEAKER_06 48:04

Okay, so so there's an assumption that I get try to get them to change their mind. Um and and and sometimes that's possible, but often not. Um so so I I guess if if I had to give you one word, it's um respectfully. Uh so engage with people respectfully. So you you meet them on their ground and you try to understand their concerns. Um and then maybe the environment, uh, you know, psychological and other uh environments, uh such that you can engage in a conversation which addresses those concerns and uh and and perhaps uh some information or or perspectives that uh they may not have thought of but had previously dismissed that that can then change what they do. So um so in so an example of this is that you you get um you know previously we've got a lot of pushback on wind farms because they kill birds, etc., even though the evidence is pretty slim on that, um, that marine-based wind farms kill whales, even though the evidence is zero on that, um, and that solar panels um heat up the environment and create deserts, um, uh, and there's basically no evidence of that either. In fact, uh solar farms, if they're well designed, can increase biodiversity, they can improve water relationships under the under the panels, they can improve agricultural productivity if they're well designed. And so sometimes actually introducing that um into the discussion can work, but only when it aligns with the values that those people have. If it's if it's uh you know at right angles to the values, you know, if it's uh you know not aligned, um, then it won't have any impact. But if it does align, um then it can have impact. So so it's actually about understanding the values of the people that you're dealing with.

SPEAKER_02 49:58

Okay. One more question.

SPEAKER_04 50:03

Thanks very much. Um as you're probably aware, James Hansen has has recently argued, or has argued for a while, that that um in the last quarter of a century um reductions in human-made cooling aerosols plus reductions in climate change-related albedo actually had more of an effect on temperature changes than in fact the CO2 increases themselves. And I'm interested in in your comments on that. And partly related to that, in the past you've been fairly dismissive of the need for any sort of solar radiation management. Uh, and I'm wondering if if there would be a point when you would concede that perhaps we might need to do that if we still can't control the runaway temperature increases.

SPEAKER_06 50:49

Okay. So I'll get I'll do deal with solar radiation management first. So so um uh so so for people who don't know that terminology, it's it's where where you uh put something like dust in the atmosphere that's reflective of heat or um in mirrors in space and similar things. And and this idea has been around for a long time, and uh and there's a few issues with that. One is that if you reduce um solar radiation on Earth, you actually reduce biological productivity. Um we're already in a world where we we're having trouble feeding um the world. Um and if you reduce that by say 8% or so, um, then you've got a real problem uh in terms of feeding the world. So you you you know you have to um balance out um you know these factors. Um secondly, is that uh there's a lot of uncertainties about solar radiation management, and you could do a lot of harm by that um uh at regional level, so by drying out regions or increasing um torrential rainfall in others, um, and and typically you get a you know, wet gets wetter, dry gets drier sort of scenario under most of those scenarios. Um then and so that's not a good thing. Um uh then there's the the sort of problem of rogue operators, and so it's where you know someone like uh the newly minted trillionaire decides, well, I don't need anyone else to do this, I'll just go and do it by myself, um, without you know an effective uh governance mechanism, without any sort of checks and balances there. And uh and and so that could lead to some really problematic outcomes. Um and lastly associated with that is um we we see what what we call termination shock risk. So so assuming that our rogue billionaire or trillionaire um uh establishes this program which keeps the world cooler than it would otherwise be. Um and uh and that's go going for a decade, and there's an evidence base that that's the case. Um, and then that that trillionaire says, well, pay me another trillion, or I'm gonna stop my program, um, because then all of that accumulated global warming starts to get expressed in a really quick um period of time. And um and so so that's the termination shock concern. And so um people like Aaron Tang have written um extensively about this and the various risks associated with that. So I'd actually recommend you read a few of Aaron's papers, The Slippery Slope, sort of arguments. Um the the the obvious response here is that um with renewables um becoming so cheap, it's the cheapest energy in uh history as a species, um, the much better thing is actually just shift really quickly away from fossil fuels into renewables, so we don't actually have to do that. So we don't have to run the risks of solar radiation management and all of those things that I've just talked about. Now, in in terms of um James Hanson, uh so so what we we see is that uh the expressed climate is is a function of multiple things, some which warm the climate, some which cool the climate, and we've known that for a long time. Uh we just don't necessarily have pinned down all of the minor contributions to that, um, nor do we fully understand the impacts of cloud dynamics. You know, as a science community, we don't impact the understanding the impacts of cloud dynamics. And so um one of the the sort of concerns, and I think you're alluding to this, is that going back a few years um uh we cleaned up uh through international agreement the the fuel supplies used by shipping across the globe. So in the old days where people used to use bunker fuels, which was really dirty oil, um, like uh you know, quite thick and viscous sort of stuff, like uh, you know, a lower grade than diesel, um, that used to produce lots and lots of particulates in the in the uh exhaust from these ships. And so these particulates generated cloud droplets, the the moisture collected around the particulates, and you could actually see the the paths that these ships took across the Pacific or Atlantic Ocean, and those paths lasted for many days in in some cases. So you could see this cloud along the trail, and so there's very clearly um an influence of that exhaust on those clouds, and those clouds then reflect sunlight back out into space, so it doesn't warm the earth, so it's a cooling effect. Um, so a few years ago, back in 2020, I think it was uh there's an agreement to move away from bunker fuel and and to use diesel, which is a cleaner burning fuel, uh, reducing those particulates, and you saw much, much less of that cloud across our oceans, um, and that meant you got a warming spike, and that's probably what happened in 2024 that generated the that warming spike was a big contributor to that. Um, so so what we have to do is we need to understand all of the different contributions, the cooling ones and the warming ones, and then aggregate that in a way that enables us to make sensible decisions about where we want to go in the future.

SPEAKER_00 56:03

Okay, um stand here for a minute before we thank Mark, because once you guys start clapping, you'll lose attention, and I need to keep you all focused on me for a second. Um, really quickly, um Canberra Environment Centre has an introduction to seed saving workshop on June 27th, a social bike ride on the 11th of July, or are working on greening your finances, which is very important, on July 28th. Um so if you're not already on the Canberra Environment Centre mailing list, make sure you sign up before you leave tonight. Um, make sure you order pizza and have another drink and talk to someone next to you because this has been a hugely impactful hour, which is what we set out to do. Um next month, next impact hour will be on the 21st of July. Um, and that is with poet and artist Jackie Malens, who is gonna talk about art and activism. And then the month after that, I'm gonna talk. I get to take over the stage for an hour, um, maybe half an hour, much high for an hour, um, on fashion. So if you want to talk about the Canberra puffer jacket and whether it's sustainable or not, then you need to come along to the August chat because I'm gonna tell you that it's not. Um okay, so anyway, thank you, Mark. Um, wait, I've got more to say. Um, then you can clap. Uh there was a paragraph that I missed that Jen had written, and she had actually written in the introduction, but I'm gonna use it for the thank you. Um, one of the things that Jen most admires about Mark is that he lives his values. So everything he has spoken about tonight and all the actions that you can take and things that you can do are actually things that Mark and Marguerite do in their home life. I'm just gonna lump you in with your dad, um, I'm sure you do. Um so she says uh whether he's helping shape international climate policy, communicating complex science to the public, or gifting his garden produce to friends and neighbours, um, there's a consistency between what he says and what he does. That integrity, generosity, and commitment makes him an inspiration, not only as a scientist, but as a person. So thank you so much, Mark, for spending an hour here with us. It has been truly impactful. You can all clap now. Thanks.

SPEAKER_06 58:10

Thanks, Jill. Thanks, everyone. And I'll hang around for a few minutes if you want to chew my ear.