Welcome to 100 Climate Conversations. Thank you for joining us. Those of you that are in this gorgeous, beautiful building, that is the Powerhouse museum here with us live and everyone that’s listening on the podcast. Today is number 47 of 100 conversations happening every Friday.

Before we go any further, I would like to acknowledge the Traditional Custodians of the ancestral homelands upon which we meet today, the Gadigal people of the Eora Nation. We respect their Elders, past, present and future and recognise their continuous connection to Country.

My name is Pat Abboud. I have been working with the climate conversations team over the past year and I’m very much looking forward to introducing you to the wonderous mind and incredible research work of Sarah Perkins-Kirkpatrick. Dr Sarah Perkins-Kirkpatrick is a climate scientist at the University of New South Wales Climate Change Research Centre, who models future heatwave trends in Australia and globally. Perkins-Kirkpatrick leads research to understand the drivers of this phenomenon and the implications on our health industries and infrastructure. Please join me in welcoming Sarah. Very early on, you knew that you wanted to be a scientist. You had a passion for science at a very young age. Let’s rewind right back to that moment where you realised science is my thing.

So, you’re right. I did have a passion for science as a kid, but I ignored it for a long time because I had other people say, ‘you should do science.’ Like, no, I don’t want to do science because you tell me that’s what I should do. But when I hit high school, senior high school, I realised that I just really enjoyed it. I did geography and chemistry and biology as three of my subjects, and I absolutely loved them. So, I just really enjoyed it. I had a good mind for it. I liked asking why. And that’s what you do in science. That’s what you do in research. You ask why and you find out why.

And when I hit university, I worked out by then that I really liked atmospheric science. So, that relates quite closely to climate change. Atmospheric science is basically like meteorology. So, studying the weather, its interactions, what causes the weather, why the weather’s different in different parts of the world, the different pressure systems and the different circulation systems across the world, why they occur. And also to a certain extent, how that interacts with the oceans, which is quite important when you think of climate as opposed to just atmospheric type processes.

And there’s something very specific, I suppose, to your experience entering the world of science, and that is that you live with ADHD.

That’s correct.

Sarah, how has having ADHD shaped your schooling and academic experience?

I think for me and a lot of people with ADHD – and it is a spectrum. I’m probably not on the severe end. We hyperfocus on things. So, if you’re lucky enough to find your passion that’s it. You may not be good academically, but if you can find what you really enjoy, you’ll be the best in the world at it. And I think I was very lucky that I found something that I was really good at and that I enjoyed.

Do you think it’s had some sort of impact or any sort of impact on the fact that you’ve focused very much on this incredibly niche area of climate science?

Yes, I think there was a bit of luck involved. I noticed as I finished my PhD that there was not a lot on heatwaves yet. It was starting to bubble up, but I was able to, I guess, have the foresight that’s where I needed to sit and also realised that I had the skills to do it. And I actually really enjoyed researching heatwaves. So, there was that hyperfocus. I was able to set myself up to go down a rabbit hole that needed research done and that I really, really, really enjoyed.

What is a heatwave?

So, this was actually the research question I started with as I started looking at heatwaves. How do we define – what is it and how do we define it?

In the simplest of terms?

So, it’s a few days in a row where it’s really hot. That’s about as simple as it gets. There are different ways at the scientific level that we can define that. And when I started doing the research, there are so many statistical ways to estimate a heatwave. There were too many, way too many. They’re all very similar. But every paper I read had like, oh, we do it this way, we do it that way. And oh no our way is better, and it was just, you know, a hot mess, really.

Okay. And so, following on from that, how are heatwaves and climate change connected or linked?

So, it’s hot when we have a heatwave. And it has to be that sort of like prolonged window of time. And as climate change increases, as we put more greenhouse gases into the atmosphere, the average temperature of the globe rises. As we see that average temperature increase, we see a higher frequency in extremes and higher intensity of extremes like heatwaves. So, we’re going to see more of them and they’re going to be hotter simply because we’ve just ramped up average conditions. It’s a very – it’s actually one of the simplest relationships between climate change cause and the effect on natural hazards.

Can you chart the change, like have we had, you know, three heatwaves in the last two years?

So, we have – the last few years we’ve had La Niña summers, which means cooler, wetter conditions. And we’ve certainly seen that in Sydney and over the eastern seaboard. So, that reduces the likelihood of heatwaves. So, we obviously haven’t seen that many over most of Australia the last few years. But certainly since the 1950s, which is where solid records are really there, some places in Australia we can go further back, but for the whole country. I can’t tell you exactly the exact trend off the top of my head, but we’ve seen a significant increase in both the frequency and intensity of heatwaves basically all over the country. So, heatwaves that were, for example, 3 to 4 days long have now become a little bit longer and have become a couple of degrees hotter as well. So, the hottest day instead of say being, for example, 40 degrees might be 42 to 43 degrees.

How do you actually measure the frequency of a heatwave?

Basically, if you’re looking at past climate records or future climate projections from models, you basically fit statistical tools to say, ‘Okay, well, let’s pick up at least three days where the weather’s hot or longer, and then let’s see how many of those occur in a year, how hot they are over that year, and how that changes on a year by year basis.’

For people that have only just come into the world of heatwaves now with us. What are the impacts, broadly speaking?

My goodness, where do we start? So, the first one is health, I think is the one that it’s getting – is starting to get the most attention. When it’s hot for a really long period of time, people can’t cope. It is more of an insidious impact. It’s not as immediate as impacts from other types of climate extremes, but it can affect the old, the young, the pregnant, people with underlying diseases. And I would say as climate change worsens, very young and fit and healthy people too. Diseases that are exacerbated, things like heart disease, kidney disease. Old people are affected because they don’t cool down as efficiently as younger people.

There’s also impacts on ecosystems if it’s hot for a long period of time, things dry out, water dries out, trees dry out. Animals also can’t cope, similar to humans in that way they can’t shed the heat quickly enough. There are impacts on infrastructure. So, we’ve had heatwaves in Australia and even overseas as well, where train lines have buckled, and trains can’t move. Air conditioning breaks down on trains above a certain amount of – I think it was like 38 to 40 degrees. Buildings can crack under certain amounts of extreme heat. There are geopolitical tensions. So, if crops are dying out because it’s so hot, there’s not enough food resources that can lead to escalated tensions. If we’re talking about heatwaves in the ocean that can affect marine ecosystems and aquaculture as well, leading to more geopolitical conflict.

The list goes.

The list goes on. It could affect aircraft, it’s happened in the States, where it’s been too hot for planes to fly, ice caps melt, especially – you think with the heatwave, it’s only a few days, but it can really exacerbate the melting process and escalate it. So, once it starts, it then ramps up further.

I mean, thank you, because what you’ve just done there is actually made heatwaves much more tangible for people listening. And to help us to understand that there is real world impact and not just on climate change, but as individuals.

And also what we eat and do. So, everyday items like coffee and wine as well that most of us enjoy. To a certain extent they’ll be affected by climate change and heatwaves because, you know, grapes burn, for example, if it gets too hot.

Production cycles get affected. Okay. I think the thing that really wakes people up when we’re talking about climate change is the impacts on our health. So, you mentioned a few things there, but let’s go deeper. Can you explain, I suppose, the areas that you’re looking into in the moment, specifically around the impacts on our health when we’re looking at heatwaves and what they do to us or can do to us.

So, I’m again, I always look through things with as a climate scientist, I have that lens on, but I have been collaborating with people in health sciences to work out well, if we have a heatwave in the future, and it’s X or Y degrees with X or Y humidity, how may that affect people living in certain parts of the world? So, that’s research that would really only just started, but say if we got a heatwave in the Middle East, which would be in the mid-50s, how would that affect people as opposed to a heatwave of Europe that would be in the high 30s.

So, this is predictions in order to have proactive solutions?

Yes, it’s still like – it’s not a thought experiment as such but it’s you know this is what could happen. It’s not saying this will definitely happen, but if these conditions occur this is what we predict the effects will be.

Preparedness.

Exactly. Yes. And like 20 years ago, we couldn’t do that. We didn’t have the scale of the data to do that. We didn’t even have the understanding to do that. But now we have more confidence in our climate models. We have more confidence in our data and our analyses and even our understanding of climate change to say, ‘Alright, well now we can apply this to the health impacts.’

Can you give me some sort of real-world examples of some of those predictions that you kind of making?

If you think about Sydney and some of the worst heatwaves where have been in the mid-40s, whether you’re in Penrith or the city centre, it’s mid-40s. In the future they’re probably going to be – those heatwaves are going to be maybe 4 to 5 degrees hotter around about, could be a bit higher, a bit lower depending on where exactly you are. So, we’re looking at heatwaves closer to 50 degrees, maybe more.

And just to be clear, we’re not being alarmist. This has come from research that you’re doing, that’s been done and it’s very likely that temperatures are going to increase.

Well, if we go back to the Black Summer, so that was the summer in 2019-2020. It was so hot at the beginning. There were so many bushfires. The whole east coast, south-east coast was on fire effectively. We had, it was some time in December, I can’t remember the exact days, but we broke two records in temperature in Sydney – or even I think it was a whole of Australia sorry, the day after one another. So, we had one record broken and the very next day we smashed that record again. That is unheard of, statistically, like nothing’s ever impossible, statistically speaking. But you would never ever – like the chance of that happening without some sort of pressure on the climate is like insignificant, tiny, minuscule. Yet it happened one day after another.

To see that and to live that, it opened my eyes, even as a climate scientist, at just how quickly things are changing. You know, I’ve looked at the climate models, I’ve seen it. I was like, oh, yeah, 10, 20, 30 years, whatever that may happen. But to have it happen so soon, you know, things are changing quite rapidly. So, to say, yes, Sydney could have a heatwave, I’m not going to put an exact number on it, but a heatwave of 50 degrees Celsius at some point in my living life. Yes, I would – it’s likely, it’s very likely.

What I didn’t say earlier about heatwaves are they are relative to the local climate. So, when I say it’s going to be really hot for a few days, what’s really hot in one country or one city even is going to be different for another location. So, you think about Hobart, it’s one of the cooler climates of Australia. Heatwaves for them are cooler in absolute temperature compared to Alice Springs or Darwin or the Middle East. So, it’s relative to that location and people are adapted to the climates that they live in, so are its ecosystems, etc. So, you got to keep in mind that yes, the temperatures were warm, but they’ll be warmer in one location than the other.

Developed countries that have good access to air conditioning, good infrastructure, money to keep themselves cool will cope better than countries that don’t. So, countries that are developing where populations work outside a lot in the heat or they work in factories that aren’t cool, generally, not always these countries are in tropical or desert regions. They’re already in quite harsh climates. They’re going to be worse affected as well because they just don’t have the resources to keep cool.

Yes, you’re making me think about my first trip to Dubai. I was perplexed at why it was full of shopping malls. And, you know, if you’re talking about heatwaves, it feels like every time I’ve been there – I have been there many times, it’s a heatwave all the time.

So, I’ve been there in the middle of their summer, which was 45 degrees. And I don’t know the humidity, but it would have been at least 80 or 90 per cent. And that’s another thing actually that we haven’t touched on yet. Dry heat by itself isn’t as bad as heat coupled with high humidity. If there’s a lot of moisture in the air, which is what happens when it’s really humid –

When you say it’s not as bad in terms of the damage it’s doing?

Exactly. So, if it’s really humid and hot, your body can’t keep cool. Your body’s sweating and trying to shed this heat via moisture, which is sweat. It can’t evaporate from your skin because there’s already too much moisture in the air and so your body can’t keep cool. And that’s far worse than a dry heatwave where there’s a low moisture content. Because if you do sweat in those conditions, your body – it evaporates from your skin and it keeps you cool.

How can we better protect ourselves during a heatwave?

Don’t go out in the heat. Like bottom line, do everything you can to minimise that. Looking at Sydney, looking at the geography of Sydney, the west is affected more so by the heat than the east because the east is right near the coast. You get a sea breeze that does have quite a nice cooling effect. If you’re living out in the western parts of Sydney, you don’t get that sea breeze going so far west. So, it does get hotter during heatwaves out there. Try not to go outside in that heat. I can’t – like that’s the bottom line. Don’t walk your dog at midday when it’s 47 degrees outside. That will hurt you. It doesn’t matter of your age. That will do you some damage.

Try and air your house out at night to keep it – which is the cooler part of the day. Shut it up during the day so you’re not letting that heat come in. Have it nice and dark if there’s light there’s heat because it gets trapped inside. If you can make small improvements around your home, like having greener areas around your house, having trees, having grass, if you have the resources to water it, that keeps your local environment cooler. It can keep it cooler by a few degrees. If you can have a house with a lighter coloured roof, that will reflect a lot of the – some of the heat out and not absorb it more into your system.

Yes, I mean, they’re very sort of simple, but incredibly effective, right?

Even having fans instead of turning on your air conditioning. So, fans can be effective up to 38 degrees Celsius. Yes, it doesn’t have that overpowering cooling effect that an air conditioner has, but creating that breeze is enough for your body to stay cool up until about the 38-degree mark. So, that’s a really cheap way of people being able to stay cool. If you’re absolutely desperate, then go to your local shopping centre where it’s that more communal cooling system. We probably need more of that in the future, actually. But bottom line, do not go out in the heat. If you need to go outside, do it earlier in the day. Don’t go out at midday.

And again, looking at solutions. As a climate scientist who’s incredibly invested, how would you like to see responses at a more local level?

If they don’t have as much support as they need from government at higher scales, it’s more about the mitigation. So, have incentives like build greener areas, make sure it’s a nice leafy suburb because the under canopy will be much cooler than where the trees, where they’re sitting. So, let’s have nice leafy suburbs. The new suburbs that we are building, plant trees. You can have – and where I live in Canberra, they have initiatives to not have dark roofs on houses, if you’re building a new house. To have a certain wattage of a solar system on your roof. There are initiatives that can be done at the council level, all across Australia to do that, to stop having gas plumbed to your house and have incentives around that way.

You don’t need the federal government to say, well, this is your target to do that. That can be done. And it is starting in some local areas in Australia, but there also need to be places that should people not cope in their houses, that they can go and stay cool, whether it’s a shaded swimming pool or the local shopping centre that has evaporative cooling or offset air conditioning. What we need to do, bottom line, is stop burning fossil fuels. That’s what we need to do. It doesn’t matter at what scale it needs to happen at every scale. That’s the single biggest contributor to anthropogenic climate change.

I was waiting for you to get there.

We need more incentives up in the federal government level, obviously the international level as well. How that transpires down to the everyday person, that’s a more complex level, but I actually believe it needs to come from higher up for the incentives to start working. There’s a lot of state government, there’s a lot of local government initiatives that had they had better funding or better incentives from government higher up, they would have more money to drive this change.

You mentioned weather patterns like El Niño and La Niña earlier. And I think because that’s so much firmly planted in the front of people’s minds at the moment because obviously, we’ve just been through it. Can you tell us a bit about those and the impacts that they have on heatwaves? I suppose you know, the other way around now in extreme weather.

I think pretty much all Australians have heard of El Niño and/or La Niña. There is a phenomenon that occurs in the Pacific Ocean, right? So, it’s to do with sea surface temperatures and how the atmosphere responds. But basically, for Australia, if we have an El Niño, it means that we have hot and dry conditions over the eastern two thirds of Australia. When that flips into its opposite state, which is La Niña, it’s cold and wet conditions for roughly the same area of Australia.

El Niño in Spanish means boy, little boy. Because it happens at Christmas. So that’s where the name came from. Latin America names this phenomenon. La Niña is the opposite, so little girl. And that doesn’t flip from one phase to another year by year. It can stay La Niña for three years, because that’s what we’re experiencing now. El Niño doesn’t usually hang around for quite that long and it’s semi periodic, so it’s not like it’s every three years we’ll see, you know, one La Niña or one El Niño doesn’t always happen like that. It’s maybe every 7 to 10 years you’ll get at least a couple of phases there. So, we know, for example, if we have El Niño, we will have significantly more heatwaves and they’re going to be hotter. La Niña you’re much less likely to see heatwaves. However, because of climate change that is changing.

One area of research that you’re sort of moving towards, which I think again is incredibly fascinating are marine heatwaves. And the reason I want to talk about this is because you again, at the beginning of our conversation, we talked about the geopolitical impacts.

Yes.

And I think there’s a great example here of how that’s actually playing out, which I’m incredibly fascinated by. So firstly, tell us, what’s the difference between a heatwave and a marine heatwave? Why are we making that distinction.

When we’ve been talking about heatwaves in this conversation we’ve been talking about atmospheric heatwaves. So, heatwaves that occur with hot air above the earth, and we’ve been talking about their effects or that measurement over land where people live. About 5 to 10 years ago, the area of marine heatwaves opened up. And a lot of research has gone into this recently. So, basically measuring spells of hot temperatures, but in the ocean. That research field actually came together in a quite an organised fashion, unlike atmospheric heatwaves, where everyone was just throwing everything in. And they’ve actually been changing much more quickly than atmospheric heatwaves. So, they’re also increasing frequency and intensity because of climate change, but at a more alarming rate, I would say.

And so what sort of drew you closer to marine heatwaves?

Marine heatwaves obviously occur in the ocean. I’m not an oceanographer. I don’t study the ocean as such. But because I’d had experience in looking at atmospheric heatwaves and I’ve found them really fascinating, I’ve been working with oceanographers who understand processes in the ocean to identify these events. So, it was kind of a natural progression, I think, to move from or do both, basically look at what’s going on on land as well as how hot it is in the ocean.

Okay. So, as I mentioned, geopolitical issues, heatwaves, climate change. Explain to me how they are actually coming together and why.

So, I don’t think anyone really realises until it actually happens. So, it was about ten years ago now, there was a heatwave off the northeast coast of America around Maine region, and it affected lobsters and the lobster industry. So, at first it got really hot early in the season. Bumper lobster season. Everyone loves lobsters.

You had me at lobster.

Everyone was happy. But then what happened over the course of the season, there was too many lobsters. It was too warm, and they were just producing way too many lobsters. So, the price of lobsters went down and that caused economic tensions between America and Canada because they were competing for this niche aquaculture industry. I don’t know how heated it got. Pardon the pun. There was a huge economic impact that no one really saw coming. It just goes to show if that could happen in the ocean, it can happen with something to do with atmospheric heatwaves as well.

So, the bigger implication there is, I suppose what you’re saying is that, you know, we’re talking about the impact on ecosystems broadly.

Yes, exactly. And we have a lot of aquacultures here in Australia too. We’ve got a lot of salmon farming down off Tasmania. There are oysters that are really badly affected by hot water. Basically, anything that lives in the ocean is tuned to a very small temperature range because the ocean really doesn’t fluctuate as much as air temperatures having a heatwave that’s relatively hot to that location, that’s going to blow anything out of that very delicate ecosystem. You know, you’ve only got to think about coral bleaching in the Great Barrier Reef, those hot temperatures will affect other parts of the ocean as well.

Every three years, the Australian Research Council – ARC will fund different Centres for Excellence in areas of national priority. People interested in research will make proposals and hopefully get funded to look deeper into these issues that are, I suppose, somewhat hidden, from day-to-day life. And your part of a new centre announced for 2023, which is very exciting weather of the 21st century. What will you be investigating?

So, there’s already been two Centres of Excellence around climate change. And the current one that’s still going is on climate extremes so, that’s a natural fit. Very nerve wracking with all the work coming. But it’s good work, it’s very exciting. When we’ve talked about climate change in the past, that’s been about more general things. So, we know, for example, heatwaves will get worse by about 4 to 5 degrees. I’ve been throwing rough numbers at you. What we want to look at is more of the specifics. We know climate change is going to make these things worse. But how are the day-to-day weather phenomena that drive these hazards or these conditions, how are they going to be affected? We know climate change will affect them, but we don’t really have the detail we need in our climate models and our observations yet to understand.

That high pressure system that’s really important for heatwaves is that going to shift further or south? Is that going to stay stagnant for longer? Is that going to change? Are we going to see more of them or less of them? And how does that interact with the land surface? How will that drive ocean temperatures? How does that sit in the face of an El Niño summer verses a La Niña summer. We’ve only just started to scratch the surface on those sorts of really detailed analyses. So, that’s what we want to drive now in Australia. We need it. We’ve needed it for 20 years, but we’re finally at a point where we think we can really chip away at it solidly.

What sort of impact has the changing government had on climate science research –

Relief.

Right. There was no hesitation from you there.

No. It was a breath of fresh air, let me put it that way. I think a lot of nervous expectation because we don’t have any time left to stuff it up anymore. I feel like there’s a lot of pressure on the current Australian government to get it right. They don’t have any wiggle room. We had wiggle room back in the 1980s when this was becoming an issue, and that was 40 odd years ago.

As a climate scientist, do you feel like you’re being heard now?

More, yes. I would say more, but probably still not enough. I think we are making change. And I do want to stress that the change we’re making is good. We shouldn’t kind of get really agitated and really anxious, at least we’re doing something. Let’s sit on that and go, all right, well, how can we manage this more? How can we perfect this more? There is certainly some urgency to it 100 per cent, but we’re at least we’re doing something. But we do need to do more, and we need to ramp up. I do think our government has an opportunity here, a very important opportunity to ramp up very quickly just in case something happens in the next cycle of elections that can’t be undone again.

What you’re talking about as well, I suppose that we haven’t covered yet is collaboration, because in your line of work, it’s not just the climate science that creates solutions, it’s the climate science backed up by collaborators who implement the solutions to the problems. How important is that collaboration in terms of across research, government and industry?

It’s exceedingly important. We need to have in terms of at the research phase, we need to have – I can never say this word, interdisciplinary research to do it properly because especially for something like climate change, it has such broad impact.

So, what does that look like?

It’s working with people outside of your little sphere, your little silo to understand a common goal. So, heatwaves impact health, for example. You have all this health knowledge. I have all this heatwave knowledge. Let’s work together because us working separately ain’t going to solve that problem. And then also collaborating with people and solutions to say, alright, well here’s the issue. Here’s what we know about this issue. Let’s collaborate to solve it. You know, again, bring your own respective tools and ideas and understanding to solve that issue. So, that’s actually something else we’re doing in this new Centre of Excellence is working with the people who need our data and who use our data. So, people in consulting, for example, state, federal government, renewable energy industries to say, right, this is what we can do. Is it useful to you? Yes or no? Okay, no, it’s not. So, how can we maximise our resources to produce something for you to create a better solution?

All power to you.

Thank you.

It’s a huge job. And you’re doing a wonderful job of it. Please join me in thanking Sara Perkins-Kirkpatrick. If you want to follow the program you can jump online, subscribe wherever you get your podcasts, or join us for a live recording in this very beautiful building. Go to 100 – that’s the number 100climateconversations.com. Thanks so much.

This is a significant new project for the museum and the records of these conversations will form a new climate change archive preserved for future generations in the Powerhouse collection of over 500,000 objects that tell the stories of our time. It is particularly important to First Nations peoples to preserve conversations like this, building on the oral histories and traditions of passing down our knowledges, sciences and innovations which we know allowed our Countries to thrive for tens of thousands of years.