Welcome, everyone to 100 Climate Conversations. Thank you for joining us here at the Powerhouse. And thank you to everybody who’s listening on the podcast. I’d 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.

Today’s number 58 of 100 conversations happening every Friday. The series presents 100 visionary Australians that are taking positive action to respond to the most critical issue of our time climate change. We are recording live today in the Boiler Hall of the Powerhouse museum. Before it was home to the museum, it was the Ultimo Power Station. Built in 1899 it supplied coal powered electricity to Sydney’s tram system into the 1960s. In the context of this architectural artefact, we shift our focus forward to the innovations of the net zero revolution.

My name is Pat Abboud and I am very happy to be here today sitting by the wonderful Libby Gallagher. Let me tell you all about this incredible human and the wonderful work that they’re doing. Libby Gallagher is a landscape architect with over 20 years of professional experience and director of Gallagher Studio, an award-winning design firm based in Sydney that promotes climate resilience in city planning. Gallagher is the founder of Cool Streets, an initiative that grew from Gallagher’s PhD research into the best ways to adapt cities to climate change and urban heat. Please join me in welcoming Libby and make her feel very, very welcome.

I’m really excited to talk to you today, Libby, because I’ve been through the brief of your work and didn’t realise that I’d walked through one of the most beautiful projects you’ve created a Pirrama Park many a time. And you were saying before we started recording today, the most beautiful thing for you is seeing it grow over time. And I think that’s the sort of fundamental difference with landscape architecture, right?

That’s it. It’s a long game. You’re always thinking about what you deliver today is not what it’s meant to be. You’re always thinking about 10, 20, 30 years down the track. And that’s what I love about it. It’s just it’s an evolving thing. It’s not static.

When did you know that you wanted to work with the natural environment? Was there a light bulb moment?

I don’t think there was. It was always part of my DNA. So, I grew up on the edge of a national park and loved the bush. Like, I was always playing in the bush. And it was so innate, Pat, that I don’t think I ever questioned that sense of that’s what normal life is.

And where there any influences in your family that sort of geared you towards this area of work.

Well, looking back, I mean, my dad and my mum were incredible gardeners, just incredibly intuitive gardeners. But in my actual family branch, I’ve got actually a great great grandfather and a great grandfather who worked in Darwin Botanical Gardens, set up Darwin Botanic Gardens and then –

When did you discover that?

Just recently. Just recently when I was up in Darwin and I went to the Botanic Gardens and saw the house that my granny grew up in, which was in the gardens of the Botanic Gardens. I think it’s there definitely in the DNA, that idea of, you know, natural process, botany, horticulture.

We’ll get into the detail of how you sort of working in landscape architecture and the connections to climate change and solutions around climate change. But you had a bit of a crisis moment, if you like, when it comes to climate change. What happened?

Well, it was actually when I just finished working on Pirrama Park, which you mentioned earlier, and I had been working in practice for like – I think it was like maybe at that point 13, 14 years. And I really loved practice. But this desire to deal with climate change just became really, really, almost unbearable. It was waking me up at night. I was getting these kind of nightmares at night. I know that’s really morbid, but I started to think a lot about what can I do?

What triggered that? Was this something that you read in particular or a story that you saw, or was there something that sort of tipped you – because having nightmares is pretty extreme?

Well, I think at that point in time, they’d been an enormous amount of publications about the coral reef disappearing, the Great Barrier Reef disappearing. And I think it had been bubbling along in me for a very long time. I remember hearing about climate change when I was at high school, and I don’t know, it just became more and more pervasive and it was almost like I started to think, what can I do? What can I really do? Yes, I love design and I love landscape architecture, but I wanted to think about really tangible ways that I could create or develop something that could help my colleagues, but could also contribute to this massive fight that we’re in. And I just – I think at that point I decided to just say, ‘Okay, it’s now or never.’ So, I quit my job, which at that point was pretty terrifying and went back and became a student again, which was –

This is when you started your PhD?

My PhD at Sydney University, and I was a total fish out of water there, Pat. I was the only landscape architect in that faculty doing a PhD on climatology and urban design. So I was really in a new realm and it was fantastic. It was kind of scary but exciting.

A real turning point.

A turning point. Absolutely. A turning point for me personally, because it felt like the weight lifted because I felt like I was able to really tangibly do something. It didn’t actually make the nightmares worse. They lifted and I felt like, oh, I can be part of something, I can do something.

Can you unpack the sort of focus in detail of your PhD? Because I think it’s interesting to understand where it started and then how you sort of grew from there in terms of creating a bit more of a sense of hope around climate change, that there is a solution we can get to.

Absolutely. I wanted initially to think about how I could tackle climate change in the way that we design our cities, and then I narrowed right into streets. And it sounds strange, why streets? But for me, I’d worked a lot in streetscape environments as a landscape architect. And they are really hard to deal with. Lots of different people have ownership over them and everybody lives on the street. It’s sort of one of the parts of our lives that we experience every day.

You’ve got to please so many people get.

You’ve got to please so many people, but it’s also like this huge resource, this huge public resource that could be modified or adapted to try and contribute to this issue. So, I knew lots of my colleagues were working in architecture modifications and other people were thinking about parks and big city proposals. I was just interested in like suburban streets. How would you modify a suburban street to get the best possible outcome in terms of addressing climate, bringing CO2 out of the atmosphere, thinking about how you can minimise CO2 emissions? So, I did a lot of very detailed climate modelling. I was a real fish out of water in it. I kind of had to teach myself multiple programs, but I was really interested in thinking about the street as almost a series of components that you pull apart, like the road and then the curb and then the trees and what type of trees.

Like a Lego model.

Like a Lego model, pulling them apart and then working out what’s the CO2 profile of each of those parts? What takes – what is a contributor to CO2? What reduces CO2 emissions? And then if I put them all back together, what would I say to a council or a government authority or a community about what they should focus on? So, should they focus on painting their street white or should they focus on putting more trees in? And what type of tree should they be? And what layout should they be in? So, I was interested in putting back on my design hat through the scientific lens and thinking about, okay, all of these different components, they fit together in different ways. Here are different solutions. What has the most impact?

So, your PhD research and the process of work that you went through was, I suppose, the birth of the Cool Streets project.

It was the absolute birth. So, it was the genesis of thinking about this is the – this is what I found from the research. And I suppose the big message of the research was, you know, trees. Actually, trees have the biggest impact if you’re going to be really serious about ‘green streets’ in inverted commas, which I heard lots of people talking about. I was like, well, what does that mean? It’s actually trees and its big trees and it’s a mix of spaces. So, if you were a local government, that’s what you should focus on. Don’t worry so much about the profile of the materials on the street. Think about the greenery on the street.

When I first read about the heat island effect, it’s quite a complex sort of theory and idea and area of research to grasp. But how do you go about describing the heat island effect and its links to climate change when you’re talking to everyday people in the street who you want to sort of bring around?

Yes, how I would describe it in a really everyday way is that heat island is, it’s kind of everything bad that we’ve designed in our cities. It’s actually the amount of buildings we’ve put in our cities, the amount of pavements we’ve put in our cities’ pavements that have – don’t absorb water and the lack of trees means that we’re kind of created an urban heat little island.

That’s capturing the heat.

Capturing the heat. So, when the sun hits those areas, it basically absorbs the heat and it takes a much longer time than, say, rural areas to cool down. So, in a way, we’ve got two things going on in cities which makes them really vulnerable. We’ve got that phenomenon, the urban heat island plus coupled with the global climate effect, which is obviously that amount of CO2 that’s released into the atmosphere that is warming up, acting like a blanket, basically keeping the whole global climate warmer. So, what you find is that plus urban heat is making cities incredibly vulnerable to heat. So, the more we kind of build these kinds of environments, the worse it will get. We’ve got to think about ways to adapt what we’ve already got. We’d love to have these visions about let’s demolish everything and start again and create these green eco cities.

So it’s more retrofitting.

It’s retrofitting. It’s thinking about, what are the things that we should be kind of shoehorning in adapting into our city fabric to make it work better?

It’s interesting, just hearing you describe the pavement in that way. Like when I’m walking on the pavement in my own street, I never think about the heat that it’s holding. It’s just not the first thought that crosses your mind. It’s how quickly am I going to get to where I need to go?

And a lot of people don’t think about it. You just sort of know you experience it, and you feel it, but you don’t necessarily think about why it’s occurring.

Or where it’s coming from. You assume it’s the sun. But it’s actually being captured and it’s making it worse.

It’s making it worse. And it’s exacerbating all of these issues. That’s why cities are so incredibly vulnerable, because they’re kind of dealing with two things. They’re dealing with this phenomena that we’ve constructed ourselves and also these kind of global climate drivers that are affecting climate patterns across the world.

You’ve designed projects all around Australia. You have a very specific interest in Western Sydney, my hometown. Why is that an important region for you to focus on? Why specifically Western Sydney?

I think Western Sydney is almost like – it’s dealing with a lot of problems coupled with all of those other things I mentioned. It’s away from the coast, so that means it gets a lot hotter. It’s 10 degrees hotter in Western Sydney on heatwave days than Eastern Sydney because we don’t have the, you know, there’s no moderating winds and it’s also the place where we’re building a lot of housing. So, there’s an enormous amount of people living in those environments and a lot of them are very vulnerable to negative consequences of climate.

So, I was really interested in helping those communities. I mean, obviously, look, I’m interested in helping every community that’s interested in adapting, but those communities in particular and communities that are maybe more socio economically disadvantaged have less ability to be able to go inside and switch from an air conditioning unit, maybe less ability to be able to go to a pool or go to the coast and cool down. I was really interested in trying to think about how we work with that, you know, to help those people in those areas.

What does that sort of tangible impact look like? So, what I’m talking about there is the benefits of urban tree cover.

Well, it’s quite dramatic. I mean, a lot of research that’s been driven over the last 20 years looking into that question. In some instances, the data has found that it can be up to 10 degrees cooler in forested areas and non-forested areas because not only are you standing under the shade of fantastic trees, but what the trees do when they’re combined and obviously when they’re cooling themselves down on a hot day, they transpire, which means that they’re like natural misting systems, they cool the air. And so, it’s like nature’s air conditioners. They are really mechanisms for cooling. And, you know, there is debate about certain tipping points where they reduce the transpiration in certain heat wave events.

But in lots of instances, you know, in moderately hot to sort of hotter days, they’re really fantastic mechanisms for cooling. And they also shade buildings, which means that they’re kind of dealing with that issue of the need to switch on the air conditioning unit, which then is linked to the amounts of fossil fuels that are being burned to basically drive that –

Its the cycle.

It’s a cycle. So, you sort of need to think about – that’s why I think the trees story is so, you know, it’s kind of simple, but it’s also incredibly complicated because they provide such a fantastic mechanism for taking carbon out of the atmosphere, but also driving cooling in these different ways.

On Cool Streets, we’ve talked about it a little bit, but can you go into more detail around the sorts of benefits the program has for the communities that you work with?

Cool Streets is a community engagement project that works in partnership with councils and local communities to deliver and empower communities to make the right choice for planting on their streets. The tagline is to cool the planet one street at a time, and the idea is that local communities are engaged with choosing what is right for their streets. So, they will come to a weekend event. So, we often – we do three events, come down to the street usually on a Saturday morning, come and meet us and we just simply first go is just to ask them about trees. We show them some images of small, medium and large trees and just ask them, which one do you like? Got to say Pat, every time it’s the small trees, the worst environmental outcome. The small trees, every community chooses those.

Do you think that’s because it’s like it doesn’t cover the frontage of their homes, all that sort of stuff.

And it’s neat, it sort of, you know, it looks tidy, it won’t interfere with the pavements. So, it’s an interesting thing. It’s a really – it’s every place we’ve done it in and we’ve done that in nine different communities and every time it’s small trees, first choice, and then we share the environmental benefits. So, what the different trees, the three different trees would mean in terms of shading their properties and reducing their electricity bills. What the tree does in terms of taking carbon out of the atmosphere. And then we – usually it’s always the big tree at the end that’s the best. And after that information we’ve found significant changes in preferences. So, it’s always, you know, medium to large trees that become the most popular choice after the information is shared. And then we just have a big panel next to us and ask people to put their final choice on that panel so all their neighbours can see, oh, that’s my final choice.

So, that first fact finding mission is really helpful for us. And we take that information away and we do a bit more digging into what they’ve said, ask them a few more questions, and then we come back with real designs for their street. Two different options again, with this is the exact species. This could be the mix of trees and then the environmental profile of both, and they choose their final option again, democracy. So, everybody in their street can see what was the most popular one and that’s why they’re getting it. This is this is the choice that they’ve made as a community. At the end of that phase, we come back and plant the trees, give everybody a watering can, because we want them to care for their trees and take ownership of those trees. They are their choice. That’s their legacy. And they are now custodians of those trees.

It’s a huge investment because you’re doing that street by street, right?

Street by street. And look, often it can be a catalyst for a greater discussion about the importance of trees in the community. So, it doesn’t necessarily mean that we would imagine every street in Australia has to do that process, but it might be in particular environments or communities where heat’s a real problem. It’s a great conversation starter. It’s a great way to initiate a dialogue with the wider community about why trees matter.

What are the benefits, how do you unpack the benefits to kind of get them on board?

Really simple data. So, really simple information about this is the amount of CO2 that’s taken out of the air, which equates to how many cars taken off the road by this one tree. So, we will show that for each option. And we’ll also say, really tangibly, this is the benefit to your electricity bill. So, if this tree at maturity, let’s look at how much electricity costs at the moment, this is what the benefits would be for you not having to switch on that air conditioning unit to cool your house.

How many degrees are we talking in terms of like reduction of heat when you’ve got good tree cover?

Well, it can be up to – I mean, it varies with the density of heat. So, in some of my modelling, just to give you an idea in tangible terms, if I was just looking at a typical street verge next to some suburban houses, getting the right mix of trees could reduce their consumption of that house by providing shade, saving up to $450 a year, just by reducing the need to switch on the air conditioning unit. So yes, it can be in degrees. So, some researchers have found up to 10 degrees. In other ways, it can be –

So trees can reduce temperatures by up to 10 degrees.

Yes.

That’s quite substantial.

It’s quite dramatic and it depends on – the other factor Pat is it’s also the type of tree. So, you know, when you stand on the side of rainforest tree like a brush box, you get a certain kind of – it’s a much denser shade, whereas maybe under a gum or a eucalypt, it’s a lighter kind of shade. So, you’ve got to think about them in combination and how they provide that shade density when you need it, particularly in the summer months, and maybe when you need more solar access in the winter months you think about lighter canopy trees or trees that lose their leaves. So, it’s quite a nuanced way of thinking about planting. But it’s, you know, residents really grasped it as soon as we started to communicate it to them.

If you’re doing it street by street, as I said, it’s a real investment. So, it’s a long term and long haul project.

Yes, it is. And it’s a bit of a labour of love. But the thing that’s really encouraging to me is that the project has opened the door to a lot of different people valuing trees and seeing trees in a new way. And I think that’s – I suppose my big takeaway is that I’m interested in taking one little seed or one little place and seeing how it evolves and grows. It’s sort of that top-down approach. We’re pretty good at announcing policies and big ideas, but I’m really interested in sort of flipping it the other way and thinking about a grassroots up approach.

Yes, well, it’s sort of taking the action of giving it, putting it in people’s hands.

Putting it in people’s hands, empowering them, but also encouraging them to care for the trees. It’s their choice. They’ve gone on the road to choose this layout. They’ve got ownership over it.

And there’s investment there.

There’s investment. And I mean, I just thought I’d just tell you one little story about one person just to illustrate this idea is that I met one guy who was – his name is Balla. He’s on the very first pilot project, and he was such an unassuming guy, Pat. Just very sort of low key, came with his family, you know, made his choices. He became the one that was so empowered by the process, made his final choice. He took his blue watering can and he became the custodian of the trees on that street. He watered them, cared for them.

I just went back last year and he’s standing under that tree now. That tree that was planted seven years ago is now nine metres tall, and he’s standing under the shade of that tree and he’s so proud of it. And he told me in unbelievable detail about how every other tree was going and this one was going well, and I needed to prune that one. You won’t necessarily get everybody being like Balla, but if you just get one or two Ballas, it can just add up and make a huge difference to a community.

Was that in Blacktown?

In Blacktown.

In the pilot project?

Yes.

So, what are some of the sort of broader impacts that you’ve seen play out?

Yes, well, I’ve seen the shift in the interest in and acceptance of tree canopy. I’ve seen that councils are much more on board on empowering the residents to make the choice themselves. So, historically a lot of councils would have said, ‘This is our plan for every street, you don’t really get a say. You might get a little bit of a say, but not much.’ So, I’ve seen a sort of a mind shift in the way that councils are delivering their tree planting policies rather than the top down they’re more willing to take a grassroots approach and hand over the keys to the decision making a little bit more. That’s been a real shift.

Obviously, seeing the trees in the ground is amazing. So just – it’s a little piece by piece, Pat. It’s not necessarily like I can say there’s a million trees we’ve done. It’s just little bit by little bit. But I think it’s the catalyst and the conversations and the way that it starts to empower certain councils to do this and different communities to maybe have conversations in their schools about why trees matter and –

Well it’s a multilayered approach, because obviously the community impact is there. You gave that great example of Balla, councils are recognising that community’s getting on board.

Yes.

So the slow process gets faster and faster as more people take up those processes.

That’s exactly right.

So what’s the best practice model of the sort of – the kind of street where it works in terms of the trees that you select and what would work best?

It’s nuanced, Pat. So, it’s different depending on the orientation of the street. There’s some kind of rules of thumb. So, if you’ve got really exposed houses that are facing west on that street, try to get some nice dense, shaded bigger trees and maybe some fast growing trees like eucalypts in there to get shade immediately, but long-term shade protecting those houses. But it is nuanced, because people have different preferences. So, you have to pull apart not only people’s perceptions, but actually what works best. If you’re trying to reduce the amounts of emissions, you’ve got to kind of combine the research with these people’s preferences and figure out what is the happy medium? How do we bring these two together? And it’s all about the way the streets oriented and what that community, what that particular community prizes.

So, I gave you that one community. In another community in Western Melbourne it was all about climate change. They were really interested in the carbon sink idea, so they were sort of more outward looking. In Lane Cove the message that got cut through was those gum trees are really good for animals. That gives animals habitat. That’s what cut through. And you know, most people then chose the bigger trees because they understood, oh, this is going to provide habitat for those animals that I so value. So, it’s different with every community Pat. That’s why the process is really important. So, if you can just dig a little bit deeper, take the time – look, you can spend an enormous amount of money on top-down tree planting policies that go in, plant a million trees, bang, come out. But a lot of them fail because you’re not having the chance –

The community is not engaged.

The community doesn’t support it, doesn’t understand it. You know, it feels other than. It feels sort of enforced on them. And I’ve heard a lot of councils say, we put all this great tree planting in in this new residential area and they saw people ripping the trees out because they didn’t have any relationship to it. No ownership of it.

Well, it’s interesting because it really is a genuine combination of the climate science, urban design, landscape architecture and community engagement. You really are sort of massaging those things all the time. In order to achieve a really impactful result.

Yes. You summed it up exactly.

Well, let’s look ahead. Are there currently requirements for council to have a certain percentage of tree canopy? Like what sort of policies would you like to see in place to support greater uptake of trees in our urban areas so we have cool streets everywhere?

Yes. So, I think the local councils are doing a lot of work in terms of delivering trees and in parks and there are a lot of councils taking on targets for canopy cover. I would say the biggest thing that needs to happen is enshrining minimum requirements for trees on private land. And I’m not saying that that’s only one type of private land, but it should be all types of private land –

What does that mean? How does that translate?

It means every bit of industrial land, every bit of commercial land where there’s an office block, where there is a private home that everybody should be doing the contribution. It shouldn’t just be all on private gardens to provide greenery for the city that we need. If we’re going to deliver it, everybody needs to play a part and the streets play a part, the parks play a part. But if you think about all of that private land, it’s like 60 to 70 per cent of our cities is private land. We actually need that land, we need people to plant trees.

Some of the things that we’ve thought a lot about. I do a lot of policy work as well as the Cool Streets work, and we just completed a big project with Dr Michael Zanardo, who’s a fantastic architect, where we were basically testing what is an appropriate target for all of these different land uses, and could you embed that into policy? And we found that it would be very easy to do with no additional cost in terms of additional housing costs and it could be realised tomorrow. Now that’s a piece of work that’s sitting at the moment as guidance that if it was enacted in policy would make a huge difference to delivering greening across the city.

Are the international models that you look to for inspiration where you know that there’s tree canopy cover everywhere and it’s exactly as you want it to be that you sort of look at and go, wow, that’s what we need.

That’s what we need. When I think about it Pat, the ones that I really love, are just like the guerrilla groups. For me, they are the inspiring people, I mean, obviously I love policy and I’m interested in that, but I’m really interested in like little tactical guerrilla communities that are doing their own thing and trying to make a difference in their own way.

I just read the other day about one in L.A. where this couple have got together this approach where they basically scatter wildflowers because they see that bees are being decimated and they want to provide more wildflowers. That sort of tactical idea of everybody makes a difference. How can you contribute? That’s the most inspiring to me, Pat. It’s not necessarily the big, you know, visionary sort of top-down approaches. I love that local people are just doing something fun, like using a water pistol to spread seeds into an area that they can’t get to grow a wildflower garden. Or people that are doing things like guerrilla grafting on trees, fruit trees to get the fruit again.

As you’ve been saying, I think the message here is that it is incredibly important that sort of working at – or to work at this local level because you are really putting the power in people’s hands. That’s really what it’s about.

And that’s what defeats hopelessness is being able to encourage people to take some action, do something, no matter how small it feels to be part of a solution. And I think that’s what’s given me hope, is that idea of, you know, doesn’t necessarily have to always be somebody else. The other, the government, the big corporations, the multibillionaire, entrepreneurs who can do this, everybody can play a part. And that’s what I’m really interested in.

Libby Gallagher, thank you so much. Please join me in thanking Libby for sharing her wonderful wisdom. To follow the program online you can subscribe wherever you get your podcasts. And visit the 100 Climate Conversations exhibition or join us for a live recording, go to 100climateconversations.com.

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.