Prepare For Heatwaves 

EP.16 – Prepare for Heatwaves Transcript 

Izzy: Hello and welcome to the Carbon Copy Podcast with me, Isabelle Sparrow. 

Brad: And me, Bradley Ingham.  

Izzy: We’re back for another fascinating episode of our series, Do Something Bigger, where we’re exploring 25 big local actions that you can take for climate and nature. 

Brad: We’re already on episode 16, so once you finish this, do go back and listen to the rest of the series and subscribe to hear the next ones as soon as they land. 

Izzy: Talking of catching up. Hi Brad, this is actually the first time we’re chatting since you became a dad. How’s it all going? 

Brad: It’s certainly been a bit of a change in life experience. Obviously, my daughter, she’s amazing. But yes, sleep deprivation is absolutely a thing. 

Izzy: Well, thank you very much for taking time away to help with this episode. And actually, sleepless nights are really quite relevant to this topic. We’re right slap bang in the middle of summer now, and 2025 has already been one of the warmest on record. The UK experienced its driest ever spring, and England its hottest June on record, with an average temperature of 16.9 degrees Celsius. 

Brad: That doesn’t sound that hot to me. 

Izzy: Yeah, I thought that until I realised that that’s the average, including night time. So that’s to say that temperatures were in the mid to high teens at night for a lot of the month, which makes sleeping really difficult and means the stress of the super hot days continues all night as well. 

Brad: Ah, so that explains why I’ve not been sleeping well then. 

Izzy: Oh yeah, nothing to do with the newborn baby. 

Brad: Yeah, can’t be that, can’t be that. 

Izzy: I actually spoke to our first guest, Professor Stefán Smith about this, and about why heatwaves can be so dangerous for health. Stefán is a researcher and lecturer at the University of Reading with interests in energy and the built environment. Before we come on to the health impacts, let’s hear from him why heatwaves are becoming more and more frequent in the UK, and why those of us who live in towns and cities experience even more extreme temperatures. 

Stefán: Climate change, it’s real. Greenhouse gases are emitted into the atmosphere, and they act like a bit of a blanket in the sense that they trap certain types of heat in the atmosphere, which means there’s more energy in the atmosphere, which drives a lot of the climate and weather processes that we experience. And so, as a part of that, then during summers we get more intense levels of heat because there’s more energy in the atmosphere. That’s why we’re beginning to see these sort of increasing number of heatwaves.  

In terms of then our experience of that in urban environments, essentially the way we build our towns and cities means that we’re changing the characteristics of the land and the surface. And so therefore that radiation which comes in to the atmosphere and hits the earth, the way the properties of the ground have been changed because of our buildings, etc., it changes the way that energy is absorbed, the way it’s reflected back into the atmosphere, and the kind of interactions happen between the surface and the atmosphere. Which means that we experience then in those urban areas a different type of kind of energy balance than we see in rural areas. And then that leads as a result to us experiencing more heat in our urban environments. 

Brad: Yeah, I guess that makes a lot of sense, doesn’t it? And actually, you can really feel the difference in temperatures, even with urban places, if you move from a more built-up bit to a less built-up bit, things really do cool down quite noticeably. 

 Izzy: Yeah, I think we’ve both had the issue before coming into London from our relatively rural respective hometowns and ending up just carrying a load of jumpers around all day.  

Brad: Yeah, that’s definitely not a vibe when you’re absolutely roasting down on the tube. But yeah, this is all very related to the urban heat island effect. And it’s basically exactly what it sounds like. Heat getting trapped in urban places, creating islands where the temperature is significantly higher than in the surrounding areas. 

Izzy: Yeah, so I wanted to know why high temperatures within these urban settings didn’t seem to be coming down at night. So like back to this earlier point we were making about the nights being so warm. When you think of places that are typically hot, like a desert, they don’t stay hot all night. In fact, in deserts, the nighttime temperatures are actually pretty chilly a lot of the time. So I asked Stefán to explain how the urban heat island effect continues even at nighttime and what this means for human health. 

Stefán: There’s a few things happening there. That kind of lump of concrete, it’s absorbing all that energy and it has some large specific heat capacity, which means it can absorb a lot of energy before it raises by one degree Celsius, which means it can release a lot of energy as well before dropping a degree. So it’s holding onto the energy longer than your desert would do or your green pastures. It dampens that cooling effect. 

Another thing is that if you suddenly now have surfaces which aren’t horizontal but are vertical and they’re facing other vertical surfaces which are of a similar temperature, then the net radiation exchange between them is minimal because they have similar properties in terms of their thermal characteristics and they have similar temperatures, which means therefore that they are exchanging energy but the net result is almost zero. So that’s called radiation trapping. And so because of that, you maintain more of the heat then in that urban, we call it an urban canopy layer. So yes, it exacerbates the heat extremes at night, which is uncomfortable for people when they’re sleeping. 

There’s evidence to show that during heatwaves, there’s increased mortality. Death rates do go up. People that are particularly vulnerable, so that’s whether old, very young or ill, critically ill. Heat stress is experienced by everyone and it’s your body’s ability to deal with that heat stress and regulate its own core temperature, which is critical. So if you’re not getting relief from heat because nighttime temperatures are remaining high, it means your body is under stress for a longer period of time and so your body’s having to deal with that. And if you’re unwell, then that becomes particularly difficult for you. 

 So the ability to keep yourself cool is really important and find ways to keep yourself cool. And again, the vulnerability is not then just in terms of your physical well-being or your physical state at the time, but it’s also your ability to deal with the conditions that you have. Hence why the very young are vulnerable because they’re reliant on other people to kind of keep an eye on them and regulate their fluid intakes and make sure that they’re sort of doing things to keep themselves cool and potentially also with people with forms of disability, which means they might be reliant on other people to do those sorts of things for them. So yes, so you do see it. One example was in the 2003 heatwave in London and there was a notable spike in increased death among elderly people during that time. 

Brad: Well, this is all a bit sad, really. And I guess in this country, we don’t really have the infrastructure in place like in our buildings that are used to having these extremes of heat. Like when it’s been hot around where we are recently, just like being able to like cool down our bedrooms is like it’s actually quite a difficult thing to do. And I imagine if you are one of these people that does have a disability or have caring needs, it’s then making it even more difficult for that. So yeah, it’s quite a difficult situation. But this is carbon copy and I’m wondering, you know, there must be things that we can do, right? 

Izzy: There definitely are. Stefán told us about some easy ways that people can make the places where they live a little bit more bearable in high temperatures. 

 Stefán: The first thing people can do is behavioural. So thinking about things that they can do to cool themselves down. So making sure that they’re drinking lots of water. 

I have a colleague from Greece who says, well, we open the back door and the windows at the front to have a bit of a through draft and they take regular cold showers during the day, right? So there’s kind of learned behaviours to kind of deal with how you keep yourself cool during those intense periods. The thing about what you can do to your surrounding urban environment to try and change it is more challenging. If they’re in a position of, let’s say, refurbishing a building that they live in, a home is something they can think about what types of materials are put on the outside of the building. Materials which reflect light more, so lighter materials and that don’t absorb heat as readily would help. 

Thinking about where you might find shade or introduce shade so you’re not exposed to direct sunlight and also shading the building or parts of a building. So again, it’s not exposed to direct sunlight. Different types of shading, you can think about awnings, you can think about planting trees or vegetation which grows fairly tall to provide sort of shade that way. The idea I said about evapotranspiration, so moisture being released into the air and it cooling the air temperature down. So if you’re planting more vegetation around your property then you’ll be getting that effect as well. And also if you have the opportunity to introduce water into your garden then that will have a very local effect. I mean, you’d have to be sitting near the water to kind of experience that. But those are things you can do to create sort of pockets of sanctuary to get out of the heat to kind of experience localised cooling. 

Izzy: The world is heating up but you have the power to make a difference. This series of the Carbon Copy podcast accompanies our year-long campaign 25 Big Local Actions in 2025 and there is loads of information on the Carbon Copy website about what you can do locally to make where you live or work a safer, happier and more resilient place. So if you’re all fired up, head to the show notes for all the links you need to get started. 

 Brad: Now we’ve talked a lot about urban heat but the whole country is affected by heatwaves so we wanted to explore a bit more about some of the consequences in more rural areas and what we can do to address them. 

Izzy: Yeah, that’s right. So very often heatwaves happen alongside dry weather and that combination of high temperatures and no rain is really challenging for the farmers who produce our food. Added to that, dry vegetation and peat is highly flammable meaning wildfires are becoming more and more common and harder to manage here in the UK. 

Brad: So we spoke to Dr Laurence Couldrick CEO of the West Country Rivers Trust about some of these issues and the work that they are doing to protect agricultural land and wildlife from the impacts of hotter, drier weather. 

Laurence: Our climate is changing because of the greenhouse gases we put into the atmosphere and we see that impacting on our catchments, on our rivers, on our land in lots of different ways; but they’re all integrated because they change how we receive our rain, they change how we receive our cloud coverage, they change how the heat patterns affect us. So you can’t really just talk about heatwaves without looking at all the other linkages. And what we’ve also seen over the last sort of 70, 80 years or so is a change in our landscape to a more intensively used environment with less want to retain our water. So we try to channel our water off of our landscapes because of flooding very quickly and what that means is we get sort of polluted and flooded water but it also means we don’t end up with water in the soils, we end up in drought. And when it comes to heatwaves what we find is the more moisture that’s in the soil the less that surrounding area, the temperature of that surrounding area is. So there’s been lots of work especially with some of our partners in France on irrigation of fields around towns and cities, and it reduces heatwaves from 45 degrees down to 35 degrees. So that’s a huge impact yet we don’t talk about that. 

Now that’s in irrigation of soils but actually what we know is if you have healthy soils with a lot of organic matter, which by the way stores a huge amount of carbon, it also holds on to more water. And so therefore your soils are moister, they don’t dry out as quickly, they hold on to their nutrients which is good for the farmer and as I say they’re not only holding on that water for droughts but it also means it reduces that temperature, the air temperature surrounding that land mass. So there are huge win-wins within there. So as I say we don’t talk normally just about heatwaves we talk about all those other things and that’s on the water side. There’s a whole other side with the drier it becomes the more prone it is to things like wildfires and those sorts of things as well. So there are lots of different dynamics that we can look at from a rivers and water perspective. 

 We link to and work with a lot of the groups that do things like moorland restoration and deal with the impact of heatwaves on wildfires and those elements that’s a component of it. Most of the time our work is as I said the link with direct heatwaves is more around how it’s linked to drought management and water resilience and so a lot of our work with farmers revolves around how can they store more water on their farm. Instead of just farming milk or beef or sheep, how do they farm water as well and for that as I said we work with them on things like soil management. So as I said the soil itself is the biggest single resource they can manage to increase the amount of storage of water and moisture within their land and then that’s useful for the crop but anything excess drains down percolates through into the lower subsoils that feeds things like groundwaters. 

But the other thing we’re doing is rather than just that replenishing and recharging common water sort of areas and the benefit that has we’re also trying to harness some of the floodwaters that usually are lost to the system in ponds and lakes around farms. And so that gives the farmer a direct resource that they can use to offset mains water usage or usage of boreholes or even rivers when we see these hotter conditions we see the rivers drying up and even boreholes drying up. So having some of these surface water stores is really helpful. But what it also does in specifically into heatwaves again it’s another place where it reduces that temperature so combined with things like tree planting and other nature-based solutions natural habitats what it means is if you’re a dairy farmer or a beef and sheep farmer there are always cooler places for your cattle to go which again link back to cattle health, herd health all of these things has huge advantages. And we haven’t had to deal with that in the same way in the past but actually farmers are coming to us and asking to how do they improve their resilience for water management in those drier periods for these sorts of things that water availability, heatwaves, managing those sorts of stresses. 

Izzy: Yeah so it was quite a few months ago when we recorded this conversation and we just had that very very warm dry spring and again it was one of those, I think this keeps happening on this podcast, where I just hadn’t ever really thought about it but the idea of cows and sheep and other grazing animals really suffering in the heat as well it’s a really big problem right. So if it’s so warm that livestock is getting ill or even dying then as well as that being really tragic, I mean for those of us who don’t eat meat the whole thing is pretty tragic anyway but even more tragic I suppose, as well as that it’s just another financial impact on the farmers who are already finding it so tough.  

Brad: Yeah I know what you mean I do remember like when it was that really warm spring like driving past and seeing cows in the field they’re all like desperately huddled under like one tree in a field somewhere I’m just like oh god yeah they didn’t look very happy. I mean you know if cows can look sad then that’s what they looked like. So obviously West Country Rivers Trust covers a large area across West Dorset, Somerset, Devon and Cornwall, parts of England that have historically experienced a fair bit of rain. We asked Laurence about how heatwaves and drought were having an impact in this part of the world specifically. 

 Laurence: Yeah so I mean a very recent example is a week and a half ago, two weeks ago we had one of the largest wildfires on Dartmoor, which for this time of year is unheard of. And part of the problem there is is in the past we’ve asked quite a lot of our landscape and a lot of those moorlands those peatlands have an artificially higher level of drainage than they would normally have and so therefore when they dry out quicker when there hasn’t been rainfall, which there hasn’t been it’s been the driest spring on record, what we get is quickly it gets into conditions where it can have wildfires. So we’ve had wildfires up there now in areas where we can restore the peatland and re-wet it and have it sort of holding on to its moisture like a sponge we just don’t see that same risk in quite the same way within there. So that’s a very close and topical example of right now what we’re facing. 

Izzy: Water resilience is important not just in rural areas but in towns and cities as well. Laurence told us about some things that people can do to ensure they’re better prepared for hotter drier weather. 

Laurence: I’ve spoken a lot about the agricultural side which is what we spend the most of our time because 80 odd percent of our catchments are agricultural, but obviously a lot of the people that might be viewing this will be members of the public that aren’t farmers aren’t linked to that world. And it’s just a reminder that everything we choose everything we do has a link back into the environment, even something you might think well where’s the carbon benefits or where’s the impact of how much water you consume. Well, all the water you consume has to be pumped there has to be treated to get to you, there’s a huge carbon cost to that but there’s a huge environmental cost to that. That water’s come from the river and therefore the more that’s coming out the less that there’s in the river, there’s less there for wildlife, so it’s being more water efficient being more savvy around these things is a huge benefit that people can do, not only for carbon sequestration but also for climate and catchment adaptation in terms of improving the resilience of our systems. 

Brad: I think we haven’t really talked as much about the collective action that people can take for this action, and about how people can access support and sanctuary from heat even if they are on lower incomes or are vulnerable. We spoke to Stefán about this. 

Stefán: It’s been talked about a lot it relates to kind of ideas of fuel poverty and inequality and being able to… I mean I appreciate the things I’ve just talked about as ways of creating sanctuaries depend on you having the money, the land, you might not have a garden you might live in a flat. There’s lots of constraints which I kind of ignored in describing the sort of the picture of things that you might do and that’s been recognised for a long time. So kind of talk about community level sanctuaries for getting out of the heat. I mean it’s also been talked about in terms of providing places people can go during winter you know if there’s fuel poverty that you can go to places which are heated so there tend to be public places, libraries, local community centres in relation to finding sanctuary from excessive heat. Churches have often been talked about because they’re generally cold which is great in extreme heat. So there are opportunities in what we already have in our towns and cities that could be utilised. They rely on community engagement and a collective effort to think about who are the vulnerable people in our communities how would we get them to these places and kind of the infrastructure needed for that. That would be a really effective way to do things as well. I mean even visiting parks, so finding parks where people can go to sit under the tree or if there’s a large lake sitting near those places there’ll be a cooling effect, localised cooling effect which they can experience there as well. 

Izzy: So there are some ideas there about making things easier. The impacts of climate change are already making life challenging at times and even if we do manage to reach net zero and prevent any further heating the climate has already changed and extreme weather events are likely to continue. We asked Stefán about his research and how it can help people to be more ready and more resilient to these events. 

Stefán: I mean one of the things that we’re, the kind of research group that I work closely with, are interested in is that cities are dynamic in the way we do things and experience them. Because that’s the real experience that people have of their urban environment. Commuting to work across the city if it’s in a large city you might be using underground transport mixed with buses and a bit of walking or something, so in that process you’ve got very different environments that you have experience of. And therefore the heat stress that you might feel during a heatwave will depend very much on that kind of transect of your commute, your working day, your return back to home, leisure activities you might be doing. So I think that’s something to be mindful of that people can think about is actually how do I navigate the city how do I what’s my mobility like in the city and how is that influencing the experience I have of extreme heat during heatwaves? 

And some of that might be also down to timing. I know it’s not an easy thing but can you shift for example your working day so that you’re not experiencing the peak heat conditions which might happen and might coincide with when you’re commuting back from work. Or if it is during the peak of the day can you think well okay rather than using the underground or bus can I introduce more walking, are there parts where I can get some relief because if I actually make the journey a bit longer, take my time a bit and break it up by walking some of the journey through a park, by a lake, under trees, those are sorts of things people can do. That’s one thing which we kind of are looking at and trying to understand kind of how flexible people can be in what they do and how that might influence their experience of extreme heat and the kind of the worsening of that extreme heat by urban heat islands. 

Brad: So Laurence also told us about his hopes for the future and the work that West Country Rivers Trust and others are doing to help make this happen. 

Laurence: I mean it’s great that organisations like yours look at how do we reduce things like emissions and dealing with the kind of the root cause of climate change and I think that is vital and we do a lot of work in that area. But a lot of our time is looking at the adaptation that needs to happen in our catchments to make them more resilient to the impacts of climate change and obviously a lot of the adaptations especially the nature-based ones have carbon sequestration potential and benefit that system as well compared to the engineered solutions. So things like managing our soils, understanding that environment is going to be hugely important and holding more water in our landscape. Another key component that we’re sort of keen to see in the Rivers Trust and National Trust and the Beaver Trust are launching a campaign on making space for water, which is around our river network has been artificially straightened and incised and narrowed and constrained, and what that means is you kind of people go that’s the river and everything else is land and the land is dry and the river is wet, where actually the way it used to be is that river had a whole wetted area and it wetted all the surrounding area because it would flood, it would move, it would shift. And if we want to hold more volume of water that’s the other thing we need to do is kind of make more space for water give it that flexibility to create sort of a more wetted area, more water storage. 

It used to be in somewhere like in the Tamar where I’m based at the moment 20% of the catchment area was wetland. Post-war that was drained down for food production, it’s now 4%. So that’s a huge decline in that area of a place where we would naturally store vast quantities of water and there’s nothing I see on the horizon that allows us to reinstate that at scale and at speed within there. So I think we’re going to see, we’re starting to see a lot of the different funding streams unite together, so ultimately making more space for water and getting our soils in as best nick as possible is some of the key things we see at a catchment level that would make a huge difference. 

Izzy: So this has been a bit of a different one hasn’t it? It’s much more about how to live with the consequences of our changing climate and how to navigate this new hotter drier world we live in. Should we sum up what we’ve learned? 

Brad: Yeah let’s go for it. I think we’ve learned more about the different urban heat island effects and why even at nighttime very built-up towns and cities remain warm during heatwaves. 

Izzy: Yeah and we’ve learned about the importance of green and blue infrastructure, how vegetation and bodies of water can dramatically reduce the temperature in the areas surrounding them and how vegetation can also help to protect the soil in dry weather. 

Brad: We’ve learned about the challenges of agriculture in hotter drier weather and about the importance of water efficiency. 

Izzy: And finally we’ve learned about ways we can adapt our own behaviour to help cope with the heat and how we can help others who are more vulnerable to find places of sanctuary. 

Brad: You’ve been listening to Do Something Bigger from the Carbon Copy podcast. It was written and presented by me and Bradley Ingham. 

Izzy: And me Isabelle Sparrow. Our editor was Alex Orosa. Huge thanks to Professor Stefán Smith of the University of Reading and Dr Laurence Couldrick of West Country Rivers Trust for speaking with us, and thanks of course to you for listening. Our next episode is called Turn to Public Transport where we’ll be going on a journey with guests from the Campaign for Better Transport, GoodMaps and Community Rail Lancashire. Until then, goodbye.