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Professor Mark Gaterell demystifies the role of construction in our net-zero future

  • 11 November 2021
  • 15 min listen

38% of global carbon emissions come from the construction and built environment sectors. As COP26 continues in Glasgow, Professor Mark Gaterell chats to the Life Solved podcast about why we need to find sustainable futures for our cities and buildings.

Sustainable building

In his work at the School of Civil Engineering and Surveying, Mark's focused on how to future-proof buildings and ensure that those we have can adapt to changing climates.

Why is this such a vital part of the climate change conversation? Because our homes, workplaces and businesses all add to the amount of carbon in the atmosphere when reliant upon fossil fuel-powered heating and hot water. Mark says that the massive number of people living in urban areas all adds up to a significant carbon footprint:

From about 2015, we had just over half of the global population living in urban areas. I think by 2050, 70% of the global population will be in urban areas. So the way that we design and manage our cities is going to be increasingly important

Mark Gaterell, Professor of Sustainable Construction

It’s not just the insulation, tech and energy used by buildings that play a part in this, though. Mark says that by thinking about how buildings work on a city-wide scale and interact with their environments, there’s an opportunity to design smarter systems too:

We need to consider how we manage the space between those buildings and the materials we use, the biodiversity or the planting that we adopt in those spaces so that we don't just continue to cause problems for ourselves.

Mark Gaterell, Professor of Sustainable Construction

Redefining decarbonisation

When looking at the built environment from this perspective, Mark thinks that a more holistic view of what decarbonisation means emerges. Rather than thinking about energy use in isolation, he’s looking at how buildings can be adapted, retrofitted or designed to actually reduce the demand for energy in the first place. That includes things like insulation but also their aspect in relation to the sun’s ‘free’ energy, as well as a building’s suitability for the different heating tech options on the market.

Citizens of the future

Another interesting angle that engineers must take into consideration is what the needs of future citizens will look like. Buildings often outlast their original intended use here in the UK (Victorian sewers, anyone?!), so assuming present concepts of comfort will apply in climates 25 years from now might spell problems further down the line.

So how are builders thinking around this?

We work a lot with psychologists and social scientists to help us understand what our occupants expect of comfort in their buildings and how they perceive the comfort provided to them. And that is essential.

Mark Gaterell, Professor of Sustainable Construction

What’s more, Mark says that as we make decisions upon sustainability as nations, we must also consider how we can support developing countries to also take part in the climate fightback:

It's as simple as some very specific positive action. The time for rhetoric is well and truly over.

Mark Gaterell, Professor of Sustainable Construction

Episode transcript:

Anna Rose: Welcome to Life Solved, the research podcast from the University of Portsmouth, where we explore how breakthroughs here are changing our world today and in the future. Across the first two weeks of November 2021, the UK hosts COP26, the UN's Global Climate Change Conference. It's here that world leaders and the public are discussing the collective actions we need to take to prevent the damaging impacts of climate change upon our world and environments. The University of Portsmouth is proudly contributing to the COP conversations, offering expertise and ideas on everything from sustainable trade to global citizenship, plastic pollution and marine biology. But each day, COP is visiting a different set of major challenges facing our world, and so in these In Focus episodes, we're taking a closer look. Today we meet Mark Gaterell, professor of sustainable construction here at the University of Portsmouth. His research focuses on our homes and workplaces and how they interact with environmental challenges.

Mark Gaterell: I'm particularly interested in how the built environment interacts with this idea of climate change. And in two particular ways, I think the first is how we can work with our built environment to mitigate or to reduce any future challenges or damage to the climate in the way that we build and operate those buildings. And the second is thinking about adaptation. How can we ensure that the built environment that we have can adapt to the changes in the climate to which we are already committed as a consequence of our previous actions so that our built environment continues to perform well now and in the future, almost despite whatever future climate actually emerges?

Anna Rose: So what changes need to be made to the building and planning process? How do they tie in with other scientific disciplines? And can we be sure of a positive future by decarbonising our home and work environments?

Mark Gaterell: To get rid of demand by design. That's the key, for me, to the successful decarbonisation of buildings.

Anna Rose: Conversations on the environment and the future of our world have been had for decades. But as the countries meet at COP26, this focus has never been sharper. A topic that isn't often at the top of the list is sustainable buildings. And in a world where CO2 pollution is often focussed on the likes of air travel and farming processes, you might be surprised at the level of impact our homes and offices have on emissions.

Mark Gaterell: In the UK, we can probably say a little under half of the total final energy consumption comes from buildings in terms of heating and hot water. So just in terms of our buildings, I think they are, you know, significant contributors to CO2 or the consumption of energy. From 2015, we had just over half of the global population living in urban areas. I think by 2050, that's likely to be 70 per cent of the global population will be in urban areas. So the way that we design and manage our cities is going to be increasingly important.

Anna Rose: And the focus shouldn't just be the buildings themselves. It's just as important to consider the outside as much as the inside.

Mark Gaterell: What's important and interesting about cities is when you start to group these buildings together, it doesn't just become a question of how well the buildings perform, it also becomes a question of how well the spaces in between the buildings allow us to manage the interior environment of those buildings, help us to clean the air around those buildings and provide an environment that is low in pollution and that contributes to us being able to manage the interior spaces of those buildings. So that's why I think at city scale, it becomes really complex and really interesting for people like me to think about. And you know, we are living in an increasingly urbanised world. If you look at any of the figures, those kind of excess deaths that occur as a consequence of heatwaves, particularly in cities, there are very real consequences to this. So at a city scale, yep, let's think about the buildings, but we have to think about cities by design and to minimise the impacts now, but also the likelihood of impacts in the future.

Anna Rose: So clearly, not only should future planning consider the buildings, but the spaces in between. Professor Gaterell takes it even further. Thinking about the ways that humans living in cities will respond to these changes in the future,

Mark Gaterell: The way we currently group buildings together in cities generally elevates the temperature in those cities at night-time. So we get higher night-time temperatures because the heat that is absorbed during the day, gets rereleased and elevates the temperature in a city. If you combine that with climate change, then the likelihood is that people will turn to cooling systems more readily because the night-time temperatures are higher. So you'll get an air conditioning plant on your flat that will take the heat out of the flat and put it back outside, and that will then contribute to an elevated temperature. So, you know, we run the risk of entering into these kinds of very non-virtuous cycles where we continue to elevate those city temperatures, continue to rely on air conditioning plants that again artificially raises those temperatures. So we really have to think about how we not only design buildings but how we manage the space between those buildings and the materials we use, the biodiversity or the planting that we adopt in those spaces so that we don't just continue to cause problems for ourselves.

Anna Rose: If the only focus needed were on new builds, this kind of planning would be comparatively simple. But with the buildings that we live and work in today consuming such a high level of energy, we need to consider the current day housing stock as well if we are to effectively decarbonise the built environment.

Mark Gaterell: We have to think about the existing building stock and how we improve the performance of that existing building stock. And for me, decarbonising the built environment isn't about putting green electricity in the grid. Decarbonising the built environment is about reducing the demand for energy, whether that's cooling energy or heating energy by good design, getting rid of the demand for it. If we have no demand for it, it becomes extremely easy to supply it.

Anna Rose: And there are further lessons to be taken from existing city infrastructures. There's evidence above and below ground in 2021 that should be informing any future planning.

Mark Gaterell: Let's be honest, the asset lives of some of our buildings are far longer than probably was imagined when they were constructed. And the same is true for our infrastructure. You know, we're all aware of Victorian sewers still being central to the operation of London, and the same goes for our buildings. We have built assets that have easily exceeded their projected asset life. I think, for a reasonable planning horizon, I guess we look at 2050, perhaps 2080.

Anna Rose: With a big mix of construction types in any city and a need to include both old and new builds in the planning process, it's clear that decarbonising our urban environment is a complex challenge and certainly doesn't have a one size fits all solution. Next, the day to day human needs of a city dweller needs to be considered. And as Professor Gaterell explains, an individual's needs 30 years from now might be just as hard to predict as a building's.

Mark Gaterell: Build a building that on paper, should perform perfectly. Soon, as you put people in it, you know it doesn't quite work like that. So we are quite contrary and curious creatures when it comes to comfort. Some of our perceptions are quite subjective. And so we need to understand that more if we are going to deliver buildings that provide appropriate and affordable comfort. So we work a lot with psychologists and social scientists to help us understand what our occupants expect of comfort in their buildings and how they perceive the comfort that's provided to them. And that is essential. And it is particularly important when we're looking at the adaptation side of our climate change argument because over time, it's very likely that our perceptions and expectations of comfort will change in line with what the climate is doing. Currently, we sort of apply very static benchmarks of what temperatures need to be delivered inside the building. We measure performance against some of that. That is changing and that needs to change. And that understanding of how our perceptions and expectations will vary over time becomes key to designing a building that requires a minimum amount of energy to provide appropriate affordable comfort.

Anna Rose: So at this point, you might be thinking that the decarbonisation of buildings is a little conceptual and abstract, more of a wish than a future reality. This isn't the case, and as Gaterell explains, there are solutions that can be put into place here in the United Kingdom right now.

Mark Gaterell: So for the UK, you start to make sure your living spaces are on the southern elevation, the spaces that don't necessarily need some much direct solar access or sunlight or on the northern Oliver. You know, just images, rules of thumb. But we think about how we place spaces around the building and how we use that, how we then manage the space between these buildings to allow Sun in the winter sun in low angles so that we can benefit from that free energy. So it's the grouping of buildings in a very, quite simple design philosophies that are well known that could easily be built into our, you know, regs and the way we build.

Anna Rose: And whilst we've heard a lot about cutting edge environmental technologies, they can only be a part of the plan.

Mark Gaterell: It probably makes me sound like a bit of a technophobe, and I'm not. But, you know, for me, it's about appropriate technology. So just because we can doesn't mean to say we should in technology terms. And so it's about selecting appropriate technology because technology isn't resourceful or free. You know, there are impacts with generating data, there are impacts with the provision of technology. And so we have to be very clear about why is this technology appropriate? Why are there these data that we are going to collect? Why are they useful? How do they actually materially help us improve the performance of what we do? If we can't necessarily answer those questions directly, we need to question about why are we doing it? Because nothing is pain-free. None of these things are pain-free. There is a resource cost to them. The one that's in the news is air source heat pumps, you know, a big drive to put that in. Again, for me, that's probably only appropriate in a certain proportion of housing. And so it isn't the answer. It's part of an answer where it's appropriate. But some of those messages kind of get lost in the headlines.

Anna Rose: Heat pumps were just one of the UK government's environmental policy announcements just before COP26. So let's be candid. Where is the country on the environmental leaderboard?

Mark Gaterell: I think probably if I was being generous, it would be in the should try harder column. There are certainly lots of things that we need to get on top of. I think this gap between, you know, the design intent and buildings and then what we actually get in practise, that's a real problem for us both in, when we think about that in terms of the climate change strands, mitigation and adaptation. If we can't guarantee or fully understand what this building is going to do once we've built it, then it means our mitigation measures are likely to be less effective. And it also makes it more difficult to think about how we are going to make sure that this thing can adapt as the climate evolves. And so it's a fundamental challenge for us, and I don't think we are on top of it yet. It's as simple as some very specific positive action. You know, the time for sort of rhetoric is well and truly over. And I also I would like to see some very and I don't, you know, this isn't my field, so I don't know what the nature of this support would be, but support for developing nations so that they have an opportunity to have the kind of lifestyle, not the lifestyle, but the kind of lifestyle that we have. But in a way that doesn't simply repeat the mistakes that we've made over the last couple of centuries. And so, you know, we are supporting people to improve their quality of life, but in a way that doesn't simply continue to, you know, damage the environment and for ourselves that, you know, for the other, the other nations, some demonstrable specific actions that will affect real change. What they look like, I don't know. But as I say, I think the time for rhetoric is sort of well and truly over, and this is an opportunity to get past that.

Anna Rose: And while some of the world's finest minds are intent on thrashing out a deal at COP26, we shouldn't forget that as consumers, we can make a difference too.

Mark Gaterell: We are demanding more. It's so much part of the way that people think now than it ever used to be. And so I think given that we live in a kind of market economy, you know, if we demand it, they will have to supply it. So and I feel that is, you know, that is building. So you can certainly argue whether it's happening quick enough. Yeah, probably not at the moment, but there are real signs that there is a change in our mindset and that we are, as I say, becoming more informed, intelligent, demanding consumers.

Anna Rose: In this episode, we learnt that we need to adjust the buildings of our past as much as we need to plan for the future in the drive for a decarbonised world. And we've also found that humans are an adaptable bunch. Not only can we make changes today to benefit the years ahead, but we can also change our expectations and needs in the decades to come to match the realities of the climate change we are already committed to. Thanks for joining us for Life Solved. If you want to find out more about research at the University of Portsmouth, go to the website port.ac.uk/research. We'll be back next Thursday with another episode of Life Solved. Catch you then!

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