In the Hot Seat with Dr. Charles Simpson

Dr Charles Simpson

Health, Heatwaves, and the Built Environment.

Over the past few months, we at Shade the UK have been launching our interview series, In the Hot Seat, where we engage with experts across both academia and industry to gain insight into how their work is impacting climate change research and where the space can further evolve.

Recently, we sat down with Dr. Charles Simpson from UCL’s Bartlett School of Environment, Energy, and Resources to look into the work that he and his team are completing and identify what needs to be done to combat the growing threat of heatwaves on public health.

Hi Charles! Thanks very much for joining us today.

Looking into your academic background, you seem to have quite varied experience. Could you describe your academic journey and how you found yourself researching the effects of climate change and heatwaves?

Happy to be here!

I’ll start with my PhD. My PhD was in particle physics, an area that I was really excited about when I was leaving university and that was really the one thing that I wanted to work on because I found it so interesting. But by the end of my PhD, I was ready for a change in direction and I knew I wanted to work on something possibly more applied, for instance in something with more social purpose.

I knew that I had a lot of experience with computing and data science so, in looking for jobs and a new career path, I found an opportunity at the British Antarctic Survey. Seemingly, it was a postdoc job, yet they were advertising it as if it were a computing job, which to me was a clever way for them to try and attract a different sort of applicant.

Which worked, and they got me!

This was working on a research grant investigating the effects of climate change. What I mean by this in this instance is taking the outputs of global climate models and then trying to work out what that means for different aspects of society, whether that be health or agriculture or something similar. I believe that the first paper I wrote in environmental science looked into the effects of heat on agricultural workers and was trying to extract some insights on that from these global climate models.

During my time here, I had quite a lot of freedom to shape what I was doing in terms of my research. I think, to a certain extent, the institute was still trying to figure out what it wanted to achieve in its climate research at that time, so they were happy for me to be creative about the areas I wanted to explore. This worked out perfectly for me, as this was a relatively new field for me, yet I was able to look into it in the way I wanted.

As my work progressed, I started reading more and more about climate and health and how the health impacts of climate get attributed. That led me to reading a lot of the work from Clare Heaviside. While I was still working at the Antarctic Survey, I saw that she had posted on Twitter about a job that she was hiring for about the health impacts of urban heat.

This work seemed more to do with climate adaptation rather than just predicting the effects of climate change and overheating and really doing something with this information. And that is how I ended up working with Clare at UCL. Working alongside the team here has been amazing, and they have really shaped my research interests in a lot of different ways.

So, for how long have you been there at UCL?

I started at UCL about two and a half years ago now.

This leads me into my second question. You are currently working at the Bartlett School of Environment, Energy, and Resources. Could you dig more into the mission of the School and the research that you and your team are doing?

The Bartlett as a big department is all about the built environment. It originally started as a school of architecture, but it has grown to be something more all-encompassing, relating to anything to do with sustainability and the built environment. There are people working on energy systems, building energy efficiency, how to adapt buildings for climate change, and how to protect heritage buildings - there is a wide variety. It’s also not all about research, there is a lot of teaching as well.

The job that I do, however, is on the research side. Usually, that means completing some kind of data analysis or calculation on climate data and then publishing what I find.

On the HEROIC project that Clare is leading, our focus has been estimating heat-related mortality based on urban climate modelling and health statistics. On the team, I complete much of my work with Dr. Oscar Brousse - he completes much of the modelling and I estimate the health impacts. A lot of the research on this project was on urban heat-reduction strategies on relatively large scales. When I say ‘large scales’, I mean that our research can be as broad as looking into what would happen if we changed all of the roofs in London - what’s the biggest impact that that could have on heat? This included painting them with reflective materials to bounce back the light of the Sun, and we also looked into solar panels.

One of the things that we wanted to avoid in this research was just looking into the most high-tech solutions, as often that is what people are interested in, even if they are not the most cost-effective tool.

When it comes to your HEROIC work, some of the scenarios that you modelled were likely quite hypothetical - for instance, few reflective materials will have a reflectance of 85%. Were there any solutions, whether at the micro- or macroscale, from your research that could conceivably be implemented with a relative degree of ease? And would have a strong impact on heat-related mortality?

Of course, again looking into installing more reflective materials, this is something that could have a big impact, but the idea of replacing all roofs would be incredibly expensive and we are unlikely to get that kind of investment.

In terms of something with more immediacy and improving people’s experience of the environment, installing shading could be quite quick and feasible and would be very cost effective, particularly in the outdoor environment. This would not necessarily be just trees and vegetation because you cannot put trees everywhere across an urban environment. It takes a while for trees to grow and can often get in the way.

The problem here with trying to install lots of permanent shade structures all over a city is that, given that climatic conditions can be very variable, you don’t want them up all the time. You would only need them at certain times of the day or the year. What you might want is to have a diversity in the shade that is provided - say, one side of the street could be shaded and the other not. This would allow people to choose where on the street that they are walking, but this gets a bit outside the area of my research. It seems more sociological to a certain degree.

We have discussed the HEROIC project quite a bit. However, I have also seen that you have worked on another large project at UCL, the PAICE project. Could you provide a bit of background to this project and describe what the key learnings are as they relate to climate and heatwaves?

PAICE is still a relatively new project, so I can talk about what we want to do, as opposed to what we have done.

We are working with the Climate Change Committee secretariat and the Greater London Authority. The overall idea is to think about how the healthcare benefits of net zero policy should be incorporated into decision making. What I mean by healthcare benefits is when you have a climate mitigation policy - so you are trying to reduce greenhouse gases - there are certain things alongside this that will improve people’s health in a more immediate way.

The common one that people discuss is around air pollution, and for good reason. Fossil fuel burning creates air pollution, which has an impact on people’s health in a very direct manner. So, much of the point we are trying to make in this research is that there are many things that we want to be doing to benefit the climate, but adding to that case by providing an alternative, health-based reason for doing so. This will help accelerate the transition to net zero.

This project is quite broad and we are trying to cover a lot of ground. We have some researchers who are specialists in food and agriculture, transport, buildings, and energy.

Much of my role also includes using a systems-level approach to engage with our stakeholders and understand whether that can help them in their decision making, having a more joint-up strategy.

One of my main areas of focus has been on air conditioning. Air conditioning, many people see it as a problem for net zero. If it’s getting hotter, more people are purchasing air conditioning units, particularly at a faster rate than we are transitioning the energy grid away from fossil fuels, this presents a problem. A question that I’m trying to think about is what we are actually trying to avoid when it comes to air conditioning. Is it just a matter of us needing to get to a net zero energy grid first before air conditioning stops being a problem? Does it stop being a problem when we reach net zero? If you have a properly renewable energy system then using that energy on air conditioning could cease to be a problem.

Air conditioning, aside from just its energy demands, could be a problem in dense urban areas as there is a transfer of heat from indoors to outdoors. There is a bit of a feedback loop there, so this could be a problem in its use other than just its energy consumption.

But it is also a relatively easy-to-use and immediately useful way of preventing overheating. When it comes to principles around passive cooling and ventilation, this is something that needs to be incorporated into the original design and architecture of a building. Installing air conditioning units wouldn’t require such large-scale changes to building design.

Considering both HEROIC and PAICE, alongside any other research that you have worked on, how would you say your findings could be applied to benefitting the lived experiences of those susceptible to heat-related illness?

The research I do often considers the largest scale of environmental impacts, more along the lines of planning and regulations. It is not so much about the things that individuals can do, it’s more about how we as a society make large, collective decisions about how we manage the challenge.

Something that can be taken away from HEROIC is looking across the different scales of impact. It is not just looking at an individual residence but an entire street as a whole, a local neighbourhood, the rest of the city. All of these factors are going to possibly contribute to what your experience is.

What we have seen over the past few years is that there are things that people can and will do to adapt individually; when conditions get bad enough, people will learn to manage by adapting their homes, possibly by installing air conditioning or introducing more shade, changing their work patterns, and so on. That does not mean it will be easy or won’t cost anything, but those who can look after themselves will learn to do so out of necessity.

On the other hand, if we leave everything up to individuals and organisations to look after themselves then we are unlikely to get the overall outcome that we would want to see. It might not be fair to leave individuals to figure it out themselves or, generally speaking, it might become much more expensive to tackle it without a more unified approach. That is why addressing heat strategically, potentially at a city-wide scale, might be a fairer and lower-cost approach than leaving it to individuals. In reality, there will likely be a combination of individual adaptation and larger scale strategic planning.

In particular, how can we address challenges in the outdoor space through individual action? We need a centralised planning body that can determine regulations around building development, infrastructural planning, and what factors need to be considered in the layouts of public streets.

Yes, but there’s the issue of a lack of action. I often consider how many people need to suffer, or even die, because of extreme heat to put it at the top of a planning agenda.

The problem with focusing on mortality is that it’s all based on population-level statistics, which removes granularity from the data. You don’t know where those people were when they died - were they in their overheated home? Were they outside?

If you are trying to make the argument for outdoor infrastructure to make the public realm more livable, you can’t really point to mortality because there is not enough information on where that happened. Putting trees out in public spaces might do a lot to cool the local environment, but it’s a struggle to say with any certainty that this is necessarily going to save any of those lives. You don’t have the information that would be required to draw that direct line between public space and mortality.

We should not be focusing so much on mortality because that is not most people’s experience with thermal comfort. And I think you also shouldn’t need to make that argument in order to justify making public spaces more comfortable.

Sure, much of the research does concentrate on it, including my own research, but I think part of that is statistical convenience. It is very unambiguous whether someone has died or not in terms of the data analysis and you can get access to aggregated death statistics relatively easily. You can therefore complete that analysis of ‘this much of a temperature increase leads to this much more mortality’ quite neatly.

But if you think about the overall number of people affected, that figure is going to be much higher than the number of people who have died.

I think what you at Shade the UK did with 40 Degree Stories was quite good as it did pick up on a lot of the stuff that you can’t look into just with statistics.

Heat-related illness and mortality are both something that the research should focus on, but I have seen on your research profile that you also look into the economic impacts of extreme heat. Would you be able to talk about that and the necessity of creating more heat-resilient systems?

The economic areas that I have looked into are downstream of health. As part of HEROIC, a big idea it was to be able to think about whether these large-scale, city-wide heat-reduction initiatives are worthwhile and to argue an economic point behind them. This is informed by the way that appraisal generally works in central government, which we can argue about whether it is a good approach or not, and how impacts often get monetised.

It is essentially estimating how much people are willing to pay in order to save a life or to avoid a risk of death.

In HEROIC, we were modelling a scenario with the reflective roofs where we can say that this solution will decrease the temperature across the city by a certain amount, which would lead to a reduction of X number of deaths. Therefore, according to this economic evaluation method, we can say that it would be justified to spend these hundreds of millions of pounds on a reflective roofs policy for the benefits that we would see from a societal perspective.

Taking this into account, would you say that there are any areas of research that you don’t think are being explored sufficiently in climate adaptation? Where would you like to see your research going next?

Aside from my work in air conditioning that I am interested in now, I think generally the link between indoor temperatures and health has not been very well quantified.

A lot of the evidence that we work from is on those large population statistics studies where they are using time variations and outdoor temperature to try and quantify the impact of temperature on health, whether that is extreme heat or cold. The issue here is that this means the differences between buildings are absent from the big picture, which would be crucial to our understanding. We need much more granular data in order to make that link. It is really important for us to know how interventions that we would make would be effective at a building or neighbourhood level, in terms of health impact. The evidence there is lacking.

I think we could do with more long-term monitoring of indoor temperatures. Currently, we don’t know whether the impacts seen because of heat are based on vulnerable people in buildings in an average temperature range, or normal people in extremely hot buildings. It is somewhere in the combination of the two that makes up the overall health impacts, but we don’t know to what extent each is a contributing factor.

And yet, if we knew that, we could inform more targeted policies. It might take more individualised health data being linked to individualised building temperature data, but that could be very hard to achieve. It wouldn’t necessarily be possible to measure the temperature data in particular, but we could infer from overall building design and the cooling features that certain residences possess what the temperature would look like.

There are some people that I have spoken to who would be very interested in doing randomised control trials for interventions on the energy efficiency of buildings during winter, or something equivalent in the summer. The challenge here is that they would be very hard to do, owing to the sheer scale of these hypothetical trials. Alternatively, if there were mechanisms for funding retrofit, we could do more of an observational study and compare those who take the funding versus those who don’t. Again, very hypothetical.

Dr. Simpson, this has all been a very fascinating conversation, thank you for your insights!

For our interview series, we want to generate more of a conversation around academics in the field about the areas of research that need to be explored in climate change and overheating. If you were to ask the next academic in our series a question, what would it be?

The main thing that I have thought about recently is around the information that people need now.

Say you are talking to a local authority about preparing for climate change and they want to complete some kind of local climate adaptation report. They will often say that they need more information, but specifically around what the climate projections are going to be for their area in the future.

Yet there is likely other information that we need in order to prepare for climate change rather than just that which is future facing.

Dr. Simpson, it has been a pleasure! Thank you very much!