New podcast episode: The carbon footprint of high latitude neighbourhoods with Nilusha Welegedara

EPISODE  7- The Carbon Footprint of High Latitude Neighbourhoods

An increase in greenhouse gasses is the main culprit of climate change around the globe with 50 to 60 per cent of emissions being produced by cities. Find out more about how neighbourhood carbon emissions are contributing in this podcast episode with Nilusha Welegedara.

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Thank you, Nilusha Welegedara, for making this episode possible.



Host: You’re listening to the Land Use Podcast brought to you by the Alberta Land Institute.

Nilusha: Cities consume almost 75 per cent of the world's primary energy and are responsible for generating 50 to 60 per cent of greenhouse gas emissions. High latitude cities are warming two to three times faster than the global average. We have also a responsibility to reduce greenhouse gas emissions by small actions. So maybe switch off the light and walk to nearby shop. Like small, small things together can make a big contribution.

Host: Welcome back to the Land Use Podcast. I'm Aysha Wu with the Alberta Land Institute and today we’re talking about the carbon footprint of residential neighbourhoods, specifically here in Edmonton, Alberta.

Before we get into it, I want to acknowledge that Edmonton resides on Treaty Six territory and Region Four of the Metis Nation, the traditional gathering place for diverse Indigenous peoples including the Cree, Blackfoot, Métis, Nakota Sioux, Iroquois, Dene, Ojibway/Saulteaux/Anishinaabe, Inuit, and many others whose histories, languages, and cultures continue to influence our vibrant community.

Greenhouse gasses are gasses that trap heat from the sun and warm the Earth, thus the greenhouse part of the name. The gasses, which include carbon dioxide, methane, nitrous oxide, and water vapor, occur naturally but are also affected by human actions such as burning fossil fuels. Greater concentrations of greenhouse gasses in our atmosphere trap more heat and cause global temperatures to rise. Rising global temperatures are already causing many issues globally, so in order to mitigate the negative effects of those rising temperatures, it's important for us to understand the sources of greenhouse gas emissions caused by human activities.

For this episode, we will be focusing on recent research conducted by Sandeep Agrawal and Nilusha Welegedara about the carbon footprint of residential neighbourhoods in high latitude cities. Nilusha is here with me today so welcome, Niulsha. Do you want to introduce yourself and tell us about what you do?

Nilusha: Sure. Thanks, Aysha. My name is Nilusha Welegedara. I'm a postdoctoral researcher at the Urban Environment Observatory Lab and Research Manager at the Alberta Land Institute, University of Alberta. I have conducted and involved in several research projects at the Urban Environment Observatory Lab, focusing mainly on greenhouse gas emissions and urban heat island effects in high latitude cities.

Host: Awesome. So just to start off really quick, could you give me a brief explanation of what a carbon footprint is?

Nilusha: Actually, the carbon footprint is the total amount of greenhouse gasses that we are generating by our actions, and there are a number of greenhouse gasses we know. Mainly carbon dioxide, methane, nitrous oxide, chlorofluorocarbon, ozone, and water vapor.

Host: So clearly you have worked in this field for a bit. What sparked your interest in the topic?

Nilusha: According to National Aeronautics and Space Administration – we call NASA – or Goddard Institute for Space Studies lab – or GISS –  in 2023 the Earth was about 1.36 degrees celsius warmer than it was in the pre-industrial average. Also the past 10 years are the warmest on record. So we know that the main reason behind global warming is increasing greenhouse gasses in the atmosphere so we need to take immediate and effective actions to reduce greenhouse gas emissions from all sectors to reduce the threat of climate change and global warming.

Host: Yeah, that's pretty significant. You worked on a previous study in 2021 about greenhouse gasses. Did that at all inform the newest study that you worked on?

Nilusha: Yeah, actually in previous study we used a small sample of neighbourhoods, only 12 out of 402. The study was mainly conducted to look at the direct emissions from residential, commercial, and institutional buildings, and personal transportation and waste generation using provincial and city energy intensity factors. But in this study we just mainly focused on household energy related greenhouse gas emissions from residential neighbourhoods.

So we got data from 334,000 housing units and vehicle kilometer traveled by residents of each residential neighbourhood across the Edmonton region. So we had a very large data set for this study compared to our previous study.

Host: That makes sense. I feel like if you did the two studies kind of together it would have just been humongous, right?

Nilusha: Yeah, yeah it’s true.

Host: So what was this research process like?

Nilusha: Professor Sandeep Agrawal, the director of the Alberta Land Institute and Associate Dean, and I recently conducted this study at neighbourhood level to find out the greenhouse gas emissions from household energy consumption and to identify the leading greenhouse gas emissions sources in high latitude cities like Edmonton. So we also look at the relationship between household greenhouse gas emissions and some population or socioeconomic characteristics, and also we look at some possible ways to reduce greenhouse gas emissions in high latitude cities.

For this study, we look at household energy related greenhouse gas emissions in 265 residential neighbourhoods in Edmonton. As I mentioned, we consider 334,000 housing units and vehicle kilometer travel by residents. The City of Edmonton and Natural Resources Canada kindly provided us the data. So we developed a model to calculate emissions, and then we calculated per capita energy related greenhouse gas emissions from each neighbourhood, and then we created maps to find out the distribution of greenhouse gas emissions across neighbourhoods in the City of Edmonton.

Host: Wow, that sounds like a huge project. How long did it take?

Nilusha: It took nearly one year.

Host: Wow!

Nilusha: Yeah, it was pretty intensive. We had all the data and we look at and created a number of maps. So we published this study. So that study, we have a number of maps and different statistical analysis to identify relationship between greenhouse gas emissions and social economic factors.

Host: Oh, that's so interesting. Can you tell me what the significance of high latitude is for greenhouse gas emissions?

Nilusha: Yes, definitely. Actually, I will start with cities – why we did this for city. Cities have higher capacity to reduce global greenhouse gas emissions because cities consume almost 75 per cent of world’s primary energy and are responsible for generating 50 to 60 per cent of greenhouse gas emissions. Urban household energy consumption substantially impacts city emissions, especially in North America, because of the increasing demand for resources especially comes with the urbanization. So we look at high latitude city. 

So I need to mention there's no exact definition for high latitude cities like Edmonton. The city is located about 52nd and 53rd degrees parallel north, it is typically considered a high latitude city. These high latitude cities are warming two to three times faster than the global average, causing an increase in surface temperature and experiencing more frequent extreme weather events, as we saw over the past few years. Also, in general, high latitude cities have higher household energy consumption and greenhouse gas emissions because these cities face opposite temperature extremes that need heating in cold winters and cooling in warm or hot summers. Also, most of these cities largely rely on fossil fuel based electricity generation.

Host: I see why Edmonton is relevant to that kind of research then for sure.

Nilusha: Yeah, definitely.

Host: Was there anything that you found particularly interesting about the study?

Nilusha: Actually, we found a number of really interesting things through this project. The first one, we found that per capita greenhouse gas emissions from residential buildings in Edmonton outweighed per capita greenhouse gas emissions then those from personal transportation. For example, emissions from dwellings are 45 per cent higher than those coming from personal transportation. So it highlights that there's urgent need to reduce greenhouse gas emissions from homes, especially in high latitude cities like Edmonton.

And especially, more emissions are coming from single family detached houses than attached housing units, such as apartments and row houses, because detached houses use more energy for space heating. Attached dwellings like apartments and condominiums, duplexes, row houses, they share walls and use less energy for space heating, definitely lowering emissions. It shows that constructing multifamily apartments and row houses will help in reducing greenhouse gas emissions. 

Also we found that size of the house can significantly influence greenhouse gas emissions. Larger houses need, definitely, more energy for heating and cooling, causing more greenhouse gas emissions. Even though new homes, especially in suburbs, are built with energy efficient materials and technology, their carbon footprint has not been reduced as expected because the floor area of these houses is increasing.

Host: Oh!

Nilusha: Yeah, constructing bigger homes increases the cost. Also they increase greenhouse gas emission, needing more cooling and heating requirements as well as increase embodied carbon – that’s the carbon resulting in energy needed to manufacture more housing materials.

Host: Oh, interesting. I don't know if this is relevant, but I'm just curious, was there any difference between, like, small apartments and then larger apartments?

Nilusha: We didn't have – we didn't do that kind of analysis.

Host: Okay, fair enough.

Nilusha: Yeah, definitely the floor area gives you much influence on greenhouse gas emissions. So if the floor area is higher, the emissions is going up.

Host: Ok. I feel like it really relates to kind of need for increased density in city centres and like-

Nilusha: Yeah, definitely, yeah.

Host: Yeah, those big apartment buildings, smaller units kinda thing.

Nilusha: Yeah.

Host: Yeah, that makes total sense.

Nilusha: We need more dense urban areas, so that's one of the things we found through our study. And also, from a perspective of personal greenhouse gas emissions from personal transportation, we found lower emissions in the downtown and the immediate surrounding areas compared to suburban areas. The emissions from personal transportation significantly increase when a higher percentage of residents in the neighbourhood drive to work, making it the more major contributor.

Also, we found that the neighbourhoods with more commuters who travel less than 15 minutes and have a higher density of bus stops produce lower emissions through personal transportation. This may link to a higher percentage of residents using actual public transportation due to proximity to work and the availability of public transportation, as indicated by the high number of bus stops. So these results support adapting the 15 minute city approach which can substantially reduce the community level emissions.

Host: Absolutely. Yeah, because Edmonton is, like, such a car city, right?

Nilusha: Yeah, it's a car centric city, yeah. Now we need to, like, increase the density. We need secure public transportation. That is really important.

Host: Absolutely.

Nilusha: Yeah, so to reduce the greenhouse gas emissions through personal transportation. We also found that the emissions are not evenly distributed across the city and are associated with income levels.

Host: Oh!

Nilusha: Especially affluent neighbourhoods tend to produce more emissions because of having larger homes with higher floor areas per person as well as higher private vehicle ownership and usage. So it was not distributed equally. We have seen southwest side of the city has higher emission compared to other areas.

Host: Oh, so are we looking at, like, Terwilliger kind of area?

Nilusha: Yeah, like Southwest, yeah, like, larger homes and the public transportation also sometimes not much.

Host: Right. That makes sense. So you kind of touched on some of it. So obviously transportation is going to be big and density is going to be big. What other ways could the findings be applied?

Nilusha: So actually we have to increase the carbon sequestration – carbon sink – so we have to increase the green cover in the city. So that's one of the major thing, like, we are emitting more and we have to sequester more too. Otherwise carbon dioxide concentration and greenhouse gas concentration goes up.

At the same time, not only government, we found that the residents themselves also have a responsibility to reduce the greenhouse gas emissions. Especially they can do retrofit in their existing houses, also they can go for greener energy sources, such as solar panels, if they want to have bigger houses. So it reduces the use of fossil fuel based electricity for their heating and cooling. There are some restriction for high latitude cities like Edmonton. So like sometimes temperature goes very low in the city, so sometimes heat pumps are not working. But in summer, maybe, we have to use cooling and sometimes hybrid technology helps to reduce the greenhouse gas emissions from houses.

Also we have to reduce the dependency on private vehicles, it’s also one of the major thing. Also constructing the smaller, low carbon housing, utilizing inbuilt green sources, especially the solar panels as I mentioned. Retrofitting is a big thing, also, reducing the greenhouse gas emissions.

Also we found that collective actions and community programs are likely more effective than individual actions to reduce greenhouse gas emissions because more people can engage, more residents can engage and encourage residents to adopt a sustainable lifestyle. Also more educational and awareness programs at the neighbourhood level, especially in local schools, because they are the future generation that face the effect of climate change and need to reduce greenhouse gas emissions to hold the increase global warming well below then two centigrades level as outlined by the Paris Agreement.

Host: Absolutely. And it –  I think what you said about community is so poignant because if you're connected to a community of people who are kind of working towards this, it kind of helps hold everybody accountable, right? You're not just on your own trying to, you know, do solar and retrofitting.

Nilusha: Right, definitely. And some studies have found there is a peer effect, also. Like reducing greenhouse gas emissions when they're talking about having electric vehicles and having solar panels also can give some peer effects, also.

Host: Kind of more motivated to work for the greater good, right?

Nilusha: Right, definitely. Yeah.

Host: Okay, that makes sense. So do you have any recommendations then for future research in this field?

Nilusha: Actually in our study, also, we highlighted that we need more studies considering special – or – including embodied carbon. In this study we didn’t consider, like, how much carbon is associated with the producing building materials. And maybe we need more studies using building codes and incorporating spatial regression and some of the analysis.

Also we have found there is a gap in research at the neighbourhood level, especially in high latitude cities. So we need more studies to reduce greenhouse gas emissions. So the main point we have found in our study is that we need – neighbourhood specific emissions are crucial – developing community level greenhouse gas mitigation action plans in high latitude cities. So it need to focus on more neighbourhood specific action plans to find out where more greenhouse gas emitting, where we need to apply more mitigation measures.

Host: Right. So it's kind of now about, like, how do we kick start these community initiatives and also it's interesting that you're kind of talking about, you know, you did this study on how are people living now and what's the effect, but also that we need more research on how the houses are being built themselves. Because that's absolutely a big one I didn't even think about.

Nilusha: Oh yeah, and actually, like building codes. Like we compared mature and new houses, but we didn't compare after retrofitting, how much it's reduced. And so we need more studies in that field – like the contribution of retrofitting on reducing greenhouse gas emissions from existing buildings.

Host: Right. Of course. Because it almost makes you wonder if it's better to just build efficient houses or if it's better to fix old ones.

Nilusha: Yeah, that's true, yeah. We have, like, more houses that are required to retrofit. like the new houses built with new technology and materials but old houses still have some energy dissipation – energy dissipating from windows and doors, and so we need more retrofitting.

Host: I feel like if anyone – anyone who's lived in, like, an older house or an older apartment knows exactly what you mean by that, like the winter it’s just freezing cold in there.

Nilusha: Definitely like If you go in there by a window, you feel that.

Host: Absolutely.

Nilusha: So we need more retrofitting to reduce emissions from, especially from old, mature neighbourhoods.

Host: Yeah, absolutely. That's kind of all the questions that I had, but is there anything that you wanted to add before we wrap up?

Nilusha: So, sure, maybe as residents we have a responsibility to reduce greenhouse gas emissions because now we are facing the consequences of increasing greenhouse gas emissions. So we have to hold the global temperature increase to well below two centigrade. Otherwise, if we go beyond that threshold, we have to face catastrophic events. So as a resident, as a person we have also responsibility to reduce greenhouse gas emissions by small actions. So maybe switch off the light and just walk to nearby shop. Like small, small things together can make a big contribution.

Host: Absolutely. They all add up, right?

Nilusha: Yeah, so we all have responsibility to reduce emissions and, also, the government intervention is also required to reduce the emissions too.

Host: Yep, definitely. Okay, Well, perfect. Thank you so much, Nilusha. Thanks for joining me.

Nilusha: Thank you for having me.

Host: And that's it for this month's episode. As always, we have resources listed in the description if you're interested in learning more. If you enjoyed the episode, leave a like and a comment. Feedback is always welcome. Make sure to subscribe for more and follow us on Facebook, Instagram, X, and LinkedIn. And thank you again for tuning into the Land Use Podcast.