Hark! The Data Angels Sing: Carbon footprints to you we bring

As we enter the festive season, another major update to Carbon & Place www.carbon.place has arrived. The Beta of the Place-Based Carbon Calculator v2 (PBCC) is now publicly available. It is also accompanied by a journal paper which goes into detail about the data and methods.

This is the first public release of the PBCC since the end of CREDS in 2023 and brings several significant upgrades, including:

• Bringing the PBCC to Scotland and Wales for the first time
• Providing annual carbon footprints for each year from 2010 to 2020
• A completely reworked and improved methodology, with much more data and detail.

There are lots of exciting updates and new data to explore, so let’s get stuck in.

The original PBCC, launched in 2020, was a snapshot of our carbon footprint in 2018, and since then, the most frequent request has been to update the tool with more recent data. The many datasets we rely on to calculate carbon footprints have different release schedules and are usually released with a one-to-two-year delay, which is why the most recent footprint that could be calculated in 2020 was for 2018. The results have now been updated to 2020, but as 2020 was affected by the COVID-19 pandemic, the PBCC uses 2019 as its main reference year. The pandemic caused multiple problems with data collection and significant behavioural changes, making it a highly unusual year. These data-collection issues are also why we were only able to update to 2020 rather than a more recent year. Still, we expect further updates in the future. We also took the opportunity to go backwards in time and calculate footprints back to 2010, which is the earliest year it is practical to calculate neighbourhoods’ carbon footprints in the UK.

Adding 10 years of carbon footprints was significantly more challenging than adding 1 year. This is because we now must account for changes in neighbourhoods over time. As neighbourhood populations change over time, so do their carbon footprints, and it was necessary to capture that change as part of the carbon calculations.

The new Demographics tab in the pop-up reports highlights how the population and housing stock have changed over time for each Neighbourhood. It also provides the new “Community Photo,” an automatically generated image showing the distribution of household types in each Neighbourhood. The image-based approach is an experiment in alternative ways to show data. It replaces about 200 numbers with a hopefully more intuitive visualisation of demographic data.

Figure 1: The demographics tab in the pop-up report highlights the demographic and socio-economic makeup of the Neighbourhood. A key part of place-based decision-making is understanding the people who live in each place.

Adding emissions over time also enables tracking progress towards net-zero, allowing us to identify not only high-carbon areas but also those making the least progress.

Figure 2: A new map layer grades areas based on how much they have decarbonised between 2010 and 2019. Highlight areas where current policies have been the least effective.

With our significantly improved understanding of each Neighbourhood, we were able to significantly improve the underlying methodology for calculating carbon footprints. For all the nerdy details, read the paper. But the main difference is that, rather than treating neighbourhoods in aggregated bands, each Neighbourhood now has its own unique synthetic population in the model which mirrors the real populations demographics (e.g. age, household size, household composition), socio-economic characteristics (income, tenure, housing type) and location (city centre, sub urban, small town, rural etc). This has allowed us to include far more detail in the model and include parts of the carbon footprint, such as vehicle purchases, that were missing from the original tool.

The PBCC maintains its mix of real and modelled data, so some parts of the carbon footprint, such as gas and electricity consumption, are based on observed energy consumption. At the same time, we fill in the gaps using models to understand local consumption patterns for items like food and flights, where detailed local data is unavailable. The Living Costs and Food Survey (LCFS) remains the bedrock of understanding household spending in the UK, but what has changed is the level of nuance and understanding we can bring to each Neighbourhood by selecting LCFS subsamples that accurately reflect the people in each Neighbourhood.

No model is perfect, and the paper discusses the limitations of using synthetic populations. However, I feel confident in saying that this latest version is the best possible with the currently available data, and that the overall insights we can draw from the PBCC are true, even if there will always be some uncertainty in modelled data.

Figure 3: The historical tab shows how the total carbon footprint has changed over time and the contributions from different parts of the footprint.

Adding Scotland and Wales to the tool was another popular request, and so was high on my priority list. Each of the devolved nations does things slightly differently with its statistics. Generally, England is the easiest country to work in, and it gets harder in Wales, Scotland, and Northern Ireland, which is why Northern Ireland is still not included in the tool.

Scotland, in particular, was very challenging to add to the tools due to their combined decision to delay the Census until 2022 and then to change the Data Zone boundaries significantly. Unlike England and Wales, where adjustments for boundary changes were required only in a handful of locations, in Scotland, they were needed almost everywhere, leading to a standard warning message being added to all Scottish results.

As I said, the tool is in Beta, which means we will be making refinements over the next year and responding to feedback.

But the next big step for the PBCC will be to add the local future scenarios that I am working on with my colleagues in EDRC.  The plan is to provide each Neighbourhood with a pathway to net-zero that reflects the characteristics of the people and the place, and to provide communities with realistic local goals for achieving net-zero.  I look forward to telling you more about that in 2026.