Part 1. Scaling education: What is the carbon impact?

I have lost count of how many times over the past two years, someone has raised the carbon impact of zoom calls. It usually comes up in a discussion around the environmental benefits of working or studying from home. Is there data that we can use to get a real comparison? We had also been talking about the need to scale education globally. Could we find carbon emissions data that could be used to compare different approaches to learning? Would it allow us to compare the carbon impact of different approaches to scaling education.

This was a 2-week sprint to see if we could answer some of these questions and find suitable carbon emissions data. The first part will give some background on the problem and explain our assumptions and the estimates we used. In part 2 I hope to be able to share what we did and an analysis of the data.

Scaling education

The number of student places will increase globally over the next 30 years, HolonIQ  predict an increase is around 2Bn learners (  Populations are growing, more people are wanting post-secondary education, especially in developing countries. In addition, PWC ( advances in technology will lead to e-skilling of workforce will need re-skilling in the future. Education needs to grow and is doing so also meet the sustainable development goal 4 around education.

Scaling education is simplified here to mean more learners enrolled in higher and further education globally. There could be other ways to scale the education sector e.g research capacity or work based learning.

To keep this simple, we limited the scope to find data on carbon emissions for the following:

  1. Working and studying from home – the increase in heating or cooling the home, use of electronic equipment needed to teach or study online will all impact on carbon emissions
  2. Increased use of technology – the use of video conferencing, video streaming, social media, online learning applications will all impact on carbon emissions
  3. Campus emissions – i.e. the scope 1, 2 & 3 emissions, there was some overlap (se below) but the over data points are frequently not reported as part of an institution’s carbon footprint
  4. Travel costs for students attending a course and living away from home, they need to travel to the institution at the start of the year.
  5. Building bigger campuses or new ones – building is a major contributor to carbon emissions globally, it can also impact on the local environment, increase water usage, etc.

There are other environmental, social, financial or practical considerations to also be considered but we have put these to one side for now.

So back to the main question, how big is the impact and can we compare different approaches to scaling education. Does online learning have a lower carbon impact than teaching on campus? What about all those zoom calls? How do different approaches compare?

To try to answer these questions we needed to quantify the carbon emissions of the activities we mentioned above.

Data assumptions

The following measures of carbon impact have been used in the calculations.

Working and studying from home

Work or study from home data is based on the Homeworking Emissions White Paper that suggests an additional 5KWh per hour of heating, assuming an 8-hour working day, adjusted for seasons This gives 6.22 kg Co2 per day extra. For staff it assumed 33% of homes already used heating as someone else was present during the day. The figure for students assumes four people share a house, 1.25KWh per hour used. (1.55 kg CO2 per day extra).

Commute to work/study is based on students average travel distance of 18 miles per day (return trip) from an article in the Times on the average student commute.  We used a carbon impact figure for a bus journey equal to 3 kg CO2 per day. A car journey would be almost double. 20% of students live on or near campus. Staff commuting was assumed to be the same. I was tempted to use a larger figure but many universities and colleges actively encourage staff and students to walk, cycle or use public transport. Many are providing electric vehicle charging points as well.

Increased use of technology

Use of IT in the home was also based on the Homeworking Emissions White Paper which suggested 140W per hour, assuming an 8 hour working day or 1.12 KWh extra electricity per day or 0.261 kg CO2 per day extra.

Online conference calls and streaming video are based on  The overlooked environmental footprint of increasing Internet use that gave a figure of 150-1000g per hour depending on the system, cameras on etc. I used the lower figure of 150g and suggested 3 hrs per day of online calls/video streaming on average which gives us 0.45 Kg CO2 per day.

If we compare the figures based on 150 days (30 weeks) of study, a commuting student uses 0.45t CO2 per year academic year and studying online the figure is 0.34 tCo2 per year. The commuting figure could be reduced further if students used more zero or low carbon forms of transport walking, cycling, electric vehicles, etc. The study from home figure could be reduced if net zero or low carbon forms of heating were available. We know students may live in rental accommodation with low EPC ratings and high energy costs. So improving student accommodation could make a difference and another approach might be to provide local study centres with energy efficient buildings for students to meet and work.

Campus emissions: Scope 1, 2 and 3 emissions

These figures are based on HESA Data for 2020-21 giving us a scope 1&2&3 figure of 539 t Co2 per 1000 students. The scope 3 figures seem very low, not all institutions reported scope 3 emissions. It is the best data we have at present.  Scope 3 should include staff and student commuting emissions but we calculate them separately assuming most institutions have not reported then as part of scope 3.


For UK students travelling to university at the start and end of the year each we have assumed 24 g CO2 per year based on one return trip by train from London to Edinburgh.

For international students we have used data from this article from 2019 on how the University sector must tackle air travel emissions which suggests students from the 0.8 t CO2 per return flight for the EU, 5.5 t CO2 return flight China and 5 t CO2 for rest of the world. In the scenarios I used a figure of 5 t CO2.

For both UK and international students, we assumed only one return trip per year. We might expect students would make multiple trips each year, parents or friends would visit them as well.  One trip could be seen as the necessary level of travel to be able to complete an academic year. The impact of more international flights would significantly increase the carbon emissions.

New Buildings

This figure has been based on the work of Helmers et al (1) of 13.7 kg Co2 per m2 per year  (written off over 50 years) and the University of Sheffield ~30k students and 541,266m2 of internal space (from Hesa Estates Data ). Gives us 18m2 per student, so 1000 students = 18,000m2 and kg Co2 = 13.7 x 18000 = 246.6 tCo2 per year for a new building per 1000 students.

The paper also suggested a figure of ~125 kg Co2/m2 per year covering building lifecycle impacts, but I believe they are mostly covered by the scope 1,2,3 carbon costs already included.  This figure could be used as an alternative to the campus emissions figure above.

Summary of the carbon emissions and assumptions we have used.

Table of emssions data figures
Table of emssions data figures

In Part 2. Scaling Education: A simple carbon calculator we will use these data assumptions to compare several scenarios for scaling education and compare the carbon emissions.

Existing Emissions

In scaling education we assume that the existing education systems remains relatively static. Using these figures we came up with an estimate for the existing carbon emissions for Higher and Further Education in the UK. Assuming the majority of learning takes place on campus.

Scaling education existing emssions
Table of existing emssions

An estimate for the existing carbon emissions for UK further and higher education is around 5 million tonnes of CO2 per year, or about 1% of UK carbon emissions. In addition international students already add another 3.6 Million tonnes of CO2 per year.

Reducing existing emissions should be part of any strategy to scale education globally.

If you have any comments please contact

Disclaimer: This was a short 2-week sprint not a long study and the data assumptions above and the emissions calculator have not been properly checked or reviewed. Reports use grammes, kilogrammes or metric tons of carbon, sometimes by day or annual or by activity. The opportunity to one figure wrong by a factor of 1000 is just too easy. We have sense checked figures against different sources but there could still be errors and you may want to challenge our assumptions.


1. Helmers, E.; Chang, C.C.;Dauwels, J. Carbon Footprinting of Universities Worldwide Part II: First Quantification of Complete Embodied Impacts of Two Campuses in Germany and Singapore. Sustainability 2022, 14, 3865.

2. Higher Education Student Numbers

3. Further Education Student Numbers

4. UUK International Student Recuitment Numbers

By Paul Bailey

Head of co-design, part of a research and development team

3 replies on “Part 1. Scaling education: What is the carbon impact?”

We are aware of the SUSTEACH model, thanks for highlighting it here as it is a useful tool. Our aim was to come up with some comparative figures and get an idea of the scale of the challenge.

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