Measuring and mitigating the carbon footprint of digital content

How to deliver the best possible information for our audience without undue harm for the planet.

An intro from Lauren…

This is a guest post from Alisa Bonsignore of Clarifying Complex Ideas. I first met Alisa years ago at Confab Intensive in Portland, where we kept each other company on a very hot and humid run. I think it must have been a bonding experience, because we’ve stayed in touch via Twitter, LinkedIn etc ever since. Alisa develops sustainable content strategies for global clients who use her pioneering metrics to measure and mitigate the carbon footprint of their digital information. She is an Associate Fellow of the Society for Technical Communication, a Certified Master Gardener specialising in xeriscaping (the practice of designing landscapes to reduce or eliminate the need for irrigation), and a keynote speaker. She is a research nerd, an avid reader, and a crochet enthusiast who is taller than she looks on Zoom. You should follow her on LinkedIn for — among other things — the delightful posts she shares with wishes for people at the start of the week. They never fail to make me smile.

Over to Alisa…


Let’s start at the beginning: all the bits and bytes of our digital content generate carbon emissions, which contribute to climate change. While most of us have heard of ESG reporting (environmental, social, and governance reports) or sustainability communications (the broader storytelling around ESG), it’s much less common to work in organisations that talk about the carbon footprint of the content itself. This leads many people to ask, “But wait: how bad can it be? If it was a problem, surely I would have heard about it.” 

There are overall assessments of the impact of digital content as an aggregate. Some estimates assert that information and communication technologies (ICT)—the devices that we use to provision our content as well as the content itself—contributes between 2.1% and 3.9% of the total annual greenhouse gas emissions.1 For reference, this is comparable to the impact of the much-maligned aviation industry at 2.4%.2

There are also regional studies providing aggregate data; ICT represents between 25%-33% of the electricity consumption (and corresponding emissions) of European households.3

“Ah but wait!” you say. “Renewable energy fixes that.” Yes and no. 

Humanity has nearly doubled its energy consumption in the past four decades, as we see in Figure 1. So yes, you’re correct that we’re increasing our percentage of renewable energy, but our increased overall consumption limits the amount of headway that we’re making on a true green energy transition.4 Digitisation is driving a significant amount of that consumption.

A chart titled 'We are using more energy than ever before. It shows that energy consumption has grown significantly between 1980 and 2019, and that renewable energy generation has not grown fast enough to keep pace.
Figure 1 — The world is using more energy than ever before. While renewable energy production is increasing, it’s not keeping pace with our growing demand. Source: Our World in Data.

Why it matters

We’re already seeing these effects play out on the global stage. According to the International Panel on Climate Change (IPCC), human-induced change of the climate system is already widespread.5 However, entrenched, systemic inequalities make the situation worse. The impacts will be unevenly felt, with more dramatic consequences experienced by women6 7; those experiencing poverty8 9; and Black, Indigenous, and people of color (BIPOC).10

For example, after the 2004 Indian Ocean earthquake and tsunami, nearly three-quarters of the deaths were female. And globally, people of color are more likely to experience the first and worst effects of worsening heat and natural disasters. Climate is a threat multiplier, accelerating existing instabilities and worsening health, inequality, and hunger on a global scale. If we know that the most vulnerable among us will be hardest hit, we have an ethical obligation to make a difference where we can.

This isn’t a problem for individuals to solve at home

For most of my Gen X lifetime, we’ve heard about our climate or carbon footprint: the impact that our individual lives and choices have on the Earth’s climate. Carbon footprint is a legitimate concept, but it became famous after a BP marketing campaign. The messaging shifted the emphasis to personal responsibility, effectively drawing attention away from the fact that BP is one of the top 15 largest polluters in history. It was a remarkably effective campaign that placed the weight entirely on the shoulders of the individual.

But individuals are not the largest contributors to climate change, and individual action will not solve the problem. Even if every human implements personal behavioral changes in every area that we can—from vegan diets to EVs and home solar—the IEA notes that all of these dramatic changes will only reduce greenhouse gas emissions by about 4% by 2050.11 But home is not where we have the most leverage. 

A report published by the Carbon Disclosure Project (CDP) stated that 100 companies are responsible for more than half of all greenhouse gas emissions since the start of the industrial revolution 250 years ago. Since 1998, these organizations have been responsible for 71% of all emissions.12 If most emissions happen at the organizational level, then it makes sense that we have the most opportunity to leverage our impact at work.

How to calculate the impact

To calculate the carbon footprint of any form of digital content—websites, images, emails, podcasts, videos, etc.—you only need to know a handful of information:

  • File size
  • Number of hits/downloads
  • Energy per gigabyte
  • U.S. EPA emissions calculator 

Measuring the file size

Websites are the most ubiquitous form of content, so let’s use a web page as an example.
If you have questions about your web page size, or that of your competitors, use the calculator at Pingdom.com (Link opens in a new tab)

I’ll use The Nature Conservancy as an example because their website is roughly the average weight of 4.0 MB. As we see in Figure 2, running the home page through the Pingdom calculator on 5 January 2023 revealed that the site was 4.1 MB.

A screenshot from Pingdom showing data for the nature Conservancy website. See copy and caption for a description.

Figure 2 — Running The Nature Conservancy website through the Pingdom calculator reveals that the site is about average at 4.1 MB but is slow to download and weighed down by backend scripts.

You can use the Pingdom calculator to identify not only the total weight of the page but the weight of the components of the page. For most web pages, page weight comes from imagery, usually about half of the total. These are usually stock art images that look nice, but don’t add to the user experience, such as:

  • A bank website featuring a woman looking at her mobile phone
  • An environmental organisation featuring a large splash image of trees
  • A healthcare website with generic images of people in scrubs and masks

None of the above images convey meaning for the audience. Sure, the bank has a mobile interface, but this image conveys none of the benefits. The environmental organisation supports biodiversity, but the image shows only one kind of tree. The images on the healthcare website could be used by anything from an insurance company to a hospital to a medical device manufacturer; they add lots of page weight, but no information.

The Nature Conservancy website is a little different. Images are not the heaviest element of their page. As we can see in Figure 2, more than half of the page weight comes from backend scripts and tracking.

How many hits?

Now we have the weight of the page. How many hits does it get each year?

Similarweb says that The Nature Conservancy gets more than one million hits per year.

Run the numbers

Calculating the Impact
Webpage Size4.1 MB 
Hits/Year1,100,000Multiply size by hits: 4,510,000 MB
Data Transferred4,510 GBDivide by 1,000 to convert from MB to GB
Energy Used3,653 kWhMultiply data by 0.81 kWh/GB
Emissions1.6 Metric TonsRun 3,653 through the EPA greenhouse gas equivalencies calculator
Figure 3 — The home page of The Nature Conservancy website generates 1.6 metric tons of emissions per year, equivalent to driving more than 3,900 miles (6,313 km) in a gasoline-powered passenger car, according to the EPA calculator.

This one web page contributes 1.6 metric tons of emissions annually, as we see in Figure 3.

Note from Lauren: Alisa’s calculation uses the EPA data which is US-specific. There’s also a UK-specific version and other countries might also have similar resources.

What you can do about this

We don’t have to abandon digital content. However, by measuring the impacts, we can balance the value of our content creation against its planetary impact. We can ask ourselves; is this digital format the best resource for the user experience as well as the planet?

I often use video as an example. A two-minute-long video has the same emissions impact, regardless of the content. However, a two-minute setup tutorial or troubleshooting guide has immediate and measurable value for the audience. There is less audience value in a two-minute marketing video of smiling employees chatting in the hallway, or B-roll footage of teams brainstorming in front of whiteboards.

What form of content delivers the clearest information for the audience with the smallest carbon footprint?

  • Does everything need to be a video? (Hint: probably not.)
  • Could this video be a podcast? (Maybe.)
  • Could this podcast be text? (Probably.)
  • Is this image generic stock art or does it show a product or service in action? (Most often, it’s the former, and adds no value.)

Also, consider size and frequency:

  • Could this podcast be shorter, or released less frequently? (Typically, yes.)
  • Do we need to send image-loaded email newsletters to customers daily? (My inbox says no.)

Sustainable content is still plain, straightforward, accessible, and usable. It’s clear, concise, and compelling: everything that we want our content to be. We don’t need special permission from management to measure or create it. We just need to implement conscientious content strategy, effective content design, and include sustainable content metrics in our arsenal of best practices.

Using this calculator allows us to deliver precisely what our audience needs without harming the planet in the process.

Footnotes

  1. The real climate and transformative impact of ICT: A critique of estimates, trends, and regulations, Charlotte Freitag, Mike Berners-Lee, Kelly Widdicks, Bran Knowles, Gordon S. Blair, Adrian Friday (Link opens in a new tab) ↩︎
  2. The Growth in Greenhouse Gas Emissions from Commercial Aviation (2019, revised 2022), Jeff Overton (Link opens in a new tab) ↩︎
  3. Young people, ICT and energy – status and trends in young people’s use and
    understanding of ICT and energy consumption, Toke Haunstrup Christensen, Ruth Mourik, Sylvia Breukers, Tomas Mathijsen, Herjan van den Heuve
    (PDF opens in a new tab)
    ↩︎
  4. Energy Production and Consumption, Hannah Ritchie, Pablo Rosado. Max Roser (Link opens in a new tab) ↩︎
  5. Understanding and Attributing Climate Change, Gabriele C. Hegerl, Francis W. Zwiers (PDF opens in a new tab) ↩︎
  6. Women, Gender Equality and Climate Change, UN Factsheet (PDF opens in a new tab) ↩︎
  7. Climate change and gender-based health disparities, Kim van Daalen, Laura Jung, Roopa Dhatt, Alexandra L Phelan (Link opens in a new tab) ↩︎
  8. Poverty and Climate Change: Reducing the Vulnerability of the Poor through Adaptation, OECD (PDF opens in a new tab) ↩︎
  9. Effects of income inequality on evacuation, reentry and segregation after disasters
    Author links open overlay panel, Takahiro Yabe, Satish V. Ukkusuri
    (Link opens in a new tab) ↩︎
  10. EPA Report Shows Disproportionate Impacts of Climate Change on Socially Vulnerable Populations in the United States (Link opens in a new tab) ↩︎
  11. Net Zero by 2050: A Roadmap for the Global Energy Sector, IEA (Link opens in a new tab) ↩︎
  12. The Carbon Majors Database, CDP Carbon Majors Report 2017 (PDF opens in a new tab) ↩︎

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