
On an average website, image files are the biggest source of carbon emissions
Photo: ookawa/iStock
Reducing the carbon footprint of your digital activity
It’s tempting to dismiss digital sustainability as too big of a challenge to tackle, writes Substrakt’s Zosia Poulter. But there are some straightforward tactics you can use to start reducing your organisation’s carbon footprint.
The rise of digital technologies and solutions has mostly been seen as a force for good in the arts and culture sector. For marketing teams, digital has offered us new ways of engaging with customers in quicker, more data-driven and flexible ways.
Websites, CRMs and paperless marketing promised, among other things, to set us free from the shackles of print deadlines and make our organisations more efficient and greener. Or so we thought.
The reality, as we are all now aware, is that digital has its own impact on the environment. Data storage and transfer demand natural resources. Data centres use electricity and water to power and cool the servers where data is stored. And our digital content is data.
Every word, image or video we publish on our channels or send out as mass marketing emails has an impact on the planet. That impact is most commonly calculated as carbon emissions (the amount of CO² released into the atmosphere).
In the early days of the internet, the carbon footprint of content was fairly insignificant. In 1994, there were just 3,000 websites compared with an estimated 1.7bn in 2019. Page weight (the size of a single webpage measured in bytes) has also grown. This is because we’re publishing ‘heavier’ files like images and video.
The bigger the page weight, the more energy needed to transfer the data from the data centre to your device – resulting in more carbon emissions. And so it may not come as a surprise that today, if the internet were a country, it would be the 4th largest polluter in the world.
Calculating the carbon emissions of a single page
By the end of 2024, the average page weight on the internet was 2.7MB. A random sample of six UK cultural organisation homepages gives a comparable average of 12.7MB. The sample also shows how page weight can differ vastly between websites in our sector.
Organisation 1 | 51.6 MB (includes autoplay video) |
Organisation 2 | 9.4 MB |
Organisation 3 | 5.1 MB |
Organisation 4 | 4.9 MB |
Organisation 5 | 3.9 MB (includes autoplay video) |
Organisation 6 | 2.7 MB (includes autoplay video) |
Average | 12.9 MB |
But what impact does this megabyte storage have on the environment? Measuring the exact carbon footprint of digital content isn’t a straightforward business. This is because carbon emissions differ depending on:
- The source of energy (whether a data centre is powered by fossil fuels or renewable energy sources)
- The time of day energy is drawn from the grid
- The device used to access the site
In her recently published book Sustainable Content, Alisa Bonsignore attempts to overcome this complexity with a formula that uses baseline averages to evaluate the carbon footprint of digital data.
It doesn’t uncover the precise impact (that would be impossible) but it’s a good starting point to help you begin to measure, compare and benchmark the carbon emissions of your digital marketing activity.
Using her formula reveals:
- 500,000 page views of organisation 1’s homepage over the course of a year would amount to 8.2 metric tons of carbon emissions, the equivalent of driving over 20,000 miles in a petrol-fuelled car
- 500,000 page views of organisation 6’s homepage over the course of the year would amount to 0.43 metric tons of carbon emissions – the equivalent of driving just over 1,000 miles in a petrol-fuelled car
The difference in carbon emissions is stark. Multiply this by the hundreds of pages on any given cultural organisation’s website and the numbers get serious. The good news is, despite all this complexity, there are actions you can take to reduce these emissions.
Use video and images with purpose
On an average website, image files are the biggest source of carbon emissions. They’re a hugely important ingredient of our digital activity – from marketing an event, to making collection objects accessible online – but do we need as many? And are they all effective? You can reduce page weight by limiting the number of images and videos on a page, making sure that every image is published with a clear purpose.
As evident from the example page weights above, it is possible to host video content without breaking your page weight budget. Website caching – where page content is stored locally on a device or browser after its first load – can also help reduce the number of times data is transferred from a server.
Audit your content with a sustainability lens
Tools like Pingdom can tell you the page weight of any given page on your website – and how that breaks down by content type. You can use Alisa Bonsignore’s formula to translate this into carbon emissions and start to build up a picture of your content ecosystem from a sustainability perspective.
Review high traffic pages to see where you can streamline your content to reduce emissions. And delete content that no longer serves user needs.
Apply the principles of content design
Content design is the process of creating and structuring content that meets user needs. It’s a practice that involves using data and evidence to understand your audience and how they journey through your product.
Like the slow content movement that encourages quality over quantity, content design is about streamlining content and creating friction-free experiences. And that’s good not only for sustainability, but for SEO and accessibility too.
Understand the carbon impact of AI
Generative AI tools like Chat-GPT can be used in a variety of ways to support admin, creativity and data analysis. Aside from the ethical implications of these tools, they also demand a huge amount of energy and resources.
According to a recent study, 100 words generated by Chat-GPT consumes 500ml of water (to cool the power-hungry servers). While it’s important to keep on top of developments in technology, consider if and how these tools contradict your environmental commitment.
Build a broader culture of ethical digital activity
Digital sustainability isn’t just about your organisation’s website and marketing activity. Reducing your digital carbon footprint requires a 360° view that includes scrutinising your technology infrastructure, internal communication tools, staff habits and behaviours among other things.
It’s tempting to dismiss digital sustainability as too big of a challenge to tackle – especially when we’re only really starting to understand it. But the value can extend beyond simply reducing emissions. It can build a better user experience too.
Join the Discussion
You must be logged in to post a comment.