The internet produces more than 900 million tons of CO2 each year. It’s therefore really important that we make websites as eco-friendly as possible.
This means not only thinking carefully about the code and files we use, but also about the kinds of content we produce and how we present and manage it.
If the internet was a country, it would be the 13th largest emitter
sustainablewebmanifesto.com
Did you know that 91% of web pages get no traffic from Google? Before we even start creating content, the first questions worth asking are: do people want or need this? How will I ensure people find it once it’s live?

Better UX, less carbon
According to author and UX expert Gerry McGovern:
- A 1,000-word piece of content that takes 20 hours to create on a laptop, takes four minutes to read and is read only once emits 2.3kg of carbon pollution
- If that same piece of content is read 10,000 times, it would be viewed for 666 hours and emit 116kg of carbon
- However, if your content creator spends twice as long on creating the piece, taking 40 hours to make the article as useful and short as it can be, the amount of time it takes to read the piece could be halved. This would mean reducing the time spent on reading it to 333 hours and the carbon emissions to 62kg
- You can save even more carbon by making it quicker and easier for people to find your article in the first place. The less time spent navigating to the content, the better it is for our planet
- You can design a brilliant and effective page with just 100kb.
[Source: Gerry McGovern, Digital is Physical presentation]
Video streaming needs vast amounts of energy and data, and the higher the resolution, the more data is sent and received.
4K video streaming, or Ultra HD, on a phone generates about eight times more in emissions than standard definition. But, on such a small screen, the viewer might not even notice the difference.
Say no to PDFs
PDFs are terrible for the environment, says author and UX guru Gerry McGovern. “So many […] reports are published as diesel-sucking, bloated, pollution-puffing PDFs. Well written HTML is the most environmentally friendly language you can use to publish on the Web.”
A PDF has nine times more impact on the environment than a page of optimised HTML. [Source: Gerry McGovern, Digital is Physical presentation]
They’re also not accessible, hard to update and a nightmare to view on a mobile device.
How you can help
- Test, measure and optimise your site structure, navigation and information architecture. Make it easy for people to find information as quickly as possible
- Choose system fonts where possible to reduce the need to download additional fonts
- Use networks such as Cloudflare (which we recommend to all our clients for both security and page speed benefits) to make use of Content Delivery Networks (CDNs) and server caching. This reduces the amount of data that needs to be downloaded on each website visit
- Optimise your site for mobile devices. For example, we use a separate optimised theme on our website for mobile devices. It displays static images rather than video. It also uses less code because certain interactive features have been removed to speed up the user journey
- Ensure your web servers run on 100% renewable energy
- Make videos useful, informative, short and accessible. Do not create video content that does not have a clear focus, aims and objectives. Use a lower resolution
- Switch videos from autoplay to play on demand
- Only create PDFs if absolutely essential and reduce the file size as much as possible
- Create optimised web pages as alternatives to PDFs. If information is worth publishing, it’s worth making it easy to find, read and update.