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How we’re reducing the carbon footprint of our websites


Websites have a carbon footprint from the energy used to power and access them. Discover how we’re working to reduce the environmental impact of our websites to make our network even more digitally sustainable.

Computer keyboard with a green sapling growing in between the keys

Terms like ‘virtual’, ‘wireless’ and ‘the cloud’ that describe how we access or use the internet can give the impression that it doesn’t physically exist.

However, the infrastructure that powers it, the websites it hosts and the data it generates are all powered by electricity. And when this is generated by burning fossil fuels, it has a significant impact on the environment.

Measuring digital’s carbon footprint

Researchers at Lancaster University estimate that the information and communication technology (ICT) sector accounts for an estimated 2.1–3.9% of global emissions, a figure that puts its carbon footprint on a par with the global aviation industry.

To understand the impact of digital carbon emissions from Unilever’s websites, we audited pages on to find out what actions we could take.

Here are five ways we’re ensuring our sites are as sustainable and accessible as possible.

1. Green hosting

All Unilever sites are on Netlify, which uses Google Cloud and Amazon Web Services as cloud providers. Google Cloud is a fully green web-hosting provider. This means the energy that runs their data centres and hosts our sites is generated from clean, sustainable sources such as wind, solar or hydro power. Amazon Web Services plan to use 100% renewable energy by 2025.

2. Reducing the energy load of our images

Images are the most popular resource type on the web. They’re also the largest in terms of data and energy use. To reduce this load, we save images in WebP instead of older formats such as JPEG and PNGs. This allows images to be compressed into smaller file sizes that use up to 30% less data than a JPEG without loss of image quality.

3. Viewing in an energy-saving ‘dark mode’

To the left of the search bar on you’ll find a button called ‘Theme’. This gives visitors the option to view the site in dark mode. This option can save up to 42% screen energy when the site is viewed on an OLED screen, which most mobiles use, because it uses less data and is faster to load. Dark mode also makes the site more accessible as it creates less strain on the eyes.

4. Adding a play/pause button to videos

We have added a play/pause button to all our videos. Some do still autoplay, which we know is energy intensive. But we are continuing to look at ways to optimise video content and where possible we aim to replace videos with animations, illustrations and static images.

5. Zero-waste design thinking

The heavier and more complex a website or web page is, the more energy is required to send and process data. We ensure all our designers, developers and product managers work to a target budget of 1.5 megabytes for each page (the global average is 2.4 megabytes). This makes pages more accessible and looks to ensure that every asset adds value to the user experience.

A foot in the right direction

Even if we can’t easily see or definitively calculate the footprint that cyberspace leaves on our physical environment, the impact is real. And making our corporate websites more carbon-efficient is something the planet and site visitors will thank us for.

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