Website Sustainability

When it comes to being more environmentally conscious, your website's carbon footprint often isn't the first thing that comes to mind. Explore these pages to learn more about how your website impacts the environment and how you can make more environmentally conscious choices to reduce your website's carbon footprint.

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How do websites impact the environment?

The more complex a website is, the more energy it takes to load. The more energy it takes to load the greater the impact it has on the environment.

It's that simple.

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How can we measure our website’s digital carbon footprint?

It’s almost impossible to measure the amount of CO2 produced by a web product - after all we can’t measure fumescoming out of the exhaust pipes on our laptops!

“If the Internet was a country, it would be the 4th largest polluter”Freitag et al

However there area a few measurements that directly impact our digital carbon footprint:

  • Data transfer:
    Roughly half the data transfer from early 2020 is images. Making images the single biggestsource of carbon emissions on the average website. While most technologies become more energy efficient such as web data centres and transmission networks, websites themselves are a technology that is becoming less efficient as time goes on.
  • Carbon intensity of electricity:
    The level of pollution caused by digital products depends on the carbonintensity of the energy being used to power them (e.g.sustainable sources will have a less pollutive impact).



Every website has a carbon footprint, which is made up of the servers, networking, data exchange and client technologies required to host, run and browse the websites. Our websites are powered by electricity. The larger a website is the more electricity it will take to run.

It’s estimated that the collective C02 emissions from the internet equals 1.7 billion tonnes. By comparison the C02 emissions generated by the 2019-2020 Australian wildfires was 0.7 billion tonnes.


From 2017 to 2020 the average size of a web page has increased by roughly 30%. But websites haven’t really improved by 30% in this time. If anything, the more efficient other technologies (laptops, mobiles etc) are becoming the more that websites seem to be left behind. When we make webpages unnecessarily heavy (with media), we are not just wasting electricity; we are wasting an opportunity to create faster and more inclusive online experiences.




Water usage

The huge enormity of data produced every year (e.g. from Cloud storage, OneDrive, Google Drive) are stored in thousands of data centers around the world, where massive servers keep the internet going. Those servers require a great deal of energy and produce a great deal of heat. Without adequate cooling, the servers can overheat, fail or catch fire. Companies can either use traditional air conditioning to cool the servers, which is expensive, or use water for evaporative cooling. The latter is cheaper, but it also sucks up millions of gallons of water- which is not good in our age of climate change.

According to an article in the Washington Post researchers have said that large data centres can use up anywhere between 1 million and 5 million gallons of water a day — as much as a town of 10,000 to 50,000 people.



Device usage

The lifespan of our electronic devices is becoming increasingly shorter. Meaning that we have more wastage in throwing our old devices away, the manufacture of new devices and the repeated purchase and manufacture of new devices.



Cloud storage

More than 90% of data stored in the cloud is stored and never used again. JISC –Exploring Digital Carbon Footprints




Educational staff scrolling through LinkedIn could be generating up to 2,792 metrictonnes of CO2e per year. JISC –Exploring Digital Carbon Footprints




Sending or receiving just 70 emails a day can contribute up to 84kg CO2 e per year. JISC –Exploring Digital Carbon Footprints



Dynamic Animation

This can not only have a negative impact on how accessible your website is, it’s also bad for the environment.



Artificial Intelligence (AI)

In its latest environmental report, Microsoft disclosed that its global water consumption spiked 34% from 2021 to 2022 (to nearly 1.7 billion gallons, or more than 2,500 Olympic-sized swimming pools), a sharp increase compared to previous years that outside researchers tie to its AI research.

ChatGPT gulps up 500 milliliters of water (close to what’s in a 16-ounce water bottle) every time you ask it a series of between 5 to 50 prompts or questions. The range varies depending on where its servers are located and the season. The estimate includes indirect water usage that the companies don’t measure —such as to cool power plants that supply the data centers with electricity.




For OLED screens that light up each pixel individually, darker colors require less energy to illuminate, with black being the lowest energy color and white being the most energy intensive. What you might not expect is that blue pixels use approximately 25% more energy than red and green pixels.


Why should I care?

The Internet accounts for about 10% of global electricity consumption. –Web Neutral Project

“We have a duty to act now –collectively, collaboratively, with urgency and at pace to ensure that future generations can live on this planet.” –Steve Frampton, climate commissioner for UK higher and further education

We’ve ignored the problems of climate change and species extinction for so long that simply doing no harm is no longer enough to be sustainable.

We all have a responsibility to preserve our future as a species and look after our home planet. If we all start to make small changes it will help reduce our collective carbon footprint.

How can I make a difference?

Sustainable Web Design Choices


  • How this can help: 
    Getting rid of unused media and files will help save energy and reduce C02 impact. Not to mention it can help speed up your website!

Reduce Image File Sizes

  • How this can help:
    Larger images take longer to load and so use up more electricity and have a larger C02 impact. Try a simple change such as reducing the file size or swapping to icons (which are generally smaller and so have a smaller C02 impact).

Use Video Sparingly and Strategically

  • How this can help:
    Video content has the largest C02 impact so use it sparingly and strategically! All our content should have a purpose and video content should be used on webpages when it can be most impactful.

Simplify Your Website Navigation

  • How this can help:
    Content for the sake of content is clutter. A simple website navigation not only helps to save on your website's wider C02 impact it will also improve your user's experience of navigating through your website.

Review Your Web Performance

  • How this can help:
    Review your website performance to gain an understanding of how users are currently engaging and behaving on your website. This data can help you make informed design choices that help improve and speed up your user’s experience.

Outside the Box Thinking

  • How this can help:
    Can we create experiences in the web browser that work even if an internet connection is completely lost? Although from the web we don’t need to always be connected to it.

IT Sustainability Tips

Digital sustainability isn't just limited to your website. Did you know that even your email inbox has a carbon footprint? If we all start to make these small changes it will help reduce our collective carbon footprint.

Turn off, don't hit standby!

  • Not only is turning your PC off better for the environment, it's also healthier for your PC meaning that it will operate faster and potentially contribute to a longer life span.

Reduce your email traffic

  • Did you know that sending and receiving around 140 emails a day creates as much C02 in a year as flying from London to Bruges?* Reducing the amount of unnecessary emails can help reduce your C02 impact. Check out the Email Carbon Impact Calculator to see how much C02 emissions you could be producing -just from your email inbox!
    *stats from CWJobs

Get smarter with email attachments

  • A PDF generates 9 times more CO2 than the same text content in optimized HTML. An email attachment generates 25 times more grams in C02 than a simple text email.* By making smart swaps such as uploading documents once to OneDrive and emailing the link or simply pulling text out of PDFs you can easily reduce your carbon footprint.
    *based on a text email and attachment containing 1,000 words from Gerry McGovern author of World Wide Waste