Benchmarking your website’s environmental sustainability

At Supercool, we build websites for the arts, culture and heritage sectors. We care deeply about the planet and our impact on it. Over the past few years, we’ve been working to upskill the sector in digital sustainability.

During 2024, I discussed the challenges of digital sustainability with people across the sector and learned that cultural organisations struggle to know what good looks like. So, to answer this question, we’ve partnered with Digital Carbon Online to create the first ever Cultural Website Sustainability Benchmark Report.

We tracked the carbon footprint of key pages across 66 arts, culture and heritage websites for three months. The report highlights key areas to focus on, as well as providing the sector with a benchmark to measure against.

Why does the carbon footprint of your website matter?

Many organisations have worked hard to reduce their carbon footprint. From reducing single use items in the bar and cafe, to investing in new heating systems that reduce energy consumption. But across the sector, digital sustainability is a missed opportunity.

The websites we tracked for just three months generated the same carbon footprint as 114,012 plastic water bottles. A single web page being viewed just once has a low carbon footprint. However websites often have tens of thousands of visitors so the carbon footprint quickly adds up.

Indigo’s Act Green Report, which researched customers’ attitudes to sustainability revealed that “50% of audiences expect cultural organisations to make changes to the website to decrease their digital carbon footprint”. In addition, 85% of under 35-year-olds feel “cultural organisations have a responsibility to influence society to make radical change to address the climate emergency”.

Your website is also one of your key audience touch points – more people will use and engage with your website than will ever make use of your building facilities or see a show. There’s an opportunity to use your website to demonstrate you care about your environmental impact. And reducing the carbon footprint of your website often goes hand in hand with improving website performance and user experience.

Reducing the carbon footprint of your website doesn’t just meet audience expectations, it also meets your funders’ expectations and builds brand loyalty. With arts councils placing significant emphasis on sustainability, and younger audiences being more eco-conscious than ever, reducing the impact of your website – and shouting about it – could directly lead to more ticket sales and fundraised income.

How does a website create a carbon footprint?

The internet is currently estimated to contribute more global greenhouse emissions than the airline and maritime industries, and it is predicted to balloon from approximately 4% today to 14% by 2040.

Every website has an environmental impact. Energy is used to store your website on servers, deliver content across networks and power the devices end-users use to view webpages. Each step in this process has a carbon footprint.

Measuring this carbon footprint is difficult – we don’t always know the power sources of users’ devices and even green hosting can use non-green energy sources from time to time, depending on the energy mix of the grid. However, the Green Web Foundation has developed a standard practice when measuring the environmental impact of websites, which gives us a consistent, evidence-based estimate of the carbon footprint of any particular page.

Arts, culture and heritage websites in particular have the potential to have a significant environmental impact using this form of measurement. That’s because cultural websites tend to have large, complex pages that make use of rich video and image content, advanced coding techniques to build digital experiences, and an increased adoption of AI. All these contribute to the page weight, which in turn increases the carbon footprint of web pages.

Key findings from the report

The report highlights how environmentally damaging cultural websites can be. While a single page load usually produces less than 1g of CO2e, due to the large number of users, this quickly becomes a significant impact.

During the course of the report, just under 9 million page views were tracked, producing 9,436kg in CO2e emissions. That’s the equivalent of 10 flights from London to New York.

When compared with other sectors, the arts, culture and heritage sector does better than some like higher education, construction and eco brands, but not as well as other like healthcare, supermarkets and banks (based on data from Abstrakt’s Website carbon impact study). This highlights the benefits of looking outside the sector to find smart solutions to user experience challenges and crafting compelling websites and content that have a low impact on the planet.

The report highlights where organisations should focus their energy. Homepages, event listing pages – such as a What’s On page – and pages with information about visiting the venue accounted for 96% of page views. Reducing the impact of these pages would drastically reduce the impact of the website overall.

One of the lowest impact page types to be measured were Support pages. As well as being low impact, these pages accounted for just 0.62% of page views. While we wouldn’t recommend any pages having a large carbon footprint, there’s room here to add more rich and engaging content to pages where organisations are aiming to raise funds.

The report also features case studies from organisations that have successfully lowered the carbon footprint of their websites. These case studies highlight the practical steps organisations can take including:

• Running content audits and deleting content that’s no longer used (which will also improve SEO and user experience)
• Reducing the number of pages by combining multiple pages (this also improves the user experience)
• Technical improvements like optimising the website for modern image formats and moving to green hosting

Something the most advanced organisations have in common is prioritising sustainability in all areas of their business. For these organisations, sustainability isn’t a tick box exercise, but something they focus on and invest in on a regular basis.

Supporting the sector

The arts, culture and heritage sector is enhancing society and people’s lives in many different ways. This study doesn’t suggest cultural organisations reduce their websites to the point they can no longer continue to engage with audiences and visitors. But it does provide direction, a means of measuring website impact, and the tools and insight to make focusing resources easier.

Download the report.