Sustainable design for the web is a movement that focuses on leading towards a more environmentally conscious future. At its core, it puts strong emphasis on saving energy and reducing the amount of pollution generated from everyday devices.

The number of internet users is growing at a staggering rate. According to Cisco, two-thirds of the world's population will be connected by 2023 (Reference).

Moving towards zero-carbon futures is more important than ever, but at the same time, our need for data and web services has never been greater – including the emissions it creates.

A 2018 paper published in the Journal of Cleaner Production estimated that by 2040, 14% of the world's electricity will be used to power communication technology. This is up from just under 4% in 2020 (Reference).

The main goal in sustainable web design is to reduce CO2 emissions. It is impossible to measure the approximate CO2 output of a web product. We cannot trace the path of energy from a website or app back to the power station where it is being generated, and know with absolute certainty the exact amount of greenhouse gas emitted.

If we can't measure the carbon output, then we need to find something that is measurable. The two primary factors that could be used as indicators of carbon emissions are:

To measure the data transfer for web pages, we calculate the page weight, meaning the size of the web page in kilobytes when someone visits it for the first time.

Reducing page weight requires a wider scope. As of early 2022, the median page weight was 1.95 MB for “mobile” setups and 2.17 MB for “desktop,” which had increased 11% in the course of a year – but only by a fraction of that figure on mobile (Reference). Roughly half of the data transferred is images, making them by far the most significant source of carbon emissions on average websites.

Bottom line: saving on data transfer means a more efficient use of energy, which is essential to reducing carbon emissions in the modern web environment.

The level of pollution caused by digital products is determined principally by the carbon intensity of the energy being used to power them. A carbon intensity (CO2/kWh) refers to the number of grams of CO2 that are produced per kilowatt-hour of electricity.

We don’t have direct control over the energy supply of web services, but we can dictate where to host our project. With a data center using such a large amount of power, putting your data center in an area with low-carbon energy will reduce its carbon emissions.

We want to keep our servers nearby to the majority of our users. The further data travels, the more energy is needed. Locating our servers closer to where our website visitors are, we can reduce average latency and provide a better experience for them. This is an ideal win-win for both parties.

Some people might say that web professionals' job is not to take care of sustainability. We just build the products and services people are asking for. It is up to the consumer to use the internet wisely and make smart decisions about their device and data usage such as purchasing low energy devices.

Another argument is that it's the job of the government to deal with environmental issues around the internet. We’ve heard it claimed that individual professionals and organizations can't make any impact on their own, and that regulation is needed to limit the industry's impact. Margaret Mead, an anthropologist, once said “Never doubt that a small group of thoughtful, committed citizens can change the world; indeed, it’s the only thing that ever has.” However, government intervention should not be seen as a replacement to individual efforts. It is necessary in addition to them.

In the face of the climate emergency, success will depend on every single one of us taking individual action and collaborating with those around us to have a real impact. We all have a role to play in shaping the future of the web, and together we can create something that will benefit everyone for generations.

So, yes, it is our problem, and while no single web project is likely to “solve” everything at once, we each play a part.