Greening the Web: How We Can Create Zero Carbon Websites

  • We tend to think of the internet as being clean and immaterial.
    • In total, the global internet uses more electricity than the whole of the United Kingdom (416.2 terawatt hours of electricity per year to be precise).
    • In fact, 2% of global carbon emissions come from the electricity used by the internet.
    • To put it in perspective, if the internet was a country, it would be the sixth worst polluter in the world, equivalent to Germany.
    • According to, the average web page today is nearly four times the size that it was in 2010 and is continuing to rise.
    • As a result, it is estimated that the internet could grow to account for 3.5% of global carbon emissions within the next 10 years,

First, we must understand three simple principles:

  1. We cannot manage things that we cannot measure.
  2. Data transfer consumes electricity, so reducing data transfer will reduce energy and emissions.
  3. Renewable energy produces far fewer emissions than other sources
  • Luckily this is now possible using the free tool for estimating website CO2 emissions at that provides data on the CO2 emissions per page view, the annual CO2 emissions (based on a specified amount of page views), the annual energy consumption and whether or not the website is hosted in a data centre powered by renewable energy. Using this tool it is possible to benchmark your own website against competitors and set targets for your own carbon reduction.
  • find ways to make the website more data efficient.
    • Firstly, we can reduce the weight (in KB) of all of our web pages. Reducing page weight has numerous additional benefits including faster load times, which improves user experience and SEO, as well as reduced data usage for users with limited internet connections. This can be particularly important for mobile users and website visitors from low-income groups, particularly in developing countries where internet data is very expensive relative to local wages.
  1. We can write code cleanly and efficiently.
  2. We can use vector graphics and CSS effects to create a visually engaging experience with much smaller files than traditional images such as JPEGs and GIFs.
  3. We can upload images at scale instead of relying on CSS to resize them. If you’re using WordPress, this is not as important as it supports responsive images.
  4. We can offload large media to third-party providers who are green-friendly.
  5. We can compress files, images, and videos to reduce file sizes without visible loss of quality. Check out these posts on image optimization and lossy compression. A little lossy compression can easily decrease a web page by over 90%! 
  6. We can avoid autoplay on videos, asking the user to choose to play videos if they are of interest.
  7. We can minimize custom fonts, which can actually add up to a large proportion of overall page size. Considering web-safe fonts is another great option.
  8. We can decide to no longer support older browsers such as IE8 and use only modern web fonts, such as WOFF and WOFF2 which utilize higher compression methods. Check out this tutorial on using stripped down versions of local fonts.
  9. We can reduce tracking and advertising script, which consume data while rarely adding any value to the user. Check out how to analyze third-party performance on your website.
  10. We can utilize mobile solutions such as AMP to instantly strip down the current version of a web page.

Take the WordPress host Kinsta for example. They have four different types of cache, which are all automatically done at the software or server-level:

  • Bytecode cache
  • Object cache
  • Page cache
  • CDN cache

The second thing that we can do the reduce data transfer is to reduce the number of times that our pages are loaded. Reducing traffic might sound like heresy, but actually, there can be good reasons to do so that are beneficial to the website owner and to the user. Although we assume that traffic is inherently good, there are scenarios where people visit pages that are not useful to them. This is highlighted in bounce rate statistics, which show the number of visitors that immediately realize that they have loaded a page that is not what they want. Improving SEO and user experience can significantly reduce bounce rates, while also streamlining user journeys, enabling users to find the information that they want with fewer steps, meaning that a website can deliver the same level of value with fewer page views.

Switching Your Website to Renewable Energy

  • The Green Web Foundation has a very good database of hosting providers that claim to use green energy, although it should be noted it is still worth checking directly.
    • On average, a Google data center uses 50% less energy than a typical data center.
    • Because of their renewable energy and carbon offset programs, Google’s net operational carbon emissions in 2016 were zero.
    • Compared with five years ago, Google now delivers more than 3.5 times as much computing power with the same amount of electrical power.
  • 3 Simple Steps to Lower Emissions
    • Benchmark our website carbon emissions.
    • Reduce data transfer by reducing page weight and unnecessary page views.
    • Switch to a web host powered by renewable energy.