What's my website's environmental impact?

With the climate crisis in mind recently I've been looking at what environmental impact my website has.

The stats

For this analysis I used websitecarbon.com. Every time a visitor comes to my website, without any cached version of it, the carbon footprint is just 0.52g of CO2 produced. My current host, Digital Ocean, doesn't appear to be using green energy which brings down the overall score to 72%. Potentially with a host which uses green energy this could be improved by around 9%.

Performance gains

In terms of performance my website performs very well with a Lighthouse score of 100%. Overall this helps reduce the energy consumption my website has for both the data centre and end user devices. The steps I took to achieve this score included:

Switching to HTTP/2 for more efficient delivery of assets by loading them in parallel rather than one at a time.
Compressing images to download and render more efficiently.
Though only currently supported in Chrome, I implemented the loading=lazy attribute for images. This way the browser should only start loading image resources after more essential items like layout and text content.
Using responsive images to load the most appropriate sized image for the available viewport space and, in some cases, available bandwidth.
Implemented a ServiceWorker to cache parts of the website for repeat visits, therefore reducing the number of HTTP requests needed per repeat visit.
Implemented a dark mode for users on supporting operating systems to reduce energy use when it's enabled.
Switched to a newer more efficient version of PHP.

Further reducing my website's environmental impact

Some other ways I might consider reducing the impact of my website on the environment include changing to a host that uses green energy. I could review the overall user experience of the website to see if there are ways to make it easier to navigate with fewer wasted page loads. Finally I could consider looking at using content delivery networks to load my website from locations closer to different users.