A well-thought-out structure, limiting the amount of content and materials embedded in the site and moving the site to an energy-efficient eco-server are the keys to reducing CO2 emissions.
We have reduced the number of websites of our companies from 3 to 1.
Thanks to the use of bichromy (limiting the number of colors to two), and thus abandoning the use of white color, the photos on the site have little weight therefore monitors use less energy to display them. The site is much "lighter" and more environmentally friendly.
We have reduced the number of images, videos and files embedded on the page. We've also compressed each element to take up as little space as possible