The climate footprint of the internet is significant. This presentation provides practical advice on how to reduce the impact by 70% via careful optimization.

Danmark: 500 g CO₂eq/kWh

Carbon intensity by Electricity Maps

For a greener data center, we look at location in relation to our target audience, carbon intensity and technical capabilities for caching and compression.
DTHS front page after

DTHS before and after ✨

A light website can easily contain the elements you expect from a typical website, and have a modest footprint at the same time.
Just by saving as JPG - here using - filesize is down 89%

Images; sizes and formats

Choose the optimal image format for the material, scale images to fit the visitor's device, and serve them only when needed.
Transfonter; converting to woff2, subsetting to Latin only.

Fonts; identify, reduce, optimize

System fonts are sustainable and better for dyslexic users. For custom fonts, reduce styles, optimize woff2/subsets, and use variable if needed.
Grafisk fremstilling af kvinde der redigerer lyd på en PC

Sound; time to retire MP3

Opus and AAC formats can reduce bit rate. HE-AACv2 can achieve 41% of MP3 size. AAC is well-supported by Chrome, Safari, and Firefox.
Poster for a video by AFLD

Video; recompress 🎥

Find the optimal settings when compressing video for web. Loading times, especially on mobile, and data usage will improve a lot.
Handbrake Summary tab; Format: MP4, Web Optimized; Other settings: default.

Handbrake compression settings

Finding the right HandBrake compression settings for your video will take time. MP4 video + AAC audio, around 800 Kbps is a reasonable starting point.
Phone on a green table cloth, with the Green IO Podcast webpage opened.

Green I/O Podcast by Gaël Duez

Green I/O inspires tech sustainability. Guests offer knowledge to responsible tech builders creating a greener digital world. Hosted by Gaël Duez.
Hanna Smith, outside, leaning against a white wall, smiling.

#LetsGreenTheWeb with Hannah Smith

Hannah is the Operations and Training Manager for the Green Web Foundation and founder of #LetsGreenTheWeb. She’s also co-founder of Green Tech South West.…