To reduce energy consumption and CO₂ emissions:
1. Compress image files
2. Disable unnecessary plug-ins
3. Minimize videos, pop-ups and slide shows.
4. Link to or embed videos (rather than re-post them).

Resources:
https://www.forbes.com/sites/neilyeoh/2017/07/26/your-web-use-leaves-a-carbon-footprint-heres-how-you=can-reduce-it/#33c5a07b9401