Edit: A lot of people seem to hate on the article without reading it.

Here is a supporting scientific source, by the same author: https://www.sciencedirect.com/science/article/pii/S2666188825000863

The environmental impact of our online habits is far larger than most realize, and as digital communication continues to evolve, we must consider its long-term consequences on the environment and human life. We should take the easy steps of cutting wasteful energy use in our communications and it can start with eliminating email signatures.