On an individual level :
- plant trees
- consume only the necessary
- limit car, planes, trains transportation
- Reconnect to the cycles of the earth
On a collective level : - policies against gas emissions - Laws: Same as speed limitation for cars, limit energy consumption per habitant - true information/news/education - Bans of polluting products ( plastics, heavy metals, ...etc ) - Change obsolete, unnecessary, inefficient and polluting tech