Field believes strongly in fighting climate change. He co-founded the charity Cool Earth with Johan Eliasch. Cool Earth protects endangered rainforest and works with the local communities to combat climate change. Field was the instigator of the idea of a global Commonwealth network of protected forests, though he failed to raise political interest for a number of years; according to Field, when the Queen was told about the idea, she supported it enthusiastically, and the initiative was launched as the Queen's Commonwealth Canopy in 2015.