The Darksun setting from D&D had magic be powered by life. Powerful spells could turn nearby plant life to ash, and large scale mage wars are how Athas became basically a desert planet. The few who still use magic are either Preservers or Defilers, Preservers are very careful to not take too much power and make sure they don't kill things by taking too much, while Defilers don't care and are happy to ruin land to fuel their magic.