Well, I care because many people don't know or care that every day they are contributing to polluting the soil, air and oceans, thus making the world an unhealthier place. I care because 25% of our medicines are derived from rainforest species, yet the rate at which the Amazon is being destroyed is accelerating every year. And I also care because it feels great to explore tide pools, hike and sit on a front porch while it rains, and I wouldn't want to lose the chance to do those things due to humans messing things up. I want to save coral reefs, protect polar bears, find out how to prevent droughts, reduce pollution, and make the world a healthier, better, more beautiful place.
That is why I care.