Corals are in a lot of trouble and reefs are in great danger. Twenty percent of the reefs in the world have been destroyed. Even more are under threat now. This is because of humans! We dump waste and poisons in the oceans that make corals sick. Also, global warming is making the oceans get warmer, which is not good for corals. Finally, humans dump sand on corals to make beaches. We must remember that without corals, there would be no reef!