The worldwide destruction of coral reef habitats is one of the more depressing things in a world that has no lack of depressing tales of human depravity. While no solution is a cure-all and nothing beats an International Accord to Stop Acting Like Self-Destructive Idiots, there are some brave experiments going on that makes me less depressed:
Jolts of electricity revive damaged coral reef

Look at the photos and feel happiness. The Global Coral Reef Alliance carries more updates on other restoration projects, and can always use some cash as well.