Forget the hockey stick, this is the most important graph in the climate change biz, the relationship between the global average temperature and the number of pirates. We trot out Wellington Grey's handiwork every September 19th, on International Talk Like A Pirate Day.
The Sierra Club takes TLAP Day seriously too, and notes "it's important to do more than just talk the talk. Ye've got to walk the walk, plank or not. And, these days, that means being sensitive to the environmental impacts of yer plundering." They have prepared a green pirate quiz , So smartly, me lubbers, check it out.