Famous director James Cameron has been making the headlines lately for his switch to a plant-based diet, and now the filmmaker is advocating for others to make the switch as well. On October 5, pro-vegan documentary Earthlings posted a clip of Cameron on its Facebook page. In it, the director discussed how all environmentalists should be vegans. “You can’t be an environmentalist, you can’t be an ocean steward, without truly walking the walk. And you can’t walk the walk in the world of the future, the world ahead of us, the world of our children, not eating a plant-based diet,” he says. According to the Food and Agriculture Organization of the United Nations, current estimates put the livestock industry’s contribution to global greenhouse gasses at 18 percent.