Climate change is a priority issue for us here at Greenpeace. We realised years ago that it has the potential to wipe out most of the gains the environmental movement has made in other areas. Disruptions to ecosystems will likely harm everything from minke whales to coral reefs to polar bears. Whole forests will be lost, and hundreds of thousands of species will become extinct. Climate change will also bring devastation to people and communities, especially some of the world's poorest.