The Arctic Ice has been shrinking. Each year there has been less, as global warming has been greater near the north pole. Scientists can track the area of ice coverage, its thickness and the years of its formation. Though it is extremely cold, it is not without its own cycles of life, including life trapped within the ice, that plays a critical role in the interconnected ecology of the oceans and the entire ecosystem—from plankton up through predator species such as the Greenland Shark, believed to have the longest-span of vertebrate species (about 250 years, most spent at great depths).