Cambridge University scientists, Nick Toberg, John Fletcher and Professor Peter Wadhams, measure sea ice thikness on a Fram Strait ice floe. Greenpeace is on a month-long expedition in the icy Arctic campaigning for a global sanctuary to be declared around the uninhabited area of the North Pole. Arctic sea ice has already disappeared by 75% in the last 30 years, and scientists on board the Greenpeace ship Arctic Sunrise are working with 3D scanning experts and engineers to capture the true shape of Arctic sea ice for the first time.