Historical cases

Over the past several decades, Earth's polar ice caps have gained significant attention because of the alarming decrease in land and sea ice. NASA reports that since the late 1970s, the Arctic has lost an average of 20,800 square miles (53,900 square kilometres) of sea ice per year while the Antarctic has gained an average of 7,300 square miles (18,900 km²) of sea ice per year. At the same time, the Arctic has