Arctic ice minimum extent, 2007. Satellite image showing the Arctic polar ice cap (upper centre), with Greenland (centre right). The Northwest Passage is also seen (centre), a sea route connecting the Atlantic Ocean (right) to the Pacific Ocean (lower left) through the Canadian Arctic Archipelago. The receding sea ice widened the Northwest Passage, making it fully open in August 2007. Declining sea ice is due to global warming, and the Arctic temperatures were at a record high in 2007, having risen by 1.7-2.2 degrees Celsius in the past century. Image produced using observations by the SSMI (Special Sensor Microwave Imager) instrument aboard the US Air Force's Defense Meteorological Satellite Program (DMSP) on 14th September 2007.