The north pole region as an indicator of the changing arctic ocean: The need for sustaining observations

Sustained observations of environmental conditions in the North Pole region are critical to understanding the changing Arctic Ocean. The Transpolar Drift conduit of sea ice and freshened upper-ocean waters across the Arctic Ocean passes over the North Pole region on its way to the North Atlantic through Fram and Nares Straits. The exported ice and freshened water stratifies the sub-Arctic seas and limits the vertical convection that ventilates the world ocean. Key variables such as ice thickness, bottom pressure, and hydrography in the North Pole region are thus sensitive indicators of changes over the whole Arctic Basin and how these affect the global ocean. Drifting buoys installed in the North Pole region by Great Britain, Canada, France, Germany, Japan, and the U.S. address what would otherwise be a dearth of ocean, ice, and atmosphere observations in the central Arctic. A suite of satellite remote sensing tools such as ICESat/ICESat-2 from the U.S., GRACE from the U.S. and Germany, and CryoSat2 from the European Union extend the conclusions from central Arctic Ocean in situ observations to other regions. Detecting and understanding climate change requires observations over decadal and longer scales. We propose an international program as the key to sustaining these observations in the North Pole region. Such an international program would help immeasurably by 1) facilitating financial sharing of the burden of long-term measurements among several nations, (2) reducing logistics costs through economies of scale, and 3) providing a buffer against national funding, logistics, and geopolitical difficulties.