The Arctic is a bellwether of climate change, with surface temperatures rising twice as fast as the global average. September sea ice extent in the Arctic has decreased by 40% since the 1970s; a Northwest Passage has opened; and a nearly ice-free Arctic will likely occur by mid-century. This rapid amplification of warming in the Arctic has powerful and enduring global impacts, including prospects for mineral and energy exploration, expanded fisheries, faster shipping routes, and an increase in tourism. However, these opportunities bring with them potential hazards.
The Arctic also holds unique natural archives of Earth's climate history. Sediment cores from oceans and lakes along with ice cores from glaciers and the Greenland ice sheet reveal historical information about sea ice cover and the physical state and composition of past atmospheres. Melting ice is uncovering surprising artifacts from past societies, exposing a wealth of new information for historians and anthropologists. Finally, polar regions provide a unique window into the space environment, as terrestrial magnetic field lines guide ionized particles from the magnetosphere, Sun, and galaxy into the atmosphere over the polar cap.
Questions surround the sovereignty of Arctic waters as well as the shared governance necessary to regulate mineral and energy exploration, transportation (both shipping and overflight), fishing, pollution, environmental conservation, and security interests. Scientific knowledge of the changing Arctic is key to successful diplomacy and international policy. The 4 million residents of the Arctic (including 400,000 indigenous people) must respond to a changing climate as well as an influx of visitors, technologies, and cultures from the lower latitudes. This increased access to Arctic regions requires emergency response mechanisms for disasters such as oil spills, shipwrecks, and search and rescue efforts. Thawing permafrost, combined with melting sea and land ice, leads to coastal erosion, damage to fragile ecosystems and societal infrastructure, an increase in wildfires, and the release of large stores of carbon dioxide and methane into the atmosphere (a "carbon bomb"). Ocean acidification, chemical pollution, and noise pollution stress marine ecosystems, while shifting migration patterns on both land and sea threaten biodiversity and species extinction. Furthermore, "What happens in the Arctic doesn't stay in the Arctic," requiring communities at lower latitudes to adapt to sea-level rise, changes to regional weather patterns driven by a modified polar jet stream, and shifting ocean currents caused by increased Arctic meltwater.