Vital Signs

Over recent decades, Arctic air temperatures have warmed at a greater rate relative to global means.

Many components of the Arctic land surface are directly influenced by snow cover from fall through spring, including the surface energy budget, ground thermal regime, permafrost, and terrestrial and freshwater ecosystems.

Globally, precipitation over land has likely increased since 1950, consistent with increases in total atmospheric moisture. Climate models project an increase in Arctic precipitation, a transition from snowfall- to rainfall-dominated climates, and a higher frequency of heavy precipitation events.

Ice loss from the Greenland Ice Sheet has immediate and global influence on sea level rise, with impacts including coastal erosion, saltwater inundation of freshwater resources, and increased flooding frequency.

As the frozen interface between the ocean and atmosphere, sea ice plays a key role in the Earth’s climate and polar ecosystems.

Arctic SST is an essential indicator of the role of the ice-albedo feedback cycle in any given summer sea ice melt season.

Primary production by single-celled phytoplankton and sea ice algae forms the foundation of the Arctic Ocean’s unique ecosystems and the fisheries they support.

The biological, physical and climatic conditions of Arctic tundra ecosystems are changing profoundly, as vegetation and underlying permafrost soils are strongly influenced by warming air temperatures and the rapid decline of sea ice on the nearby Arctic Ocean.

Surface air temperatures (SAT) represent one of the strongest indicators of Arctic change over the last 50 years.

Snow covers the Arctic land surface (land areas north of 60° N) for up to 9 months each year, and influences the surface energy budget, ground thermal regime, and freshwater budget of the Arctic.