Indicators

Despite the low annual temperatures and short growing seasons that are characteristic of high northern latitudes, wildland fire is the dominant ecological disturbance within the region’s boreal forest, the world’s largest terrestrial biome.

The Arctic continues to warm at a rate that is currently twice as fast as the global average. Warming is causing perennially-frozen ground (permafrost) to thaw, with permafrost in many locations currently reaching record high temperatures. Organic carbon contained in soils of the permafrost region represent a climate-sensitive carbon reservoir that is affected by warming air and ground temperatures and permafrost thaw. 

The ivory gull (Pagophila eburnea) is a high-arctic seabird associated with sea-ice throughout the year. It breeds at high latitudes, mostly in the Atlantic sector of the Arctic.

Marine populations are expected to remain within their preferred thermal conditions, and therefore to shift their spatial distributions to track changes in ocean temperatures. Many different indicators show changes in Arctic physical conditions, with an increased rate of change from 2005 to present day. Given these rapid physical changes and expected responses of marine populations to changing thermal conditions, the spatial distribution of Arctic and subarctic fish communities will likely be a sensitive indicator for contemporary and ongoing Arctic climate change.

The Arctic Ocean contains only about 1% of global ocean volume but receives greater than 10% of global river discharge. Consequently, terrestrial influences via river inputs are much stronger in the Arctic Ocean than in other ocean basins. Rapid change in the Arctic system is altering land-ocean linkages, impacting coastal and ocean physics, chemistry, and biology. 

Lake ice is an important component of the cryosphere for several weeks to several months of the year in high-latitude regions. The presence (or absence) of ice cover on lakes during the winter months affects both regional weather and climate (e.g., thermal moderation and lake-induced snowfall). Hence, monitoring of lake ice is critical to our skill at regional forecasting.

The abundance of migratory herds of caribou (North America and Greenland) and wild reindeer (Russia and Norway) in circum-arctic tundra regions has declined 56% over the last two decades. Caribou and wild reindeer are a key species in the arctic food web contributing to nutrient cycling between terrestrial and aquatic systems and the abundance of predators and scavengers.

Permafrost is an important component of the Arctic landscape, influencing hydrological systems and ecosystems and also presenting challenges to infrastructure development. Permafrost temperature and active layer thickness are key indicators of changes in permafrost conditions.

The Eastern Bering Sea (EBS) is a highly productive ecosystem characterized by a broad continental shelf and narrow slope to a deep-sea basin. Commercial fisheries in the EBS represent over 40% of fish landed annually in US waters, and the system has long supported one of the largest fisheries in the world: walleye pollock (Gadus chalcogrammus).

Despite the low annual temperatures and short growing seasons characteristic of northern ecosystems, wildland fire affects both Boreal forest and adjacent tundra regions. In fact, fire is the dominant ecological disturbance in boreal forest, the world’s largest terrestrial biome.