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.
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.
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).
Over the past five years, ocean acidification (OA) has emerged as one of the most prominent issues in marine research. This is especially true given the newfound public understanding of the potential biological threat to marine calcifiers (e.g. clams, pteropods) and associated fisheries, and the associated human impacts for small communities that directly or indirectly rely on them (e.g., Mathis et al., 2015a; Frisch et al., 2015). Cooler water temperatures and unique physical processes (i.e. formation and melting of sea ice) make the waters of the Arctic Ocean disproportionately sensitive to OA when compared to the rest of the global ocean. Even small amounts of human-derived carbon dioxide (CO2) can cause significant chemical changes that other areas do not experience, and these could pose an existential threat to some biological organisms.