Scope of activities
The Arctic is the fastest changing region on Earth, with changes observed in physical, biological, and socioeconomic systems. Over the past several decades, Arctic air, ocean, and land temperatures have increased at a rate more than twice the global average, a phenomenon known as Arctic amplification. Arctic sea ice extent has decreased dramatically, with summer melting occurring earlier and both the summer and winter sea ice extent shrinking faster. Boreal and Arctic permafrost (perennially frozen ground) thaw increases carbon emissions that further exacerbate global temperature increase. Additionally, the Greenland Ice Sheet, the largest ice mass in the Northern Hemisphere, is retreating, and the associated melt contributes to increased sea level rise. These changes will affect the environment and associated natural resources in the Arctic, and will ultimately have a large economic impact.
These changes do not happen in isolation, but involve feedbacks that impact multiple components of the Arctic’s natural and human systems, as well as the larger Earth systems. Understanding these interactions, including impacts to the environment as a result of human behavior, is becoming increasingly important, and is also useful for predicting future Arctic and global changes. For instance, changes in atmospheric constituents, clouds, and circulation affect the surface energy budget in the Arctic, thereby affecting sea ice extent. Decreasing sea ice extent, in turn, alters the air-sea interaction impacting the energy balance of the atmosphere and ocean. Similarly, sea ice and marine ecosystem changes are affected through changes in ocean circulation and heat and freshwater budgets. Changes in the Arctic affect global atmospheric circulation by altering the jet stream and the polar vortex, which in turn influences midlatitude weather in the United States.
Changes within individual components of the Arctic system can have cascading impacts on the integrated system. For instance, sea ice change, thawing permafrost, changing storm strength, and increased sea level due to glacial melt all have an interconnected effect on Arctic coastlines, such as increased flooding, leading to erosion, which can have large economic impacts. Interactions between human and natural systems also have broad implications to Arctic Indigenous communities.
In recent years, ocean primary productivity in nearly all regions of the pan-Arctic was higher than in the past, which can be linked to lower sea ice cover and increased nutrient availability. In addition, with changes in sea ice and water temperature, some species are responding with spatial or temporal changes in their distributions. For example, in 2017, commercially important Pacific cod and pollock in the Bering Sea expanded north approximately 500-1,000 km in less than 12 months. The Western Arctic bowhead whale—an important species for Indigenous ways of life—provides another example. Although the population has shown a steady increase since commercial whaling ended, the autumn migrations in 2019 and 2020 exhibited new extremes of opposite degrees in whale densities near Barrow Canyon, with very low densities and a far offshore distribution in 2019 and record high densities and nearshore distribution in 2020.
The impacts on the terrestrial ecosystem are also significant. Plant species in the Arctic are exhibiting changes with extended growth season, earlier snow-melt, and altered precipitation patterns. Wildfire frequency and intensity are impacted by air temperature and weather patterns while soils, permafrost, hydrology, the terrestrial ecosystem, and human health are impacted when an area burns. For example, enhanced fire activity, permafrost thaw, and changes to local and regional hydrologic cycles are also expected to enhance the release and deposition of mercury trapped in Arctic soils and tundra. This in turn can have negative impacts on human health.
Computational models that quantify the drivers of past and current Arctic change, as well as the interactions and feedbacks of these changes with Earth’s natural and human systems, are needed to understand the interconnected Arctic system. Models help represent the state of understanding of systems and are the principal mechanism through which current understanding can be projected into the future. Models of both the individual components of the Arctic as well as the comprehensive Earth system are needed. Different kinds of observations are also needed, including intensive short-term observational campaigns, long-term satellite and in situ observations, and observations that detail the Arctic climate and environment on the geologic time scale, as well as observations that include generations of Indigenous Knowledge. Modeling and observational capabilities across agencies, along with research on Arctic and Earth system processes, enhance our understanding of Arctic system interactions.
By addressing this priority area, the U.S. Arctic research community will have a better understanding of the Arctic system and its connection to the Earth system as a whole. This will include reduced uncertainties in predictions and an increased ability to inform strategies that minimize the negative impacts and take advantage of the opportunities of a changing Arctic.