RESEARCH HIGHLIGHT

Losing the Edge: Coastal Erosion in the Arctic

October 12, 2004

IARC Researcher David E. Atkinson is studying the mechanisms and forces that drive coastal dynamics in the Arctic. Dr. Atkinson came to UAF in July 2004 to join the Atmospheric Sciences group. He specializes in arctic climatology and is currently looking at coastal dynamics.

Coastal dynamics has several aspects. These include erosion, which is a movement of sediments away from a coastline; aggradation, which is a gaining of sediments; reshaping of barrier islands and coastlines; and flooding during storms. Therefore, scientists need to know where sediments are going and where they will reemerge.

Coastal erosion is a big problem in the Arctic and the effects can impact area residents and structures as well as wildlife. In the last 50 years, Native communities that were once transient have settled in coastal areas where there is access to hunting, fishing, and transportation. Coastal communities have used sea walls and other man-made barriers to hold back erosion. These measures have worked to an extent, but as areas of open water become larger, wave and wind effects also increase and eat away at these temporary solutions.

Sediment is only one part of the erosion equation. Carbon also moves from the terrestrial to the marine environment and can impact the ecology of both areas. This also affects the global carbon cycle, which is important for climate change studies. Wind, especially high wind, is one of the mechanisms researchers refer to as a 'forcing,' since it can drive other conditions such as erosion. Wind generates waves, and high waves can cause further coastal erosion.

The intensity of waves is in part controlled by the amount of open water that is present. Coastal areas with large expanses of open water have much more potential for wave action than a frozen shoreline. Studies from 1950-2000 have indicated a warming trend in the Chukchi and southern Beaufort Seas, with a corresponding decrease in sea ice coverage. Longer, warmer seasons translate to more open water and more waves. Dramatic changes have taken place in coastal zones, with the edge of the summertime permanent ice pack retreating rapidly over the last several years. Dr. Atkinson is also participating in the Arctic Coastal Dynamics project (ACD), an observational program that determines how coastal erosion actually works across the Arctic. As part of its work, ACD is collecting data on the number and type of storms in each region and comparing the characteristics of summer and winter storms. As with arctic cyclones, summer and winter storms have different characteristics, including their duration and intensity. They also found that the storms with the strongest erosive potential occur in early fall in the Chukchi Sea area, off north/northwestern Alaska. Computer models, created thus far, predict an increase in storm activity. However, until recently, it has been difficult for researchers to study shore zones. Equipment placed in these areas is subject to damage by sea ice. Nevertheless, studies underway are seeking to learn more about what happens to sediment and carbon just after it goes into the water, as well as current and future trends in coastal storminess. Recent reports, such as the Arctic Climate Impact Assessment (ACIA) report (http://www.acia.uaf.edu/), have pointed out that the Arctic is a key area in the study of climate change and that changes are in effect magnified in the Arctic region. This can be a difficult concept to understand, but as Atkinson pointed out, a temperature increase of a few degrees in a temperate climate may result in a slightly longer growing season, whereas in the Arctic it can mean the difference between freezing and thawing.

Dr. Atkinson was recently interviewed about his work on coastal erosion by Alaska Public Radio and by a crew from French Television 1.