Sea Ice: Hazards, Risks, and Implications for Disasters

Abstract The role of sea ice as a natural hazard is discussed with a focus on Arctic and sub-Arctic regions where risks associated with human activities and ice processes are the greatest. Hazard assessment and emergency response need to consider a range of controlling factors that can lead to events initiating an accident, failure, or full-scale disaster. These factors include environmental hazards, equipment, procedures and settings, and people. Quantifying risks associated with the presence of sea ice requires the joint consideration of the probability of specific hazards and the magnitude of their impacts. Both of these also depend on the type and level of human activity, such that disaster risks are substantially higher in the Arctic than in the Antarctic. We identify three types of sea-ice hazards: (1) broad, long-term hazards and associated risks associated with a rapid reduction in summer ice extent; (2) near-term hazards resulting from changes in sea-ice extent and dynamics such as increased coastal erosion and threats to coastal infrastructure; and (3) immediate risks and the potential for disasters derived from the combination of sea-ice hazards and human activities such as shipping or offshore resource development. A review of key properties and processes governing the role of sea ice as a hazard focuses on recent rapid changes in ice extent and concentration in the Arctic and resulting threats to coastal systems. Other key factors include the distribution of old perennial ice that has a greater thickness and higher mechanical strength than seasonal ice, patterns of ice movement that determine advection of ice hazards, and the degree of ice deformation that can generate thick, rough ice and represent a hazard in its own right. These factors are examined in the context of a case study for the Beaufort and Chukchi Seas in the North American Arctic. Linking specific environmental hazards to the geospatial distribution of human activities and vulnerable ecosystems allows for an integrated Arctic hazards assessment, currently still in its infancy. The need for coordinated environmental observations in informing hazard assessments and emergency response is discussed in the context of recent increases in maritime activities in the Arctic.