ERA Acute – Extending an Environmental Risk Assessment Model to the Marginal Ice Zone

ERA Acute is a globally applicable method and software tool for environmental risk assessment (ERA) of acute oil spills (Stephansen et. al, 2017a and 2017b; Libre et al, 2018), and is to be implemented as the new industry standard ERA methodology on the Norwegian Continental Shelf (NCS). This paper describes the proposed adaptation and further development of the established ERA Acute method to enhance the functionality for ERA of acute oil spills in the Marginal Ice Zone (MIZ). Due to the highly dynamic nature of the MIZ, the pilot ERA Acute MIZ proposes to use high temporal resolution data on ice concentrations and presence of Valued Ecosystem Components (VECs) in newly developed functions to calculate impacts in the MIZ. Based on literature and preliminary sensitivity tests; parameter values and risk functions have been proposed for the MIZ (ice concentrations in intervals between 10–80 %). The functions reflect that presence of ice reduces the available space for surface activities; foraging, diving, entering and exiting the water and concentrates the oil in the same space between ice floes. These functions will now be further revised, tested and implemented in a software tool. This paper presents the proposed ERA Acute MIZ methodology.