New risk assessment methods for Arctic oil spills

A new study by HELSUS members suggests a new method for assessing the risks posed by oil spills to arctic ecosystems.

The Arctic is warming, and as a result, the ice-free period in the Arctic Ocean is becoming longer. Simultaneously, the interest towards expanding sea routes through the Arctic Ocean is growing. The risk of oil spills is also increasing with expanding maritime activity.  

A recently published study by Helle et al. (2020) emphasizes the need to understand oil spills and the risks they pose to arctic ecosystems. The authors support taking a proactive, rather than reactive, approach to reacting to oil spills in the Arctic. We interviewed HELSUS Fellow Inari Helle to find out more about the method and  how the researchers came to develop it. Helle is a member of the Environmental and Ecological Statistics research group at the University of Helsinki.  

Traditional models for assessing oil spill risks, according to Helle, require vast amounts of data in supporting the function of algorithms in assessing the spreading and fate of spilled oil. “These models are usually also deterministic, and they don’t take into account the high uncertainties related to many relevant factors” Helle points out. The method, suggested in the newly published article, employs “a simpler approach in describing the spreading of oil, while providing a way to conduct spatially explicit season-wise oil spill risk assessment also in the areas where we do not have that detailed data”, Helle says.  ”It also quantifies risk with explicit uncertainty estimates” she adds.  

The method combines species’ densities and the spreading of oil to estimate the population that could potentially become exposed to spilled oil. This information is then complemented with species-specific exposure potentials and sensitivities to oil to further estimate the proportion of the population that will die due to oiling. When asked about the advantages of their model, Helle names its wide applicability. The model allows for assessing large areas, such as shipping routes, instead of focusing a few potential accident locations. “Further, as the method is probabilistic, we can answer questions like ‘what is the probability that the risks or impacts exceed certain limit’ and so on. We believe that these properties make the approach useful not only for risk assessment purposes but also for the decision-making related to the management of oil spill risks”, Helle argues. 

Helle has always been interested in understanding the impacts human activities have on the environment and how they can be mitigated. “The global economy depends strongly on maritime traffic and it is evident that shipping will increase also in the Arctic”, Helle mentions. “If we want to reduce the risks that this development poses to sensitive arctic ecosystems, we need methods to assess the risks beforehand.”