Mineral deposits
containing commercially exploitable metals are
of interest for seabed mineral extraction in both the deep sea and
shallow sea areas. However, the development of seafloor mining is
underpinned by high uncertainties on the implementation of the activities
and their consequences for the environment. To avoid unbridled expansion
of maritime activities, the environmental risks of new types of activities
should be carefully evaluated prior to permitting them, yet observational
data on the impacts is mostly missing. Here, we examine the environmental
risks of seabed mining using a causal, probabilistic network approach.
Drawing on a series of expert interviews, we outline the cause-effect
pathways related to seabed mining activities to inform quantitative
risk assessments. The approach consists of (1) iterative model building
with experts to identify the causal connections between seabed mining
activities and the affected ecosystem components and (2) quantitative
probabilistic modeling. We demonstrate the approach in the Baltic
Sea, where seabed mining been has tested and the ecosystem is well
studied. The model is used to provide estimates of mortality of benthic
fauna under alternative mining scenarios, offering a quantitative
means to highlight the uncertainties around the impacts of mining.
We further outline requirements for operationalizing quantitative
risk assessments in data-poor cases, highlighting the importance of
a predictive approach to risk identification. The model can be used
to support permitting processes by providing a more comprehensive
description of the potential environmental impacts of seabed resource
use, allowing iterative updating of the model as new information becomes
available.