Risk Assessment has long been implicitly or explicitly embedded within any impact assessment such as Environmental Impact Assessment, Appropriate Assessment, Strategic Environmental Assessment, etc. and is a necessary perquisite of Risk Management. The breadth of present and future risks in the marine environment (e.g. from shipping, marine litter, ocean acidification, climate change, and the blue growth sector) may significantly affect human societies. Despite this, any prioritisation of marine hazards has to be done on a site-specific basis and will pertain to a sea region or sub-region.
Understanding and performing a Risk Assessment requires certain basic concepts to be defined:
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Hazard: the potential that there will be damage to a human asset/activity, or to the environment.
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Risk: the amount of asset/activity/environment etc. that may be affected.
These are phrased by, for example, the UK Department for Environment, Food and Rural Affairs 2001 risk assessment guidelines1 as:
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Hazard: A situation or biological, chemical or physical agent that may lead to harm or cause adverse effects.
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Risk: The potential consequence(s) of a hazard combined with their likelihoods/probabilities.
Taking these together, we therefore regard Hazard as the cause and Risk the probability of effect (likely consequences) leading to adverse or unwanted effects especially on human and valued assets.
Recently, a typology of hazards has been created to try to summarise the nature and number of marine hazards2. As the potential consequences (the risk) of a hazard (the cause) can occur for different types of asset, methods for assessment of risk may differ between industries and whether the Risk Assessment refers to financial decisions, environmental concerns, human health and welfare concerns, or damage to a physical structure. There are increasing frameworks adopted which emphasise that Risk Assessment must be incorporated into marine management34. A six stage process was developed within the VECTORS project for assessing the risks associated with offshore energy, fisheries and aquatic invasive species (Table 1). The methods used to perform the Risk Assessment will be dependent on which risks, assets and end-points need to be investigated and consequently each Risk Assessment will be site, activity or pressure specific.
Table 1. Six steps of an ERA and associated key questions
1. Problem formulation
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What needs to be assessed?
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2. Hazard identification
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What can go wrong? What are the hazards?
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3. Cause identification
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What can lead to the hazard occurring? (What causes the hazard?)
Quantitative: How often or how likely is it that these causes will occur?
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4. Exposure assessment (This is a quantitative step that is not necessary but adds value to the risk assessment)
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Quantitative: How does the hazard reach the receptor? At what intensity? How long for and/or how frequently does the hazard reach or affect the receptor? How likely is it that the receptors will be exposed to the hazard?
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5. Consequence or effect identification
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What are the consequences of the hazard if it occurs?
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6. Risk characterisation and estimation for consequences
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What are the risks (quantitative or qualitative measure)?
Quantitative: What is the probability of the consequence happening? This can be estimated for both before and after preventative and mitigation measures are put in place.
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There are many methods of performing a Risk Assessment and, as an example, the Bow Tie analysis has been used in the VECTORS project to assess offshore energy and fisheries. A Bow Tie diagram clearly visualises the scenario being considered and differentiates between preventative and mitigation measures – effectively ways to prevent an event from happening, and if it does, ways to mitigate any effects (Fig. 1). The power of a Bow Tie diagram is that it summarises numerous risk scenarios that can be understood by all stakeholders. Originally designed for the risks associated with health and safety practices, the wide scope and capabilities of Bow Tie analysis can be adapted to review governance aspects, ecological assessments and investigations, and it can be expanded to include quantitative information as well as incorporating factors that may affect the adequacy of any control measures.

Figure 1: Simplified representation of the Bow Tie approach to risk assessment and management. Any cause can lead to the hazard event in the centre of the diagram, which can result in any of the consequences.
Hence the Bow Tie method for risk assessment and analysis and its software make it highly relevant to both policy makers and other stakeholders even though the diagrams are only the first stage. Complex information can be included in clickable boxes, as can links to relevant documentation such as permits, EU Directives, EIA reports etc. The analysis can be made quantitative if probability information exists for the hazard under study. As different depths of analysis will be needed by different stakeholders hence the method serves many purposes such as dissemination to those who may only need to know the top-level outcome, such as the public or the media for example. Developers and regulators designing, operating and regulating a development can access all of the deeper information to help make more informed decisions; the risk assessment can be improved as more information becomes available. The Bow Tie therefore allows information to be communicated at various levels, from simple diagrams to complex data sets.
Risk assessments were also undertaken for Ballast Water Management.