Environmental management

Report: An operational risk-based process to assess and avoid serious harm in the deep sea

• A six-step risk-based process is proposed to help manage and avoid serious environmental harm from deep-sea mining.
• The framework uses a precautionary approach, assuming complete loss of ecosystem values unless monitoring shows otherwise.
• It combines input and outcome controls to guide adaptive management and ensure mining stays within safe environmental limits.

This report outlines a practical and science-based method to assess and manage the environmental risks of deep-sea mining. The goal is to help regulators and mining companies avoid causing ‘serious harm’ to deep-sea ecosystems, a requirement under international law. The authors propose a six-step process that blends risk assessment, monitoring, and adaptive management.

The process begins with identifying potential environmental pressures from mining and linking them to vulnerable parts of the ecosystem, called ‘receptors’. These could be species, habitats, or ecosystem functions. The framework uses both input controls (e.g., limiting sediment plumes or noise) and outcome controls (e.g., tracking changes in species or habitats) to manage impacts.

A key feature of the approach is its precautionary starting point: it assumes that mining causes complete and permanent loss of a given ecosystem value in the affected area. This conservative assumption allows operations to begin cautiously, with the understanding that they can only continue if monitoring shows that impacts are less severe or that recovery is occurring.

The six steps include:

• Identifying potential interactions between mining activities and ecosystem components.
• Using ecosystem models to understand how impacts might spread.
• Ranking risks and identifying where mitigation is needed.
• Conducting detailed risk assessments for high-risk scenarios.
• Setting clear limits for what constitutes ‘serious harm’.
• Monitoring and adjusting operations to stay within those limits.

The framework also includes a method to estimate how ecosystems might recover over time, using monitoring data and simple models. This helps determine how much mining can occur before crossing environmental thresholds.

Overall, the report offers a structured, transparent way to manage deep-sea mining in highly uncertain environments. It emphasises the need for ongoing monitoring and evidence-based decision-making, ensuring that mining can only continue if it remains within safe ecological boundaries.