Defining serious harm

Paper: Moving towards an operational framework for defining serious harm for management of seabed mining

• A three-tier ‘traffic light’ system is proposed to define levels of harm to the environment from polymetallic nodule mining: detectable (green), significant (orange), and serious (red).
• The framework provides clear thresholds and limits to guide when management actions should be taken, including when to stop mining.
• It offers a flexible, science-based process that can be adapted to different mining sites and environmental conditions.

This report presents a practical framework to help regulators and mining companies define and manage “serious harm” to the marine environment from deep-sea mining, especially in areas beyond national jurisdiction like the Clarion-Clipperton Zone (CCZ).

The core of the framework is a three-level classification of harm:

• Detectable harm (green): Minor effects that don’t require extra management.
• Significant harm (orange): Moderate effects that require action to avoid or reduce damage.
• Serious harm (red): Major, often irreversible effects that require mining to stop.

To apply this system, the report outlines a step-by-step process.

First, the environmental effects of mining activities are assessed (including effects from sediment plumes, noise, and habitat disturbance). Then, the severity of these effects is evaluated based on how much of the ecosystem is affected, how long the damage might last, and how sensitive the species or habitats are.

Thresholds and limits for harm must be tailored to each mining site, considering local species, habitats, and environmental conditions. Adaptive management, where thresholds can be updated as new data becomes available, should be used.

Importantly, the framework is designed to work alongside other tools, like pressure-based thresholds (e.g., for noise or pollution), and can be integrated into the International Seabed Authority’s (ISA) Mining Code. It also aligns with global conservation goals and practices used in fisheries and environmental impact assessments.

By offering a clear, science-based method to define and respond to environmental harm, this framework helps fill a major gap in the regulation of deep-sea mining.

This paper was published in Ocean and Coastal Management, 1 September 2024.