Comparing environmental impacts of deep-seabed and land-based mining: A defensible framework

Area of Science:

• Environmental Science
• Marine Biology
• Ecology

Background:

• Climate change and biodiversity loss are interconnected global crises.
• Transitioning to electric vehicles (EVs) to mitigate climate change necessitates increased mineral resources, like nickel and cobalt for batteries.
• Current land-based mining for these minerals causes biodiversity loss, prompting exploration of deep-sea mining.

Purpose of the Study:

• To present a novel framework, the Environmental Impact Wheel, for a holistic and quantitative comparison of ecosystem impacts between land-based and deep-sea mining.
• To address the lack of comprehensive comparative studies on the biodiversity impacts of different mining strategies for EV resource acquisition.

Main Methods:

• Developed the Environmental Impact Wheel framework, adapted from ecological restoration principles, to assess mining impacts.
• The framework incorporates a suite of physicochemical and biological components, including six key attributes (physical condition, community composition, structural diversity, ecosystem function, external exchanges, absence of threats) with multiple indicators.
• Outlined a five-step process for applying the framework: defining scope, scales, selecting indicators, aggregating data, and generating impact wheels for comparison.

Main Results:

• The study proposes a structured, data-driven methodology for comparing the environmental consequences of land-based versus deep-sea mining.
• The Environmental Impact Wheel provides a comprehensive tool beyond qualitative assessments, utilizing empirical data across multiple environmental metrics.
• Identified the need for establishing indicator thresholds to quantify the severity of environmental impacts for effective comparisons.

Conclusions:

• A standardized, holistic framework is essential for objectively comparing the biodiversity and ecosystem impacts of land-based and deep-sea mining.
• The Environmental Impact Wheel offers a robust method to guide decisions on resource extraction for the EV transition, balancing climate mitigation with biodiversity conservation.
• Further development requires defining specific indicator thresholds aligned with clear environmental goals to facilitate informed decision-making.