Key points
- The deep sea is one of Earth’s most fragile and least understood environments.
- A group of scientists led by CSIRO has created science-based tools and frameworks to help guide precautionary and informed decisions about mining.
- The research is independent, transparent and designed to support strong environmental protection.
As deep-sea mining gains momentum, scientists are playing a key role with rigorous, independent advice to ensure that if mining activities do occur it can be approached with extreme caution and care for the marine environment. Recent scientific assessments aim to clarify the environmental risks, offering data-driven insights to inform policy.
A research consortium led by CSIRO has developed a comprehensive set of tools and frameworks designed to support environmental decision-making around potential deep-sea mining activities.
While the findings don’t advocate for mining, they highlight the role of rigorous research in guiding decisions that balance sustainability, responsibility, and long-term impact.
The release of this body of work, which includes eight reports now publicly available, marks a major milestone in scientific efforts to manage and protect deep sea ecosystems should deep-sea mining be approved by the International Seabed Authority.
The research was commissioned by The Metals Company Australia Pty Ltd (TMC) and focuses on the Clarion Clipperton Zone (CCZ) in the Pacific Ocean.
Any new industry should be subject to rigorous and transparent assessment prior to any operations and any new approach to resource extraction brings concerns – particularly around its possible environmental impacts. In the case of deep-sea mining, these concerns are heightened by limited existing knowledge and the remote, poorly understood nature of the deep ocean. As the national science agency, CSIRO’s role has been to provide independent, science-based evidence to inform decision-making amid uncertainty and differing world views.
“Science done well can provide the unbiased information that decision makers need,” said Dr Piers Dunstan, Senior Principal Research Scientist at CSIRO. “It’s really important to have a trusted source of information when there are so many different opinions about what’s happening.”
A first-of-its-kind framework
This project represents the first time that ecosystem-based management (EBM) principles have been applied so comprehensively to the deep sea. The consortium, comprising CSIRO, Griffith University, Museums Victoria, the University of the Sunshine Coast, and Earth Sciences New Zealand (formerly National Institute of Water and Atmospheric Research (NIWA) and GNS Science), used an EBM framework to assess environmental risks and develop management strategies that can adapt as new knowledge emerges.
The deep sea remains one of Earth’s least understood ecosystems, and that complexity made the challenge both scientifically compelling and vitally important.
“The deep sea is really poorly understood,” said Dr Dunstan. “What attracted us to this project was the opportunity to develop a very high-level assessment to support decision-making – both about whether mining should go ahead and, if so, under what constraints.”
Rather than focusing on a single dataset or indicator, the research was intentionally designed as a modular, integrated system of interlinked studies.
“Each piece of the work complements the others,” said Dr Dunstan. “We started quite simply with ecosystem models that were described by experts. Then we moved over time to more quantitative assessments, where we're describing the expected impacts on the seabed and the potential impacts in the pelagic environment. From there, we considered how this information could be used to make decisions about what constitutes ‘serious harm’ and we developed a process that stakeholders could work through.”
Key reports and research outputs
In line with CSIRO’s commitment to transparency and open science, all reports and supporting materials from this project have been made publicly available to support independent review and informed decision-making.
The key outcomes include:
- A clear definition of ‘serious harm’ using a traffic light system – green for minor impacts, orange for moderate, and red for major, irreversible damage. This would help regulators know when to act or halt mining operations.
- A full ecosystem model of the CCZ, linking surface waters to the seafloor, which predicts that mining impacts are likely to be localised to the seabed.
- A suite of environmental indicators to monitor changes in biodiversity and ecosystem health, tailored to both worst-case and best-case mining scenarios.
- A risk-based management process that assumes full ecosystem loss unless proven otherwise, ensuring a precautionary approach to mining.
- A quantitative risk assessment of the impacts of seabed mining operations and the impacts of toxic metals in pelagic ecosystems
Each of the eight reports is accompanied by detailed methodology and recommendations, with many also slated for publication in peer-reviewed scientific journals.
“Our research and modelling provide new insights into the specific ecosystem type and environmental conditions of the CCZ,” said Dr Dunstan. “There are clearly impacts on the seabed from deep-sea mining.”
Models and observations suggest that there is a disconnection between the bathypelagic (at depths between 1000 to 3000 metres) and epipelagic (upper ocean down to 200 metres) zone in the CCZ, meaning the transfer of impacts from deep-sea mining is constrained.
The research looked at functional groups at the species level, finding that some groups may be quick to recover if disturbed by mining, whilst others may be slow to recover, or not recover at all.
“Essentially, our research shows that monitoring is critically important if mining were to go ahead. And this monitoring would validate any modelling undertaken,” said Dr Dunstan.
Scientific independence and transparency
CSIRO has been explicit in stating that it does not advocate for deep-sea mining, nor does it participate in regulatory processes. Instead, CSIRO’s role is to provide the robust, trusted science needed by regulators such as the International Seabed Authority (ISA).
“We’ve provided independent, science-based tools that help decision-makers navigate the complex challenges of deep-sea mining,” said Dr Dunstan. “This project sets a new benchmark for environmental assessment in one of Earth’s most fragile ecosystems.”
Dr Dunstan also said CSIRO’s deep experience in marine ecosystem science positions the organisation well to contribute rigorous, impartial analysis in an emerging field marked by significant uncertainty.
“We are a world leader in ecosystem-based management and the tools that are needed to implement ecosystem-based management and adaptive management,” said Dr Dunstan. “We have experience across a very wide range of different types of ecosystems in the marine environment, and that led us to the place where we felt we were well placed to provide robust science and advice in a system that was very poorly understood.”
Laying the groundwork for future decisions
With momentum growing around the world for evidence-based management of the deep sea – and increasing geopolitical attention on who benefits from seabed resources – this research arrives at a critical juncture.
“This project has closed important knowledge gaps,” Dr Dunstan said. “It shows that, even in places we know very little about, science can develop tools to assess risks and support decision making.”
CSIRO researchers believe the methods developed through this project can be applied to deep sea environments globally, regardless of location or mining proponent. As nations, industries and regulators continue to weigh the benefits and risks of seabed mining, this research sets a new benchmark for environmental oversight.
“What I hope people take away,” said Dr Dunstan, “is that this work shows how science, when done with integrity and transparency, can help navigate complex challenges and support responsible, informed decision-making.”
All reports and findings are publicly available.