Pacific Beckons Deep Sea Mining, The Next Geopolitical Frontline

First, the energy transition is driving up demand for nickel, cobalt and manganese, with agencies projecting at least a doubling over the next two decades. Second, supply chains are concentrated in a handful of countries, making democracies nervous about choke points.

Policymakers and firms therefore see seabed minerals as a hedge: a way to diversify sources of“critical minerals” for clean energy and military defense.

Spanning 1.7 million square miles in international waters, the CCZ is earmarked for mining by 17 contractors under ISA licences.

At the same time, climate-driven shifts are drawing key tuna species – bigeye, skipjack and yellowfin – into the CCZ. Models suggest biomass increases of 10% to 30% for these species under warming scenarios. The result? Tuna fisheries and mining operations are set to share the same patch of ocean.

Mining plumes – clouds of sediment and metals stirred up at the seabed and discharged at the surface – could spread tens to hundreds of kilometers horizontally and hundreds of meters vertically.

For tuna and their plankton prey, the risks include stress on gills, disrupted feeding cues and exposure to contaminants. Mid-water food webs could be hit hard: Studies suggest over half of zooplankton and micronekton could be affected, rippling up to tuna stocks.

For Pacific economies reliant on tuna, this overlap represents a looming collision of industries. These tensions are already playing out in parts of the Pacific, including on New Zealand's doorstep.

In 2025, the Cook Islands – a self-governing nation in free association with New Zealand – signed strategic agreements with both China and the United States: the former through a“Blue Partnership” for seabed mineral research and grants, and the latter via a joint commitment to science-led, responsible development.

This underscores how great-power competition is now converging on Pacific seabed resources.

In the same year, the US Department of the Interior began exploring deep-sea mineral leasing in federal waters near American Samoa. Local leaders flagged risks to tuna fisheries and culture, urging extended consultations.

The process remains exploratory, but it shows how seabed plans can collide with livelihoods even before a single robot touches the seafloor.

There are still plenty of unknowns about the environmental impacts. But we know mining removes life-bearing sediment and nodules and that sediment plumes can travel kilometers beyond the site. Decades-old disturbance tracks still show reduced biodiversity.

A 2024 study warned that plumes could mobilize metals into mid-water habitats, threatening marine life we barely understand. Recovery could take centuries – if it happens at all.

The ISA has approved exploration but not exploitation; negotiations keep stalling amid calls, led by Pacific nations, for a moratorium or precautionary pause until science catches up.