Deep Sea Mining Exposed: Inside the Fight to Save the Ocean's Last Frontier

Deep sea mining is no longer theoretical. In this episode, Andrew sits down with Matthew Gianni, co-founder and Political and Policy Advisor of the Deep Sea Conservation Coalition, for an in-depth look at what's actually happening on the seafloor and in the negotiating rooms deciding its fate. Matthew spent years as a commercial fisherman, including five years as a deep sea trawlerman off the Central California coast, before moving into ocean conservation with Greenpeace International and eventually co-founding the DSCC to fight destructive bottom trawling on seamounts. That history shapes everything he has to say about what's coming next.

The conversation covers the science and the politics in equal measure: what seamount trawling studies off Tasmania revealed about how quickly deep coral ecosystems can be destroyed, why the deep sea is far from the "biological desert" some mining proponents describe, and the 2024 discovery of "dark oxygen" being produced by the very polymetallic nodules that mining companies want to extract. Matthew also walks through the current state of play at the International Seabed Authority, including a fresh update from the July 2026 meetings in Kingston, Jamaica, the leadership change from Michael Lodge to Leticia Carvalho, the legal fight over The Metals Company's push for a US mining license outside ISA authority, and why the economics of nodule mining may not add up even on the industry's own numbers.

Whether deep sea mining moves forward is still being decided right now, and Matthew makes the case for why the decisions being made in 2026 will shape the deep ocean for generations. This is a dense, detailed update for anyone trying to understand where deep sea mining policy actually stands, straight from someone who has been in the room for over a decade.

Takeaways:

• Matthew Gianni co-founded the Deep Sea Conservation Coalition after years as a commercial fisherman and deep sea trawlerman, then a career at Greenpeace International running its ocean program.
• Seamount trawling studies off Tasmania showed how fast deep coral ecosystems can be wiped out once bottom trawling begins.
• The 2024 discovery of "dark oxygen" production from polymetallic nodules raises new questions about what deep seabed mining could disrupt before science even understands it.
• The International Seabed Authority is legally obligated to act "for the benefit of humankind as a whole," which is central to the current fight over mining regulations.
• The Metals Company is pursuing a US mining license through NOAA to bypass ISA authority entirely, a move Matthew calls "unilateral mining" that risks undermining the Law of the Sea Convention.
• The economics of nodule mining are being challenged even within the ISA's own analysis, with mined metals representing a small fraction of global terrestrial supply.
• A leadership change at the ISA, from Michael Lodge to Leticia Carvalho, has shifted the tone of negotiations, though Matthew says the fundamental disagreements remain unresolved.

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