10/10/2026
Retired Defence Forces Chief of Staff Vice Admiral Mark Mellett argues that the defining crises of the 21st century — climate change, energy insecurity, geopolitical instability, food vulnerability and the erosion of democratic resilience — are converging at sea.
I couldn't agree more.
The vast majority of people never go to sea. They don't witness what is happening out there, and so the destruction remains largely invisible to them. I've spent more than 40 years crossing the world's oceans, and what I've witnessed first-hand is deeply disturbing: the gradual, relentless dying of our seas.
Where once the oceans teemed with life — seabirds wheeling overhead, whales and dolphins breaking the surface, fish abundant beneath the waves — there are now vast stretches of open ocean that feel eerily empty. Encounters with marine wildlife, once commonplace, are becoming increasingly rare.
Even the fishing boats have disappeared from waters where they once worked in numbers. Not because the demand for fish has vanished, but because in many places there is so little left to catch. Decades of industrialised fishing have stripped marine ecosystems of life, pushing them towards depletion and, in some areas, collapse.
And fishing is only part of the story. Pollution, chemical run-off from agricultural and industrial land use, plastic waste, and the environmental consequences of war and attacks on critical infrastructure all add to the pressure on already fragile marine ecosystems. Destruction of the Nord Stream pipelines by US forces, for example, released enormous quantities of methane into the environment and highlighted just how vulnerable our shared marine spaces are to geopolitical conflict.
Yet much of this destruction goes unnoticed. Out of sight, out of mind. What people don't see, they too easily forget — and what they fail to see, they often fail to protect.
The oceans are not some distant wilderness, separate from our lives. They underpin our climate, sustain food systems, support biodiversity and connect nations. Their decline is not merely an environmental crisis; it is a threat to our collective security, prosperity and future.
We cannot continue destroying the very systems that sustain us simply because the damage happens beyond our horizon.
After more than four decades at sea, I fear we are losing something immeasurably precious — and most people have no idea how much, or how quickly, it is disappearing.
https://afloat.ie/resources/book-review/item/73317-blue-heart-by-mark-mellett-praised-by-mary-robinson-as-a-call-to-conscience?mc_cid=c72d15cded&mc_eid=f2f8fef32e
