Dear Editor,

My parents’ marriage was against the law in Maryland in 1966 so they moved west. By the time I was born in 1973 they had settled in Monterey County, California — the same year the last cannery on Cannery Row shut down. The Hovden Cannery closed its doors, marking the end of an era. Where it stood, the Monterey Bay Aquarium would eventually rise, a monument to what we’d lost and hoped to restore.

When I was 12, in 1985, I became a guide at that aquarium — the youngest in my class. Standing in a building literally constructed on cannery’s ruins I told visitors about kelp forests, sea otters, and the remarkable return of the sardines. Through the 1980s and 1990s they came back. The ocean, given a chance to rest, proved resilient.

As a child who often felt out of place in the local community, the ocean was my refuge. I learnt that the ocean can be a patient teacher. But the lesson she’s teaching now, according to leading scientists, is one from which humanity may never recover. Worse, its impact will be felt across the entire nation — first with rising seafood costs, then with far more serious consequences.

Last week scientists announced the world has reached its first climate tipping point. Coral reefs — supporting a quarter of all marine life and nearly a billion people — are in widespread, irreversible collapse. Since 2023 over 80 per cent of the world’s reefs have suffered the worst mass bleaching event ever recorded. Underwater explosions of colour and life are turning into bleached wastelands.

This is fundamentally different from the sardines. When sardine populations crashed in the 1940s and 50s, the fish survived elsewhere. The ocean remained intact. When fishing stopped, they had somewhere to return. Recovery took decades, but was possible.

Coral reefs are the foundation. When they die the habitat disappears. The three-dimensional structures providing shelter, feeding grounds, and nurseries collapse into rubble. Unlike sardines that bounce back in decades, coral reefs take centuries or millennia to rebuild — if they can rebuild at all under continued warming.

Scientists are clear: We’ve crossed a threshold. Unless we reverse global temperatures to just 1°Celcius above pre-industrial levels — not just stop them rising, but bring them down — these ecosystems will be lost. Small refuges may survive, but vast, thriving reefs will be gone on any timeline that matters to our children.

Here’s what keeps me awake: This is just the first domino.

The same report warns we’re approaching other catastrophic tipping points — the Amazon rainforest, Atlantic ocean currents regulating weather worldwide, and ice sheets controlling sea levels. Each one, if it tips, could trigger others in a cascade of irreversible changes.

These aren’t abstract threats for any American. The Atlantic Meridional Overturning Circulation, including the Gulf Stream, could collapse within our lifetimes. If it does, global food production faces devastation. Nearly 60 per cent of land suitable for wheat would become unusable. Same for 59 per cent of corn-growing land. America’s agricultural economy would face catastrophic disruption — drastic rises in bread prices, widespread hunger, and potential mass starvation in vulnerable regions worldwide.

Amazon rainforest collapse — another looming tipping point — would remove one of the world’s largest carbon sinks, accelerating warming everywhere and intensifying droughts, heat waves, and extreme weather already plaguing communities from coast to coast.

We’re not discussing problems our grandchildren will face. We’re talking about changes fundamentally reshaping civilisation within decades.

But we still have agency. Scientists documenting this crisis also found positive tipping points in our favour. Solar power has got cheap enough that people are choosing it over coal. Electric vehicles are following the same path. We’re proving we can change how we power our world.

What we need now is action that matches the threat. Next month world leaders meet in Brazil for COP30 (30th United Nations Climate Change Conference) — the annual climate summit where countries make promises about cutting pollution. For a farmer worried about next year’s growing season, here’s why it matters: If countries commit to stopping the burning of coal, oil, and gas — and fast — we can slow the damage. If they don’t, we’re looking at soil that won’t grow crops, water that won’t come when seeds need it, and weather so extreme it wipes out entire harvests.

The small pockets of healthy coral that remain need protection from pollution and overfishing as well as every other stress we can remove. And we need to pull some of the carbon pollution back out of the air, the same way you’d pump water out of a flooded basement. It’s not enough to stop adding more; we have to remove what’s already there.

As that 12-year-old aquarium guide I taught visitors about resilience and recovery. Sardines taught me the ocean can heal when we give it a chance. But coral reefs teach a harder lesson: There are thresholds beyond which healing becomes impossible on human timescales. We’re learning the difference between damage that can be undone and wounds that become permanent.

The ocean has been a patient teacher. But this lesson — about irreversible tipping points and cascading collapse — is one we cannot afford to fail. The consequences won’t stay in the ocean. They’re coming for all of us, no matter where we live.

We crossed the first tipping point. We cannot afford to cross the next ones.

Ben Jealous

Former president and CEO of the National Association for the Advancement of Colored People

The ocean has been a patient teacher.