We Need to Talk About Our Relationship with Coral Reefs

Why the 2025 coral bleaching crisis marks a climate tipping point—and what we can do about it.

In October 2025, scientists confirmed what many had feared: we've reached our first climate threshold. Warm-water coral reefs around the world are collapsing, marking a point of no return. This isn't a distant threat or a future possibility — it's unfolding right now, asking us a fundamental question: what kind of relationship do we want with our ocean?

For over 20 years, The Reef-World Foundation has worked to protect coral reefs from local threats and help them become more resilient. But these ecosystems face an unprecedented crisis due to an array of manmade threats. Without serious systemic change, we risk losing them forever. As we mark Coral Bleaching Awareness Month this November, it's crucial to understand what we're losing, why it matters, and what we can still do to change course.

What is a tipping point?

Think of a tipping point as the moment when you can't go back. It's a critical threshold in our climate systems that, once crossed, leads to large and irreversible changes to Earth's environment. Scientists have identified several potential thresholds for vital ecosystems, like the melting of Siberian permafrost or widespread Amazonian deforestation.

Shallow-water coral reefs have now become the first to pass this threshold, collapsing primarily due to marine heatwaves. As ocean temperatures continue rising at an accelerating rate, the damage becomes increasingly permanent.

Coral and algae: friends with benefits

To understand why this collapse is so devastating, you need to know about one of nature's most elegant partnerships.

Coral reefs support a huge variety of marine life thanks to their relationship with microscopic algae called Zooxanthellae. These are microscopic, photosynthetic algae which live inside coral tissue, where they have everything they need to photosynthesise. In return for this safe home, they provide their hosts with nutrients and give reefs their vibrant, kaleidoscopic colours.

It's a perfect arrangement, a true symbiosis where both partners thrive together. 

But like with any relationship, a strain can take a toll and even end things. When facing changing water temperatures, stronger storms, ocean acidification and pollution, coral expel the algae in a desperate response, starving themselves of their source of nutrients and putting themselves at huge risk from disease and death. Without their algal partners, they lose both their colour and their primary food source, turning ghostly white and becoming vulnerable to disease and death. This is what we call bleaching.

And it's accelerating at an alarming rate. From 1 January 2023 to 11 September 2025, bleaching-level heat stress impacted 84.4% of the world's reef area. Mass bleaching has been documented in at least 83 countries and territories. These aren't isolated incidents anymore — they're becoming the new normal.

Why reefs matter more than you think

If you've ever visited a reef, you know they're magical places. The sheer abundance of life, the colours, the movement — it's unlike anywhere else on Earth.

Here's the stunning part: reefs cover less than 0.1% of the ocean floor, yet they're home to more than 25% of all marine species. Picture an underwater city where every surface teems with life — fish swirling in rainbow schools, sea turtles gliding past, tiny cleaner wrasses running their stations and creatures in colours you didn't know existed tucked into every crevice.

These ecosystems are some of the richest habitats on our planet, and they've been perfecting this arrangement for nearly 400 million years. While nothing in nature is truly permanent, that's about as close as it gets.

That's what makes their collapse so catastrophic. We're not just losing pretty underwater scenery. We're losing nurseries where fish grow up, natural barriers that protect coastlines from storms, sources of food and income for millions of people, destinations that sustain entire tourism economies and potential medicines we haven't even discovered yet. The ripple effects will be felt throughout the ocean and far beyond.

But here's the thing: it's not over yet

Yes, the situation is serious. Yes, we've crossed a threshold. But that doesn't mean we surrender.

Professor Peter Mumby, a leading reef scientist at the University of Queensland, emphasises that through aggressive action and improved local management, some reefs can survive even in more extreme conditions. Some corals are proving more resilient than expected. Some locations are responding to protection efforts. And every reef we save matters.

This is where we can learn from the coral and Zooxanthellae themselves. Their relationship is one of mutual dependence, living in a delicate balance where both partners contribute to each other's survival. Humans and marine life share a similar bond. While our survival isn't quite as directly linked, we depend on the ocean for food, climate regulation, oxygen production and countless other services. In return, we have a responsibility to protect the life within it.

Protecting reefs — such a critical link in ocean health — needs to be a priority.

Join us in building a new symbiosis

Initiatives like Green Fins, our programme working with the dive and snorkel industry to adopt sustainable practices, are moving us in the right direction. But we need to accelerate change and build a more conscious, sustainable relationship with our underwater world. More action from governments, NGOs, and the marine tourism industry is essential.

This is where you come in:

Support our Big Give Christmas Challenge (2–9 December)

During this one week, every donation to Reef-World will be DOUBLED through matched funding. Your contribution directly supports our training programs, policy development and on-the-ground advocacy, turning local best practices into worldwide solutions. At this critical moment, there's never been a more important time — or a better opportunity to make your impact go twice as far.

Partner with us

Are you a business, government agency, or tourism board? Partner with Reef-World to integrate sustainable practices into your operations, sponsor the expansion of Green Fins into new regions, or co-develop innovative financing mechanisms for marine conservation.

Become an advocate

Share this story. Talk about what reefs mean to you. Push for stronger climate action in your community. Every voice matters.

The coral and their algae have shown us how powerful a partnership can be. Now it's our turn to prove we can live in symbiosis with the underwater world — before it's too late.

This blog is contributed by our volunteer, Josh Gibbs.