Coral Reefs, Denial Machines, and the Sound of Survival

Coral reefs are dying, but not quietly. In this episode, we explore the surprising science of reef regeneration, the politics of denial, and what hope really sounds like underwater.

Transcript

Intro:

Good morning, good afternoon, or good evening, whatever it is where ever you happen to find yourself right now. I hope you’re doing amazing.

Last week, we were going to talk about what sustainability actually looks like if we chose to live that way. But, this week, I’ve been exposed to a lot of talk about coral reefs, and honestly, this is something that I’ve been wanting to dive into anyway so figured, why not? So coral reefs aren’t doing too well, that’s not been a huge secret. But there has been some news coming out lately that has some people saying that coral reefs are going to be fine.

They point to restoration projects and certain types of coral that are adapting to heat, actually even showing signs of reef growth in places like Indonesia. And they’re not wrong, some of that is real.

But we’re also living through the most widespread coral bleaching event ever recorded. NOAA says that over 80% of the world’s reefs have been affected just since last year.

So which is it? Are coral reefs bouncing back? Or are they falling apart?

That’s what we’re going to be looking at today. Because, what’s happening to coral reefs says a lot about where we are in this whole climate story. It’s how we talk about hope, how we avoid reality, and how much damage we’re willing to normalize.

Let’s start with a simple question though: Why do coral reefs even matter, why are they important?

Act I – Why Coral Reefs Matter

Starting off with the basics, coral reefs take up less than 1% of the ocean floor.

Just one percent. Sounds kinda small, not like a lot.

And yet somehow, that one percent supports about a quarter of all marine life; supports fish, crustaceans, the entire oceanic food chain, starts right there in those reefs.

For over 500 million people, reefs are more than just pretty underwater scenes, if you will. They’re dinner. They’re income. And they’re home protection.

Reefs don’t just support marine ecosystems. They act like living seawalls and they go a long way to absorbing wave energy, thereby reducing storm damage. In short, they help keep coastlines from washing away.

If we lose those reefs, in a lot of places, we don’t just lose the biodiversity, we lose the first line of defense for many, many communities.

Now, depending on where you live, this might just seem like kind of far away. But the reality is, reefs aren’t just a tropical thing. They’re a climate thing. They’re a food security thing. And they’re an economic thing.

And, simply put, they’re in trouble.

Act II – What’s Really Happening to Coral Reefs

So what’s happening? Probably the the first thing we read about is coral bleaching so let’s talk about that. 

Coral bleaching happens when ocean water gets too warm, for too long. The corals then get stressed and they eject the algae the corals rely on for food and color, and they appear white.

It’s not so much that the coral itself turns white, it’s that the algae, which gives coral all of those vibrant colors, is gone, it’s left. What’s left after the algae leaves is the coral’s exoskeleton, and, when it’s devoid of that algae, it looks white, like it’s been bleached, hence the term, “bleaching”.

If the water cools off quickly, some of those corals can recover, and some of that algae does come back. But, if the water stays warm, those corals eventually are going to die, there’s just no way around that.

Since January of 2023, NOAA’s Coral Reef Watch has been tracking what, again, is no doubt the most widespread bleaching event on record.

Eighty-four percent of the world’s reefs have been affected.

Think about that. That’s not a few spots here and there, that’s worldwide. 

Eighty four percent.

And this isn’t a “maybe” problem, it’s not something that we *might* face like we read in a lot of climate reports. This is very much a “we’re already in it” problem.

And here’s where it gets a little more complex: heat isn’t the only issue.

There’s also ocean acidification that we’ve heard about. As the ocean absorbs more CO₂, and keep in mind that it’s the biggest  CO₂ synch that we have, it reacts with the water and forms carbonic acid. That’s not a good thing. It makes it harder for corals to build their skeletons—the structures that hold up the entire reef system and where the algae lives.

If you’ve ever tried to maintain a pool or a hot tub, you know how sensitive the water chemistry can be. One little shift in pH or the mineral balance, and suddenly your water’s cloudy, your pipes are corroding… or your hair turns green, which happened to me a lot when I was a kid. And by the way, carbonic acid lowers the ocean’s PH. 

Now imagine that on a planetary scale, and without the green hair…

Scientists track coral-building conditions using something called the aragonite saturation state. It’s a way of measuring how much usable calcium carbonate there is available in the water.

Corals need that aragonite to build their skeletons. No aragonite, no reef.

And according to one massive study from earlier this year, in 2025, we already crossed a critical threshold back in the year 2000. By 2020, 43% of tropical coral reef habitat was no longer chemically suitable for growth.

Even if that water was crystal clear, even if the temperature was perfect, those reefs would still be fighting to survive because of this acidification.

Restoration efforts can help, and we’ll get into that in a minute. But we can’t ignore this reality: this isn’t just about local damage or isolated heatwaves.

The chemistry of the ocean globally speaking is shifting. And corals are caught right in the middle of that.

Act III – Stories of Resilience and Denial

So here’s where it gets a bit more complicated, and honestly, pretty frustrating.

Not everything is falling apart, which has prompted some to paint this issue as “everything’s fine!”.

In Indonesia, researchers tracked a reef that was restored after being destroyed by blast fishing a couple decades ago.

By the way, if you’re not familiar with blast fishing, it’s pretty much exactly what it sounds like—when people toss explosives into the water to stun or kill fish so they can boat by and scoop them up a lot more easily. It’s very illegal in most places, and for good reason. It doesn’t just kill fish though, it shatters coral and kinda turns it into rubble. If you’ve ever seen a war movie and seen that rubble from bombed out cities, that’s kind of what it looks like. 

In this case though, they planted fast-growing coral reefs on steel frames. And even as little as four years later, those reefs were growing just as fast as normal, healthy ones.

Really, really impressive stuff. And it shows what’s possible when people step in, when we stabilize that rubble, and give corals something to build on.

And in other places, like Palau, scientists are finding corals that didn’t bleach, even in record heat.

Steve Palumbi, and I hope I’m pronouncing his last name right, I’m just going to call him Steve—anyway, he’s a biologist from Stanford, and did his undergrad work at Johns Hopkins, so he’s no dummy, he calls these corals “the survivors”. These are the corals that didn’t go white when everything else around them did. Some colonies, some species, even just certain patches, completely different response to the same heatwave.

And that’s huge.

Because if we can find those survivors, you can start restoring reefs with the tough stuff. You can grow new corals that are more likely to hang on.

I think it’s important to note though that Steve’s work, because I don’t want to try to pronounce that last name again, involves a lot of DNA testing and conditioning the coral to withstand heat. Really interesting stuff and I’ll go on a huge digression here if I continue on so, in the interest of time, suffice to say that there’s a pretty good amount of human intervention going on here. 

And maybe that buys us a little bit of time.

But this is where the narrative kind of splits, and this is the frustrating part.

Some people see stories like this and say, “See? Reefs are fine. Nature’s adapting. No need for panic.” In fact I’ve had conversations with people who have said, and I quote, “Coral reefs are doing better than ever!” Ya, ok, If you call losing about half of the world’s coral since 1950, “better than ever”, then ok, more power to you.

So this is where things, honestly, I’m just going to say, get, just a bit more dangerous.

In Australia, when UNESCO considered listing the Great Barrier Reef as “in danger,” a huge wave of, I’m just going to say, denial tactics absolutely stormed in. They weren’t denying the science outright, rather, they were reframing it. They were hugely downplaying the warnings. There was a lot of spin coming out saying that reef recovery is proof that nothing needs to change.

Researchers called this, and I love this part, a “US-style denial machine.” Which, unfortunately, is pretty much on-point for us here in the US. If there’s any way to turn environmental collapse into a political argument, we’re going to find it, we’ll exploit it, and probably monetize it. “Yay us, We’re number one!”

So what UNESCO faced it wasn’t really about the facts. It was very much, about the framing of those facts.

Because hey, if you can convince people the reef is fine, you get to skip all those pesky conversations about fossil fuels, emissions, or the actual costs and damage that climate change is doing.

And that’s a problem.

These restoration success stories, they’re real. The heat-resistant corals? They’re real. But none of that cancels out the underlying trends. It doesn’t cancel out what’s actually happening.

Ocean acidification isn’t going away. The bleaching events are becoming more frequent. And coral habitat—chemically speaking—is disappearing. Realistically, there’s just no getting around that.

So, in other words, we’re doing CPR on a patient who’s still being poisoned. And some are celebrating every time the heart rate comes back just for a few minutes.

Here’s the kicker though:

These stories about coral bouncing back? They’re not being heard as warnings. They’re being used as excuses.

Again, things like, “See? The reef’s recovering. Told you that nature would adapt!” And, I love this one, I’ve heard this a lot,  “Jeez, don’t you get ever guys tired from constantly trying to scare all of us?” Actually I try not to use scare tactics, I don’t force this stuff down anybody’s throats but, I actually do hear this stuff a lot. 

And it’s kind of like watching a firefighter rescue someone from a burning building and saying, “Hey, maybe fire’s not such a big problem after all.”

It misses the point. Completely

Coral restoration, it is absolutely incredible work. So is identifying heat-resistant species. These are lifelines. They buy us time while we deal with the root cause.

But if that cause, which is unchecked emissions, if it keeps accelerating, no amount of work, no amount of ingenuity that will matter in the end.

That said though, I came across something recently that I thought was just pretty cool. I wasn’t sure how to weave it in, or where to weave it in, but I wanted to throw it out there anyway. So here it is:

Scientists, and this has been happening in the Caribbean, by the way, have been broadcasting the sounds of healthy reefs near degraded ones for about a decade, as of 2024. As it turns out, coral larvae respond pretty positively to sound.

They actually settle at higher rates when they hear, and this is a quote, “the crackles, croaks, and fish chatter—that soundscape of a healthy reef.” Personally, I tend not to think of fish as “croaking”, but that’s the phrasing that they used. If you’ve ever been snorkeling and heard that underwater crackling sound, kind of like crumpling cellophane? That’s it. That’s what a living reef sounds like.

One study showed that up to seven times more larvae settled just by adding underwater speakers that played these sounds.

Which, honestly, I think it’s pretty cool. So corals, listen.

And—wait for it—cheesy line incoming… maybe we should be too.

Ya, I told you it was cheesy. But, in the end, it’s true. And for what it’s worth or, more accurately, in my defense, several articles ended with that same line, so I figured, hey, why not?

So yeah, coral reefs are fighting, they’re fighting hard to stay alive. And the people are putting in a lot of effort to restore them.

But l think it’s a huge mistake to confuse resilience, both man induced and natural, with invincibility.

Coral restoration, acoustic enrichment, heat-resistant species, they’re all amazing tools. But they’re not magic. There’s just no way they undo the massive amounts carbon that we’re still pouring into the air, and the acid it creates in the sea.

They buy us time. And what we do with that time? That remains to be seen.

And with that, I’m calling this one a wrap. What is up next? Well, the thing that we were originally supposed to do this week. And that’s the question of: What does it look like to “live sustainably” when the systems around us aren’t built for that?

So, we’re digging into what sustainability actually costs, who can afford it, and who’s being left behind in the so-called “green” movement.

And spoiler: it’s not always about reusable water bottles or solar panels.

Sometimes it’s about survival. Sometimes it’s about dignity. And sometimes, it’s about not having to choose between the planet and your paycheck.

Again, thank you so much for joining me today on Running My Mouth Off. I’m Dave and I hope that you have an amazing week.