Why is Coral Bleaching?

Gab Gab August 22nd, 2017

In my last post, I talked about the fact that coral around the world is bleaching. Today, I want to talk about why this is happening.

First I need to explain something from Geology.

It’s called the Milankovitch Warming Cycle, and it has been used as a dog whistle in oil company propaganda, as evidence that the current global climate change is “natural.”

Let’s look at the cycle in terms of atmospheric CO2.


So, what exactly is the Milankovitch Warming Cycle?

Well, it describes the natural oscillation of the global climate since the formation of Earth. The global environment has varied in temperature in a natural cycle over hundreds of millions of years.

The key thing to know is that it happens very slowly.

When I say very slowly, you are probably thinking in human terms. I don’t mean in humans terms. I mean; it moves incredibly slowly in geologic time.

According to the natural cycle of our planet, it should take thousands of years for the temperature to change a fraction of a degree.


So why does it matter how fast the Earth warms up? Won’t it just cool down as part of a natural cycle and then all the plants and animals will go back to normal?

In a word, no.

To understand why, we have to talk about how organisms evolve. You see, evolution happens when a gene mutates and causes a new trait to appear in a species. If that trait is beneficial, it will help the offspring who have it to outperform their counterparts without it. This helps that trait survive.

It’s easiest to see when we look at specific examples, so let’s have a look at polar bears. There were not always polar bears. But that species came into existence when, during an ice age, a bears’ genes mutated and caused the offspring to be white. The white bear did better than the others because it could hide in the snow, and so it was able to pass on its genes year after year.

Over time, that single genetic mutation became a new species. But again, the key to all of this is that it happens slowly over time.

Now that we understand how slowly the climate is supposed to change and how evolution works, you should be able to see how those two processes have worked together in tandem since the Earth was formed.

In the past, the climate changed slowly, and animals and plants adapted slowly.

Unfortunately, the climate is changing too fast now for any life forms to evolve with it. So when the zooxanthellae inside the coral die, and then the polyps die, that is it for coral.

Some species are hardier than other and so they will die in future bleaching events. However, we do know that all of them will die. The temperature is simply heating up too fast.

Gab Gab August 22nd, 2017

The mass extinction event that we are witnessing is part of The Holocene Extinction.

The oil companies try to tell you is that the Holocene extinction is perfectly natural and couldn’t be helped. This is 100% untrue. Man-made climate change is currently happening because of our use of fossil fuels, and the death of the coral reefs worldwide is absolutely our fault. The body of evidence is overwhelming. Science has no doubt on the matter.

And so, the answer to the question of “Why is the coral dying?” is really very simple.

The answer is us.

Gab Gab August 22nd, 2017

Coral Bleaching at Gab Gab 9/2/17

Healthy coral has color to it. In the picture above, you can see healthy coral thriving at Gab Gab reef on May 2nd, 2017. This is what it is supposed to look like.

Unfortunately, the coral around the world is dying, and I want to talk about it for a moment.

short coral bleach four.jpg

Coral is made up of many tiny animals called Polyps.

These little animals have specialized chloroplast cells inside called zooxanthellae. These chloroplasts absorb sunlight and convert it to food for the polyp. Without them, a polyp will die.

When the water temperature in an area gets too hot, the zooxanthellae stop being able to work. They are sensitive to temperature, and so they die.

When they die and the polyp pushes them out, the coral becomes white (since polyps have no color.) Eventually, the polyps die and the coral becomes nothing more than skeletons covered in algae.


The reefs on Guam are bleaching. This is part of a worldwide event, which is being driven by climate change.

I wanted to share these pictures and videos in an effort to draw attention to the fact that this is happening, and how awful it is.

These pictures are taken at Gab Gab, just like the one at the top of the page. The difference is only a few months, but the difference in the temperature in the water is extremely noticeable.

Before, it used to be a little chilly when you first got in. Gab Gab is a reef that goes from the surface water level down more than one hundred feet. Deeper water, in my experience, tends to be colder.

And yet, yesterday when I got in the water, it was hot.

I beg you all to take a very close look.

I think a lot of people who have never been snorkeling or diving are able to easily ignore the bleaching of the corals and the dying of the reefs.

For me, living here, it is much harder.

Coral are home to thousands of species of animals, and as they die, those animals will also die.

The diversity of life that we had in our oceans was amazing, and losing it is absolutely horrifying.

I have no words beautiful enough or sad enough to write the eulogy for our oceans. Nothing said or written could capture how beautiful this reef was just a few months ago.

Seeing the reef now as it bleaches and dies is one of the most painful things I have ever seen.