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Comment by momoschili | Hacker News Reader

In addition to looking simply at the explosive growth limited to the past 4-5 years, it seems reasonable to look at the entire plot as well. All 3 graphs in [1] date back to 1965, and look at that data it seems that the growth/population of corals was reasonably stable up until the late 00s.

edit: only goes back to 1985, error on my part, but still relatively stable from 1985-late 00s

It may be possible that this recent spike in growth indicates that there is a strong recovery, but looking at the data it also seems inarguable the ecosystem has become highly unstable as well over the past 20 years, with drastic increases and decreases in all 3 populations that are much greater variance than from the mid 60s to early 00s.

While I agree with you that it's possible that this coral death is overhyped, your own conclusions don't seem to be evidence-based themselves.

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> It may be possible that this recent spike in growth indicates that there is a strong recovery, but looking at the data it also seems inarguable the ecosystem has become highly unstable as well over the past 20 years

Could you expand on how the recent explosive growth is unstable and fits with the predictions that the coral is dying?

And GPs post was evidence based, your interpretations were not, they were subjective and a bit handwaving, which is why I would like clarfication on your above view.

Explosive growth is generally speaking not stable. I will defer to the dictionary definition of stable. I'm just using words how they are defined.

From an ecosystem perspective, simple "coral coverage" is not a good enough metric to indicate that the coral reef is healthy. We also need to understand the biodiversity, is one coral taking over because it is better adapted and creating a monoculture? It's not clear. I made a point to not jump to conclusions, simply stating that explosive growth does not indicate a healthy ecosystem.

Thank you for the clarification. Some may interpret "not stable" meaning that it could be detrimental to it's life, not just the textbook velocity definition.

Could you answer the second part of my question:

> "How does explosive growth fit with the predictions that the coral is dying?"

To your statement:

> "We also need to understand the biodiversity, is one coral taking over because it is better adapted and creating a monoculture"

I'd say that we should not assume one way or another. It very may well be, or not. That data is probably out there and I'd be interested to know the answer. If the answer is yes, it's very healthy.

I'd also like to know what species these scientists are breeding. If it's only a select few species, is that healthier than the species that have adapted naturally and are growing fine?

Explosive growth does not happen in a vacuum. Sometimes it's due to a pre-existing boom and bust cycle (eg lynx and hares, rabbits and wolves, etc). Sometimes it's due to the elimination of key species or ecological instability (eg hares in australia with no predators, boom of sea urchins in california, cuttlefish booming due to overfishing), or maybe it's something completely different altogether.

Given that there is no history of a pre-existing boom and bust cycle in the data, I think we can rule that out. So clearly something is happening that wasn't happening before. The question you want answered is one-dimensional and ill-posed in this situation to allow you to better understand the dynamics at work.

The GBR is not that old, and it experienced a major boom during it's creation, obviously.

We really don't have enough data to rule anything out as we weren't tracking it that long relatively to say for sure. We also don't know all the variables.

They tried the "but what about biodiversity" argument back in 2020 when the regrowth started.

It is automatically true that in an ecosystem that experiences a population decline, when the population starts growing again the subtypes that grow fastest will become more common than those which grow slower, and thus there will be a temporary decline in biodiversity. That doesn't indicate a problem of any kind. It's just the natural state of affairs.

The graphs date back to 1985. The font is small though, so it's easy to misread.

> it also seems inarguable the ecosystem has become highly unstable as well over the past 20 years

That's extremely arguable! Extrapolating from a tiny number of data points is how AIMS managed to screw up previously. There's really very little data on which to build predictions about long term trends. We have no idea how stable or unstable coral sizes are because it's just not been monitored for long enough to say. We're zoomed in to a tiny, tiny part of the coral's history, which is far longer than humanities own.

I agree, but I would assert that it is no more arguable than your own interpretations

Edit: Ah I see that it is 1985, that certainly is a significantly shorter cycle of data.

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