Great Barrier Reef has lost half of its corals since 1995 | Hacker News Reader

Great Barrier Reef has lost half of its corals since 1995

bbc.com

123 pointsmakerofspoons26 comments

Depressing. The government isn't remotely taking the ecology seriously enough, except where tourism is affected, and even then the mining/Adani is more important.

If I understand correctly, the primary factor harming the corals is warmer ocean temperatures and ocean acidification. I'm not sure Australia has much influence over those.

I think quite a lot of damage has also been done by runoff from agricultural grazing areas. But you're right the corals probably wouldn't have survived warming anyway. Perhaps the parent comment was making a reference to Australia's indirect impact on supplying a large amount of coal to the rest of the world. Australia also has a fairly high emissions per person for it's small population.

That's right. The reefs were already under severe stress and agriculture policy and coastal development in general have pushed pushed it to the edge. They can't manage so much as a ban on oxybenzone-based sunscreens. And all that's before getting into coal lobbying and supply, watering down the Paris agreement while in Madrid. The Queensland government has always had to be dragged into the future kicking and screaming, but now the federal government is behind them too. Just depressing.

The full throated support of the coal industry by the Australian government seems embarrassingly short-sighted.

Time for some GMO corals baby

Not the worst idea in the world. BUT, we're going to need to think carefully about taking million year processes and trying to speed them up to reverse climate change.

As much as we should be cautious about complicating the problem further, we have roughly 20 years before the cumulative greenhouse effects really take effect. At what point do we stop worrying about what might happen in the far future and focus on what we know will happen within our lifetimes? I get that knock-on effects might cause more problems further down the line, but the impending end of the world seems like a more pressing concern.

This, except for geoengineering. Developing the infrastructure to apply it at planetary scale will take years, and then actually applying it will take trillions of dollars. If by some miracle it turns out to not be necessary, we have plenty of time to cancel it, but now (really, 10 years ago) is the time to start spending 100s of billions of dollars preparing (and 100s of billions reducing emissions, of course).

FWIW, my preferred approach is ocean-powered olivine weathering, as in Project Vesta. But we'll need multiple approaches.

"but the impending end of the world seems like a more pressing concern". While climate change may lead to a mass extinction event that will likely wipe out a lot of species, including our own, it will not likely lead to the end of the world. Isn't it the short term thinking you are advocating here that lead us into this situation to begin with?

Planet Earth will continue to exist and the natural world may eventually recover, but a manmade extinction event and the possible extinction of human life is a good enough definition of "the end of the world" for me, though perhaps I should have said "the end of the human world". I agree that it's not worth fixing climate change at the expense of the future, but the situation is bad enough that fixing it is worth some level of risk - we had the time for a methodical, considered approach to climate change when we found out about it decades ago, and we didn't do anything.

I also think the decision to accept some long-term risks to alleviate the (frankly terrifying) short/medium-term dangers we face is very different to the decision to exploit natural resources in service of the industrial revolution.

That would create a monospecific ecosystem, but the idea deserves being examinated further.

In any case hermatypic corals are often two species in one. Modifying one of them could not be enough

Not necessarily GMO, but there is some research into seeding corals with more resilient Zooxanthellae - the algae that is symbiotic with the coral itself. Often it's the Zooxanthellae that dies in the higher temperatures and that causes the coral to die because it derives nutrients from the algae.

People like to talk about technology saving us, but there is only one technology that can stop climate change now. I can't remember what it's called though. It's kind of a big wooden frame with a big metal thing that slides vertically. Used to be popular in France at one time.

Do we have evidence of what happened with coral reefs in earlier historical eras with much lower temperatures?

It’s surprising to me that the corals seem to be unable to survive the 1 degree warming (to date), and troubling because even if we stopped all carbon emissions at this point (IIRC) a 2 degree increase is pretty much guaranteed.

Tragically, I fear it’s already too late for the corals. But I wonder if we have evidence that they can adapt to temperature shifts under the right circumstances, and maybe there’s something we can do to help the ecosystem adapt?

> Do we have evidence of what happened with coral reefs in earlier historical eras with much lower temperatures?

Some extinctions happened. In most of the other cases, the corals had much, much more time to adapt.

Imagine going 0 to 60 in a minute vs going 0 to 60 in a millisecond. One of those is going to crush you into a paste. We're halfway through that millisecond, watching things get pasted all around us, and trying to figure out if we can somehow stop this process.

Gradual warming and cooling, even to relatively extreme temperatures and CO2 levels by today's standards meant that corals had many, many generations to adjust. Today, not so much.

That’s a helpful analogy, thank you.

It seems that most of the heat impact of global warming is absorbed by ocean waters (https://e360.yale.edu/features/how_long_can_oceans_continue_...) Coral reefs typically live in rather shallow waters (less than 500ft according to wikipedia), because of their dependency of sunlight. So at this depth, there is already a strong daily variation due to day/night cycle, and I imagine a 1 degree average warming on earth is much potentiated in this environment.

Perhaps there is something to be done actively in short term in those environments to prevent this warming, but its so fragile as there are countless interactions between all the microorganisms that I that must be an enormous undertaking, if even possible.

As the oceans warm we can help out by seeding corals in areas that were previously too cool to allow for coral survival. Corals can be easily "fragged" (branches broken off and glued onto other rocks can grow - this is often done in the reef aquarium trade) and moved to areas that are not as warm. Under natural circumstances this kind of migration would take a while but perhaps humans can help speed up the migration into waters with more favorable temps.

That is an interesting idea, however one caveat I see is that the same warming that is killing the corals also changes the ocean currents and heat distribution in ways we can't fully predict yet. I can see this making the site choice difficult.

As a matter of fact, corals themselves provide a lot of historical data in a manner similar to tree growthrings: https://www.ncdc.noaa.gov/news/picture-climate-how-we-can-le...

There are corals that live in warmer waters such as in the Red Sea which has some of the warmest sea water on earth. There are also groups doing research on ways to help corals adapt to higher temperatures [1]

I also wonder if we'll start to see the GBR move south along the coast of Australia as waters that were previously not favorable to corals are now starting to warm.

The other problem in addition to warming is that as CO2 levels rise pH of seawater is going down. Hard corals require a pH that is somewhat alkaline (around 8.3 is ideal).

    [1] https://www.coralvita.co/

The marine fauna has been wiped a couple of times before. Corals will survive (probably), they had seen a few bad times before-

But coral reefs is a different and complex machine. Probably not, or will transform in a totally different structure. What we see now toke three thousands of years to physically develop. If you wipe a reef now, maybe you could expect a return to shape after 500 years. Reefs had survived atomic bombs.

Surprise! The Great Barrier Reef is Not Dying from Global Warming https://wattsupwiththat.com/2019/08/16/surprise-great-barrie...

Coral expert debunks Great Barrier Reef myths https://www.oversixty.com.au/news/news/coral-expert-debunks-...

"We just had a massive bleaching event, but we know from past research that corals are able to recover from the brink of death."

Oh, it wasn't dead, it was just on the brink of death. That's much better.

Coral doesn't typically die due to rising ocean temperatures... it flees the reef. I think these articles are trying to be contrarian on semantics. Not great.

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