
70-90% of all existing coral reefs expected to disappear in the next 20 years - throwaway5752
https://www.cnn.com/2020/02/20/world/coral-reefs-2100-intl-hnk-scli-scn/index.html
======
kls
I volunteer in coral restoration efforts, the article is complete junk science
and is just another environmental disaster that the climate change gang is
trying to latch onto. If they succeed they will have successfully divert money
away from critical research and restoration efforts to chase a fix that will
certainly see our reefs die, while the true killer is ignored.

There is very clear science on what is killing the coral reefs and it is not
ocean warming:

[https://www.sciencedaily.com/releases/2019/07/190715164652.h...](https://www.sciencedaily.com/releases/2019/07/190715164652.htm)

[https://www.npr.org/2019/07/16/742050975/floridas-corals-
are...](https://www.npr.org/2019/07/16/742050975/floridas-corals-are-dying-
off-but-it-s-not-all-due-to-climate-change-study-says)

[https://www.sciencedirect.com/science/article/pii/S187734351...](https://www.sciencedirect.com/science/article/pii/S1877343513001917)

~~~
CarelessExpert
From your first link:

> collaborators have discovered that the problem of coral bleaching is not
> just due to a warming planet, but also a planet that is simultaneously being
> enriched with reactive nitrogen from multiple sources.

> Improperly treated sewage, fertilizers and top soil are elevating nitrogen
> levels, which are causing phosphorus starvation in the corals, reducing
> their temperature threshold for "bleaching."

From your second link:

> "What our study shows is that water quality and not just water temperature
> are important for coral survival,"

Meanwhile, the posted article says in its second paragraph:

> About 70-90% of all existing coral reefs are expected to disappear in the
> next 20 years due to warming oceans, acidic water and pollution

Seems to me like all of these sources agree: Climate change _and_ pollution
combine as culprits in coral reef die-offs, with in fact the latter
exacerbating the effects of the former.

It does appear that the scientists disagree on the relative importance of
these two issues:

> "Trying to clean up the beaches is great and trying to combat pollution is
> fantastic. We need to continue those efforts," Setter said in the release.
> "But at the end of the day, fighting climate change is really what we need
> to be advocating for in order to protect corals and avoid compounded
> stressors."

Does that mean this article is "junk science"? Personally, I don't think so...

~~~
kls
In the presence of warmer water the reef will not die, in the presence of the
chemicals the reef will die. Ocean warming does allow the chemicals to mix
more freely but is not the cause, nor will fixing it stop the process of reef
bleaching. The Bikini Atoll reefs where nuked and they are now doing fine even
in the warmer temperatures, what the Atolls lack is industrial level farming.
Further Cuba, which is in the same thermocline as the Keys has seen no where
near the die off as Florida has. This is due to less industrialized farming.
If the chemicals are removed the reefs don't die.

~~~
CarelessExpert
> In the presence of warmer water the reef will not die,

So, I scanned through all three of your articles, and none of them make the
claim that coral reefs do _not_ bleach when only exposed to temperature
stress. They only state that pollution is an additional stressor that
increases temperature sensitivity.

That coral reefs "will not die" due purely to temperature stressors is a
pretty huge claim.

Do you have any citations that support this claim?

~~~
kls
"Although water temperatures at Looe Key exceeded the 30.5 °C bleaching
threshold repeatedly over the 3-decade study, the three mass bleaching events
occurred only when DIN:SRP ratios increased following heavy rainfall and
increased Everglades runoff."

[https://link.springer.com/article/10.1007/s00227-019-3538-9](https://link.springer.com/article/10.1007/s00227-019-3538-9)

"Porter, who has studied coral for 50 years, says the new research finds that
coral die-offs happened long before high water temperatures reach the reef."

[https://www.npr.org/2019/07/16/742050975/floridas-corals-
are...](https://www.npr.org/2019/07/16/742050975/floridas-corals-are-dying-
off-but-it-s-not-all-due-to-climate-change-study-says)

~~~
CarelessExpert
So that second quote doesn't really support the claim that temperature has
_no_ relationship to bleaching events. It only implies that bleaching can
happen exclusively due to pollution.

The first one is suggestive, though! At least in that specific region. Of
course, that paper doesn't go so far as to make the claim you're making, only
stating that "reducing the risk of coral bleaching, disease, and mortality
under the current level of temperature stress".

But it does indicate that pollution is an extremely important factor in
bleaching events

Given Australia has recently been experiencing repeated mass bleaching events
over a very large area, and given you claim that that affirmatively is _not_
associated with ocean temperature changes and is _only_ associated with
pollution, then you should be able to provide evidence that pollution levels
have significantly and consistently increased near the Great Barrier in
correlation with those events.

Does that data exist?

~~~
kls
Sorry it took so long to get back to this, while not a scientific piece it is
the laymen summation of a lot of research specifically concentrated on the
Great Barrier Reef:

[https://www.marineconservation.org.au/pollution-great-
barrie...](https://www.marineconservation.org.au/pollution-great-barrier-
reef/)

A good article on why wetlands are critical to reef systems:

[https://www.newscientist.com/article/2148247-plan-to-save-
gr...](https://www.newscientist.com/article/2148247-plan-to-save-great-
barrier-reef-from-encroaching-farm-pollution/)

And finally to answer the question to my knowledge this is the most
comprehensive study and recommendations on the GBR.

[https://www.reefplan.qld.gov.au/__data/assets/pdf_file/0029/...](https://www.reefplan.qld.gov.au/__data/assets/pdf_file/0029/45992/2017-scientific-
consensus-statement-summary.pdf)

The end result is they recommend reducing waste run off as the primary driver
for saving the reefs. There is an ongoing study to reproduce the claims we
have seen here in the Keys but it has not concluded.

The Keys and Australia (as well as Belize) are extremely similar in that all
of them are barrier that exist with a fresh water outflow from wetlands. Where
Florida and Australia are similar is that both use their wetlands to support
industrial scale agriculture and are both in poor health.

If we want to get into specifics it is actually one form of agriculture that
is causing the most damage (in both Florida and Australia) and that is
sugarcane farming. In the past sugarcane farming was not a cost effective
endeavor in the US or Australia, with the ethanol fuel additive mandates that
all changed as it increased the already high demand for sugar. Sugarcane is
grown on the banks of canal systems and low lying marshes. In Florida it is
grown in the everglades from Lake Okeechobee down. Given it's close proximity
to the wetlands there is no time for soil containment of the high levels of
nutrients used to rapidly grow the sugarcane.

Specifically in Florida, historically citrus was traditionally the
agricultural cash crop, citrus is grown in sandier soil with high
concentrations of limestone. These is generally off of the wetlands by at
least 600 yards and expands all the way inland until you get to the Florida
prairies where the land is more valuable as cattle land, when only looking at
it from an agricultural value standpoint.

Until the introduction of sugarcane farming directly into the wetlands,
Florida did not see significant coral die-offs. I have watched the reefs of
Mainland Florida die off thru the last few decades ending with all of them
being dead in the early 90's. This was due to diversions of flow in the
everglades, done for agricultural purposes, and it killed the mainland reefs.
The restoration of flow was done to restore the Everglades to it's natural and
historic outflow which was traditionally out of the bottom of Florida into the
gulf basin, In that exact time I have witnessed the Florida Keys reefs start
to experience the same fate.

~~~
CarelessExpert
> Sorry it took so long to get back to this

No worries! I appreciate the effort you're putting into your responses, even
if we might disagree in our conclusions. :)

Now, not to boil down your extensive post, but I'm going to highlight a key
statement from that 2017 paper that you describe as the "most comprehensive
study" about the GBR:

> unusually warm sea temperatures in the northern Great Barrier Reef resulted
> in widespread coral bleaching in 2016 and 2017.

This directly contradicts your claim that ocean temperature has absolutely no
effect on coral survival.

In fact, in multiple places that paper speaks to climate change as a key
contributor to coral die-off. Here's another one (Section 5, "Condition of
coastal and marine ecosystems", "Summary of evidence"):

> Mid-shelf and outer shelf reefs in the southern half of the Great Barrier
> Reef have shown the capacity to rapidly recover from previous disturbances;
> however, a severe mass thermal coral bleaching event in 2016 resulted in
> significant coral mortality, especially north of Port Douglas.

I honestly don't know what to say at this point.

I'll be extremely blunt: I feel like you're cherrypicking, not just papers,
but statements within papers, to support a conclusion you've already come to.

Again: I absolutely agree with the conclusion that controlling coastal
pollution can have a profound effect on reef health. That is unquestionably
true. But the evidence is clear that climate change _is also an important
factor_ , as indicated in the very papers that you cite, and that coral will
continue to die off if we don't work to solve both problems. Finally, I agree
that coastal pollution management is lower hanging fruit that, if addressed,
may give us more runway to address the larger issue of climate change, as
these reefs may then be more resilient to increased water temperatures if
pollution stressors are reduced or eliminated.

~~~
kls
So on the 2016 and 2017 bleaching there is no doubt that in the presence of
higher temperatures the nitrogen (and for that matter micro-metals like zinc
in sunscreen) become more deadly. Ocean temperature is only speculation as
they did not measure other variables. There is an effort in Australia to
reproduce the findings in the US but it has not concluded. I am trying to find
that information. The prevailing though is those warming events coincided with
a water quality event which make the water quality events (the true killer)
even more deadly. The belief is that that link will established just as it was
in Florida.

The issue is though that die off has been observed in the absence of
temperature and the survival has been observed over what was believed to be
threshold but die-off always happened with the ratio of nitrogen to phosphates
hit a threshold.

I try provide the links as they are, not trying to cherry pick my opinion is
based on experience with the reefs and the range of studies I have seen. There
is no doubt that there is still a prevailing theme of temperature as it was
long believed to be the primary driver, it takes time for the mind-shift to
happen even in the research community.

I am also trying to find the Cuban reef study as it sits in the same
thermocline as the Florida Keys barrier reef. I will post them when I find
them as I said I help out and help my daughter with her studies, I am not a
researcher but I feel I have a pretty good handle on the scope of research and
findings on reef destruction, I just don't have every paper at my fingertips
like the researchers do. I have a query out to a few of the Mote scientist to
see if they can provide me with some public accessible links to those studies.

------
makerofspoons
Climate change may also drive the collapse of food webs globally in the
oceans:
[https://journals.plos.org/plosbiology/article?id=10.1371/jou...](https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2003446)

