You may have heard some mixed opinions about the state of coral reefs. Some will argue that coral conditions are in a natural flux, or that reefs will have time to adapt to our changing oceans. Others have found that coral populations have sustained irreparable damage. Now several new studies help show that things are a LOT more complicated than you might imagine.

Table of Contents:

What's Wrong With That Reef?

Why Should We Care?

Are They Really Doomed?

Can Science and Technology Help?

The Take-Away

A Coral Reef Doomsayer

"This is now serious; I find it very unlikely that coral reefs as I knew them in the mid-1960s will still be found anywhere on this planet by mid-century. Instead, we will have algal-dominated, rubble-strewn, slowly eroding limestone benches."

Those were the stirring words uttered by Peter F Sale, an ecologist and reef management expert from the University of Windsor, Canada. He was invited to comment on the state of global coral populations at the European Geochemical Society's Goldschmidt conference in Prague just last week.

"Even if Paris is wildly successful, ocean warming and ocean acidification are going to continue beyond the end of this century."

Sale is talking about the 21st Climate Change Conference (COP21), due to be held in Paris, France this coming December. There, scientists and world leaders will come together to discuss strategies for protecting our world from the encroaching damages of climate change - one of which is the worldwide decline of coral reefs.

"The extreme gravity of the current predicament is now widely acknowledged by reef and climate scientists," John (Charlie) Veron, a coral expert and former chief scientist of the Australian Institute of Marine Science, added in a recent statement. "They also accept that only drastic action starting now will prevent wholesale destruction of reefs and other similarly affected ecosystems."

Veron and Sale point to the mass-bleaching of tropical corals to justify their worry. Rising temperatures in conjunction with heightened ocean acidity (a consequence of rising C02 levels) weakens the symbiotic partners of coral - the algae that help make reefs strong and give corals their vibrant colors - in what some scientists call a doomsday 'double whammy.' (Scroll to read on...)

The result is a historic number of ghostly pale reefs incapable of repairing themselves, resisting disease, and - as shown in a shocking study last November - even properly reproducing.

"Even if we can fix what's killing these corals, it's going to be hard for coral populations to recover, because the surviving corals might not successfully produce enough offspring to repopulate reefs," the study's authors reported.

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Why Care About Coral?

So why would world leaders care about coral? For one, these intriguing animals are directly tied to some very key industries. Tourism and fisheries, for instance, heavily rely on coral around the world. Reefs have also long served as important natural buffers for eroding island nations, keeping their beaches and ports in tact even in the wake of powerful storms.

A 2014 report from United Nations investigators even found that warming ocean climes and ocean acidification will cost the world economy over a trillion dollars by 2100 - the great majority of those losses being due to coral decline.

And that estimate was based on the idea that ocean warming and acidification will stay at current rates. The trouble is, it has been well established at past COP conferences that halting the rise of carbon emissions (natural and man-made alike) completely and immediately is an impossible task. (Scroll to read on...)

That's why world powers are currently aiming limit their carbon emissions to halt the world from warming any more than an additional two degrees Celsius (3.6 °F) - known as the Copenhagen Accord.

Unfortunately, many climate experts believe that the Accord's two degree limit is "utterly inadequate," and it appears that Sale agrees. At the conference, the ecologist and his colleagues pressed that a carbon and climate limit half (only 1°C) of what has been set would be the minimum goal that's "scientifically defendable, and would give reefs a good chance."

"We need to wake up to the idea that business as usual, even clever taxation schemes, will not act fast enough to reduce global emissions," added Ove Hoegh-Guldberg, a contributing author to the latest Intergovernmental Panel on Climate Change (IPCC) report, which will be a talking point at COP21. "This is a global emergency, which requires us to decarbonise within the next 20 years, or face temperatures that will eliminate ecosystems like coral reefs, and indeed many systems that humans depend on."

"Knowing what we are doing, do we have the ethical right to eliminate an entire ecosystem from this planet? It's never been done before," Sale said in his closing remarks. "But watching as our actions lead to the loss of all coral reefs on the planet is like removing all rainforests. I don't believe we have that right."

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Why the Coralpocalypse Won't Happen

However, some may argue that, while Sale and his peers are making some important points, these experts are ignoring a very important focus: the reefs themselves.

"Coral reefs are sometimes regarded as canaries in the global climate coal mine - but it is now very clear than not all reef species will be affected equally," said Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University. (Scroll to read on...)

Three years ago, Hughes helped lead what was called "the world's first large-scale investigation of how climate affects the composition of coral reefs."

"Previous studies around the world have focused on total coral cover as the main indicator of reef health, but we wanted to explore what happens within the coral assemblage itself," the researcher explained in a statement. "The way these individual species are mixed together is extraordinary flexible."

The resulting report, which was published in the peer-reviewed journal Current Biology, concluded " that climate change is likely to result in a reassortment of coral reef taxa rather than wholesale loss of entire reef ecosystems."

In other words, we might not be "watching as our actions lead to the loss of all coral reefs on the planet," as Sale fears. Instead, humanity might be witnessing how our influence on the world creates distinct 'winners' and 'losers' among a unique groups of animals.

[This is not unlike how changes in atmospheric climate are influencing tree migration. You can read about that here.]

Hughes' report was quickly followed by other papers reaching similar conclusions. For instance a 2014 study published in the journal PLOS ONE found that as some of the more iconic tropical corals - like those that dominate the Great Barrier Reef - continue to decline, their smaller and less prevalent cousins are beginning to thrive. Likewise, increased ocean acidity has even created some never-before seen habitats, where corals are finding sanctuary among the submerged roots of mangrove forests. (Scroll to read on...)

"Although many corals are becoming less abundant, there remain a number of species that are holding their own or increasing in abundance and these corals will populate tropical reefs over the next few centuries," researcher Peter Edmunds, of California State University, explained.

What policymakers have to be wary of, Hughes and his colleagues argue, is not a vanishing of coral, but the less noticeable effects a subtle shift in species might have.

"For example, if susceptible table and branching species are replaced by mound-shaped corals, it would leave fewer nooks and crannies where fish shelter and feed," the researchers wrote. "A critical issue for the future status of reefs will be their ability to provide ecosystem services like reef tourism and fishing in the face of the changes in species composition."

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Is 'Playing God' the Answer?

So how then, can we save the coral reefs of today and even restore them to the grandeur of the 1960s that Sale remembers? Some researchers have proposed that tampering with nature, not coddling it, is exactly what reefs need.

Past studies have revealed that like with all species, some corals can mutate to adapt to warming waters and - perhaps - even acidification. These helpful adaptations can then be spread to new offspring, slowly making a reef more resistant to climate change with each generation.

Now, researcher Mikhail Matz at The University of Texas at Austin is arguing that "corals do not have to wait for new mutations to appear."

"Averting coral extinction may start with something as simple as an exchange of coral immigrants to spread already existing genetic variants," he said in a statement. "Coral larvae can move across oceans naturally, but humans could also contribute, relocating adult corals to jump-start the process." (Scroll to read on...)

This, in a way, would be not different than how farmers cross and breed crops to stand the heat. The result, however, would be a hastening of processes that may have never occurred naturally - essentially tipping the scales so that reefs that serve nations' needs change and survive first. Some have even proposed that lab-side alterations could be possible, although the release of GMO corals has not been a seriously considered option.

Lastly, some experts have gone as far as to propose that localized "climate engineering" could ensure essential reefs stay as they are. A technique called Solar Radiation Management (SRM) has reportedly been assessed by scientists from the Carnegie Institution for Science, the University of Exeter, the UK govt's Met Office Hadley Centre, and the University of Queensland, and it proved more effective at preventing future mass-bleaching events than even the most aggressive CO2 reduction strategy considered by the IPCC.

And while that sounds like some pretty good news, many critics say that the SRM method is pretty radical, and even reminiscent of the doomsday cause dreamed up for the latest Hollywood thriller "Snowpiercer." It involves injecting gas into the stratosphere, forming microscopic particles which reflect some of the sun's energy to limit rising sea surface temperatures.

"Coral reefs face a dire situation regardless of how intensively society decarbonizes the economy," noted researcher Peter Cox. "In reality there is no direct choice between conventional mitigation and climate engineering but this study shows that we need to either accept that the loss of a large percentage of the world's reefs is inevitable or start thinking beyond [conventions]." (Scroll to read on...)

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So What's the Take Away of All This?

While the future of corals is still very much unclear, a need for action to protect them is not. Earlier this year, on World Ocean Day, United Nation's Secretary General Ban Ki-moon reminded us that "the oceans are vast - but their capacity to withstand human damage is limited."

"This year, governments are seeking to adopt landmark agreements on climate change and ending poverty," he said. "Corals sustain so much marine life... Given how critical oceans are to the health of our planet and the prosperity of people... we must commit to using the gifts of the oceans peacefully, equitably and sustainably for generations to come."

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