The colourful world supported by coral reefs is under threat as oceans absorb greater quantities of carbon dioxide, says Rod Salm. In this week's Green Room, he says we must accept that we are going to lose many of these valuable ecosystems, but adds that not all hope is lost.
I've been privileged to see many of the world's finest and least disturbed reefs.
Imagine all the colour and vibrancy of coral reefs fading away into fuzzy, crumbling greys and browns, and you're left with a coral graveyard that could become the norm
Mine were the first human eyes to see many of the remotest reefs at a time when we really could describe them as pristine.
I would never have dreamed that they were at risk from people, far less than from something as remote then as climate change.
Today, despite the doom and gloom one reads so much about, one can still find reefs that are vibrant, thriving ecosystems.
But sadly, too, there are more and more that look like something from the dark side of the Moon.
These degraded reefs have been ravaged by destructive fishing, bad land use practices that smother them with silt, and pollutants that foster disease and overgrowth by seaweeds.
More alarmingly, there are large areas that are killed off and degraded by warming seas linked to climate change.
We've all read that global warming poses a tremendous threat to our planet, and that coral reefs will face an uphill battle to survive in warmer waters.
Yet the greatest threat to our oceans and to all of its wonders is little known, nearly impossible to see, and potentially devastating. This is not climate change, but does stem from the excess carbon dioxide emissions that contribute to climate change.
The ocean absorbs about one-third of the CO2 entering the atmosphere - a natural process that for millennia has maintained the carbon balance of our planet.
In recent times we have upset this balance; global CO2 emissions are at an all-time high, and our oceans are absorbing more CO2 and at faster rates than ever before, causing a shift toward greater acidity.
This removes carbonate from the water; and carbonate is an essential building block for calcifying organisms, like corals, molluscs, sea urchins and many other important creatures that live on reefs or help to build them.
Too much carbonic acid lowers the natural pH balance of the oceans, causing acidification, which wreaks havoc on marine habitats and species.
Just imagine all the colour and vibrancy of coral reefs fading away into fuzzy, crumbling greys and browns, and you're left with a coral graveyard that could become the norm if we don't address the threats to our oceans.
The high visibility of coral bleaching makes this relatively easy to see and study, but ocean acidification is difficult to detect by sight alone
We need to find ways to convince people to take action, but that is a major challenge.
Given the difficulties that many coral reef managers around the world have in controlling such pressing direct threats as destructive fishing, overfishing and pollution, they are understandably hesitant about taking on an issue that they feel is beyond their ability and mandate to tackle.
Climate change is often seen as too daunting and too global for them to address, and too abstract for them to communicate.
Fortunately, in some respects, the sudden and startling onset of mass coral bleaching linked to warming seas has changed that a little.
We have developed and are applying some straightforward, practical actions to design marine protected networks and zone the individual sites to protect areas that are naturally resistant to bleaching
These areas are key, as they provide larvae that are transported to more vulnerable reefs where they settle and enhance recovery.
The high visibility of coral bleaching makes this relatively easy to see and study, but ocean acidification is difficult to detect by sight alone.
It is creeping, progressive, and insidious - likened by some scientists to osteoporosis of the reef - a weakening of the reef structure that makes corals more vulnerable to breakage from waves and human use.
We simply do not know yet whether we have reached or surpassed the point of no return for some coral species.
If current emission trends continue, we could see a doubling of atmospheric CO2 in as little as 50 years.
This would lead to an unprecedented acidification of our oceans that coral reefs would be unlikely to survive, a scenario that should spur us into action to try and find solutions.
A significant lowering of ocean pH would mean potentially massive coral loss. That would lead to the death of countless marine species as well as the devastation of economies dependent on ocean health and productivity.
'Meeting of minds'
It would also mean the end of an era for coral reef and scuba diving aficionados around the world.
But, more importantly, it would remove the livelihoods of hundreds of millions of people around the globe who depend on reefs for food, income, coastal protection and stability.
Current estimates predict that we could lose all coral reefs by the end of the century - or, in the worst case scenario, possibly decades sooner, if we don't take action now to prevent ocean acidification.
We have to maintain hope and optimism and keep trying to find solutions.
The Nature Conservancy recently convened leading climate change experts, top marine scientists, and prominent coral reef managers from around the globe for a "meeting of the minds" session to chart a course of action for addressing ocean acidification.
The key findings and recommendations from this gathering were compiled into the Honolulu Declaration on Ocean Acidification and Reef Management.
The most logical, long-term solution to ocean acidification impacts is to stabilise atmospheric CO2 by reducing emissions around the globe.
Yet the Honolulu Declaration also outlines tangible steps that can be taken now to increase the survival of coral reefs in an acidifying ocean, while also working to limit CO2 emissions.
For example, we need to identify and protect reefs that are less vulnerable to ocean acidification, either because of good flushing by oceanic water or biogeochemical processes that alter the water chemistry, making it more alkaline and better able to buffer acidification.
We can achieve this protection by designating additional "marine protected areas" and revising marine zoning plans.
We also need to integrate the management of these areas with reform of land uses that generate organic wastes and effluents that contribute to acidification.
At the local level, we may need to restrict access to more fragile coral communities or limit it to designated trails, much as we do with trails through sensitive environments on land.
We should consider designating "sacrificial" reefs or parts of reefs for diver training and heavy visitor use.
Another intriguing option is the prospect of farming local corals that prove more resistant to acidification, and "planting" them in place of those that weaken and break apart.
The consequences of inaction are too depressing to contemplate.
Global leaders, reef managers, and citizens around the globe should give all the support they can to the Honolulu Declaration to ensure the survival of the beauty and benefits of our marine treasure trove for future generations.
Dr Rod Salm is director of The Nature Conservancy's Tropical Marine Conservation Program in the Asia-Pacific region
The Green Room is a series of opinion articles on environmental topics running weekly on the BBC News website
Do you agree with Rod Salm? Is too little being done to halt human activities harming fragile marine ecosystems? Are efforts to save coral reefs being overshadowed by problems on land? Or are you optimistic that scientists, conservationists and politicians will find a way to save the colourful underwater worlds?
The oceans sustain all life on earth. There are phytoplankton which regulate the bio chemical balance in the oceans.
If the ph drops too much, then the phytoplankton may die. If they die, evrything dies. Nothing makes it.
MR SPIRIT, GLASTONBURY, UK
I agree that coral reefs faces long term problem of acidification. What about short term problems in the mean time so that reefs will survive to face the acidification issue. Also looking at all issues of global warming effect, by the time that CO2 level reaches the concentration twice as the present or even at 450 ppm, would coral reef fate still be the issue to worry about. After all Homo sapiens disappear, coral reefs can still have time to adapt to the environment.
Hansa Chansang, Phuket, Thailand
It is only logical that if two-thirds of the Earth's surface is oceans, what happens to those oceans will affect the entire world, including the creatures that live on the land.
Donna Metreger, Be'er Sheva, Israel
I wouldn't worry too much about ocean acidification - the current levels of CO2 in the atmosphere are approximately one tenth of those when the corals first evolved and are near the lowest they have ever been.
Corals will not notice a lowering of pH in the slightest.
Bleaching occurs when the algae that the coral lives in symbiosis with are expelled by the coral. This often occurs as waters warm or cool and is quickly reversed when new algae that are more suited to the new temperatures take the place of the old ones.
So global temperatures warming from the current lows also won't kill off the corals.
I do, however, agree with fact that coral reefs should be protected from over-fishing, boating and pollution as these do have the potential to destroy the marine and reef environments.
James S, Auckland, NZ
If you would like to DO SOMETHING to help coral reef decline, please support organizations that are actively working to save them including ReefCheck.org. Reef Check has volunteer teams in over 90 countries carrying out citizen science, student education and expeditions. You are welcome to participate and help save reefs.
Gregor Hodgson, Pacific Palisades, California, USA
I've recently moved to Kaua'i feeling a desire and need toward working to preserve one of the most beautiful places in the United States. I am agast at the destruction the near shore reefs have endured from excessive developement, bad strom water runoff management, and lack of nutrient reduduction via sound waste management. What will become this place, and others? Time will tell, I have confidence in the ability of the natural world to rebound from the destructive forces of our species. However lets do all we can to correct this problem, be aware and get involved. Now is the time to re- investigate our role on this planet, and a time to give back.
keith l conant, princeville, Kaua'i, Hawaii
A very well written and well structured article. Not only giving us the facts but also ideas to pursue. In business jargon "We need answers, not problems" and the article gives some which added to the quality of the piece.
I live on Bonaire, a divers paradise. I have been diving here for 20 years and the degradation of the island's reef is not in question.
Our Marine Park is very active in trying to prevent further reef damage at local level, but like all Marine Parks, it needs helps from governments to slow down coastal construction, provide infrastructure to deal with run off and to create legislation to prevent damaging fishing techniques.
Congratulations to the writer and all those people that are doing whatever they can to protect the reefs whatever the cause of their decay.
Ron Sewell, Bonaire, Netherlands Antilles.
Mark, Coventry / UK and all other people who speak of Global Warming saying it's all utter rubbish... (this includes my parents)
I believe we could be in real trouble, one way or another. However I always say one thing to those who are in total doubt or denial; It might be a natural cycle that is warming the planet, or nature might find a way to regulate any damage we may cause to the earths eco system. But for the sake of our children's children are you prepaired to take that risk??
Paul M, Wellington, NZ.
Acidifcation may be a threat but we should not rule out more hefty pollutants. Corals especially appear vulnerable to urine and sun protection oils produced and spread in the sea by visitors such as tourists. The very divers and snorklers that 'inspect' the coral bleaching may very well be causing it. We should compare for once the pristine coral reefs that are never visited by tourist to the man-trodden beaches of the big tourist resorts. You want to preserve coral? Then start diving clean. Or stay out of the water.
Peter Ambagtsheer, Apeldoorn The Netherlands
Mark from Coventry, UK wants a break.. I feel like breaking something but I'm not sure he would like it. The facts are we are losing these ancient creatures and habitat by slow death and there is nothing 'cloudy' or 'funny' about that. For some 400 million or so years they have contributed to life's diversity and to quibble over weather it is CO2 emissions, over fishing or agricultural run off, seems petty to the extreme and just for good measure, you, Mark from Coventry seem to be the one 'clouding the issue' with your arrogance.
Keith Cook, Auckland, New Zealand
We continue to look for the 'technological fix' to take care of our biosphere inbalances. The root of all this is that we are a species in overshoot, consuming far too many resources and creating too much waste (including the favourite villain, CO2).
The only solution is, and will be, a natural one. All species that go into overshoot, inevitably crash in numbers. When this happens, the die-off of the human species will reduce to population to a level that is in balance with the biosphere life processes. It is very simple ecology. Everything else is fantasy.
Thank you for taking time to read this.
Mr Rpnald Brown, Phuket, Thailand
Definitely too little is being done. Why isn't Coral an Endangered Species? Surely that would make the legislation easier to pass. What about Artificial Reefs? It would be good to see some more purpose-sunk wrecks. The Coral farming is an interesting idea too.
Jane, Playa del Carmen, Mexico
Sounds simple and foolish, but could over harvesting of the Ocean's sea shells be making the Ocean more acidic? In a fish tank, just one shell added can have profound effects on the acidity.
Elizabeth Parrish, Seattle
I agree that much of a damage is man made through a thorough fish pouching for aquarium use. In order to capture a life fish from the reef a poison is spread through out the area to numb the targeted biome of fish, unfortunately the side effect is catastrophic for the coral. Just a note.
Tomasz Stanek, San Bernardino, California USA
I think its awesome wat they are doing because its leting the world knw that all though this is an issue no one really knws about it is an issue that is real and its now.! If these great people and scientist did not pick up on this problem who knows wat devestating consequence could have cme out of the distruction of this beautiful live'n coaral.
Tamara, Auckland New Zealand
This gentleman talks of "hope", but when you end the article you discover that the only thing he can muster to support the hope is a "Mind meeting", that is to say, another gathering of talking people. I lost my hope on those meetings many many years ago...
Fernando Villegas, Santiago de Chile
Ocean acidification is the forgotten problem. It is so overlooked that the climate change denialists don't have any of their usual pre-prepared responses (it's entirely natural event etc.. ). It is also worrying that some of the proposed geo-engineering solutions to climate change (for example the rather fanciful mirrors in space solution) will do nothing to curb the increasing concentration of CO2 in the atmosphere that is responsible for the acidification of oceans. We have to raise the profile of this issue. Firstly, so that the public is aware that our CO2 emissions are causing more than one problem. Secondly, to emphasize that we can only get ourselves out of this mess by curbing our emissions.
Paul A, London, UK
Certainly not enough care has been taken of the marine environment for decades. Although the marine environment is arguably the most important in terms of global weather and also atmospheric composition it has largely treated as an open sewer. The sad fact is for most people it is 'out of sight, out of mind'. For example Broward, and Miami Dade councils of South Florida... have denied the mounting scientific evidence that effluent being pumped over coral reefs causes damage and favour the "It does no harm" opinion. Such dangerous opinions in the legislature of so called 'developed nations' will ultimately end in the ruin of some of the more accessiable reefs in Southern Florida. And sadly by the time that people believe it to be true - it's often far too late. As a marine biologist I am constantly saddened by the attitudes of people that could make a difference in terms of environmental protection legislation and frustrated that there is little funding or help for early career marine biologists who desparately want to "make a difference" and show the importance of protecting fragile habitats such as coarl reefs and mangroves in a global context. Once it's gone it's gone. That's the sad thing about it - but it doesn't have to be this way.
Claire Phillips, Oxford
I feel very strong empathy for Dr Salm. I walked away from this 14 years ago. He is still watching it face to face. There is only one answer; we had to stop - and we had to stop about 40 years ago, when Kennedy was committing us to flying to the moon, he should have been committing us to living on the planet we had. We have to stop, and make a balance with the levels of human activity that the planet will tolerate. Until that message sinks in to the minds of 6 billion people; there is nothing that can be done for now. At present course; that understanding will not register till the World's ecosystem has collapsed; taking our human society and economics crashing down with it. The governments of the world cannot pump enough money to keep this "more more more" expectation ramping up an ever steepening curve for much longer. At least 4 billion people, of the 6 billion people presently on the planet, go into free fall, and that will be that. In a couple of million years, the oceans will cool, the ph values will settle, the coral will flourish again . . and it will be as if we were never here, even in the blink of an evolutionary eye. The only question left is . . if any of us survive the die back - will the humans that remain evolve to be smart enough to learn our lessson, make peace with our home, and not mess it up all over again ? How long will it take you to explain it to 6 billion people Dr Salm ? Will the reefs last that long ? No ? - then I'm afraid the learning process will be one of cold hard practical experience. I am deeply sorry.
steven walker, Penzance
Fishing practices are devastating "links in the chain" that enable the life cycle of the marine ecosystem to support itself. If all "net fishing" were banned there would be little damage to and destruction of the species not being fished and their habitats. Commercial net fishing is very destructive. Just watch "blue planet" until the message gets through.
Shaun M White, Edmonton, Canada
Although I am not in any way an expert that could agree or disagree with Mr. Salm, I strongly believe we are doing far too little to stop damaging our environment and start to repair what has been damaged. I am optimistic that ways can be found to begin those repairs, and I find the idea of "farming" coral reefs very interesting, but I fear we have become too self-absorbed to recognize our responsibility to the planet we live on. I sincerely hope I am wrong - and I applaud Rod Salm and his colleagues for all of their efforts.
Yolanda, Greenfield USA
Much is said about save the planet and its many ecospheres ,but is anybody really going to make the sacrifices needed to make a difference? 90+ percent of the population want to be what they see on the TV,shameless ,ignorant consumers that adhere to the motto "more is better"..Even the education we recieve in schools directs us to become a well oiled part in the mechanism of consumer domination. Wise and educated men such as leaders of state know of all these problems,yet chose not to adress them because they fear the solutions would alienate them from the voter.Green seems to be good only as far as ti suits the consumer and his supplier.Shame on us all.Rod Salm has it right in his article.How right do you have it in your life?? Lets see if we can spend and save the coral reefs.Real education is what is needed to see consumerism exposed as the terrifying monster that it is. Consume less= sustained life forms.We all make a difference,even you. Best wishes.
Martin Jackson, Tavira ,Portugal.
good article but ideas for solutions exist mainly in the realm of pie-in-the-sky, particularly for the developing countries within whose waters the majority of the coral reefs lie. as such, without specific programming and funding (akin to those that might equally be dreamt up for tropical forests) from donor or developed countries, little will be achieved. the consequences of inaction are indeed too depressing to contemplate, but a small, sand wall will not hold back the tsunami.
sdw, maputo. mozambique
Lets not forget that ours is the Water Planet, if the Oceans are in peril the entire planet faces extinction, everything humanly possible should be done at all levels to stop polluting our Oceans and bring back eco systems where ever possible, set up ocean preserves and stop over fishing.
gert glende, Vancouver, BC , Canada
There are those that may argue that the effects are not as bad as predicted, but the reefs here in Pohnpei definitely seem to follow the trend. I have yet to find a part of the reef here that does not show the effects of an acidifying ocean. I'm sure that foreign fishing boats, harbored inside the reef boundaries, who recklessly dispose of their used oil directly into the water don't help the situation any!
Lemuel Recinos, Kolonia, Pohnpei, Federated States of Micronesia
This is an excellent summary of a major issue that even most marine scientists have been unaware of up until recently. ...and if you're one of those who doubt the predictions of future climate models, then you can suspend doubt now: the acidification of the oceans isn't a matter of debate, or models, or future projections, it's already happening and it will continue to happen so long as atmospheric CO2 keeps going up. That much is well understood chemistry. Yes, it's true that atmospheric CO2 level have been much higher in the past, and yes the oceans can buffer these changes, but we'll have to wait about 1000 years for that to happen. The problem is that the CO2 levels are rising SO RAPIDLY. If ever there was a good reason for reducing CO2 emissions as fast as possible, this is it.
Prof. Jon Havenhand, Strömstad, Sweden
Simple speechless. What utter rubbish. They've given up on 'Global warming' and called it 'Climate Change' as the world has stopped warming. Now we need a new 'you're all doomed Captain' scenario to keep the waning interest up. Coral reefs are suffering because of over fishing for aquarium fish, physical damage and agricultural run off, you are merely clouding the issue with CO2. You can find coral fossils dating back hundreds of millions of year, from times when CO2 levels were much might (x17 or more) than they are now. Funny how they seem to have thrived. Give us a break.
Mark , Coventry / UK
We should use bicycle power more, and the bus!
Marion Johansson, Denmark