Globe’s coral reefs suffer second worst bleaching on record during 2010

coral reef map

In October, marine scientists said the Southeast Asia and Indian Ocean bleaching “may prove to be the worst such event known to science.” NOAA pointed out in November that

As the “rainforests of the sea,” coral reefs provide economic services “” jobs, food and tourism “” estimated to be worth as much as $375 billion each year.

The former chief scientist of the Australian Institute of Marine Science wrote in December, “The end is in sight for the world’s coral reefs.”

What follows is a WunderBlog repost in which Dr. Jeff Masters summarizes what happened to corals this year.

Record warm ocean temperatures across much of Earth’s tropical oceans during the summer of 2010 created the second worst year globally for coral-killing bleaching episodes. The warm waters, fueled in part by the El Ni±o phenomena, caused the most coral bleaching since 1998, when 16 percent of the world’s reefs were killed off. “Clearly, we are on track for this to be the second worst (bleaching) on record,” NOAA coral expert Mark Eakin in an interview last month. “All we’re waiting on now is the body count.” The summer 2010 bleaching episodes were worst in Southeast Asia, where El Ni±o warming of the tropical ocean waters during the first half of the year was significant. In Indonesia’s Aceh province, 80% of the bleached corals died, and Malaysia closed several popular dive sites after nearly all the coral were damaged by bleaching. However, in the Caribbean’s Virgin Islands, coral bleaching was not as severe as experienced in 2005, according to National Park Service fisheries biologist Jeff Miller. I’ll discuss the reasons for this in a future blog post. In other portions of the Caribbean, such as Venezuela and Panama, coral bleaching was worse than that experienced in 2005.

Figure 1. An example of coral bleaching that occurred during the record-strength 1997-1998 El Ni±o event. Image credit: Craig Quirolo, Reef Relief/Marine Photobank, in Climate, Carbon and Coral Reefs

What is coral bleaching?
Coral bleaching is a whitening of the corals that occurs when stresses such as high water temperatures, increased water acidity, or pollution disturbs the symbiotic relationship between the corals and the algae that live inside them. Bleaching episodes occur when ocean temperatures rise above 85 – 87°F (29.5 – 30.5°C.) Peak warming events took place in the western Indian Ocean and north-western Pacific in 1997/98, in the north of Australia and central Pacific during 2003/04, and in the Caribbean in 2005. About half of the reefs affected by bleaching in these episodes have recovered, and one recent study cautions that non-lethal bleaching episodes and subsequent recovery of corals is often under-reported.

Australia’s Great Barrier Reef at risk
With summer now in full swing in the Southern Hemisphere, coral bleaching concern now shifts to Australia’s Great Barrier Reef. Ocean temperatures along the reef are currently up to 1°C above average, due, in part, to the current moderate to strong La Ni±a event. NOAA’s Coral Reef Watch has issued its highest level of coral bleaching alert for the northern 2/3 of the Great Barrier Reef, since the La Ni±a event is predicted to persist into at least April. Also of concern is the tremendous run-off occurring in the wake of the record flooding that has affected the neighboring Australian province of Queensland. While the floods have now peaked and the rivers of Queensland are now falling, the $5 billion disaster dumped a large amount of sediments, pollutants, fertilizers, and pesticides into the southern portion of the Great Barrier Reef, and this will act to increase the stress on the corals. However, the floods may end up indirectly benefiting some portions of the Great Barrier Reef. The cloud cover and strong winds that accompanied the flooding rain storms also acted to cool the waters along the reef. According to an analysis I did of the UK Met Office Hadley Centre global ocean temperature data, sea surface temperatures along the southern portion of the reef, between 15°S and 20°S latitude, were the warmest ever for September, 1.27°C above average. These waters cooled significantly, relative to average, during October and November, and were just 0.12°C warmer than average during November. Cooler waters will mean less potential for coral bleaching, though the pollution in the flood run-off water may end up killing some corals.

Figure 2. Forecast stress on coral due to warm ocean temperatures for Australia, Jan – Apr 2011. The northern 2/3 of the Great Barrier Reef are under the highest alert level for coral bleaching. Waters are cooler along the southern portion of the reef, due, in part, to the storms that have brought record flooding to portions of Queensland, Australia. Image credit: NOAA Coral Reef Watch.

Long term outlook for world’s coral reefs: grim
The large amount of carbon dioxide humans have put into the air in recent decades has done more than just raise Earth’s global temperature–it has also increased the acidity of the oceans, since carbon dioxide dissolves in sea water to form carbonic acid. Corals have trouble growing in acidic sea water, and the combined effects of increasing ocean temperatures, increasing acidity, pollution, and overfishing have reduced coral reefs globally by 19 percent since 1950. Another 35 percent could disappear in the next 40 years, even without the impact of climate change, according to a report released in October 2010 by the World Meteorological Organization and the Convention on Biological Diversity. Coral loss has been the most severe in Earth’s hottest ocean, the Indian Ocean. Up to 90% of coral cover has been lost in the Maldives, Sri Lanka, Kenya and Tanzania and in the Seychelles. Global warming has heated up most of the tropical ocean surface waters by about 0.5°C (0.9°F) over the past 50 years, and the remarkable bleaching episodes of 1998 and 2010 both occurred when strong (natural) El Ni±o episodes heated up Pacific tropical waters to record levels. If the Earth continues to heat up this century as expected, coral bleaching episodes will grow more frequent and intense, particularly during strong El Ni±o episodes. The twin stresses of ocean acidification and increasing ocean temperatures will probably mean that by 2050, it will be difficult for any coral reefs to recover when subject to additional stresses posed by pollution or major storms, according to a talk presented by Stanford climate scientist Ken Caldeira at last month’s American Geophysical Union (AGU) meeting.

Figure 3. Departure of sea surface temperature in the Australian region over the past one hundred years, year-by-year (red line), and decade-by-decade (grey bars.) The 2010 value is preliminary and does not include data for December 2010. If ocean temperatures and ocean acidity continue to rise in Australian waters at the same pace as has occurred over the past 100 years, the Great Barrier Reef will be in significant danger by 2050. Image credit: Australian Bureau of Meteorology.

Coral expert J.E.N. Veron, former chief scientist of the Australian Institute of Marine Science, had this to say in an excellent interview he did with Yale Environment 360 last year:

The science is clear: Unless we change the way we live, the Earth’s coral reefs will be utterly destroyed within our children’s lifetimes.

You may well feel that dire predictions about anything almost always turn out to be exaggerations. You may think there may be something in it to worry about, but it won’t be as bad as doomsayers like me are predicting. This view is understandable given that only a few decades ago I, myself, would have thought it ridiculous to imagine that reefs might have a limited lifespan on Earth as a consequence of human actions. It would have seemed preposterous that, for example, the Great Barrier Reef–the biggest structure ever made by life on Earth–could be mortally threatened by any present or foreseeable environmental change. Yet here I am today, humbled to have spent the most productive scientific years of my life around the rich wonders of the underwater world, and utterly convinced that they will not be there for our children’s children to enjoy unless we drastically change our priorities and the way we live.

Reefs are the ocean’s canaries and we must hear their call. This call is not just for themselves, for the other great ecosystems of the ocean stand behind reefs like a row of dominoes. If coral reefs fail, the rest will follow in rapid succession, and the Sixth Mass Extinction will be upon us–and will be of our making.

I might add that not only are reefs the ocean’s canaries, they are incredibly valuable in their own right. According to the World Meteorological Organization, coral reefs provide economic services–jobs, food and tourism–estimated to be worth $30 billion per year. NOAA put this figure at twelve times higher, $375 billion each year. Corals cover just 0.2% of the world’s oceans, but contain about 25% of all marine species.

— Jeff Masters, a Wunder Blog repost.

JR:  The figure of the very top comes from, which as an excellent primer on corals and coral bleaching.

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13 Responses to Globe’s coral reefs suffer second worst bleaching on record during 2010

  1. Thanks for posting this I’d been wondering what the toll on reefs had been for 2010 after writing my own piece last August. “Record Heat Killing Caribbean and Indian Ocean Corals”

    The floods in Australia are going to have a major impact on parts of the Great Barrier Reef: Charlie Vernon (cited above) told me last week they will be hammered by the run-off. And coral expert told me today that the south part of the reef that had been recovering will be hit hard.

    Some think corals will be the first major ecosystem to collapse.

  2. MapleLeaf says:

    Good luck to the liars, sorry contrarians/skeptics. trying to blame the upcoming bleaching event on El Nino. We have a moderate to strong La Nina which has just peaked in strength.

  3. Mulga Mumblebrain says:

    Maple Leaf, the denialists will have no problem. These people are pros! They can tell you that black is white and dung chocolate. The Dunning-Krugerites will eat it, too, and declare it delicious. I see too, that the article speaks of the Queensland floods easing. Not yet, they’re not.

  4. Doug in MN says:

    The higher CO2 levels are making the oceans more acidic, is our soil becoming more acidic as well?

  5. espiritwater says:

    The Following is from the Epoch Times–

    The Past Year Leaves Like a Lion– The National Weather Bureau reported 47 tornadoes…

    The past year, 2010, left roaring. The National Weather Service issued a preliminary report for December 31, 2010, with a total of 139 reported storm events in eight states… There were a total of 47 tornadoes reported in 4 states. Missouri reported four fatalities… Thirty occurrences of hail…. with Wright, Mo., reporting the largest ice balls, golf-balls-to baseball- sized. High winds killed one person…. 2010 Hurricane season Ends– According to NOAA, in the Atlantic Basin a total of 19 named storms… tied with 1887 and 1995… Of those, 12 became hurricanes– tied with 1969… Five of those reached major hurricane status of Category 3 or higher… The 2010 season almost doubled the average of those that became hurricanes (12), and more than doubled the average number of major storms formed (5). Despite the exceptionally active hurricane year, no major damage or loss of life resulted.

    I would add also, that despite the exceptionally active hurricane year (and other extremely numerous and major climatic events this past year), few in the media connected it to global warming… which begs the question… are these people dense or just greedy?!!

  6. Barry says:

    Great to see yet another outstanding climate change post by Dr. Masters at

    I’ve been a fan and reader of his for awhile. Just a couple years ago he tended to downplay any possible climate change component of weather events, as did many of his readers in the comments section. No longer. In the last year he as clearly seen the trend emerge from the noise and has done a great job in educating himself and his readers on the climate science.

    One of the most hopeful aspects of 2010 in my book was the strong engagement of Dr. Masters as a clear, respected, knowledgable and skillful voice explaining the unfolding climate threats.

    Climate hawk and hero.

  7. Steve says:

    #4: CO2 does not change soil PH like it does sea water PH. In the case of sea water CO2 reacts to form carbonic acid which over time lowers PH (more acidic). Soil is able to absorb CO2 in huge amounts when it is NOT tilled with a mouldboard plough which breaks the surface. As long as the soil is kept sealed as it it with “No Till” agricultural practices or in the case of conservation grasslands and prairies, the soil adsorbs and stores the CO2 in a stable form that does not influence PH. C02 can be reliably stored in soil in huge quantities over 10’s of thousands of years. All of the world’s soils potentially can hold many times more CO2 than contained currently in our atmosphere. When a price is placed on carbon, a significant amount of money that is generated must be funnelled back to farmers (higher rates to small farmers, lower rates to huge corporate farms) to change their soil management practices. No till has the added benefit of improving soil fertility while using significantly less oil-derived fertilizer. An additional benefit is improvement to ecosystems and habitat for native species including insects and birds. This last benefit is crucial over the coming century as species go on a climate-change induced northward march. Those that can’t are toast unless we physically move them. Native prairies and no-till farming store huge amounts of carbon, offers refuge to animals and plants and is a WIN/WIN for farmers society and native fauna.

  8. Rebecca says:

    Great article. The Great Barrier Reef may not survive 2011, let alone be around for our children or their children. Not only is it under extreme pressure from the sea temperature rise, but the current floods in Queensland will cause even more damage in the very near future.

    Besides the sheer volume of fresh water being poured onto the reef day after day, there is the chemical residues and silt to contend with. Add to that, the coal mines have announced they will discharge the pit water from their open cut mines into the river system as soon as the flooding subsides. At least that may take a while, the rain is still torrential (even as I write this).

  9. Mulga Mumblebrain says:

    espiritwater#5, the Epoch Times, the house rag of the dangerous Falun Gong cult, hardly encourages any confidence. I’d say that even the Washington Times is more reputable.

  10. Leif says:

    Requiem for the Coral Reefs of the World

    How do you morn the death of one of the world largest and diverse eco-systems?

    Do you wait until the last pulse of life is stilled?

    Think of yourself as a prehistoric hunter and you and yours have spotted a Mammoth… (Food for a month.) You posses a beautifully crafted razor sharp Clovis spear tip allowing your otherwise useless hand to strike death at a distance. But one thrust cannot kill such a beast. It will take many. Does the first person to strike get the credit? Perhaps the animal is able to yet get away. Is death the moment this magnificent creature is brought to its knees? Clearly not as shudders of last life could still mortally wound you or others.
    Is “death” reserved for the last beating of the heart? The last brain synapse? Even then the answer is not clear, as the death of this animal has brought life to your tribe, your wife, your child… The scavengers, insects, the web of life, for it is only thru death that life can be renewed.

    Do you think for a moment that the ancestor that killed the last Mammoth on earth understood what had transpired? Would it have made any difference?

    Science is telling us, clearly, unequivocally, that in 40 or 50 years the Coral Reefs of the world will be dead, assuming the status quo. Our spear tips have injured this oasis of life.

    Will mankind be able to “back off” and nurture this eco-system back to life? Will caring hands and healing efforts be enough?

    Wise and learned men have warned that the Coal Reefs are a “Lynch Pin” in the fabric of life around the world. As are the Virgin Forests, the untouched Parries, the Oceans, Rivers, Jungles, Swamps, even our Air is a product of past life…

    And death.

    Remove life, there is only death…

  11. ihatedeniers says:

    As I am only in highschool I will probably never get to see a coral reef. If La nina continues the great barrier reef will be dead or severely damaged by the end of the year.

  12. K. Nockels says:

    #11 welcome it’s so good to see that the people who will be most impacted by GW are here and willing to learn and fight like the rest of us to try to make the changes we must make to insure that not all the beautiful things in nature are lost.

  13. Doug in MN says:

    #7, Thanks Steve, I am with you on prairies and restoration, I restored 160 acres in 1993 and the land has become quite magnificent. Some rare species, both plant and animal now make it their home. I need to do some soil testing this year to see how much the organic matter has improved.