Tag: ocean

An immediate halt to CO2 emissions is an absolute necessity…

…if we are to maintain the health of ocean ecosystems, says Professor Ove Hoegh-Guldberg, Director of the Global Change Institute at the University of Queensland in this video presentation, given to a symposium at the recent Our Changing Oceans conference in Washington DC. It’s sobering viewing. Here are the primary messages from the symposium:

  • There is a large body of empirical evidence indicating that anthropogenic climate change is substantially impacting ocean ecosystems. The evidence comes from many taxa, locations and habitats.
  • Changes in biological function in the ocean caused by anthropogenic climate change go far beyond death, extinctions and habitat loss: fundamental processes are being altered, community assemblages are being reorganized and ecological surprises are likely.
  • These changes will have significant consequences for people.

Perhaps even more importantly, Ove suggests that 450 ppm atmospheric CO2 is not a comfortable target. Hat tip to Ove’s co-author John Bruno for posting this at Skeptical Science earlier today. See also Ove’s excellent climateshifts.org blog.

The Climate Show #6: Monckton and the iron in the ocean

A very wide ranging Climate Show this week, with Dr Philip Boyd of NIWA and Otago University explaining why fertilising the oceans to soak up more carbon is not likely to be our “get out of jail free” card, John Cook of Skeptical Science introducing the new Monckton Myths section of the site, plus interesting new papers on Atlantic warming adding to the Arctic’s problems, an accurate prediction of last year’s Pakistan flooding, and the coolest 1970s Datsun on the planet.

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The Climate Show

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Show notes below the fold.

Continue reading “The Climate Show #6: Monckton and the iron in the ocean”

Bloomin’ marvellous

ChathamIslandbloom.jpg

A stunning image of a massive bloom of phytoplankton off the Chatham Islands (to the east of NZ — that’s Wellington and the Wairarapa in the top left corner), snapped by NASA’s Aqua satellite on December 5th and featured this week at NASA’s excellent Earth Observatory. Click on the image to see the full (4MB) image with lots more detail. NASA describes the region as a carbon sink, because the mixing of cold but nutrient rich deep water from Antarctica, with warm nutrient-poor (but iron-rich) sub tropical water provides the perfect recipe for large phytoplankton blooms — especially in spring and autumn. A major constituent of these blooms is usually huge numbers of coccolithophores, an important component in the oceanic carbon cycle, as I pointed out the last time the Chathams featured on the Earth Observatory.

Every little bit hurts

“Coral reefs… once survived in a world where CO2 from volcanoes and methane was much higher than anything predicted today.”  That sounds like good news from John Veron, a world authority on coral. Not if you read on: “But that was over 40 million years ago, and the increase took place over millions of years, not just a few decades, time enough for ocean equilibration to take place and marine life to adapt.”

Veron is writing in an article recently published at Yale Environment 360.  He is deeply alarmed at the prospect for coral reefs and wants to communicate why as clearly and accurately as he can. He begins by acknowledging that warnings of dire threats to coral reefs have been common over past decades; in his 40 years of working on reefs he has often been concerned at the impacts of sediments, nutrients and habitat loss. But the devastation which global warming threatens is of a different order.

 

Veron is frank about the depth of his anxiety. He writes of the “long period of deep personal anguish” he felt when he realised the big picture that was emerging from his widespread research into the effect of global temperature changes on reefs. He speaks of turning in his dismay to specialists in many different fields of science to find “anything that might suggest a fault” in his conclusions. But without success.  The bottom line remains that coral reefs can be utterly trashed in the lifetime of today’s children.

He realises that such a conclusion will be treated as an exaggeration by many. People may think that while there may be something to worry about it won’t be as bad as doomsayers like him 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.”

He goes on to explain the issues with helpful clarity. Single-celled algae live in coral cells and provide the photosynthetic fuel for them to grow and reefs to form. High light conditions at the same time as above-normal water temperatures cause the algae to produce toxic levels of oxygen.

“Under these conditions, corals must expel the zooxanthellae, bleach, and probably die or succumb to the toxin and definitely die. A tough choice, one they have not had to make at any time in their long genetic history.”

They can recover from bleaching, but not if further events continue to occur while the ecosystem is re-establishing. Increasing ocean heat, which affects surface layers most, will mean increasing severity and frequency of bleaching events.

“Scientists don’t need a pocket calculator to conclude that compressing the time periods between events in this way will prevent recovery: If we do not take action, the only corals not affected by mass bleaching by 2050 will be those hiding in refuges away from strong sunlight.”

However, serious though bleaching is, the effects of ocean acidification will be much more serious, affecting coral reefs badly and also impacting on all marine ecosystems. He considers that ocean acidification has played a major part in each of the five major extinctions in Earth’s history. In the last four extinctions reefs disappeared for millions of years. Reversal of acidification is a long process which can take place only through the immensely slow weathering and dissolution processes of geological time, processes that take hundreds of thousands to millions of years.

Veron asks his readers to consider two facts:

“The atmospheric levels of CO2 we are already committed to reach, no matter what mitigation is now implemented, have no equal over the entire longevity of the Great Barrier Reef, perhaps 25 million years. And most significantly, the rate of CO2 increase we are now experiencing has no precedent in all known geological history.”

He concludes with a solemn reminder:

“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 realise it’s only a week since I last wrote on the effect of global warming on corals. Veron is not saying anything that others aren’t also pointing to, or that he hasn’t himself said before. But he’s saying it with great lucidity and there’s an urgency and poignancy to the article which impressed me and made me want to draw attention to it. Scientific reticence is not permitted to mute the expression of his profound concern. The issue is too fundamental for that.

“We cannot afford to wait until the predictions of science can be totally verified, because by that time it will be too late.”

[Brenda Holloway]

Warm oceans killing coral

This has not only been a bad year for the Amazon rainforest, it has also been a year in which coral reefs, the rainforests of the ocean as they are sometimes called, have suffered severe bleaching because of raised ocean temperatures. Not a matter likely to strike the public consciousness. A recent Yale University survey found 75 percent of Americans have not heard of coral bleaching. But the reefs are one of the world’s great ecosystems and they matter enormously.

Mark Eakin, who coordinates the National Oceanic and Atmospheric Administration’s Coral Reef Watch and is frequently quoted in reports on this year’s bleaching events, explains that coral bleaching happens when ocean temperatures get too warm and stay warm for too long, and the relationship between the coral and the algae gets stressed. This thermal stress to corals, he said, is the highest it’s been since 1998, when 15% of the world’s coral reefs died.

 

“When you have high temperatures, in conjunction with normal high light conditions, the photosynthetic apparatus in the algae starts to poison the coral. They’ll spit them out into the water. When they do this, they lose their colour, look white, which is why they’re called bleached. If that persists for a long time, it can cause the corals to die.”

In July an article in the Telegraph on the coral bleaching events becoming apparent quoted Eakin:

“The bleaching is very strong throughout south east Asia and the central Indian Ocean. The reports are that it is the worst since 1997/1998. This is a really huge event and we are going to see a lot of corals dying.”

Indonesian reefs were badly affected. Some detail is provided in a report from the International Coral Reef Initiative which indicated the extent and severity of bleaching in different areas, and commented on the high rate of coral mortality following the bleaching.

In September Pierre Fidenci, president of Endangered Species International, wrote in a Mongabay article of severe wide-scale bleaching in the Philippines. The bleaching has been observed at many sites around the Philippines featuring mass mortality of corals including the coral triangle outside the Philippines. He considers this environmental catastrophe will probably be considered the most damaging bleaching event ever recorded in the Philippines, surpassing the big one of 1998.

“Prior to this year’s bleaching, it was estimated that about 85 percent of the reefs have been damaged or destroyed in the Philippines, now the current estimate is likely to be close to 95 percent.”

The Telegraph article noted scientists in Thailand have reported reefs suffering 90% of their corals being bleached and up to 20% of the corals dead. Olivia Durkin, who is leading the bleaching monitoring at the Centre for Biodiversity in Peninsular Thailand, said: “This year’s severe coral bleaching has the potential to be the worst on record.”

In June The Maldives reported the most serious incidence of coral bleaching since the major 1998 El Niño-event that destroyed most of the country’s shallow reef coral. Since then there has been gradual reef recovery but the 2010 event will be at least a major setback.

Eakin warned in September that this year had the potential to be also one of the worst bleaching seasons for some reefs in the Caribbean. It follows hard on the heels of the 2005 bleaching which caused record losses to Caribbean reefs, according to a collaborative study published a couple of weeks ago.  More than 80 percent of surveyed corals bleached and over 40 percent of the total surveyed died as a result of the 2005 event. It will be a while before the effects of this year’s bleaching can be measured, but it is already apparent that in some locations this year’s event is worse than the event in 2005. Not only are temperatures causing further damage to reefs hit hard during the 2005 event, but new locations have also been impacted.

Eakin’s comment on the release of the study of the 2005 impacts:

“This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems, and events like this are likely to become more common as the climate warms.”

Bleaching is a consequence of a warming ocean, but it’s not the only adverse effect of global warming on corals. The other major impact is from the increase in ocean acidification as carbon dioxide emissions continue to rise. The double whammy is very clearly explained by Australian scientist and coral reef expert John Veron in his 2009 lecture to the Royal Society. I summarised his content in this post last year, and suggest any readers who’d like a longer explanation of what bleaching and acidification mean for the future of coral reefs take a look at it. The link to the video of the lecture provided in the post is outdated, but this link will get you there if you want to hear him in person. He is sombre about the outlook for coral reefs if greenhouse gas concentrations continue to rise, and nothing that has happened this year suggests he is getting it wrong.

Polar warming, Amazon drought, coral reefs bleaching and dying: I’ve gathered material for posts on all three of them within the past week. They are all sending out danger signals. They all threaten massive effects which cannot but have drastic consequences for humanity if they continue. And they’re only part of what threatens from climate change. They ought to have us scurrying to do what we are still able to do to prevent them developing further. The Cancún conference should be charged with a sense of high urgency.

I found myself applauding our Prime Minister when he said on Sunday that nothing less than the future of underground coal mining in New Zealand rests on the investigation into the Pike River tragedy. “We can’t put people into mines that are dangerous.” I also found myself wondering how that sentiment would go down with some of our economic interests. I thought John Key was absolutely right, and I presume in saying it he was not unaware of the economic implications. I guess I needn’t spell out the obvious parallel with the dangers from climate change and the perspective they put on the protests that economic interests mustn’t be harmed by climate change measures.

Johann Hari, in the eloquent article Gareth has already drawn attention to, wrote, “At Cancún, the real question will be carefully ignored by delegates keen to preserve big business as usual.”  It’s the wrong choice, Hari points out. But as he also says it’s not too late to change.