Posts Tagged ocean acidification

While they sleepwalk in Warsaw: icebergs calve, emissions climb, “pause” disappears Gareth Renowden Nov 20

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Warsaw has seen a deluge of important climate-related information released — so much that it’s been difficult to keep up — but still not enough to steel negotiators to reach an equitable arrangement that gives us all a chance at a reasonable future climate. And at the same time, the planet has been sending signals that it’s not happy. The Pine Island glacier has finally calved the giant iceberg that first started to shown signs of cracking away from the ice stream a couple of years ago. Iceberg B-31 has been described as being the size of Singapore (about 700 km2), but isn’t likely to move far from Pine Island Bay in the near future. NASA Earth Observatory coverage here and here; see also Telegraph (UK) and Antarctic Sun.

The Global Carbon Project announced earlier this week that greenhouse gas emissions are projected to reach the highest level in human history this year — 36 billion tonnes. There are some encouraging signs that the rate of growth may be slowing, but nowhere near enough to enable the planet to avoid hitting a two degree rise in the first half of this century. There’s an excellent visualisation of national emissions at the Global Carbon Atlas (and at the Guardian). See also The Age, Think Progress.

All that carbon has to go somewhere, and the global oceans are doing us a big favour by absorbing a lot of it. Unfortunately, there’s a big downside: the oceans are becoming more acidic, and at a rate faster than at any time in the last 55 million years. The prospects for marine ecosystems look bleak if we can’t kick the fossil fuel habit, according to a Summary For Policymakers [pdf] released by the Intergovernmental Oceangraphic Commission last week.

Regular Hot Topic readers will know that I’ve never been much persuaded by talk of a “pause” in global warming’s progress. If global warming stopped in the 1990s, why has the last ten years been the warmest in the long term record, and why has the ice kept on melting? To put the final nail in the pause’s coffin, Kevin Cowtan from the University of York and Robert Way from the University of Ottawa (both stalwarts at Skeptical Science), looked at global temperature records and found ways of compensating for the temperature data missing from the Arctic and Africa. Here’s Cowtan, explaining what they did.

Net result: existing temperature data series underestimate recent warming by half. If that’s all straightforward enough, take a moment to consider what will happen to warming when the factors that have been acting to restrict warming swing to the opposite phase. We’ll be heading into the unknown, and at high speed. See Real Climate, Dana Nucitelli at the Guardian, and Science Daily.

And finally: this is the time of year when the World Meteorological Association releases its preliminary look at the weather and climate events of the current year. It’s not a pretty sight. 2013 is tracking along to be the 7th warmest year in the long term record. WMO Secretary-General Michel Jarraud noted: “the coldest years now are warmer than the hottest years before 1998.” Another reason to kiss the pause meme goodbye. See Climate Central, Guardian.

Something (early) for the weekend: grim forecast for oceans and the roots of denial Gareth Renowden Oct 17

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Something of a miscellany today, coupled with an open thread, to keep you going during a brief pause in posting. First up: a study published this week in PLOS Biology looks at changes in ocean chemistry, temperature and primary productivity over the next century under two emissions scenarios, and finds that no corner of the ocean escapes untouched. From Science Daily:

“When you look at the world ocean, there are few places that will be free of changes; most will suffer the simultaneous effects of warming, acidification, and reductions in oxygen and productivity,” said lead author Camilo Mora, assistant professor at the Department of Geography in the College of Social Sciences at the University of Hawai’i at Mānoa. “The consequences of these co-occurring changes are massive — everything from species survival, to abundance, to range size, to body size, to species richness, to ecosystem functioning are affected by changes in ocean biogeochemistry.”

It’s been a productive few weeks for Mora: he was lead author on a recent study1 published in Nature that estimated when climate in different parts of the world would move beyond anything experienced in the last 150 years — have a play with this interactive map to find out when your part of the world will move into the unknown. See also Climate Central, Science Daily, and a huge amount of press coverage.

Nicely complementing Mora’s oceans study, Sebastian Ostberg and others from the Potsdam Institute for Climate Impact Research looked at terrestrial ecosystems and found that “80 percent of the planet’s ice-free land is at risk of profound ecosystem transformation by 2100″. As you might expect, business as usual emissions scenarios have the biggest impact, but even strong mitigation won’t prevent significant changes. From Science Daily:

…even if the warming is limited to 2 degrees, some 20 percent of land ecosystems — particularly those at high altitudes and high latitudes — are at risk of moderate or major transformation, the team reveals.

Physics Today‘s October issue includes an excellent overview of the rapid climate change taking place in the Arctic — The Arctic shifts to a new normal. (hat tip to John at the warren). For a very clear explanation of how Arctic changes can influence northern hemisphere atmospheric circulation, see Dr Ricky Rood’s latest post at his Wunderground blog.

David Archer at RealClimate extols the virtues of the new eight week Science of Climate Change course starting soon on Coursera. It sounds like something worth exploring, even if you don’t complete the full course or only play with the visualisations. I might be bold, and suggest that attendance should be compulsory for all climate cranks, sceptics and deniers.

Oh dear, I used the “d” word. Expect lots of faux outrage from those in denial of the need to act on climate change — but as Josh Rosenau of the National Centre for Science Education points out, the roots of that usage of the word go back long before any imagined link with genocide in Germany during WW2.

While NZ’s own little coterie of cranks and deniers lick their wounds over a lost court case, one of their “science advisers” has rushed into print in the NZ Herald drawing the longest of long bows on the import of some recent research on atmospheric aerosol formation. Chris de Freitas, the Auckland University geographer (not an atmospheric physicist or chemist, note) who long ago sold his soul to the Anything But Carbon (ABC) crowd, decides to suggest that the new research means that NZ’s pastoral farmers are working to cool the planet and should get more carbon credits than foresters. Considering that CdF consistently argues we don’t know enough to act on climate change, it’s immensely hypocritical of him to oversell the relevance of an interesting, but preliminary piece of research. For a somewhat more sane discussion of the study, see RealClimate.

And finally: I’m going to be taking a break from HT for a while, because I’m going into hospital tomorrow for what the surgeon describes as a relatively minor procedure on my inner ear2. I hope to be back at my keyboard sometime next week, if all goes well. Please accept my apologies in advance if comments get stuck in moderation, or other issues arise.

  1. Full text, free!
  2. Endolymphatic sac surgery, which if all goes well should put an end to the vertigo attacks associated with Meniere’s disease in my left ear — but it does mean drilling a hole in my skull. I’ve asked for a processor and memory upgrade while he’s in there… ;-)

New Zealand’s changing climate and oceans: new Gluckman report out today Gareth Renowden Aug 01

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The Prime Minister’s science advisor, Sir Peter Gluckman, today released a new report looking at the probable impacts of climate change in New Zealand over the next 40 years. The report, New Zealand’s Changing Climate and Oceans: The impact of human activity
and implications for the future
(pdf) is:

… intended to update the public on current scientific understandings of climate change and ocean acidification. In particular, it focuses on how these changes are likely to affect New Zealand’s climate and industries at a regional level over coming years.

The timing of the report — which appears at first glance to offer a reasonable overview of our current understanding of likely local climate changes — seems a trifle odd. In a matter of months the IPCC will release the first part of its Fifth Report, covering the underlying science, and while we’ll have to wait until March next year for the Working Group 2 report on regional impacts, Gluckman and his team would have had a firmer foundation for their report with only a modest delay.

I’ll be reading the report carefully over the next few days, and will have more to say in due course. I’m particularly interested in exploring how Gluckman approaches the risks associated with local climate changes, and his take on how the wider international context will impact New Zealand.

See also: Peter Griffin, NZ Herald.

The God Species Bryan Walker Aug 14

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It’s an arresting title, The God Species: How the Planet Can Survive the Age of Humans. For author Mark Lynas the Holocene, the 10,000 year post-ice age era during which human civilisation evolved and flourished, has given way in industrial times to the Anthropocene, an age in which the human population has undergone extraordinary growth, and become totally dominant on the planet. In the process we have interfered in the planet’s great bio-geochemical processes to the extent that we are threatening to endanger the Earth system itself and our own survival. Things are badly askew and we must help Earth to regain stability. It cannot do so alone. ’Nature no longer runs the Earth. We do. It is our choice what happens from here.’

Not that Lynas proposes to shoulder nature aside. Far from it. It’s a question of restoring nature’s balance and working within its limits. His book is about the planetary boundaries which must be respected if we are to avoid very serious environmental damage. He aims to communicate to a wide audience the findings of a group of 28 internationally renowned scientists who a couple of years ago identified nine such boundaries and wrote about them in a notable feature in Nature. Along the way he has his own suggestions for tackling the challenges involved and takes issue with other environmentalists over what he considers wrong-headed stances on many issues, including nuclear power and genetic engineering. This aspect of the book is often argumentative, but the central exposition of the planetary boundaries is straight science, set out with the lucidity apparent in his earlier book Six Degrees.

He begins with the biodiversity boundary. We’re well beyond the expert group’s proposed boundary of a maximum of ten species lost to life per million species per year. An estimated 100 to 1000 species per million are currently wiped out annually. The Anthropocene Mass Extinction is well advanced, and the death toll will soon rival that at the end of the Cretaceous when the dinosaurs and half of the rest of life on Earth disappeared.  It is now understood how important a diversity of species is to the resilience and stability of an ecosystem. This applies to the biosphere as a whole: if the current mass extinction is allowed to continue or, worse, to accelerate, the chance of a global-scale ecosystem collapse can only become more ominous. Lynas sees biodiversity loss as fundamentally an enormous market failure. We need to design systems that value nature in a direct and marketable sense and get hard cash to those in a position to protect ecosystems. ’What is needed is not more moralising, but more money.’

The climate change boundary is next on the list. Where once, along with others, Lynas would have endorsed a maximum 450 parts per million atmospheric carbon dioxide concentration and not more than a 2 degree rise in temperature as a safe boundary to avoid dangerous tipping points, he now regards that as wrong and accepts that a fair reading of the science today points to 350 ppm maximum. It’s a boundary we’ve already transgressed, but one we can pull back to if we start on reductions very soon.  We need to be carbon-neutral by mid-century and carbon-negative thereafter. The technologies required are available and can be employed within the prevailing economic system. Notions that we can restrain economic growth won’t work. He is insistent that nuclear power must be a significant part of the solution, considering that there is not time to develop renewable energy to an adequate level. The book provides a spirited defence of nuclear energy as a centralised form of baseload generation, taking both Fukushima and Chernobyl into account. To oppose nuclear is to leave the door open for coal, a far more dangerous source.

The third boundary in which we’re well over the limit is nitrogen. The production of artificial fertiliser, while it has clearly been good for the feeding of the greatly increased human population, is causing serious environmental problems. The expert opinion is that we need to reduce the flow of human-fixed nitrogen to slightly more than a third of its current value.  Lynas looks at various ways in which our use of nitrogen can be reduced. Organic farming isn’t one of them since he considers widespread organic farming couldn’t produce enough food for the world’s present population.  One possibility he canvasses is genetic engineering to produce a more nitrogen-efficient and higher-yielding crop. Here and elsewhere he refers to Stewart Brand’s book Whole Earth Discipline, in which Brand advances the causes of nuclear power, genetic engineering, and urbanisation as ways of facing up to the challenge of climate change.

The land use boundary is the next Lynas considers, urging the need for cash to make the protection of forests and other important ecosystems more attractive than their destruction. The movement of populations to cities he sees as overall a positive for sustainability because it leads to a reduction in population growth and concentrates the human impact on the land in a smaller area.  As is becoming usual in the book Greens are chided for failing to see the positives in such developments.

Other boundaries discussed are freshwater, toxics, and aerosols before he arrives at ocean acidification, the evil twin of climate change. We’re in a danger zone already, with the world’s oceans more acidic than has probably been the case in at least 20 million years. Future predictions are uncertain, but educated guesses provided by models and evidence from the Earth’s deep geological past lead him to the conclusion that ocean acidification is so serious a threat that even if there were no climate change we would still have to urgently reduce atmospheric carbon dioxide. The integrity of the marine biosphere is at stake.

The final boundary Lynas tackles, that of the ozone layer, is a success story in that humanity pulled back from a hellish future by reaching international agreement on regulations to cease the production of CFCs. It was not an easy achievement in the face of industry opposition, but politicians stepped up to leadership and private industry delivered alternative products in consequence. The strong political leadership delivered by the US was crucial, in sad contrast to the way it has politically thwarted progress on climate change negotiations.

As adviser to the president of the Maldives, Lynas witnessed at first hand the debacle of Copenhagen, being among the fifty or so present in the room where the final-hours heads of state negotiations were conducted. He tells the disappointing story of that meeting as an example of what failing to meet a planetary boundary looks and feels like. But he doesn’t regard the failure as necessarily terminal, pointing out that China, a real obstruction to progress at Copenhagen, is now leading the world in investment in low-carbon technologies and showing itself deadly serious about dealing with climate change, reaping great economic benefit along the way. The US is being left well behind.

Lynas is often impatient with Greens and environmentalists. But the arguments he engages in have to do with appropriate technological and economic remedies, not with the shared perception that we are exceeding the boundaries of nature and must pull back. On that common ground he interprets and explains the science with admirable clarity. And he remains confident we can solve the problems, given sufficient pragmatism on the means employed.

[Purchase via Hot Topic affiliates: The Book Depository (UK, free shipping worldwide), Fishpond (NZ),]

The Climate Show #16: Keith Hunter on oceans, acids and the carbon cycle Gareth Renowden Jul 15

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We learned a lot this week, as Professor Keith Hunter of the University of Otago, one of the world’s leading ocean chemists, gave us a masterclass on ocean acidification and what it means for the future of the oceans. Plus we discuss Australia’s new carbon tax, green growth campaigns in New Zealand, why China’s aerosols may have been doing us a favour and why cleaning them up might unleash more warming, and climate models having trouble with rapid climate events. On the solutions front we look at a tiny electric aeroplane setting a new speed record and a solar initiative in NZ. No John Cook in this show, but he’ll be back soon.

Watch The Climate Show on our Youtube channel, subscribe to the podcast via iTunes, listen to us via Stitcher on your smartphone or listen direct/download from the link below the fold…

Follow The Climate Show at The Climate Show web site, and on Facebook and Twitter.

The Climate Show

News & commentary: [0:03:25]

Australia bites the carbon bullet.

Going for Green Growth in NZ

Pure Advantage campaign launched

Green Growth Advisory Group launches discussion document

China’s power stations generate ‘future spike’ in global warming The paper referred to is Reconciling anthropogenic climate change with observed temperature 1998—2008 by Robert K. Kaufmann et al, pdf here.

State-of-the-art climate models are largely untested against actual occurrences of abrupt change. It is a huge leap of faith to assume that simulations of the coming century with these models will provide reliable warning of sudden, catastrophic events.

Al Gore is back: Gore’s Climate Reality project announced it would kick off with a 24-hour live streamed event on 14 September. The day’s events will include a new multimedia presentation by Gore that will “connect the dots” between extreme weather events and climate change, a statement said.

Interview: Professor Keith Hunter of the University of Otago. [0:30:00]

Professor Keith Hunter is New Zealand’s leading scientist in the field of marine and freshwater chemistry. His research interests include the effects of trace metals, both essential and toxic, on the growth of phytoplankton; the marine chemistry of the major greenhouse gas, carbon dioxide and marine surfaces (air-water, sediment-water). He directs the joint NIWA-University of Otago Centre of Excellence for Chemical and Physical Oceanography based in the Department of Chemistry, and is involved in several PGSF-funded research programmes.

Skeptical Science series on ocean acidification:

Solutions [01:10:30]

Councils asked to go solar in ‘The Solar Promise’ nationwide campaign launched this week:

Tiny electric airplane sets speed record

Thanks to our media partners:, Scoop and KiwiFM.

Theme music: A Drop In The Ocean by The Bads.

The Climate Show #15: Michael Ashley and the ineducable Carter Gareth Renowden Jun 29

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We thought we’d try for a record short show — and failed, because once again there was just to much to talk about. We have more on Eritrean volcanoes, extreme weather over the last 18 months, a new report on the dire state of the oceans, and Stoat’s big bet. Special guest is Professor Michael Ashley from the University of New South Wales, discussing the state of play in Australia, John Cook does a rapid debunk of Bob Carter, and we have electric cars, more flow batteries and the gas we do not want to smell.

Watch The Climate Show on our Youtube channel, subscribe to the podcast via iTunes, listen to us via Stitcher on your smartphone or listen direct/download here:

The Climate Show

Follow The Climate Show at The Climate Show web site, and on Facebook and Twitter.

News & commentary: [0:05:00]

The eruption of Nabro in Eritrea: Earth Observatory image.

Follow the action at Dr Erik Klemmeti’s Eruptions blog, watching Nabro from space.

Extreme weather – Jeff Masters chips in: Hot Topic post, Jeff Masters post, Neville Nichols on Aussie heatwaves.

State of the oceans report – not a good read:

Sea ice bets: $10,000 on the line at Stoat.

Interview: Professor Michael Ashley of the Department of Astrophysics at the University of New South Wales [0:19:50]

Journey into the weird and wacky world of climate change denial at The Conversation.

Monckton calls Garnaut a Nazi.

Debunking the sceptic, with John Cook of Skeptical Science [0:44:50]

Bob Carter op ed, and…

John Cook riposte.

Bob Carter: ’Between 2001 and 2010 global average temperature decreased by 0.05 degrees’
’…slight global cooling over the past 10 years’

The PIG is flying: Pine Island Glacier melt rate doubles.

Solutions [00:58:20]

ReFuel – An electric car-fest

More on flow batteries – this one’s grid scale

Shale gas/fracking and why it isn’t any kind of solution to anything

Trailer for Gasland.

The outrageous British chat show host whose name completely escapes me.

Thanks to our media partners:, Scoop and KiwiFM.

Theme music: A Drop In The Ocean by The Bads.

The state of the ocean (dire) Gareth Renowden Jun 23

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Alex Rogers, Professor of Conservation Biology at the Department of Zoology at Oxford, and scientific director of the International Programme on the State of the Ocean describes the main problems affecting the global ocean – and discusses some of the things we could do to address them in this new video. The IPSO has just launched the summary of its forthcoming report on the state of the oceans1 — PDF here. The key findings make sobering reading:

  • Human actions have resulted in warming and acidification of the oceans and are now causing increased hypoxia.
  • The speeds of many negative changes to the ocean are near to or are tracking the worst case scenarios from IPCC and other predictions. Some are as predicted, but many are faster than anticipated, and many are still accelerating.
  • The magnitude of the cumulative impacts on the ocean is greater than previously understood.
  • Timelines for action are shrinking.
  • Resilience of the ocean to climate change impacts is severely compromised by other stressors from human activities, including fisheries, pollution and habitat destruction.
  • Ecosystem collapse is occurring as a result of both current and emerging stressors.
  • The extinction threat to marine species is rapidly increasing.

The bottom line is not pretty:

[...] we now face losing marine species and entire marine ecosystems, such as coral reefs, within a single generation. Unless action is taken now, the consequences of our activities are at a high risk of causing, through the combined effect of climate change, over exploitation, pollution and habitat loss, the next globally significant extinction event in the ocean.

The report recommends immediate action on reduction of CO2 emissions, calls for a long list of actions to restore and protect marine ecosystems, and the formation of a new Global Ocean Compliance Commission to establish rules and regulations for the protection of the “high seas” — the ocean beyond national jurisdictions.

This is a cri du coeur from the world’s ocean scientists. We ignore it at our peril…

[See also Climate Progress, and the NZ Herald. The IPSO site also has more videos from workshop participants, and a great ocean cycles graphic.]

  1. Rogers, A.D. & Laffoley, D.d’A. 2011. International Earth system expert workshop on ocean stresses and impacts. Summary report. IPSO Oxford, 18 pp

The cost of losing coral: no drop in the ocean Bryan Walker Oct 21

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Climatechallenge Perhaps it will register if it’s expressed in money terms. The latest issue of the New Scientist carries an article reporting an estimate of  the loss of the world’s coral reefs at $172 billion per year. The estimate comes from the work of Pavan Sukhdev and colleagues. He’s an economist with the United Nations Environment Programme, and head of a European Commission study called The Economics of Ecosystems and Biodiversity (TEEB). It’s an international project to raise awareness about the economic benefits of biodiversity. I hadn’t come across its work before, but last month it produced a report TEEB Climate Issues Update. It’s a subset of early conclusions relating to climate change and a fuller report will follow next month.

The report addresses what it sees as three critical issues for the Copenhagen negotiations. First, the imminent loss of coral reefs. Second, an early and appropriate agreement on forest carbon.  Third, the compelling cost-benefit case for public investment in ecological infrastructure (especially restoring and conserving forests, mangroves, river basins, wetlands, etc.)

I might examine issues two and three another time, but for this post I’ll stay with coral reefs. Hot Topic covered John Veron’s lecture to the Royal Society a couple of months ago on the parlous state of coral reefs and the worse dangers ahead as ocean acidification worsens. The TEEB report confirms that outlook, quoting the Royal Society statement. But it goes further in indicating what the effects on human welfare will be.

Coral reefs are an integral part of an extensive and vital landscape of coastal ecosystems which includes estuaries, marshes, mangrove forests, dunes, seagrass beds and lagoons. These ecosystems are  biologically highly productive.

Estimates of the total number of people reliant on coral reefs for their food resources range from 500 million to over one billion. Some 30 million of the world’s poorest and most vulnerable people in coastal and island communities are totally reliant on reef-based resources as their primary means of food production, sources of income and livelihoods.

Coral reefs are often likened to ‘oases’ within marine nutrient deserts. Productivity of coral reefs may be many thousands of times higher than in the surrounding open sea. This high productivity makes the reefs critical to the survival of both marine and coastal ecosystems. It is also the underlying reason why they contribute so significantly to human welfare.

The benefits which analyses have so far attempted to quantify include fisheries, shoreline protection, tourism, recreation, and aesthetic value.  But the report says when an ecosystem is close to a critical threshold, it may become impossible to value because of uncertainty or even ignorance about the potential consequences of nonlinear behaviour.

The reported science suggests that anthropogenic emissions have brought the coral reef ecosystem to the brink of potential irreversible collapse. Thus we may have encountered our first major global ecosystem ‘threshold’. At such a point we need to consider the ethical and social dimensions of value as well as the economic. Right now it can be said:

’The imminent demise of tropical coral reefs is predicted to be an extinction event of proportions never before witnessed by humankind. The loss of this critical ecological infrastructure will damage the productivity of global fisheries and the chances of stock survival. It could thus lead to future food crises. It will impoverish over 500 million people who depend on coral reefs for their livelihoods.’

 This section of the report concludes with the rather forlorn urging that global political leaders and their climate negotiators recognize and address the risks of irreversible loss of most of the world’s tropical coral reefs by:

• providing explicitly for coral reefs in measures for coherent climate change adaptation solutions for coastal areas when establishing climate adaptation strategies and agreeing adaptation funds

• working towards agreeing on more ambitious CO2 reduction, that will improve the chances of survival and recovery of coral reefs.

It can be added that less than 350 ppm CO2 concentration is the level that the Royal Society scientists saw as needed to ensure the long-term viability of coral reefs.

Climate compendium: important insights Bryan Walker Sep 28

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Compendium’The Climate Change Science Compendium is a wake-up call. The time for hesitation is over’. So wrote Ban Ki-moon in his foreword to this UN Environment Programme publication released last week. The publication is a review of how climate science has evolved since the Fourth Assessment Report (AR4), and is based on some 400 major scientific contributions in the peer-reviewed literature or from research institutions since the deadline for inclusion in AR4 three years ago. It appears in response to the request of many governments and stakeholders for a snapshot update. Achim Steiner, the Executive Director of the Environment Programme makes it very clear that it doesn’t replace the painstaking rigour of an IPCC process, but he hopes it will provide important insights into the rapidly developing and fast moving realm of climate science so that the choices made by leaders in Copenhagen in December are informed by the best and the latest research available to the international community.

His hopes are well justified. It’s unquestionably an important document. Whether it will be read and absorbed by policy makers is another question, but I can attest that you don’t need to be a scientist to follow it and it leaves policy makers without excuse if they claim they didn’t realise how fast things were moving.

I’ve selected one of the five chapters, on Earth’s ecosystems, to give an idea of how the document presents its findings.

The compendium reports the recent work of researchers by threading frequent reference to their papers into an organised narrative.  This chapter in general terms notes that for both marine and terrestrial ecosystems, the most challenging irreversible climate-related changes include altered chemical characteristics of the ambient environment, inundation of many small islands and low-lying coastal ecosystems by sea-level rise, loss of wetland quantity and quality, and increased aridity in sub-tropical areas. It is these changes and their cumulative effects, proceeding at unprecedented rates, which will profoundly alter ecosystems and result in widespread species extinction. Since the closing date for submissions to the AR4, wide-ranging surveys and analyses suggest that such changes are occurring in all well-studied marine, freshwater, and terrestrial groups. Analysis has been used to eliminate factors such as land-use change, management practices and pollution, leaving robust evidence of anthropogenic climate change as a major cause.

In looking at marine ecosystems in more detail the compendium reports both observations and projections of the effects felt by marine species. A recent study, for example, suggests numerous local extinctions will have occurred by 2050 in ecosystems in subpolar regions, the tropics, and semi-enclosed seas. Conversely the Arctic and Southern Oceans will experience severe species invasions. All told there may be a dramatic species turnover of up to 60 percent.

Ocean acidification studies are reported, with concerns emerging that it may not only result in reduced calcification in coral reefs and other calcareous organisms but also impose a physiological strain on marine animals, impairing their performance and reducing their energy.

In coastal regions increasing extreme events are likely to impact on ecological dynamics and ecosystem functioning.  The tremendous ecological value of mangroves and their rapid degradation rates has been the subject of a number of studies. One study reports how sea level rise presents an imminent threat to freshwater-dependent ecosystems on small oceanic islands.

Moving to terrestrial ecosystems the compendium notes studies pointing to ecosystems committed to long-term change long before any response is observable.

One study, using climate projections based on a relatively low greenhouse-gas emissions scenario, predicted the local loss of at least 10 percent of the vertebrate fauna over much of North and South America, with much larger, over 90 percent, species change for the tundra, Central America, and the Andes Mountains.

Disappearing and novel climates spell ecological changes, since climate is a primary control on species distribution and ecosystem processes. Novel climates are projected to develop primarily in the tropics and subtropics, whereas disappearing climates are concentrated in tropical montane regions and the poleward portions of continents. The complexities of effects on ecosystems are all too apparent, as are the demands they place on ecosystem management. Attempted restoration in what have become essentially novel systems has to be examined closely.

The expansion of the tropical belt and the poleward displacement of the subtropical zones occupied by most of the world’s deserts has a cascading effect on precipitation patterns that determine natural ecosystems, agricultural productivities, and water resources. Shortages of water for agriculture and for basic human needs are threatening communities around the world as evidenced by southeastern Australia and southwestern North America.

The compendium proceeds with reports on studies of a number of regions. The uncertainties of future precipitation patterns in the Sahel, the likelihood of more severe aridity in the Mediterranean than previously estimated, the likelihood of drought becoming the region’s new climatology in southwestern North America, the creeping threat of climate change such as decreased dry season precipitation in the Amazon, the thawing permafrost and increased plant growth in the permafrost areas of the Arctic, the rapid shifts in plant distribution in mountains.

A final section on ecosystem adaptation points to the need to consider multiple interactions and feedbacks, and discusses strategies which have ecological and societal benefits.  The strategies include greenhouse gas reductions primarily in industrialised nations, reduced desertification in arid zones, and reduced deforestation in the tropics.

There’s little in the chapter that anyone following the subject won’t have seen mentioned somewhere in recent times. But the value of the compendium is that it gathers scattered material into a coherent narrative and sources it to the relevant research papers which have informed it. There’s a great deal of scientific work being done and it’s all pointing in the same general direction. Much more will be needed to help us cope with what lies ahead, but there’s already quite enough to declare serious danger.

A solemn warning on coral reefs Bryan Walker Aug 29

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Australian scientist and coral reef expert John Veron reckons there’s a ’great big gorilla in the cupboard’ — advancing ocean acidification. It cleans out reefs, leaving them ’horrible places — dead, empty, slime-covered.’ He paints this grim picture in a lecture given to the Royal Society in London last month. It’s available on line and I have just watched it - twice. His seriousness and the weight of his concern are deeply impressive.  Veron warned that his talk would not be a happy one. Usually his talks on coral are fun. This one wouldn’t be, but ’I’ve never given a more important talk in my life.’ It was highly focused and informative, accompanied throughout by a range of illuminating pictures and graphs. I watched it carefully, anxious to fully understand its import, and have pulled out a rough summary of some of his major points.   

But first a little background to the occasion. The Royal Society is concerned that the  coral reef crisis doesn’t receive the attention it warrants as one of the major indications of threatening climate change disaster.  It has been attempting to remedy that. In July, in combination with the Zoological Society of London and the International Programme on the State of the Ocean, it facilitated a Coral Reef Crisis meeting to identify key thresholds of atmospheric carbon dioxide needed for coral reefs to remain viable.  I’ll reproduce the summary of its findings at the end of this post.  Veron’s lecture was hosted as part of the event.

David Attenborough introduced Veron with some general remarks on the key role of coral reefs in ocean ecosystems, their complexity but also their fragility and the ease with which they can be damaged. He observed that deterioration is under way and continuing. The question is whether we can prevent it getting even worse. Veron he described as one of the great authorities of the world on coral and stressed that his knowledge was first-hand and authoritative.

Veron began with some general background on coral reefs. Their uniqueness is defined by several factors: they live at the interface of atmosphere and ocean, which is physically and chemically stressful; they are geological structures yet they are alive; they are closely attuned to the hostile environment in which they exist, dependent on light as trees are, sensitive to optimum temperature (31 degrees in Great Barrier), and dependent on the carbonate chemistry of the oceans.

Coral reefs are nature’s historians. Whether in fossil form or living their growth layers not only indicate rate of growth but also contain information about the environment in which they grew. Ancient reefs uplifted in land, of which he had some great pictures, preserve this information for us to read.

 He went on to talk about the great mass extinction events, in which corals were always deeply affected, in the Permian to the point of total extinction and in others to near extinction. 

The precariousness of their habitat makes them extremely sensitive to climate change. The mass extinctions are closely related to the carbon cycle, particularly to carbon dioxide and ocean acidification, with methane sometimes playing a part. In the present he pointed to current levels of carbon dioxide as indicating that we have broken out of the ice age fluctuation patterns in a big way.

He explained the mass bleaching phenomenon. Coral is dependent on the algae which live in its tissues. Overheating — just a little — causes the algae to produce too much oxygen which kills corals. This is something which hasn’t happened for millions of years. It started only in the 1980s.  Mass bleaching events can turn coral to rubble, though if the ocean conditions are right it will start to grow again.  He looks at carbon dioxide concentrations and what they have meant for the Great Barrier Reef (GBR) as representative of all reefs. At 320 parts per million there was some mass bleaching, but only in patches.  At 350 ppm there was a lot of mass bleaching all over the GBR and many other reefs as well. Today at 387 ppm there is compounding long-term degradation on the GBR.  Held at this level indefinitely the GBR would slowly decline.  The upper 20 or 30 metres would gradually become more or less rubble. At 400 ppm there will be more severe weather events affecting the reef and severe bleaching will occur, mainly during El Nino cycles. 450 ppm will cause severe bleaching most years, irrespective of the natural cycles. At 500 ppm there won’t be anything left to bleach.  

Ocean acidification, is a ’very, very serious thing indeed’ not only for corals but for anything that forms a carbonate skeleton. We have every reason to worry about it. He showed a picture of what a reef looks like when acidification takes hold. Horrible is certainly the word.

 ’I hate doing this job,’ he inserted here. 

The future is all about synergies, the way various factors combine to produce the effect on coral reefs. In 25 years at 450 ppm, plus acidification, plus warmer temperature, there will be mass bleaching most years, which will mean very extensive habitat destruction which in turn will mean extinctions start.

In 50 years time at 600 ppm, plus further acidification, plus even warmer temperatures, plus sea level rise of 400 mms, we get the following:  no coral will occur shallower than 10 metres, calcification of anything will be marginal, extinctions will be extensive, reefs will be highly erosional, there will be no shallow water habitats, coralline algae which hold the reefs together won’t exist, there will be major impacts from sea-level rise and super-cyclones.  At that point we are heading for a mid-Eocene climate and accompanying extinctions. Certainly our carbon dioxide levels will not be as high as then, but we are increasing them so fast that the carbon dioxide is remaining in the surface skin of the oceans; it is not getting injected down into deep water where it can be buffered by the carbonates which will de-acidify water. 

In 75 years from now at 800 ppm, plus further acidification effects, plus 5 degrees warming: some corals may survive in askeletal form, but there will be no reefs, molluscs will be in sharp decline and there will be huge biodiversity loss.

100 years ahead it will be runaway climate change which is producing the carbon dioxide. Corals will be extinct or askeletal, all other taxa will be going extinct, reefs will be wave-washed geological structures.  The sixth mass extinction, such as we had in KT will be under way. “How can it not be?”  One ecosystem after another will tumble, an extinction not just of corals but led by corals.

’However much we want to talk about the economic problems associated with climate change they pale, they’re trivial compared to the problems created if we start up a runaway carbon dioxide climate change explosion.’ (Take note John Key and Nick Smith and all the others who cheer them on.)

A reminder towards the end: 450 ppm will bring on the demise of the GBR.  ’Not a skerrick of doubt about it.’

It’s a solemn warning from a scientist who clearly wishes he didn’t have to deliver it but can do no other.  It’s not surprising that the document produced by a working group in association with the occasion should be plain spoken in its conclusion:  

Coral reefs speak unambiguously about climate change. Abrupt carbonising of the environment will destroy carbonate-based ecosystems. Changes to water chemistry will flow on to all marine ecosystems as the oceans turn hostile to a high proportion of marine life. This is the path of mass extinctions, the most destructive events in all Earth history.

 The Earth’s atmospheric CO2 level must be returned to <350ppm to reverse this escalating ecological crisis and to 320ppm to ensure permanent planetary health. Actions to achieve this must be taken urgently. The commonly mooted best case target of 450ppm and a time frame reaching to 2050 will plunge the Earth into an environmental state that has not occurred in millions of years and from which there will be no recovery for coral reefs and for many other natural systems on which humanity depends.


PS  I might be able to save our denialist commenters a bit of time if I report here Veron’s comments on Ian Plimer’s book: “Every original statement Plimer makes in the book on coral and coral reefs is incorrect…[he] serve[s] up diagrams from no acknowledged source, diagrams known to be obsolete and diagrams that combine bits of science with bits of fiction.”

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