Tag Archives: Climate Change

450 ppm must become the catch-cry for serious political action on climate change

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Ben McNeil and Richard Matear from the University of New South Wales have just published a very important article in the Proceedings of the National Academy of United States (Link to full text).  This paper further emphasises the critical importance of keeping carbon dioxide levels lower than 450 ppm, as Chris McGrath highlighted earlier this week.  While politicians fumble over the issue of gaining effective control of carbon dioxide, there is growing evidence that we must keep CO2 levels below 450 ppm or be prepared to suffer serious consequences to life on Earth.

This is a significant paper which highlights the importance of understanding the dynamics of carbonate equilibrium in seawater in our greenhouse world.   Rapid acidification of our oceans, as we now know, is an important impact of rising anthropogenic carbon dioxide in the atmosphere.   More importantly, this study confirms the worrying conclusion that calcification in the worlds oceans is in big trouble if atmospheric levels of carbon dioxide exceed 450 ppm.   We came to a similar conclusion for coral reefs in a recent article in Science magazine (Hoegh-Guldberg et al 2007) – finding as well that net calcification on coral reef ecosystems dwindles to zero at about 450-500 ppm.   The implications of failing ecosystems as important as those in the Southern Ocean are considerable. Rigorous observations such as these should spur our political leaders to make much more decisive steps to curb the rise of carbon dioxide in the atmosphere – anything less will be disastrous.

McNeil & Matear (2008) Southern Ocean acidification: A tipping point at 450-ppm atmospheric CO2. PNAS

Southern Ocean acidification via anthropogenic CO2 uptake is expected to be detrimental to multiple calcifying plankton species by lowering the concentration of carbonate ion (CO32-) to levels where calcium carbonate (both aragonite and calcite) shells begin to dissolve. Natural seasonal variations in carbonate ion concentrations could either hasten or dampen the future onset of this undersaturation of calcium carbonate. We present a large-scale Southern Ocean observational analysis that examines the seasonal magnitude and variability of CO32- and pH. Our analysis shows an intense wintertime minimum in CO32- south of the Antarctic Polar Front and when combined with anthropogenic CO2 uptake is likely to induce aragonite undersaturation when atmospheric CO2 levels reach ~450 ppm. Under the IPCC IS92a scenario, Southern Ocean wintertime aragonite undersaturation is projected to occur by the year 2030 and no later than 2038. Some prominent calcifying plankton, in particular the Pteropod species Limacina helicina, have important veliger larval development during winter and will have to experience detrimental carbonate conditions much earlier than previously thought, with possible deleterious flow-on impacts for the wider Southern Ocean marine ecosystem. Our results highlight the critical importance of understanding seasonal carbon dynamics within all calcifying marine ecosystems such as continental shelves and coral reefs, because natural variability may potentially hasten the onset of future ocean acidification.

Plot of the year in which the onset of wintertime undersaturation occurs under equilibrium conditions (McNeil & Matear 2008)

Great Barrier Reef ‘could adapt to avoid climate doom’

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“Great Barrier Reef ‘could adapt to avoid climate doom” (1/11/2008) missed the bigger picture. While I agree that corals have a capacity to adapt to warming waters, it is my firm view that the rate of adaption will be too slow to prevent major loss of biodiversity at current levels and trends in greenhouse gas emissions.

Serious threat to the future of the Reef is not a distant theoretical possibility. The Great Barrier Reef has already had two near misses. Unprecedented, widespread coral death from bleaching occurred in 1998 and 2002. About 50 per cent of the Reef’s corals bleached over a very hot summer with most corals then recovering when peak temperatures eased (only five per cent died).

The Great Barrier Reef’s capacity to survive this mounting pressure is through building the Reef’s health and its ability to repair itself. Poor quality water not only contributes to the risk of bleaching it can also inhibit the corals ability to recover after a bleaching event. Australians are responding to this challenge. We are cleaning up our rivers that now carry excess fertiliser and pesticides; restoring coastal wetlands that not only catch excess silt from floods but provide nursery habitats for many species of fish; preventing pollution from sewage; preventing overfishing of top predators such as sharks and avoiding the accidental loss of iconic species such as dugong and turtle.

The UN report “Confronting Climate Change: Avoiding the Unmanageable and Managing the Unavoidable” captures the  essence of this global problem. The strongest possible action on emissions reduction is needed on a global scale, and local action is needed to help maintain the Reef’s ability to withstand the inevitable and increasing pressure it faces each summer.

R  Reichelt
Chairman, Great Barrier Reef Marine Park Authority

Avoiding confusion for stabilization targets for climate change and ocean acidification

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Long Cao and Ken Caldeira from the Carnegie Institution at Stanford have a new paper in Geophysical Research Letters on atmospheric carbon dioxide (CO2) stabilization and ocean acidification, a critical topic for current marine science and public policy. Hoegh-Guldberg et al (2007) illustrated the essential chemistry at the heart of this problem as follows:

Essentially, as CO2 dissolves into the oceans it forms an acid leading to decreased coral calcification and growth through the inhibition of aragonite formation (the principal crystalline form of calcium carbonate deposited in coral skeletons). The increased acidity caused by increasing atmospheric CO2 is known as ocean acidification and it is a separate, though inter-related, phenomenon to increased temperatures caused by CO2 acting as a greenhouse gas.

Cao and Caldeira (2008) found “that even at a CO2 stabilization level as low as 450 ppm, parts of the Southern Ocean become undersaturated with respect to aragonite [and] therefore, preservation of existing marine ecosystems could require a CO2 stabilization level that is lower than what might be chosen based on climate considerations alone.”

These results are similar to Hoegh-Gulberg et al (2007), who concluded “… contemplating policies that result in [CO2]atm above 500 ppm appears extremely risky for coral reefs and the tens of millions of people who depend on them directly, even under the most optimistic circumstances.”

Hoegh-Guldberg et al (2007) illustrated the expected the conditions of coral reefs under different levels of atmospheric carbon dioxide and temperature increases as follows:

These findings are very significant for governments around the world and other policy-makers because much of the current policy debate on climate change focuses on stabilizing greenhouse gases, including carbon dioxide, between 450-550 parts per million carbon dioxide equivalents, thereby allowing a rise in mean global temperatures of around 2-3°C (e.g. Stern 2007; Garnaut 2008; Australian Treasury 2008).

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“Great Barrier Reef could adapt to climate change, scientists say” – Facts, fallacies and fanciful thinking.

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The Australian newspaper published an article this weekend entitled “Great Barrier Reef could adapt to climate change, scientists say”.

THE prediction of a prominent marine biologist that climate change could render the Great Barrier Reef extinct within 30 years has been labelled overly pessimistic for failing to account for the adaptive capabilities of coral reefs.

University of Queensland marine biologist Ove Hoegh-Guldberg said yesterday that sea temperatures were likely to rise 2C over the next three decades, which would undoubtedly kill the reef.

But several of Professor Hoegh-Guldberg’s colleagues have taken issue with his prognosis.

Andrew Baird, principal research fellow at the Australian Research Council’s Centre for Excellence for Coral Reef Studies, said there were “serious knowledge gaps” about the impact rising sea temperatures would have on coral.

“Ove is very dismissive of coral’s ability to adapt, to respond in an evolutionary manner to climate change,” Dr Baird said.

“I believe coral has an underappreciated capacity to evolve. It’s one of the biological laws that, wherever you look, organisms have adapted to radical changes.”

Dr Baird acknowledged that, if left unaddressed, climate change would result in major changes to the Great Barrier Reef.

“There will be sweeping changes in the relative abundance of species,” he said. “There’ll be changes in what species occur where.

“But wholesale destruction of reefs? I think that’s overly pessimistic.”

Dr Baird said the adaptive qualities of coral reefs would mitigate the effects of climate change.

I must say I’m a little amazed that Andrew Baird has come out with such poorly supported statements.  In fact, his conclusions seem to depend almost entirely on his personal opinion!  The argument that corals are able to magically “adapt” over one or two decades to climate change (even though their generation times are often longer) has come up many times over the years – always, with a complete dearth of evidence to support it.

I wrote to Andrew Baird yesterday, to try and understand if there was something that he knew that I might have missed in the scientific lecture.  In response, Andrew sent me a recent article published by Jeff Maynard and himself (Maynard et al 2008).

Unfortunately, the article is an opinion piece (a bit like the newspaper article) that is poorly supported by anything but the most scant evidence (if you could actually call it that) from literature.   I have responded to these types of articles before, but frustrated, here we go again:

Maynard et al (2008) state the following as important evidence that corals can adapt to changes in the environment, and therefore that they can adapt to the current very rapid changes in ocean temperature and acidity.

“..geographic variation in bleaching thresholds within species, sometimes over scales <100km, provides circumstantial evidence for ongoing evolution of temperature tolerance between both species and reef”

Let me start by saying that no credible biologist would doubt the role of evolution in the shaping of the physiology and ecology of corals with respect to temperature.  Biological populations evolve in response to stress.  However, the mere observation of geographic variation in thermal tolerance, does not give any hint  about the rates or the length of time that these changes have taken to occur.  Importantly, this statement does not equate to evidence that thermal tolerance can evolve in ecological time.  The only way that Andrew Baird could convince anyone of this particular somewhat fanciful leap of logic is to present data that show that coral populations can rapidly evolved in the period of years.  They can’t, and they haven’t.

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“Estate agents told me not to talk: climate expert”

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ABC News, 29th October 2008

A climate change scientist says real estate agents have threatened to make his life difficult if he continues to publish research about how vulnerable particular properties are to rising sea levels and coastal erosion.

Professor Andrew Pitman works at the Climate Change Research Centre at the University of New South Wales.

He says real estate agents do not like potential buyers asking questions about climate change based on his research.

Professor Pitman has told the ABC’s Local Radio that several agents have asked him to stop talking about how vulnerable certain properties are.

“More explicitly [they said] ‘We’re nervous about our particular market niche in a particular suburb’,” he said.

“And, ‘We are going to start making your life difficult if you keep pointing to climate change affecting our particular location’.”

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Will we leave the Great Barrier Reef for our children?

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Amidst the current policy debate in Australia on climate change is a surreal argument that policies that will destroy the Great Barrier Reef (GBR) are acceptable and economically rational. Ross Garnaut was alive to the damage to the GBR when saying Australia should initially aim for a global consensus to stabilise greenhouse gases in the atmosphere at 550 parts per million. Garnaut (2008a: 38) was brutally frank in his supplementary draft report:

“The 550 strategy would be expected to lead to the destruction of the Great Barrier Reef and other coral reefs.”

His final report does not shy away from this conclusion (Garnaut 2008b).

The Australian and Queensland governments have always silently avoided this point when explaining the costs and benefits of their climate policies. Neither has ever stated a stabilisation target for the rise in global temperatures or greenhouse gases. To do so would expose them to the criticism that their policies will not save the GBR or a host of other ecosystems.

Garnaut’s frank admission reflects the findings of research of the impacts of climate change to the GBR since mass coral bleaching occurred globally in 1998 and 2002. Rising sea temperatures and increasing acidity of the oceans due to our use of fossil fuels are now well-recognized as major threats to coral reefs and the marine ecosystem generally in coming decades.

Coral bleaching and partial recovery on Pelorus Island, GBR: (a) 1998; (b) 2002; and (c) 2004. Source: Schuttenberg H and Marshall P, A Reef Manager’s Guide to Coral Bleaching (GBRMPA, Townsville, 2006), p12.

Coral bleaching and partial recovery on Pelorus Island, GBR: (a) 1998; (b) 2002; and (c) 2004. Source: Schuttenberg H and Marshall P, A Reef Manager’s Guide to Coral Bleaching (GBRMPA, Townsville, 2006), p12.

In relation to coral bleaching the IPCC (2007b: 12) found that:

“Corals are vulnerable to thermal stress and have low adaptive capacity. Increases in sea surface temperature of about 1 to 3°C are projected to result in more frequent coral bleaching events and widespread mortality, unless there is thermal adaptation or acclimatisation by corals.”

The findings of the IPCC suggest that a rise of 1°C in mean global temperatures and, correspondingly, sea surface temperatures above pre-industrial levels is the maximum that should be aimed for if the global community wishes to protect coral reefs. The range of 1-3°C is the danger zone and 2°C is not safe. Supporting this conclusion Ove Hoegh-Guldberg and his colleagues concluded in a review of the likely impacts of climate change to the GBR edited by Johnson and Marshall (2007: 295):

“Successive studies of the potential impacts of thermal stress on coral reefs have supported the notion that coral dominated reefs are likely to largely disappear with a 2°C rise in sea temperature over the next 100 years. This, coupled with the additional vulnerability of coral reefs to high levels of acidification once the atmosphere reaches 500 parts per million [CO2], suggests that coral dominated reefs will be rare or non-existent in the near future.”

The IPCC’s (2007a: 826) best estimate of climate sensitivity found that stabilising greenhouse gases and aerosols at 350 parts per million carbon dioxide equivalents (ppm CO2-eq) would be expected to lead to a rise in mean global temperatures of 1°C, stabilising at 450 ppm CO2-eq will lead to a rise of 2°C, and stabilising at 550 ppm CO2-eq will lead to a rise of 3°C.

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Reefs in trouble – The real root cause

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Yellow band disease

Dr. Stephen Jameson recently published a provocative essay in the Marine Pollution Bulletin that has stimulated considerable debate among reef scientists and conservationists, especially on the coral list server.  His goal was to drill down to the ultimate social/political cause of reef decline, beneath the  proximate environmental causes reef scientists study:

The real root cause of coral reef decline is not carbon dioxide emissions, rising sea surface temperatures, ocean acidification, coral disease, over fishing, destructive fishing techniques, eutrophication, sedimentation, sewage, herbicides, pesticides, African dust, increasing human populations or any of the other individual or synergistic combinations of stressors affecting coral reefs locally,regionally or globally – these are only symptoms of much bigger and more profound problem.  At its core, the real root cause of coral reef decline, when objectively looking at the evidence, seems to be attributable to innate human species behavior characteristics determined by how we are genetically hard-wired.

Dr. Jameson said, “I wrote it in response to the International Year of the Reef/Science Magazine issue “Reefs in Trouble” (14 Dec 2007) that, in my opinion, missed a golden opportunity to address the “real” root cause of “Reefs in Trouble””.  And what he is really trying to get at is whether large groups of humans are capable of cooperatively managing a complex system like a reef.  “Do we really have the capability, when operating as a very large group such as a nation or group of nations, to govern ourselves effectively and live sustainably with our environment?”  There is lots of evidence that we can do so when in small, communal groups, but why when we organize as nations do things seem to go awry?

Our every day experience in the United States (and in many other countries) informs us that the state of our governance, where wealthy business and special interests use campaign financing, lobbying, and media control to manipulate government policy and public perceptions is not a viable system for conserving coral reefs or for sustainable living because it is predicated on the fact that; ‘‘He who owns the political trump card wins”

It is a great system for creating corporate profit and socializing expense at global cost, but it does not produce clean air and water in natural environments or enhance biodiversity.

Stephen is also asking: can a social, cultural community consciousness evolve into a global consciousness? There are several layers to the answer.  As he argues, there may be genetically or socially based behavioral limitations that have and will preclude the development of a new form of global altruism.  There are also complex competing forces that have designed a governance system incompatible with the conservation of species and ecosystems half way around the world.  But I think a very deep perception gap is another key problem.  Even in wealthy nations, where we have the luxury of worrying about such matters, I am struck by how few people recognize that their actions can affect other people in far away nations.  Many people I talk to in the US are aware of climate change and the decline of coral reefs, but have a hard time comprehending that their choices and behaviors could actually be causing problems for people and corals in the south Pacific.  Making people, especially policy makers, aware of the striking effects we are having on all the world’s oceans, including ocean chemistry and temperature, will be a critical battle in the broader campaign to address the real root cause.

Citation

Jameson SC (2008) Guest editorial: Reefs in trouble ­ the real root cause. Marine Pollution Bulletin 56(9):1513-1514

Scientists urge Prime Minister Kevin Rudd to crack down on climate change issues

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The Age is reporting on an open letter to the Australian Prime Minister Keven Rudd, urging the PM to make strong cuts in Australia’s greenhouse gas emissions by 2020. The letter, written by myself and 15 other Austalian scientists who contributed to the IPCC report, was released on the eve of the final report by the Garnaut review on climate change. In essence, we disagree with the recent advice by Professor Garnaut to make a slower start in cutting emissions (“Targets and Trajectories“ – a 10% reduction by 2020), and strongly advocate the PM to reduce emissions by at least 25% bellow 1990 levels by 2020:

“As a group of Australia’s leading climate change scientists, we urge you to adopt this target as a minimum requirement for Australia’s contribution to an effective global climate agreement,” the letter states.

“Failure of the world to act now will leave Australians with a legacy of economic, environmental, social and health costs that will dwarf the scale of national investment required to address this fundamental problem”.

The scientists who signed the letter are Australia’s world-recognised experts on climate change, including Dr John Church, a leading authority on sea-level rise who recently stepped down as chairman of the joint scientific committee of the World Climate Research Program. Dr Church is also a senior CSIRO researcher, but he and other CSIRO scientists signed the letter as individuals.

Also among the signatories are Dr Roger Jones, from CSIRO, who is currently advising the federal Treasury and Professor Garnaut’s climate change review; Professors Nathan Bindoff and David Karoly, who worked on the most recent IPCC reports; Professor Tony McMichael from the Australian National University, who advised the IPCC on the human health impacts of climate change; Professor Matthew England, joint director of the Climate Change Research Centre at the University of New South Wales; and Professor Ove Hoegh-Guldberg, an expert on climate change and the Great Barrier Reef.

On the back of the report is a recent poll by the Lowy institute, which is quite an intriguing read. Whilst the overall message is a positive one in that Australians want action on climate change, the feeling is that it cannot come at a cost to jobs or at a financial cost. Out of the 1001 people, 19% surveyed said they would be willing to pay >$21 per month ontop of their electricity bill to help solve climate change, and 20% would pay between $11-20. In contrast, 32% would be willing to pay between $1-10 per month, whilst 32% of people surveyed were not prepared to pay anything at all.

Interestingly, 64% of responants believed that the Kyoto Protocol hasn’t solved the issue of climate change but was “a step in the right direction”, yet 26% believed it was “purely symbolic”. On the bright side, if this poll is a genuine reflection of Australian attitudes, 73% would prefer Barack Obama to become the next president of the United States, whilst John McCain recieved only a 16% response.

Global CO2 emissions exceed IPCC worst case scenario

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A comprehensive report released today by the Global Carbon Project contains the grim news that global CO2 emissions are exceeding the most pessimistic IPCC emissions scenario. The annual mean growth of atmospheric CO2 increased from 2.0 ppm (parts per million) during the first half of the decade and from 1.8 ppm in 2006,  to 2.2 ppm in 2007.  This increase in the growth of emissions makes IPCC stabilization scenarios of 450 ppm – 650 ppm doubtful.

Annual mean growth rates of atmospheric CO2 concentration.

The report “Carbon budget and trends 2007” is a sobering synthetic analysis of the world’s carbon budget, including the sources and sinks of CO2 parsed by nation, continent, human activity and ecosystem.

Despite the increasing international sense of urgency, the growth rate of emissions continued to speed up, bringing the atmospheric CO2 concentration to 383 parts per million (ppm) in 2007.  Anthropogenic CO2 emissions have been growing about four times faster since 2000 than during the previous decade, despite efforts to curb emissions in a number of Kyoto Protocol signatory countries.

Dr. Pep Canadell, executive director of the Global Carbon Project said “This new update of thecarbon budget shows the acceleration of both CO2 emissions and atmospheric accumulationare unprecedented and most astonishing during a decade of intense international developments to address climate change.”

Fossil Fuel Emissions: Actual vs. IPCC Scenarios

Some of the report highlights are excerpted below:

Atmospheric CO2 growth: Annual mean growth rate of atmospheric CO2 was 2.2 ppm per year in 2007 (up from 1.8 ppm in 2006), and above the 2.0 ppm average for the period 2000-2007. The average annual mean growth rate for the previous 20 years was about 1.5 ppm per year. This increase brought the atmospheric CO2 concentration to 383 ppm in 2007, 37% above the concentration at the start of the industrial revolution (about 280 ppm in 1750).  The present concentration is the highest during the last 650,000 years and probably during the last 20 million years. [ppm =  parts per million].

Regional fossil fuel emissions
The biggest increase in emissions has taken place in developing countries, largely in China and India, while developed countries have been growing slowly. The largest regional shift was that China passed the U.S. in 2006 to become the largest CO2 emitter, and India will soon overtake Russia to become the third largest emitter. Currently, more than half of the global emissions come from less developed countries. From a historical perspective, developing countries with 80% of the world’s population still account for only 20% of the cumulative emissions since 1751; the poorest countries in the world, with 800 million people, have contributed less than 1% of these cumulative emissions.

Conclusions: Anthropogenic CO2 emissions have been growing about four times faster since 2000 than during the previous decade, and despite efforts to curb emissions in a number of countries which are signatories of the Kyoto Protocol. Emissions from the combustion of fossil fuel and land use change reached the mark of 10 billion tones of carbon in 2007. Natural CO2 sinks are growing, but more slowly than atmospheric CO2, which has been growing at 2 ppm per year since 2000. This is 33% faster than during the previous 20 years. All of these changes characterize a carbon cycle that is generating stronger climate forcing and sooner than expected.

Citation

Global Carbon Project (2008) Carbon budget and trends 2007, [www.globalcarbonproject.org, 26 September 2008]”

MPAs and climate change II: study finds no-take reserves do not increase reef resilience

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PI Nick Graham surveying a high coral cover reef.

PI Nick Graham surveying a high coral cover reef.

Some coral reefs scientists have argued (and prayed) that marine reserves (no-take MPAs) could limit the impacts of climate change on populations of reef-building corals.  The idea is that by maintaining healthy food webs and herbivore populations, reef managers can prevent seaweed blooms that can kill juvenile corals.  Restricting fishing would thus increase reef resilience (which ecologists define as the return rate of an ecological system to its baseline state following a disturbance).  Unfortunately, a new study tempers such wishful thinking.

The study (Graham et al. 2008 published on August 27 in the open access journal PloS One) indicates that marine reserves have no effect on coral resilience to ocean warming.

Approximately 45% of coral cover in the Indian Ocean was lost in 1998 due to temperature-related coral bleaching.  To compare coral loss within and outside of reserves, the team resurveyed 66 reefs in the Indian Ocean that had originally been surveyed before the 1998 mass bleaching event.  The surveyed sites included reefs within nine reserves in four countries.

The results indicated that “A greater proportion of [marine reserves] (71%) than fished (42%) locations showed significant declines in coral cover over the study period. There was no evidence to suggest the percent change in coral cover differed between [marine reserves] and fished areas, and in some cases declines were significantly greater in [marine reserves]”

This is an important study in coral reef ecology.  As a believer in Macroecology and a long-time disciple of James Brown (the desert ecologist, not the King of Funk) I think such a regional-scale, carefully implemented approach could be used to answer many other key questions in reef ecology.  Having read hundreds of monitoring studies while building a database of >10,000 reef surveys, I can attest that there are few targeted macroecological reef studies of this scope.  There are some monitoring programs this large.  But few studies of this scale are designed and implemented to answer a specific question.  Although the macroecological approach is rarely employed (due to obvious financial and logistical constraints), it certainly isn’t new.  Terry Hughes (Hughes 1994 Science) applied it by resurveying nine reefs on the north coast of Jamaica after a variety of disturbances wiped out corals and enabled macroalgae to become the dominant benthic organism.  Even earlier, Endean and Stablum surveyed dozens of reefs across the GBR in the late 1960s and early 1970s to assess the impact of and recovery from a regional crown-of-thorns starfish outbreak.

I imagine critics of Graham et al. 2008 and it’s implications could argue that many or most tropical marine reserves are not well-managed and that they might increase resilience if enforced.  This would be a fair point, but given the political and socio-economic realities of the region, poaching might be difficult or impossible to eliminate.  So to paraphrase Donald Rumsfeld, we might just have to conserve reefs with the marine reserves we have, not the marine reserves we want.

Change in coral cover at sites across the western Indian Ocean

Change in coral cover at sites across the western Indian Ocean. Green and red symbols represent increases and decreases in coral cover respectively. Symbols with solid borders are sites in marine reserves. Data represent 66 sites across the region. Numbers in key (size of bubble) are percent changes between mid 1990s and 2005.