Monthly Archives: April 2009

“Climate change hitting entire Arctic ecosystem, says report”

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arcticpic460The Guardian, 28th April 2008

Extensive climate change is now affecting every form of life in the Arctic, according to a major new assessment by international polar scientists. In the past four years, air temperatures have increased, sea ice has declined sharply, surface waters in the Arctic ocean have warmed and permafrost is in some areas rapidly thawing. In addition, says the report released today at a Norwegian government seminar, plants and trees are growing more vigorously, snow cover is decreasing 1-2% a year and glaciers are shrinking.

Scientists from Norway, Canada, Russia and the US contributed to the Arctic monitoring and assessment programme (Amap) study, which says new factors such as “black carbon” – soot – ozone and methane may now be contributing to global and arctic warming as much as carbon dioxide. “Black carbon and ozone in particular have a strong seasonal pattern that makes their impacts particularly important in the Arctic,” it says.

The report’s main findings are:

Land

Permafrost is warming fast and at its margins thawing. Plants are growing more vigorously and densely. In northern Alaska, temperatures have been rising since the 1970s. In Russia, the tree line has advanced up hills and mountains at 10 metres a year. Nearly all glaciers are decreasing in mass, resulting in rising sea levels as the water drains to the ocean.

Summer sea ice

The most striking change in the Arctic in recent years has been the reduction in summer sea ice in 2007. This was 23% less than the previous record low of 5.6m sq kilometres in 2005, and 39% below the 1979-2000 average. New satellite data suggests the ice is much thinner than it used to be. For the first time in existing records, both the north-west and north-east passages were ice-free in summer 2008. However, the 2008 winter ice extent was near the year long-term average.

Greenland

The Greenland ice sheet has continued to melt in the past four years with summer temperatures consistently above the long-term average since the mid 1990s. In 2007, the area experiencing melt was 60% greater than in 1998. Melting lasted 20 days longer than usual at sea level and 53 days longer at 2-3,000m heights.

Warmer waters

In 2007, some ice-free areas were as much as 5C warmer than the long-term average. Arctic waters appear to have warmed as a result of the influx of warmer waters from the Pacific and Atlantic. The loss of reflective, white sea ice also means that more solar radiation is absorbed by the dark water, heating surface layers further.

Black carbon

Black carbon, or soot, is emitted from inefficient burning such as in diesel engines or from the burning of crops. It is warming the Arctic by creating a haze which absorbs sunlight, and it is also deposited on snow, darkening the surface and causing more sunlight to be absorbed.

Climate change – is the ‘missing science’ really missing?

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The now infamous skeptic Professor Ian Plimer  launched his seventh book last week, titled “Heaven and Earth, Global Warming: The Missing Science“. Apparently Plimer, a Professor of Mining and Geology from the University of Adelaide is aiming to ‘refute every scientific argument that humans are responsible for global warming’. Remember that this is the same Professor who believes that “… the Great Barrier Reef will benefit from rising seas, that there is no correlation between carbon dioxide levels and temperature, that only 0.1 % of carbon dioxide emissions are due to human activities, and that 96% of the greenhouse effect is due to water vapour.”

Professor Plimer said his book would “knock out every single argument we hear about climate change”, to prove that global warming is a cycle of the Earth.

“It’s got nothing to do with the atmosphere, it’s about what happens in the galaxy.

“You’ve got to look at the whole solar system and, most importantly, we look back in time.

“There’s a lot of talk out there that there isn’t any science that supports my view, but I have 2111 scientific references in this book.”

Following the booklaunch, the Australian newspaper published an entertaining read titled ‘Climate sceptics ready to storm heaven with earth’s geological history‘, detailing the plight of Dr Barry Brook, who as the head of Adelaide University’s Research Institute for Climate Change and Sustainability is at the opposite end of the spectrum when it comes to academic debate (apparently Dr Brook is ill-fated enough to share a hallway just metres away from the good Professor Plimer)

Defending climatologists and thousands of other scientists, Barry Brook, who heads Adelaide University’s Research Institute for Climate Change and Sustainability, poured cold water on Professor Plimer’s book and said his colleague had only used “selective evidence” when quoting more than 200 scientists and from peer-reviewed papers.

Professor Plimer’s “stated view of climate science is that a vast number of extremely well respected scientists and a whole range of specialist disciplines have fallen prey to delusional self-interest and become nothing more than unthinking ideologues”, he said.

“Plausible to conspiracy theorists, perhaps, but hardly a sane world view, and insulting to all those genuinely committed to real science.”

Is the ‘missing science’ really missing? Over at Brave New Climate, Professor Brook systematically dismantles Plimer’s arguments:

Ian Plimer’s book is a case study in how not to be objective. Decide on your position from the outset, and then seek out all the facts that apparently support your case, and discard or ignore all of those that contravene it. He quotes a couple of thousand peer-reviewed scientific papers when mounting specific arguments. What Ian doesn’t say is that the vast majority of these authors have considered the totality of evidence on the topic of human-induced global warming and conclude that it is real and a problem. Some researchers have show that the Earth has been hotter before, and that more CO2 has been present in the atmosphere in past ages. Yes, quite — this is an entirely uncontroversial viewpoint. What is relevant now is the rate of climate change, the specific causes, and its impact on modern civilisation that is dependent, for agricultural and societal security, a relatively stable climate. Ian pushes mainstream science far out of context, again and again.

Perhaps most telling is the following ABC radio interview with Kurt Lambeck, Professor of Geophysics at Australian National University, and the President of the Australian Academy of Science. Lambeck was extensively cited by Plimer in one of the chapters of “Heaven and Earth, Global Warming”, and he doesn’t appear to be very happy at how Plimer has interpreted his work:

[audio:http://67.220.225.10/~clim2165/cs/audio/plimer.mp3]

Seems like Plimer has adopted the Bob Carter obfuscation approach to climate skepticism. I’m surprised that his words carry so much weight, and echo Lambeck’s concern that “Heaven and Earth, Global Warming” has ‘… the potential to derail any political commitment to action on climate change in Australia’.

A world without fish – what would it take?

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“A Sea Change – Imagine a World Without Fish” is a recently released documentary film about ocean acidification, the little-known ugly sister of global warming. The film website www.aseachange.net explains it “… aims not only to educate viewers about the science of our rapidly-changing oceans, but also to engage them on accessible terms.”
The full film was shown to the European Geosciences Union 2009 conference on 27 April 2009, a podcast of which is available here. After a 2 minute introduction, the film lasts for 19 minutes followed by an illuminating question and answer session.

Caribbean fish decline in the wake of coral collapse?

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A new study in Current Biology (some really interesting coral related stuff being published there lately) by Michelle Paddack and colleagues (Paddack et al 2009) documents a region-wide decline in reef associated fish in the Caribbean. The authors conducted a meta-analysis on a substantial amount of fisheries-independent, time-series data on Caribbean fish densities. Fish densities seem to have been pretty stable from the mid-50s until the mid-90s, to then exhibit significant negative rates of change during the past 10 years. What is striking is the generality of the decline that has occured the past decade, across the whole region (see figure below)

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Recorded declines in fish densities across five Caribbean sub-regions 1996-2007

Differences in fished and non-fished species were non-significant. This leads the authors to speculate that fishing is not the main driver of these changes (although certainly it plays a part). Rather, as has been documented in the western Indian Ocean, these changes in fish communities could be a response to the substantial losses of coral cover which have occurred in the Caribbean the past decades. A wicked problem, primarily for managers and communities dependent on fisheries, is that changes in fish communities seem to manifest themselves as a form of “degradation debt” – that is, there is a substantial time-lag between changes in the underlying benthic community and the response of fish communities.

Resilient ‘super reefs’ a priority for conservation efforts

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ScienceDaily, 23rd April 2009

The Wildlife Conservation Society announced today a study showing that some coral reefs off East Africa are unusually resilient to climate change due to improved fisheries management and a combination of geophysical factors. WCS announced the results of the study at the International Coral Reef Initiative (ICRI), which is meeting this week in Phuket, Thailand.

The study, published in the online journal Aquatic Conservation: Marine and Freshwater Ecosystems, provides additional evidence that globally important “super reefs” exist in the triangle from Northern Madagascar across to northern Mozambique to southern Kenya and, thus, should be a high priority for future conservation action.

Authors of the study include Tim McClanahan and Nyawira Muthiga of the Wildlife Conservation Society, Joseph Maina of the Coral Reef Conservation Project, Albogast Kamukuru of the University of Dar es Salaam’s Department of Fisheries Science and Aquaculture, and Saleh A.S. Yahna of the University of Dar es Salaam’s Institute of Marine Sciences and Stockholm University’s Department of Zoology.

The study found that Tanzania’s corals recovered rapidly from the 1998 bleaching event that had wiped out up to 45 percent of the region’s corals. Along with monitoring Tanzania’s reefs, WCS helps coral conservation in this region through training of park staff in protected areas.

The authors attribute the recovery of Tanzania’s coral reefs due in part to direct management measures, including closures to commercial fishing. Areas with fishery closures contained an abundance of fish that feed on algae that can otherwise smother corals, while the few sites without any specific management measures remain degraded; one site had experienced a population explosion of sea urchins—pests that feeds on corals.

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Doom and Boom on a Resilient Reef: Climate Change, Algal Overgrowth and Coral Recovery

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Our lab has just published a new paper in PLoS ONE, detailing the interactions of coral and algae on the Great Barrier Reef, and uncovered just how resilient some reefs can be following coral bleaching events. The southern end of the Great Barrier Reef was exposed to extended periods of high sea surface temperatures in the end of 2006, resulting in extensive coral bleaching across the Keppel Islands throughout January 2006. Following the bleaching event, a single species of fleshy macro-algae (Lobophora) overgrew the coral skeletons, causing high rates of mortality throughout the second half of 2006. But, by February 2007, corals were rapidly recovering due to an unusual seasonal dieback of the macro-algae, and astonishing regenerative capabilities of the dominant branching Acroporid corals – almost twice the rate of offshore corals on the northern Great Barrier Reef.

What is unusual about the Keppel Islands story is threefold: first, that corals recovered within months to years (reversal of macro-algae dominated reefs often takes decades), second, recovery of the corals occurred in the absence of herbivory (traditionally assumed to be the ‘driving factor’ in macro-algal phase shifts), and third, that corals recovered through asexual (regenerative) capacities rather than reseeding of reefs by larval recruitment. Understanding the processes that drive recovery following disturbances is critical for management of coral reefs, and the Keppel Islands example shows that managing local stressors (overfishing and water quality) helps reefs bounce back from global stressors such as coral bleaching events. PLoS One is an open-access journal, so the article is free to read – click on the link below, and feel free to rate and comments on the paper. Congratulations Guillermo et al!

Guillermo Diaz-Pulido, Laurence J. McCook, Sophie Dove, Ray Berkelmans, George Roff, David I. Kline, Scarla Weeks, Richard D. Evans, David H. Williamson, Ove Hoegh-Guldberg (2009 Doom and Boom on a Resilient Reef: Climate Change, Algal Overgrowth and Coral Recovery. PLoS ONE 4(4): e5239. doi:10.1371/journal.pone.0005239

The worlds most overpopulated coral reef?

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male

I remember seeing a fascinating presentation by Mahmood Riyaz on the reef slope failure of this coral reef at the ICRS conference in Florida last year – how the atoll rim was cracking due to the sheer amount of construction and concrete. Welcome to Male, the capital of the Maldives, where >100,000 people are crammed ontop of a coral reef atoll only 1.7km in length.  The Maldives have been hit hard in recent years, collectively lost over 2/3 of it’s coral following the 1998 bleaching event. In addition, being such a low lying country is likely to be problematic given the projected sea level rises, so the Maldivian government is proposes a carbon neutral approach by 2020, and is even considering diverting some of the billion dollar tourism profits to purchase a new homeland. The photo above doesn’t do justice to the population density on such a tiny atoll – check the satellite images on google earth.

Policy changes and paradigm shifts following Copenhagen

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The United Nations  climate conference in Copenhagen (which I attended ) was an excellent initiative, with some fairly interesting insights into the gulf between science and policy making. Following the conference, we were contacted by The Guardian newspaper to participate in a poll on global warming. The results are striking – almost 90% of climate scientists ‘do not believe political efforts to restrict global warming to 2C will succeed’, and that ‘an average rise of 4-5C by the end of this century is more likely’.

The poll of those who follow global warming most closely exposes a widening gulf between political rhetoric and scientific opinions on climate change. While policymakers and campaigners focus on the 2C target, 86% of the experts told the survey they did not think it would be achieved. A continued focus on an unrealistic 2C rise, which the EU defines as dangerous, could even undermine essential efforts to adapt to inevitable higher temperature rises in the coming decades, they warned.

The survey follows a scientific conference last month in Copenhagen, where a series of studies were presented that suggested global warming could strike harder and faster than realised.

The Guardian contacted all 1,756 people who registered to attend the conference and asked for their opinions on the likely course of global warming. Of 261 experts who responded, 200 were researchers in climate science and related fields. The rest were drawn from industry or worked in areas such as economics and social and political science.

The 261 respondents represented 26 countries and included dozens of senior figures, including laboratory directors, heads of university departments and authors of the 2007 report from the Intergovernmental Panel on Climate Change (IPCC). (Read more)


This sobering news isn’t helped by reports that Steven Chu, the US Secretary for Energy (who I blogged on back in February) has done a complete backflip on statement that coal as ‘his worst nightmare‘, and is now endorsing ‘clean coal‘ technologies. ‘Clean coal’ is a complete myth, and thankfully the US Environmental Protection Agency have passed a motion to deem 6 greenhouse gases (carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride) as ‘dangerous to the public‘, opening up legislation to regulate powerplants and the automotive industry. It will be interesting to see exactly where the Obama administration will take the United States under the new environment and climate change policies, which aim to invest $150 billion in clean energy and renewable sources.

New coral reef blog on the scene

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One of my PhD Students, Siham Afatta, has started a new science blog called ‘Laut & Kita’ (Sea & Us). Siham (a seasoned blogger) is targeting this as one of very few scientific blogs written in Bahasa (the official language of Indonesia), which focuses primarily on marine conservation in Indonesia. I think this is a great effort and great example of the power of blogging – check out the link below.

lautkita

New evidence from coral reefs suggest sea level rise occurs over ecological time scales

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image003Paul Blanchon and his team have uncovered evidence of extremely rapid sealevel rise 121,000 years ago in one of the warm interglacial periods.  Basically by dating coral skeletons at a place called Xcaret (the beautiful place where a fossil Reef lies exposed), Paul was able to document an abrupt reef crest “back stepping” (essentially the reef crest suddenly appearing landward in a very short time).   The abrupt loss of the lower reef crest growth but continued growth between the lower and upper reef crests has allowed these paleobiologist to draw the conclusion that this occurred due to a 2-3 m sea level rise.  What is the big news, is that it happened over decades.  Measurements of the upward growth of some corals at the “ocean surface” occurred at about 36 mm per year!

Paul is scientist who is characterised by rigour and excellence. He is based at Institute of Marine Sciences and Limnology (ICML) of the National Autonomous University of Mexico (UNAM) in Puerto Morelos on the Yucatan Peninsula.  As a paleobiologist, he is interested in how the world has changed over thousands of years.  For a long time now, Paul has been gathering evidence the great ice sheets the world can break up suddenly over very short period of times.  This latest paper is further evidence of the veracity of this idea – follow this link to see the article in Nature.

Editor’s Summary
16 April 2009

An interglacial jump in sea level

The potential for future rapid sea-level rise is perhaps the greatest threat from global warming. But the question of whether recent ice loss from Greenland and Antarctica is the first indication of such a rise is difficult to answer given the limited duration of the instrumental record. New evidence from an exceptionally exposed fossil reef in the Xcaret theme park in Mexico provides a detailed picture of the development of reef terraces, erosion surfaces and sea-level excursions in the region during the last interglacial. A combination of precise uranium-series dating and stratigraphic analysis, together with comparison with coral ages elsewhere, suggests that a sea-level jump of 2 to 3 metres occurred about 121,000 years ago, consistent with an episode of ice-sheet instability towards the end of the last interglacial. On that evidence, sustained rapid ice loss and sea-level rise in the near future are possible.