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Entries in global warming (12)

Tuesday
Dec282010

Five of the biggest marine science stories in 2010

Yes, I caved to the impulse and joined the inevitable cavalcade of “lists” that come at the end of every year.  Why?  Because these lists actually serve an important purpose: they cement the events of the past 12 months in our psyche and provide context about where these events fit into the grand passage of time.  They also give us something to read when we want to procrastinate shoveling snow off the driveway or vacuuming pine needles from behind the couch.  So here they are: five of the biggest marine science news stories from 2010.

5. National Ocean Policy.  Starting off sexy, right? Policy, yeeeahh baby!  No really, it IS a big news story that in July of this year the Whitehouse announced that the US finally has a comprehensive Ocean Policy.  That’s because such a document - and the institutions it enhrines - recognises the critical role that the oceans play in the lives of every American, even those that live far removed from the coasts.  As the biggest per capita consumers (and polluters) on the planet, the absence of a national policy to protect the oceans had long been lamented by marine scientists and consrvationists alike.  Now we have a National Oceans Council and a set of guiding principles for governing the use (and abuse) of coastal oceanic resources.  Its about time!  Read the Executive order here, and the Final Recomendations of the Ocean Policy Task Force here

4. What a load of garbage.  2010 marked the year that the concept of the “great ocean garbage patches” entered the public consciousness.  If you’ve been living under a rock and have no idea what that is, well, it’s the idea that millions of tons of plastic pollution have found their way down urban drains, to creeks, rivers and estuaries and thence to the centers of the great circular oceanic currents called gyres.  There becalmed, these floating fields of plastic debris form giant rafts of death, entering food webs and silently choking millions of animals.  The truth is slightly less dramatic; while the grabage patches are almost mind bogglingly large, the density of plastic particles within the patches is actually pretty dilute.  In fact, you have to sift a lot of water to recover appreciable quantities of the stuff; it’s just that, even then, they have vastly higher concentrations than parts of the ocean more well-mixed by large scale currents.  2010 was the year that scientists recognised that there is not only one patch (in the north Pacific) but probably a patch of sorts in the center of every gyre and that therefore this is a global problem.  Its also the year that the concept hit pop culture, partly from the well-publicised efforts of the Plastiki cruise, but mostly in the form of a new album from progressive UK hip hop outfit Gorillaz called “Plastic Beach”, a theme album conceived when the lead singer was sitting on a beach and realising how much of the sand was actully composed of tiny bits of plastic.  The garbage patch story also added the most excellent word “nurdle” to the lexicon, reason enough for it to appear on this list.  Read more about the adventures of a bona fide garbage patch researcher by following Miriam Goldstein at DeepSeaNews

3. To hack, or not to hack?  It’s pathetic, but perhaps not surprising, that the worlds leaders have not been able to agree on a binding plan of action to reduce carbon pollution and its two biggest impacts on the planet: global warming (both the atmosphere and the oceans) and ocean acidification.  First at the COP15 Copenhagen conference in late 2009 and, more recently, at the 2010 United Nations Climate Change Conference in Cancun, Mexico in December, politics consistently trumped the urgent need to reconstruct our industries and economies to prevent exacerbation of the problem (we’re already committed to a certain level of globe-changing temperature and pH shift).  While these “front end” solutions are desperately needed, a number of climate/ocean researchers around the world have been studying “back end” solution, the most familiar of which is carbon sequestration - the idea of catching CO2 from fossil fuel burning and burying it or otherwise preventing it from entering the atmosphere/ocean.  Perhaps the most controversial suggestion is to fertilise the oceans with nutrients that usually limit the growth of plankton (Iron is the best-studied), thereby causing huge plankton blooms that suck CO2 out of the air/water and, ultimately, export it to the bottom of the abyssal oceans.  The controversy of these sorts of planet-level solutions, collectively called “geo-hacking”, arise because they are designed to affect the whole earth ocean/climate system and take place in international waters, so arguments arise about who gets to decide on these sorts of things.  No sooner had I interviewed an expert on ocean fertilisation on this very blog than a UN moratorium was issued preventing any future research on this kind of solution until the risks and impacts are better understood.  C’mon UN - you can’t have it both ways: either make an internationally-binding decision about reducing carbon pollution, or allow people to move forward with alternative solutions, preferably both.  As it stand currently, we’re a boxer with both arms tied behind his back, and that’s never good.

2. BP/Macondo/Deepwater Horizon Oil Spill.  Bet you thought that would be number 1 right?  By volume, the largest oil spill in US history, affecting huge areas of the Gulf of Mexico in the peak of seafood season and threatening hundreds of miles of fragile coastal wetlands, surely it should be.  Nope.  Why not?  Well, largely because - disastrous though it was/is - it is both temporally and geographically restricted in its impact.  In other words, its effects will be found primarily in one place and for a limited (albeit relatively prolonged) time.  I argue that it is NOT these events that we (the world) need to be concerned about, but the long-term, chronic, death-by-a-thousand-cuts kind of problems.  The biggest of those are global warming and ocean acidification (see number 3).  It’s like the difference between a big financial windfall and the power of investment returns.  The local factory worker who wins a hundred million on the latest Powerball gets the news story, while tons of investors accumulate vast wealth in relative silence due to the inexorable influence of compounding interest and capital gains over time.  The BP spill was an absolute disaster that got a LOT of press and will keep many marine scientists and environmentalists busy for a long time (great coverage of both is at DeepSeaNews), but it’s a one-off event and not even on the radar in terms of the global health of the oceans.

1. Census of Marine Life.  The biggest marine science news of 2010 has to be the completion of the first Census of Marine Life; a phenomenal decade-long effort by thousands of marine biologists around the world to answer one simple question: What lived, lives and will live in the worlds oceans?  The brainchild of Rutgers marine scientist Fred Grassle, the scope was truly gargantuan: over 500 research expeditions covering every ocean, over 2,500 scientists and the discovery of over 6,000 species new to science and published in over 2600 peer-reviewed papers.  It revealed the chronic undersampling of the deep-pelagic realm and the incredible diversity of seamounts and the tropical, arctic and antarctic depths.  It also brought us some of the most stunning and engaging images of marine diversity ever captured.  The final estimate? Based on extrapolations of survey data, easily 1 million or more eukaryote species and perhaps as many as 10 million bacteria and archaea.  But CoML is so much more than numbers, it’s a peek into a treasure trove of new life, a testament to the phenomenal diversity of the oceans, and an enduring snapshot of the precious biological legacy we are lucky to be part of.  It’s often said that you don’t know what you’ve got til it’s gone.  Well, thanks to CoML we have a better idea of what a priceless gift of diversity we’ve got at our fingertips.  Now what are we going to do about it?

I’d love to read your feedback in the comments.  Did I miss anything?

Monday
Nov012010

Who you calling a crackpot scientist?

There’s an interesting article in the South African news media about a UN moratorium on the sort of geo-engineering ideas described in my recent discussion with Pete Strutton.  The general gist of the moratorium is that the UN is saying “lets not do any more of this sort of research until we have a better idea whether its going to work and at what cost”; its not an ethical prohibition in the sense of the human cloning sort of ban.  Consequently, the South African piece describing proposers of geo-engineering as “crackpot scientists” is absurdly harsh and sensationalist journalism at its worst.  I can say with confidence that scientists studying geo-engineering concepts are simply trying to propose solutions to what will certainly be the most vexing global challenge of our generation.  As stated in this Scientific American piece:

Major scientific organizations — including the American Meteorological Society, the American Geophysical Union and the U.K. Royal Society — have issued cautious calls for more research, though warning that geoengineering approaches shouldn’t supplant efforts to cut greenhouse gas emissions.”

In my ideal world, it would be a social norm that you can’t object to an idea unless you propose a justifiably better alternative.  Certainly there are questions to be answered about who gets to make the call on these global-level solutions (even mentioned here back in March).  But as it stands, with Kyoto and Copenhagen essentially failing to effectively retard the source of the issue (greenhouse gas emissions), we can ill-afford the UN to be hindering research into possible solutions, without offering something better.

Tuesday
Oct192010

Fertilise our way to a cooler planet? Five questions with Pete Strutton

My fellow Aussie and all-round good mate Pete Strutton is a marine biologist of a very different flavour to me.  Whereas I work on bigger critters like whale sharks and (formerly) coral reefs, lobsters and fish parasites, Pete studies big-time plankton and nutrient cycle stuff in the open ocean.  He also edited a book about marine ecology, which you can get on Amazon (even in Kindle format!).  Pete’s at the University of Tasmania these days but formerly of Oregon State, Stony Brook University’s School of Marine Science and the Monterey Bay Aquarium Research Institute.  I caught up with Pete recently and asked him some questions about his work.


AD: Hey Pete, can you tell us a bit about your favourite areas of research?

PS:  In general my work concerns the intersection of biological and physical oceanography. In other words, I’m basically a biologist who knows enough physics to be dangerous. What this means in practice is that I try to investigate what causes variability in the productivity of the surface ocean. To do that I need to understand physical processes such as mixing and upwelling, that vary a lot in the ocean and deliver nutrients to the surface where they are consumed by phytoplankton for photosynthesis. This is important because the oceans are responsible for about half the photosynthesis that happens globally. Or as I’ve heard many times recently, every second breath we take is thanks to phytoplankton.

So like I said, most of the work I do is trying to understand how physics impacts biology, but recently I’ve become excited about the reciprocal process: Biological influences on physics. One cool example of this that I don’t work on is the contribution of ocean animals to mixing [of ocean water]. John Dabiri at CalTech was recently awarded a MacArthur Fellowship for his work in this area. What I have done some work on is how phytoplankton influence ocean warming. As we all know, phytoplankton absorb solar radiation to carry out photosynthesis. They actually re-radiate a lot of this energy back into the water as heat and fluorescence. So when the concentration of phytoplankton in the surface ocean increases, this means that there’s greater potential for trapping heat near the surface, rather than it penetrating more deeply into the ocean’s interior.

I’ve looked at two scenarios for the variability of phytoplankton (as measured by chlorophyll concentration) and the impact this has on ocean warming. The first is natural variability, and the case I looked at was the 1997-98 El Nino event in the tropical Pacific [Journal of Climate, 2004 17: 1097-1109]. More recently I’ve become very interested in the impact that geo-engineering scale blooms might have on upper ocean warming, particularly because the goal of these blooms is to ‘cool the planet’, but I think you’re going to ask me about that next.
 
AD: I want to ask you about ocean fertilization.  I gather the basic idea is that plankton production (or algae growth) in the oceans is limited by one or more nutrients that are in short supply, so if you add that nutrient back in, you can encourage huge increases in productivity.  This growth in plankton sucks carbon dioxide out of the atmosphere and it becomes “fixed” (turned into animal tissue) and enters the food chain or, ultimately, sinks to the bottom of the ocean where it remains trapped for extremely long periods.  This idea has been termed “carbon sequestration” and proposed as a way to offset or even reduce atmospheric carbon dioxide and thus ameliorate global warming.  Where did this idea come from and who were the key players in its genesis?

PS:  You’ve described the idea very well. The most famous and relevant example is that of iron limitation. For several decades, biological oceanographers wondered why chlorophyll concentrations (phytoplankton populations) were not higher in vast areas of the ocean, in particular the North Pacific, equatorial Pacific and Southern Ocean. When they did cruises to these areas, there seemed to be plenty of nitrogen, phosphorous and silicon available. These elements are all important building blocks for phytoplankton (by the way, carbon is never a limiting nutrient in the ocean). What was stopping phytoplankton from taking up these nutrients?

An important breakthrough came in the 80s by way of technological and analytical developments. John Martin’s group at Moss Landing Marine Labs in California developed careful techniques to accurately measure trace metal in the ocean. Iron, for example, is present in seawater at extremely low concentrations – it would take about 500 olympic swimming pools of seawater to make one 5 gram nail. Most of the sampling equipment we use in oceanography, including the ships themselves, are made of iron, so contamination was difficult to avoid. To cut a long story short, the Moss Landing group developed techniques to measure iron at parts per trillion concentrations. When they made uncontaminated measurements, it became clear that dissolved iron in the ocean was extremely low, particularly in the places I mentioned above. Phytoplankton were using up all the iron (in enzymes for photosynthesis among other things) before they ran out of nitrogen and the other nutrients. That’s why these other nutrients were sitting around unused.

There was a vigorous debate in the community as to whether low light, or consumption by higher trophic levels could be limiting nutrient uptake, but in the end, for the most part, the iron idea won out. John Martin further suggested that long term (tens of thousands of years) variability in dust inputs to the ocean could be regulating Earth’s climate (glacial cycles). He is (in)famous for saying ‘give me half a tanker of iron and I’ll give you an ice age’. He tells the story of this quote in a newsletter in 1990: ‘I first said this more or less facetiously at a Journal Club lecture at Woods Hole Oceanographic Institution in July 1988. I estimated that, with 300,000 tons of Fe, the Southern Ocean phytoplankton could bloom and remove two billion tons of carbon dioxide. Putting on my best Dr. Strangelove accent, I suggested that with half a ship load of Fe … I could give you an ice age. After which we all had a beer on the lawn outside the Redfield Laboratory’ (see picture [at top] of me having a beer on the lawn outside the Redfield lab 21 years later). I often use this quote in my lectures, although I sometimes get blank stares at the mention of Dr Strangelove.

Pete and colleagues loading iron into dispersal tanks during the SOFeX cruiseIn the 1990s, somewhat cautiously, oceanographers started testing this idea at sea, first in the equatorial Pacific (1993 and 1995), then in the other regions of interest: North Pacific and Southern Ocean.
 
AD:  Can you tell us a bit about the SOFeX experiment and the SOFeX cruise in 2002?

PS:  So yes, in 2002 I was part of a US cruise to the Southern Ocean to perform a relatively large scale iron fertilization experiment. We left out of New Zealand and headed southeast towards the Ross Sea. We fertilized two patches about 15km x 15km. The two study areas were more than 1000km apart – our goal was to test the response of the phytoplankton in two parts of the ocean with different combinations of dissolved nitrogen and silicon.
 
AD:  So now, eight years later, where is this “carbon sequestration” idea headed?  Isn’t it just delaying the inevitable? Is it a viable option, or still controversial?

The “fish”: a device used to distribute the iron at a constant 10m depth. It was covered in rust, depsite being made of plastic!In general, in all of the experiments conducted so far, and there have been more than a dozen of them, blooms have been generated but the amount of ‘fixed’ carbon that ends up raining out of the upper ocean, let alone getting stored in sediments, is considerably less than hypothesized by Martin. There are theories as to why this might be, one of them is that the patches we’ve made to date have been too small, leading to dilutionOne of the plankton blooms produced during the SOFeX cruise, as seen from MODIS satellite. The red patch indicates higher productivity at their boundaries. Some are advocating that we perform even larger experiments, say 100km x 100km. My feeling, and I’m sure I’m not alone, is that iron fertilization is not the silver bullet that will save us from CO2-induced climate change. Nonetheless it is still talked about as potentially part of the solution, and it is also being considered by some in the context of carbon trading. That is, ‘I’ll go fertilize a part of the ocean with iron and suck up 10 tonnes of CO2, then sell that credit to you, Mr Coal-fired Power Plant Owner’.

AD:  SOFeX and some of your other cruises are definitely Science Writ Large.  What’s it like to work on a UNOLS vessel and how do you balance the research interests of individual PI’s against the collective goals of the cruise?  Is it fun or just a grind?

 R/V Revelle, one of the two UNOLS vessels involved in the SOFeX experimenPS:  Good question, particularly with regard to SOFeX. That cruise was very challenging. Even though we had two large ships in the end, there was still strong competition for space on the ship and this translated into competition for time to do science. We wanted to do lots of different tasks, like scan the region as quickly as possible to map the evolution of the patch as seen in surface properties, compared with detailed station measurements that required us to stay in one location for up to 6 hours. These types of sampling were often in competition with each other which makes it particularly challenging for the chief scientist (who constantly has people lobbying for time). To further complicate matters, I was running a drifter that was supposed to mark the center of the [fertilised] patch as it was moved around by the currents. We had real-time radio communication with this drifter, but on a couple of occasions, the GPS dropped out. So although we were getting updates from it, we had no idea where it was. We ended up spending way too much valuable sampling time searching for lost drifters.

On a totally non-scientific note, the other challenge of SOFeX was the food. There was a breakdown in communication re the ordering of supplies prior to sailing and we ran out of a bunch of staples: Bread, eggs, milk, cheese. You’d reckon they could increase our beer allowance (1 per day) to compensate, but no. Oh well, we still managed to have the occasional ‘safety meeting’ in an undisclosed location…

 [AD: If you have questions about geo-engineering or other parts of Pete’s research, post them in the comments and I’ll see if we can get some answer for you]

Thursday
May202010

12,081ft - The oceans, by the numbers

I was inspired by recent articles highlighting a revised calculation of the ocean’s average depth as 12,081ft, to consider the seas in a numerical light today. To that end, here’s a few random, sourced numbers and back-of-the-envelope calculations that might be food for thought:

0.87% = Amount we can see by diving from the surface (about 100ft) over the average depth
0.28% = Amount we can see by diving over the deepest part (Challenger Deep, Marianas Trench off the Philippines)
2.9 = Number of times deeper the deepest part is, compared to the average.
5,400 = Number of mammal species in the world
25,000 = Number of fish species in the world
Millions? = Number of marine invertebrates species in the world (no-one really knows)
2.3 Million = The number of US citizens directly dependent on ocean industries (source: NOAA)
$117 Billion = Value of ocean products and services to the US economy (yr 2000, source: NOAA)
50% = US population living in coastal zones
48% = The proportion of all human-produced CO2 absorbed by the oceans in the Industrial era (NatGeo)
0.1 = The pH drop in the surface oceans since 1900
0.35 = Expected pH drop by 2100 (source)
18 = The number of times more heat absorbed by the oceans than the atmosphere since 1950 (source - TAMU). Global warming is an ocean process far more than an atmospheric one.
3.5 Million = Estimated tons of plastic pollution circling in the Great Pacific Garbage Patch, and growing.

And yet:

30 = Number of times thicker the atmosphere is (out to the “edge of space” about 60 miles) than the average ocean. That would be the atmosphere that astronauts describe as a “thin veneer” on the planet…
0.06% = Thickness of the average ocean, compared to the radius of the earth. I think we can argue that the water is the veneer, not the air
$4.48 Billion = NOAA’s 2010 budget, including the National Ocean Service, Weather Service and Fisheries Services. (source NOAA)
$18.7 Billion = NASA’s 2010 budget, i.e. 4 times the size of the agency that looks after our own planet (source NASA)
$664 Billion = Department of Defense base budget 2010, not counting special allocations (source DoD)
0.6% = The amount you would need to cut Defense in order to double the NOAA budget

Some sources:
http://www.corporateservices.noaa.gov/~nbo/FY10_BlueBook/NOAAwide_One_Pager051109.pdf
http://www.corporateservices.noaa.gov/~nbo/10bluebook_highlights.html http://news.nationalgeographic.com/news/2004/07/0715_040715_oceancarbon_2.html  
http://oceanworld.tamu.edu/resources/oceanography-book/oceansandclimate.htm
http://web.archive.org/web/20080625100559/http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Orr_OnlineNature04095.pdf  

Wednesday
Apr282010

Tilting the three-way tango - disease as a loss of diversity

ResearchBlogging.orgDisease is a funny old thing.  We're taught from very early on that disease agents are "bad" and that, by contrast, the infected are somehow poor and unfortunate victims of nasty evil bugs.  This is clearly a cultural bias, wherein we project our own concerns about getting sick onto all other animals; there's no real reason to think that a bacterium or virus has any less right to be here or any less important role in the ecological processes of the world than does the dolphin it infects, or the fish or the lobster.  We have all survived eons while avoiding extinction, which makes us winners in the great game of evolution, the microbes every bit as much (or more) than their hosts.

Still, biases run deep.  This is important because sometimes they cloud our perceptions of whats really going on.  Consider coral diseases for a moment.  What, you didn't know that coals get diseases?  That's OK, neither did most folks, including many scientists, until fairly recently.  Lets picture a nice reef coral, maybe a handsome Porites, infected with one of the many "band"-causing agents (diseases that march across the surface of the coral, destroying tissue along a coloured front that gives the disease its name).  Most folks would perceive that the coral (good) was quietly minding its own business when it was "infected" by the microbe (bad), causing disease.  But actually it took at least three players to tango in this case; the coral had to be susceptible to the pathogen, the pathogen had to be infectious to the coral, and the environment had to set the scene that made the interaction swing in favour of the pathogen.  This simple "disease triad" is the most basic model of how infectious processes take place, but its just that: a basic model.

These days, disease studies are becoming a lot more nuanced, and its revealing a whole new world of how diseases start and stop.  Rocco Cipriano, a microbiologist colleague of mine at the National Fish Health Labs in Leetown WV, has been promoting a model lately where an infectious disease of fish (furunculosis) is caused by a disruption to the natural community of bacteria on the skin of fish; a community in which pathogens have no place normally.  The furunculosis agent (Aeromonas) is excluded from these communities by bacteria better adapted to living in normal fish skin and its associated mucus layer.  That is, until an environmental modulator, like a temperature spike or pollutant, shakes things up a bit; what ecologists would call disturbance.  And what is the first outcome of disturbance in most systems? Loss of diversity, in this case among the normal bacterial community.  Some bacteria disappear from the skin of the fish, freeing up resources (space, food) that are exploited by other bacteria - opportunists that can come in and pounce on the new space or food.  When that space and food consists of the fish itself, we call those bacteria pathogens.  This same process happens after any ecological disturbance, like a hurricane on a reef or a tree falling in a rainforest: opportunists come in and pounce on a newly-available resource; then as things settle down a succession takes place, until the early colonisers are displaced by more typical fauna.  In this view, disease is nothing more than a byproduct of disturbance and loss of diversity in the normal microbial community.

Which brings me back to corals and to the recent paper by Mao-Jones and colleagues in PLoS Biology.  These folks used a mathematical model to show that much the same holds true for the diseases of corals, which, like fish, rely heavily on a surface layer of mucus as their first line of defence.  It seems that in both corals and fish, the mucus is important, but even more important are the normal bacteria that live there, continually excluding pathogens and acting as a protective guard against disease.  In a very anthropomorphic sense, the corals (and fish) are using the surface bacteria as a biological weapon against the potential pathogens, at the expense of having to produce all that mucus for the bacteria to live and feed on.  Importantly, Mao-Jones and friends show us that the derangement of the mucus community can persist for a really long time after the initial disturbance.  This is important, because you often come along and see disease starting, but you may well have missed the initial insult that got the ball rolling, which may have occurred some time ago.

I really like this idea of infectious disease as an ecological disturbance and of many pathogens as simply early colonisers in the succession back towards health (or towards death, if the disturbance was too severe).  As a model, it doesn't work for everything, though.  There are many "primary pathogens" that are specifically adapted to invade healthy animals, but its not in the best interests of those organisms to invest so much energy in adaptations to invasion, only to kill the host, thus many of those are fairly benign.  For more "opportunistic" agents, however, I suspect it holds true much of the time, and that group includes many or most of the really virulent diseases.  I dare say many of the "emerging" diseases fall in this category, and we can expect to see more of this as the global climate continues to tilt the tango in favour of the pathogens.

Mao-Jones, J., Ritchie, K., Jones, L., & Ellner, S. (2010). How Microbial Community Composition Regulates Coral Disease Development PLoS Biology, 8 (3) DOI: 10.1371/journal.pbio.1000345

Tuesday
Apr272010

Me and Terry Hughes, we got Kwan

This is a little spooky. Terry Hughes of the Center for Excellence in Coral Reef Studies in Australia, whom I know only vaguely, has been quoted on the topic of the Shen Neng 1, that Chinese coal ship that ran aground on the Great Barrier Reef. His somewhat dismissive tone sounds creepily like my recent rant on the subject.

He said:
"The [Shen Neng 1] ship grounding, in the scheme of things, is not a major incident. It's bad if you happen to be one of the corals the ship parked itself on, but it's tiny in the face of the real problem: global warming."

I said:
"I am not worried in the slightest about this incident.  Not that its a good thing - far from it - but this accident is nothing more than a tree, obscuring us from seeing one big and scary forest [burning fossil fuels]."

Terry, you're my Ambassador of Kwan.

Thursday
Apr152010

Q: When is a ship like a tree?

A: When you can't see the forest for it.

You may have followed some press in the last week or so about a Chinese coal ship, Shen Neng 1, that ran aground on the Great Barrier Reef and spilled some of its fuel oil.  This has caused a regular frenzy in the Aussie media and the global conservation and environmental news-o-sphere.  There have been all sorts of calls for prosecution of the shipping company and new stringent regulations for the transport industry and so on, along with dramatic accounts of the damage the ship did and the risky salvage operation that came next.  But you know what?  I am not worried in the slightest about this incident.  Not that its a good thing - far from it - but this accident is nothing more than a tree, obscuring us from seeing one big and scary forest.

The main reasons I am not especially bothered by the Shen Neng accident are that (1) it affected a very limited area - the G.B.R. is really B.I.G. and one ship can only damage so much of it; and (2) it was a single event in time - this was not a process or an ongoing problem, but a singular disturbance.  Science shows us that the GBR, and reefs in general, are amazingly resilient to violent disturbances like this; a decent cyclone can literally turn a reef upside down, and a couple of years later you'd never know the difference.  Indeed, periodic disturbances may  be really important for maintaining a healthy reef ecosystem.

No, the Shen Neng is just a tree, obscuring us from seeing the forest that really threatens the future of the GBR and all reefs.  Its not the 2km gash that the hull cut in the reef, nor is it the tons of fuel oil leaked into the water; it's the very concept of burning that fuel oil, and burning the thousands of tons of coal that the Shen Neng 1 was carrying.  When you consider all the other ships and all the coal and fuel they were carrying that day and every day, and all the cars in the world, the power plants and so on ... ach, you get my point.  THAT'S what we ought to be worried about, because both of the main effects of increased atmospheric CO2 - warming and ocean acidification - will likely result in unrecoverable damage to All reefs. Everywhere. In our lifetime.  Warming is directly linked to lethal bleaching events, while acidification disrupts the ability of reefs to lay down their skeleton and grow.   Oh yeah, and lets not forget the drowning effects of sea level rise, too.  The more I think about it, the more it seems that jumping up and down about the Shen Neng is hypocritical (coal is one of Australia's biggest exports, after all) and akin to complaining about the deck chair arrangements of another, even bigger, ill-fated ship.  (Ironically, if Titanic sailed today, she probably wouldn't have to worry about icebergs...)

Of course, its a false dichotomy, we should be worried about BOTH the Shen Nengs of the world AND the global climate change/ocean acidification.  But I only have so much energy/capacity for worrying about these things, so with a limited anxiety budget, I feel compelled to focus on the bigger issue and what (if anything) we can do about it - to try to reduce consumption and to try to make sensible decisions that are mindful of how much energy is involved and what the broader impacts might be.

In other words, to worry about the forests - and let the trees take care of themselves.

Tuesday
Mar302010

Ocean Conveyor running AMOC

This post was chosen as an Editor's Selection for ResearchBlogging.orgResearchBlogging.org

If you’ve ever seen the disaster movie “The Day After Tomorrow”, then you’ve been introduced to the idea that one day the global ocean conveyor might stop.  Its a pity (or perhaps not) that the movie was such a sensational introduction to the concept, because its a pretty serious possibility.  By way of short explanation: one of the things that makes life possible on this rock is that the ocean redistributes heat that arrives on the earth’s surface between the tropics, sending it to the higher latitudes by way of warm surface currents.  There, the waters are cooled and made more dense (both colder and saltier) by the polar ice caps; they then sink and begin a slow meander back to the tropics, eventually returning to the surface to complete the cycle.  Without effective redistribution of this sort, the tropics would bake and the polar zones would sink into a deep hard freeze (in both cases much more so than “normal”).  The climate in the UK, for example, would be much more like Siberia were it not of the tempering effects of the Gulf Stream continually bringing heat from the Caribbean to the North Sea.  An important point about the conveyor is that it is driven from both ends: by the suns heat near the equator and by the cooling effect of all that ice at the poles.

 Why would the conveyor grind to a halt?  The equatorial heat doesn’t show any sign of stopping; if anything its getting hotter.  No, the biggest fear is for the other driver: if the polar ice caps melt too much, there will no longer be a big enough reservoir to chill and brine the surface waters and they will cease to sink.  Some data from recent years suggested that this was happening, and happening fast.  Well, it seems as though Armageddon isn’t here just yet.  A new paper by CalTech/NASA’s Josh Willis in the journal Geophysical Research Letters uses a more complete data set than ever before to conclude that the conveyor, or more specifically a major section of it called the Atlantic Meridional Overturning Circulation (AMOC - hence the corny title of my post) measured at 41°N (near where it says “Atlantic” on the figure above), is not slowing.  In fact, there is some evidence that it may have sped up marginally in recent years, perhaps in response to warming and expansion of Atlantic waters.  The data were consistent across both satellite sources and sensor arrays deployed in the oceans, so it would seem like a pretty robust study (though I am no physical oceanographer).

I am sure I speak for everyone on the bonnie British Isles when I heave a sigh of relief.

But wait?  What light through yonder ice-shelf breaks?  Tis Greenland, and its seeing more of the sun!  In the very same issue of Geophysical Research Letters, a different group of authors report that ice loss is increasing from the Greenland ice sheet.  This is one of the major impacts of recent climate warming and the greatest contributor to increases in sea level globally.  It would also freshen the north polar waters, further reducing the driving force behind the global ocean conveyor.


My response to this news is to marvel at - and grapple with - the complexity and dynamics of the earth and its climate system.  Scientific results with seemingly opposite implications can come out (in this case in the same journal issue), but without threatening the major underlying pattern; I doubt, for example, that Dr. Willis would disagree with the concept of man-made climate change.  Faced with this seeming contradiction, its perhaps no wonder that many folks grapple with the Big Ideas at the heart of global climate change, and even doubt that it exists at all.  I for one have no doubt  that things are changing, and changing fast.  It may just be that some of the really big features of the climate system (including ocean currents) are slower to respond than others.  Its a bit like turning an oil tanker, which may be an unfortunately apt analogy…

Willis, J. (2010). Can in situ floats and satellite altimeters detect long-term changes in Atlantic Ocean overturning? Geophysical Research Letters, 37 (6) DOI: 10.1029/2010GL042372

Khan, S., Wahr, J., Bevis, M., Velicogna, I., & Kendrick, E. (2010). Spread of ice mass loss into northwest Greenland observed by GRACE and GPS Geophysical Research Letters, 37 (6) DOI: 10.1029/2010GL042460

Tuesday
Mar302010

More on the geo-hacking idea

Not so long ago I posted about the idea of capturing all the extra atmospheric CO2 into the worlds oceans by fertilising them and thereby creating enormous plantkon blooms that would convert all the CO2 to plant tissues, which would then sink to the bottom and be buried in the ocean depths.  This new scientist article probes a different angle that I didn't think of, which is Who decides what we will or won't do to change these things?  The author Jim Giles refers not just to ocean fertilising, but engineering the whole planet to combat climate change - what has become popularly known as "geo-hacking" - including sensible concepts like reforestation and cloud seeding, as well as the more absurd notions such as building giant reflectors to bounce the sunlight away.  Its a thought provoking question, so who do you think should decide these issues?  The US? UN? UNESCO?  Perhaps we need a new body with that as its sole charter?

Saturday
Dec192009

Lazy SCUBA divers - pushing back the frontiers of climate science since 1970

Confused?  Read on...
Australia's CSIRO (the primary government-funded scientific research body; the kool kids say it like SIGH-row) has taken possession of a SCUBA tank last filled by its owner, a Mr. J. Allport, in 1968.  This may represent among the oldest clean compressed air currently available, and the boffins at CSIRO (one such boffin shown below), hope to use the contents to extend the directly-measured CO2 record back a few more years.  This would help improve the quality of climate data just a teensy bit more.  Admit it, that's kinda awesome.

I should call them. I'm pretty sure I've got a ham sandwich from 1982 somewhere in the attic; that must be useful for something...

Thursday
Dec172009

Giant iceberg threatens Australia

Sounds odd right?  I mean, the sunburnt country - itself "adrift" in the southern oceans - on a collision course with a giant chunk of ice?  And yet, thats exactly the scenario unfolding off SW Western Australia.  Supposedly it broke off the Ross ice shelf, one of the largest on the planet.

The people in Perth could make a lot of gin and tonics...

Tuesday
Dec152009

70%

Some time ago I noticed there wasn't as much going on in the blogosphere with respect to marine science as I would like, but I was really prompted to start writing by the press release last week from IUCN naming the 10 species - other than polar bears - most likely to suffer as a result of climate change.  Seven of those were aquatic and we had all of them, or close relatives, in the collection at Georgia Aquarium.  In choosing these particular species, the IUCN underscored the significant role of the oceans in global climate change processes.  This is tremendously important because I think most folks still regard GCC as a terrstrial issue.  Its not: evidence is growing that the ocean is the single largest driver of climate, and the response of the oceans to increasing greenhouse gases will determine how GCC plays out, including which models - if any - most closely meet the changes we observe.  The oceans are our best friend in this respect, absorbing excess carbon dioxide and dampening the effect of all that fossil fuel burning, but they do it at the expense of their inhabitants and they can only do it up to a point.   I expect this will be a topic we return to pretty regularly; it should be higher on many people's climate change radar, and we can hope that it features prominently in discussions in Copenhagen this week.

When I thought a little more about it, it shouldn't be at all surprising that ICUN picked 70% aquatic species for their list; after all, 70% of the earth is covered in water...