Well here we go again, you know the drill. Global warming at fault, other possibilities ignored, multiple press releases. Lake Tanganyika is the second largest lake in the world for fresh water, so naturally any change it is cause for “alarm”. Unfortunately in these press releases there is no mention of a possible increase in turbidity due to human action on and around the lake, decreasing the albedo to absorb more sunlight on the lake surface, warming it. At least somebody has already asked that question previously in peer reviewed literature where they describe the Lake Tanganyika problem as “watershed deforestation, road building, and other anthropogenic activities result in sediment inundation…“.
But in our current press releases, there is this hat tip to anthropogenic: “The team attributes the lake’s increased temperature and the decreased productivity during the 20th century to human-caused global warming.”
First from Brown University:
Brown Geologists Show Unprecedented Warming in Lake Tanganyika
PROVIDENCE, R.I. [Brown University] — Lake Tanganyika, the second oldest and the second-deepest lake in the world, could be in for some rough waters.
Geologists led by Brown University have determined the east African rift lake has experienced unprecedented warming during the last century, and its surface waters are the warmest on record. That finding is important, the scientists write in the journal Nature Geoscience, because the warm surface waters likely will affect fish stocks upon which millions of people in the region depend.
The team took core samples from the lakebed that laid out a 1,500-year history of the lake’s surface temperature. The data showed the lake’s surface temperature, 26 degrees Celsius (78.8°F), last measured in 2003, is the warmest the lake has been for a millennium and a half. The team also documented that Lake Tanganyika experienced its biggest temperature change in the 20th century, which has affected its unique ecosystem that relies upon the natural conveyance of nutrients from the depths to jumpstart the food chain upon which the fish survive.
“Our data show a consistent relationship between lake surface temperature and productivity (such as fish stocks),” said Jessica Tierney, a Brown graduate student who this spring earned her Ph.D. and is the paper’s lead author. “As the lake gets warmer, we expect productivity to decline, and we expect that it will affect the [fishing] industry.”
The research grew out of two coring expeditions sponsored by the Nyanza Project in 2001 and 2004. Cores were taken by Andrew Cohen, professor of geological sciences at the University of Arizona and director of the Nyanza project, and James Russell, professor of geological sciences at Brown, who is also Tierney’s adviser.
Lake Tanganyika is bordered by Burundi, the Democratic Republic of Congo, Tanzania, and Zambia — four of the poorest countries in the world, according to the United Nations Human Development Index. An estimated 10 million people live near the lake, and they depend upon it for drinking water and for food. Fishing is a crucial component for the region’s diet and livelihood: Up to 200,000 tons of sardines and four other fish species are harvested annually from Lake Tanganyika, a haul that makes up a significant portion of local residents’ diets, according to a 2001 report by the Lake Tanganyika Biodiversity Project.
Lake Tanganyika, one of the richest freshwater ecosystems in the world, is divided into two general levels. Most of the animal species live in the upper 100 meters, including the valuable sardines. Below that, the lake holds less and less oxygen, and at certain depths, it is anoxic, meaning it has no oxygen at all. What this all means is the lake is highly stratified and depends on wind to churn the waters and send nutrients from the depths toward the surface as food for algae, which supports the entire food web of the lake. But as Lake Tanganyika warms, the mixing of waters is lessened, the scientists find, meaning less nutrients are funneled from the depths toward the surface. Worse, more warming at the surface magnifies the difference in density between the two levels; even more wind is needed to churn the waters enough to ferry the nutrients toward the fish-dwelling upper layer.
The researchers’ data show that during the last 1,500 years, intervals of prolonged warming and cooling are linked with low and high algal productivity, respectively, indicating a clear link between past temperature changes and biological productivity in the lake.
“The people throughout southcentral Africa depend on the fish from Lake Tanganyika as a crucial source of protein,” noted Cohen, an author on the paper. “This resource is likely threatened by the lake’s unprecedented warming since the late 19th century and the associated loss of lake productivity.”
Climate change models show a general warming in the region, which, if accurate, would cause even greater warming of the Lake Tanganyika’s surface waters and more stratification in the lake as a whole. “So, as you move forward, you can imagine that density gradient increasing,” said Russell, an author on the paper.
Some researchers have posited that the declining fish stocks in Lake Tanganyika can be attributed mainly to overfishing, and Tierney and Russell say that may be a reason. But they note that the warming in the lake, and the lessened mixing of critical nutrients is exacerbating the stocks’ decline, if not causing it in the first place. “It’s almost impossible for it not to,” Russell said.
Other authors on the paper are Brown graduates Marc Mayes and Natacha Meyer; Christopher Johnson at the University of California, Los Angeles; and Peter Swarzenski, with the United States Geological Survey. The National Science Foundation and the Nyanza Project funded the research.
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Here is the University of Arizona version
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Twentieth-Century Warming in Lake Tanganyika is Unprecedented
Warming in the last century threatens one of Africa’s largest inland fisheries.
Lake Tanganyika’s surface waters are warmer than at any time in the previous 1,500 years, a University of Arizona researcher and his colleagues report online in Nature Geoscience.
The rise in temperature during the 20th century is driving a decline in the productivity of the lake, which hosts the second-largest inland fishery in Africa.
“People throughout south-central Africa depend on the fish from Lake Tanganyika as a crucial source of protein,” said study co-author Andrew S. Cohen, a UA professor of geosciences. “This resource is likely threatened by the lake’s unprecedented warming since the late 19th century and the associated loss of lake productivity.”
This is the first detailed record of temperature and its impacts on a tropical African ecosystem that allows scientists to compare the last 100 years with the previous 1,400 years, Cohen said.
The team attributes the lake’s increased temperature and the decreased productivity during the 20th century to human-caused global warming.
“We’ve got a global phenomenon driving something local that has a huge potential impact on the people that live in the region and on the animals that live in the lake,” he said.
The annual catch of the Lake Tanganyika fishery is estimated at about 198,000 tons per year, more than 20 times greater than the U.S. commercial fishery in the Great Lakes, he said. The nations of Burundi, Tanzania, Zambia and the Democratic Republic of Congo border the lake, which is the longest lake in the world and the second deepest.
The surface waters of Lake Tanganyika are the most biologically productive part of the lake. For the 1,400 years before 1900, those waters were no warmer than 75.7 F (24.3 degrees C). Since 1900, the lake’s surface waters warmed 3 degrees F, reaching 78.8 degrees F (26 degrees C) in 2003, the date of the researchers’ last measurement.
The researchers used sediment cores from the lake bed to reconstruct the 1,500-year history of the lake. The scientists analyzed the cores for chemicals produced by microbes and left in the sediments to determine the lake’s past temperature and productivity.
Because sediment is deposited in the lake in annual layers, the cores provide a detailed record of Lake Tanganyika’s past temperatures and productivity and of the regional wildfires.
The instrument record of lake temperatures from the 20th century agrees with the temperature analyses from the cores, Cohen said.
The cores were extracted as part of the UA’s Nyanza Project, a research training program that brought together U.S. and African scientists and students to study tropical lakes. The National Science Foundation funded the project.
“A big part of our mandate for the Nyanza Project was looking at the interconnectivity between climate, human activity, resources and biodiversity,” said Cohen, who directed the multi-year project.
Lake Tanganyika and similar tropical lakes are divided into two general levels. Most of the fish and other organisms live in the upper 300 feet (about 100 meters). At depths below that, the lake waters contain less and less oxygen. Below approximately 600 feet, the lake water, although nutrient-rich, has no oxygen and fish cannot live there.
During the region’s windy season, the winds make the lake’s surface waters slosh back and forth, mixing some of the deep water with the upper layers. This annual mixing resupplies the lake’s food web with nutrients and drives the lake’s productivity cycle, Cohen said.
However, as Lake Tanganyika warms, the upper waters of the lake become less dense. Therefore, stronger winds are required to churn the lake waters enough to mix the deeper waters with the upper layer. As a result, the upper layers of the lake are becoming increasingly nutrient-poor, reducing the lake’s productivity.
In addition, warmer water contains less dissolved oxygen, reducing the quality of the habitat for some fish species.
Other lakes in Africa are showing similar effects to those the team found in Lake Tanganyika, he said.
The finding has implications for lakes in more temperate climates.
“Increasingly, lakes in the U.S. are warming and they’re behaving more like these African lakes,” Cohen said. “There’s a potential for learning a lot about where we’re going by seeing where those lakes already are.”
The team’s article, “Late twentieth-century warming in Lake Tanganyika unprecedented since AD 500,” will be published in the June issue of Nature Geoscience.
Cohen’s co-authors on the paper are first author Jessica E. Tierney of Brown University in Providence, R.I.; Marc T. Mayes, Natacha Meyer and James M. Russell, also at Brown University; Christopher Johnson, a former University of Arizona student now at the University of California, Los Angeles; and Peter W. Swarzenski of the U.S. Geological Survey in Santa Cruz, Calif. The National Science Foundation funded the research.
Totally amazing; that there can be millions of people feasting off the fisheries of Lake Tanganyika, and all of that human hustle and bustle is carried on without stirring so much as a blade of grass on the shoreline so as to cause some mud to fall into the lake.
Those African Tribes are simply geniuses; like the tribes who have lived for thousands of years on the plains around the base of Mt Kilimanjaro; without anybody ever disturbing a branch on a tree growing in the vast rain forests on those plains.
We should all be such stewards of our natural surroundings.
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Mike, thanks for access to Birman’s forum article (Notices of the AMS, August 2000). I’ve got my nose right up against the world of clinical medicine (like most of us in the sawbones racket), and confess freely to damned little fine appreciation of what goes on in other disciplines.
Among the problems in medical academic publishing is the fact that it’s bloody expensive to conduct clinical research, especially to the standards very properly established in the usages of evidence-based medicine, which is where those of us with Betadine on our shoes have been trying to propel the medical literature for the past decade and a half.
With this in mind, it must also be remembered that to practice medicine in these United States today, it is effectively impossible not to hold board certification in one or another of the clinical specialties, and that makes de rigeur membership in one or more of the professional societies – ACOG, IDSA, AAP, AASLD, pick your acronymic lump – because you must keep up with developments in your specialty area, and the professional societies are, all other things being equal, the best conduits of information.
The publications of these professional societies therefore become hellaciously important, and the big publishing companies – like Elsevier and Wolters Kluwer (who own the Lippincott Williams & Wilkins journals) – run those periodicals.
Okay, so couple the very high real monetary costs of conducting prospective clinical investigative trials (which are almost exclusively funded by pharmaceuticals and medical device manufacturers) with the fact that these proprietary-to-obsession publishers control the principal fora in which the reports of medical research are promulgated, and you can see that those of us in medicine have a boatload of troubles which effectively prevent us from doing the sorts of things that you guys in mathematics (who work with chalkboards and computers and don’t have to pay for lab supplies, sutures, and professional liability insurance) can manage when it comes to ensuring academic rigor and freedom.
You guys can walk away from a professional society or other institution if you deem the conduct of the ruling elite objectionable enough. Moreover, said “elite” know good and goddam well that you can, which acts as a control on their officious weaselry.
People who get their living on the basis of being able to call themselves “board-certified” (you try getting on a hospital staff without such) can’t even put food on the table much less conduct good research without jumping through the ever-narrowing and ever-more-scorching fiery hoops set up by our predecessors.
I have no reason to believe that it’s not quite similar in the other get-your-hands-dirty sciences, like astronomy, geology, meteorology, atmospheric physics – even “climatology.”
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pesadilla says:
May 19, 2010 at 5:35 am
The concept of climate change has evolved to the point where it no longer needs co2 in order to create havoc. It is now a phenomenon in its own right. (possibly like dark matter). The phrase is most useful in obtaining grants for scientific studies and is more than capable of generating large amounts of money in order to perpetuate itself. It even has its own laws like azimovs robotics laws…..
I clean them up a bit for you. They are too good to let grammar and spelling mess them up. Corrections are in bold.
0)all projects that confirm the existence of AGW will be supported and funded generously and without question.
1) Any new project which is intended to support the first law will also be funded.
1) Any project containing the words “green” “renewable” or “endangered” etc will be seriously considered, provided that their findings do not conflict with the other two laws.
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Excellent! I have taken the liberty of renumbering the Laws of ACC (after messrs. Fibonacci, Wm. of Occ’m, & Codd and Date)
Thanks Tim and Bruce for the research.
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Tim Clark says:
May 19, 2010 at 8:24 am
“There are numerous studies, including below, that differ with this paper…..
Temperature wise, it is not only the large water mass, but another factor that makes Lake Tanganyika so stable – even more stable and homogenous than the ocean in most places. This factor is volcanic activity near the bottom of the lake…..”
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Seems Vukcevic is correct. It is probably volcanic heating especially since we seem to have more sesmic activity lately. Bruce, did the paper make any mention of “…volcanic activity near the bottom of the lake…”
“The team’s article, “Late twentieth-century warming in Lake Tanganyika unprecedented since AD 500,” will be published in the June issue of Nature Geoscience.”
The team’s article, Late twentieth-century warming in Lake Tanganyika not unprecedented since AD 1250 Medieval Warm Period when the lake was significantly warmer due to increased solar activity, will be published in the June issue of Nature Geoscience.
There, fixed it for ya.
Slightly OT, but I saw an ad for a temperature data-logger that looked very nice. It seems as though it would make lake temp measurements much easier.
Look Ma, no driver — temperature logging via USB
Spurring the growth of PC-based data-acquisition (DAQ) systems is a wealth of new instrumentation systems designed to work with PCs. One such device is National Instruments (NI) USB-TC01, a USB-connected data-acquisition module that measures and records temperature via a thermocouple. The new device combines a plug-and-play setup with the capabilities and features of other NI DAQ products.
What makes the USB-TC01 noteworthy is that it needs no setup time or driver-software installation. Known as NI InstantDAQ technology, the device automatically loads everything the computer needs to take and record temperature measurements when plugged into a USB port. In addition, the module features a standard miniplug connector that lets the logger use different thermocouples to meet specific application needs.
The USB-TC01 offers temperature measurement and logging for applications in scientific labs; heating, ventilating, and air-conditioning (HVAC) units; cryogenics; industrial ovens and furnaces; engine-exhaust and combustion systems; building monitoring; and many other environments. In addition to saving time and resources in system setup, the device also exhibits the overall accuracy and reliability of more-complex measurement systems. With traditional stand-alone data loggers, measurements are made independently of the PC so data can only be viewed offline. The USB-TC01 is always connected to the PC so it can take live measurements with temperature readings displayed instantly on the PC monitor.
Optional free applications available at http://www.ni.com expand the basic functions of the USB-TC01. Or the USB-TC01 can be combined with NI LabView graphical-system-design software using the NI-DAQmx driver software.
REPLY: Or see these that I offer: http://weathershop.com/dataloggers.htm – Anthony
As a lake ecologist who has read a few dozen publications of Lake Tanganika, I recomend reading a part of the scientific literature before pronouncing judgement on one paper that builds on the earlier work. I recommend a 2009 paper that is available from ASLO.org as a free download.
http://www.aslo.org/lo/toc/vol_54/issue_6_part_2/2418.pdf
Unfortunately for Mr. Watts’ speculation, the water of this lake has become clearer since 1913. Reduced nutrient mixing due to stronger and shallower stratification evidently over rides effects of land use in the basin.
The best paper on these issues is probably Verburg and Hecky 2003 (Science).
Quite a lot of the literature on this lake should be available as free downloads–try searching using Google Scholar. These paper also talk about the equipment needed and the accuracy in measuring temperature of such a deep lake.
Enneagram says:
May 19, 2010 at 11:07 am
There is too much anger in the Green Church believers, so I would suggest to decriminalize pot to calm them down.
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Yes and make hemp, a very useful plant, legal too.
Hemp for Victory. USDA, 1942 http://www.globalhemp.com/Archives/Government_Research/USDA/hemp_for_victory.shtml
Nigel Harris says: May 19, 2010 at 7:11 am
“So, nobody is prepared to invest $18 and an hour or so to actually understand what these scientists are saying. Instead, we now know that, whatever it is that they’re actually saying, it can’t be true, because…
“… David L’s pool in Philadelphia isn’t any warmer than it was 5 years ago”
Actually I got the paper. I spent half my career as a PhD in Ivy league universities grubbing for grants and publishing in peer reveiwed journals. I know how the system works. Terms like “Global Warming” will get you grant money, trust me. Happily the past 10 years I’ve been developing safe and effective drugs with my chemistry degree.
My somewhat tongue-in-cheek comment about my pool is about how I feel about AGW. From a thermodynamic standpoint can you explain to me how a massive lake warms by 3 degrees due to a global effect like CO2 yet my tiny little pool (which is on this globe) sees a negative effect of 5 degrees in the past 5 years. No CO2 in Philly, it’s all in Africa? (which place is more industrialized by the way) Thermodynamics only apply to Africa? Local weather patterns are different? If you’re going to claim the globe’s temperature is driven by a single large factor (like CO2) then that should drive the effect all over the globe, shouldn’t it? (or it wouldn’t be a global problem). Otherwise you have to admit that it’s either not that large of a factor, or it’s tempered by other factors and their interactions with each other. And then you have to admit you don’t really understand everything about the science, because you can’t explain all the effects around the globe. So tell me, if CO2 is a nice cozy blanket that traps heat, why isn’t it happening in my backyard? I had to wear my winter coat to work today. 100 years ago on this date it was 82F.
George E. Smith says:
May 19, 2010 at 2:55 pm
Yes, the locals have lived like ninjas for thousands of years around the Lake – you can’t even hear them walking, barefoot on the dirt roads. And the fishermen slip into the water without a sound, the result of hundreds of generations of living with crocodiles. Then the missionaries came in the late 1800’s, with their thousands of clumsy, turbid baptisms every day, and the Lake began to warm, until we’ve reached the current crisis.
This has been researched by Mr. Nkurunziza (see above), an expert on Anthropogenic Local Warming (ALW) in Burundi. His policy recommendations to the IUCN for returning Lake Tanganyika to it’s optimal temperature: capture and breed Gustave, the supercroc, and seed the shores all around the Lake with these future maneaters. “I’ve seen the missionaries run away from the water screaming like little girls when they thought they saw Gustave approaching” said Mr. Nkurunziza, laughing. “Keep them out of the Lake, and the mud will settle quickly. Problem solved. The Lake will cool down.”
http://adventure.nationalgeographic.com/2005/03/gustave-crocodile/michael-mcrae-text/1
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Pat Moffitt says:
May 19, 2010 at 1:10 pm
“……I have done a fair amount of investigation on the problems with the latid and clupeid fishery (sociological and ecological) in both Lakes Victoria and Tanganyika- outside this scope. There are any number of pressing problems with these fisheries and the impacts are potentially large to the local human population. For the researchers to “imply” that CO2 induced temperature changes represents a significant concern for the lake or the residents is wrong on too many levels. The residents of Lake Tanganyika’s shores are unfortunately facing far more pressing near term threats to survival– and any chance we had to “fix” these problems of overfishing, deforestation (fire wood), pollution, habitat loss, agriculture run off, civil war, etc are now diminished because the tool set has been restricted to CO2 reduction. A good test would be checking back in a year and see where aid and research money was spent– addressing the region’s “problems”.
Remember it is actually wind that causes the upwelling (the density difference related to T being quite small) and as such these researchers have to make some serious leaps in correlating wind speed with temperature to make the nutrient links.
“If” the problem is actually some reduction in productivity as a result of nutrient deficiency — then the answer is pretty simple- add fertilizer. The efficacy of this is quite well know and has been researched and demonstrated extensively with salmon populations (replacement of decaying salmon nutrients -MDN- lost to high seas commercial fishing with commercial fertilizer causing an increase in salmon production of 3 to 5X the baseline) as well as with warm water fish populations.
I would have had less of a reaction had these researchers mentioned the fact that nutrient addition would cause an immediate increase in the lake’s food production and the well being of the resident human population– whether or not climate change is real. Failing to tell the media that an easy nutrient fix is available or how CO2 ranks with the other problems faced in this region-in my view is unethical and immoral.”
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Thank you.
Making CAGW the “boogeyman” no matter what the real cause is resulting in major damage. This fact seems to sail right over the heads of the “environuts” Whether you think CO2 is causing warming and is cause for concern or not, blindly supporting irresponsible “pseudoscience” such as this IS doing real harm to the environment and the people of the region. Responsible environmentalists should be actively pointing out the harm these quacks are doing, just as medical Doctors should denounce snake oil salesmen.
Here’s a link to a picture of the one I mentioned.
http://machinedesign.com/content/single-channel-thermocouple-0503
Mike says:
May 19, 2010 at 2:34 pm
“…. Public universities in the U.S. will allow state residents to purchase library cards for a modest fee…..”
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Thanks for the tip Mike. I guess if worse came to worse you could “donate” a subscription to the local community college at their reduced fee AND take the “donation” off your taxes.
I don’t really understand the criticism of studies without reading the original study or any of numerous background papers on the same lake. I mentioned this paper, which is availble from the top rated Aquatic journal as a free downloald:
http://www.aslo.org/lo/toc/vol_54/issue_6_part_2/2418.pdf
Among other things, this paper shows that the open waters of the lake have become substantially clearer (less turbid) over the last 100 years. The temperature data for the deepest waters show that geothermal heating is neglible and could not possibly effect the temperature of the top 100 m, the focus of most studies. The paper that Anthony cites in his lead in shows effects of run off and polution in the shallow, near shore waters to a depth of 80 m, especially near river inflows. Clearly this is a problem for the littoral, rocky bottom fish, that comprise most of the species diversity. However, since this is one of the largest lakes in the world, these nutrient inflows evidently have very little effect on the nutrient content, turbidity and productivity of the open waters of the lake (average depth over 500 m). In these main, open waters of the lake effects of climate warming on stratification and nutrient regeneration are very strong over the last 100 years. Readers should not make knee jerk conclusions without reading data rich papers that conflict with their expectations.
Gail Combs says:
May 19, 2010 at 4:25 pm
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Pat Moffitt says:
May 19, 2010 at 1:10 pm
“……I have done a fair amount of investigation on the problems with the latid and clupeid fishery (sociological and ecological) in both Lakes Victoria and Tanganyika
I did both Google and Google Scholar searches on Patrick and did not find anything beyond blog posts. He suggests that adding nutrients might be a simple solution to the reduced productivity of the lake with a volume of over 18,000 cubic km. This solution has worked well in small salmon lakes with on the order of 0.001% of the volume of L. T. but fertilizing such a big lake and deep where nutrients are quickly lost to depth may not be a simple solution IMO.
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BillD, thank you for access to Verburg & Heckey (Limnol. Oceanogr. 2009, pp. 2418-2430) on “The physics of the warming of Lake Tanganyika by climate change.” I’m going through the paper with attention to the “Discussion” session, runs from page 2421 through page 2439.
Big damned “Discussion” section, ain’t it?
From page 2425 I draw the following:
The recent net global forcing that drives climate change amounts to 0.85 W m22 (Fig. 9; Hansen et al. 2005), six times the mean of the past century (Fig. 9B). Modeling indicates that lakes will absorb less net heat than is applied by local climate forcing (Fig. 9), by enhancement of their heat outputs through the interaction with the atmosphere. Deep lakes, however, have the capacity to absorb more heat than shallow lakes, and in a warming climate heat outputs will increase more slowly in deeper lakes than in shallower lakes. This inherent tendency toward greater heat absorption with little change in surface temperature in deeper lakes will be reduced if the lakes become increasingly stratified as warming progresses, as has been the case in Lake Tanganyika.
The global hydrological cycle is expected to accelerate with climate change (Wentz et al. 2007), and global evaporation has been predicted to increase (Ramanathan 2001), which agrees with our conclusion of increased heat outputs, in part through evaporation, by most lakes. The extent to which evaporation from inland water surfaces will change in a changing climate not only affects the heat budget and stratification of the water column but will also be of great importance to the water balance and water levels in lakes and to the availability of freshwater in a warmer world
Oh, drat. Drawing on Hansen’s models. Seems as if Drs. Verburg & Heckey are paying tribute to the AGW fraud, aren’t they?
Grinding repeatedly through the paper, I’m not sure if I’ve yet found something that I can honestly call a conclusion. I don’t contest the authors’ assertion that:
Climate warming has affected the physical structure of Lake Tanganyika and substantially affected the functioning of the pelagic ecosystem
…but there is that highly damning concluding sentence to all this “Discussion,” to wit:
Although African ecosystems are remote from most of the anthropogenic activities that have driven climate warming, the Great Lakes of Africa and their riparian human populations have not and will not escape its effects.
So Drs. Verburg & Heckey consider themselves to have done what they set out to do, which was not so much to determine how the waters of Lake Tanganyika are changing in response to the well-understood rebound in global temperatures since the conclusion of the Little Ice Age but rather to validate the anthropogenic global warming hypothesis.
Which they fail to do, you understand. Drs. Verburg & Heckey observe warming. That’s fine. There’s hard evidence of that.
Is there hard evidence in their observations proving that there has been substantial acceleration in the rates at which that warming – since 1850, remember – has been pumped up by anthropogenic increases in atmospheric carbon dioxide concentrations, or are they simply falling back on Dr. Hansen’s computer models?
There is much made by the authors of expectations (Wentz et al. 2007) and predictions (Ramanathan 2001) with which Drs. Verburg & Heckey’s conclusions have been made to agree, but I’d be grateful if you – or anybody – could show me how the warming trends demonstrated by the observational data subjected to meta-analysis in this study provide support for the AGW hypothesis.
Anent that meta-analysis (’cause it sure as hell looks like a meta-analytical paper), did either Dr. Verburg or Dr. Heckey actually do any field work resulting in information analyzed to produce this publication? In the “Acknowledgments” section there is mention made of “the deployment and maintenance of recorders” conducted by “Personnel of the Fisheries Departments of Burundi, Congo, Tanzania, and Zambia” and how “Thermistor data in 1994–1996 were collected as part of research conducted by the Project for the Management of the Fisheries of Lake Tanganyika, Food and Agriculture Organization (GCP/RAF/271/FIN),” but not a whole helluva lot of sneakers-on-the-riverbank sweat equity appears to have been invested here.
But that’s neither here nor there. Again, the focus should be – when examining this wealth of information – on whether or not what has been happening in Lake Tanganyika provides insight into some sort of climate change which is distinctly different in character from the relatively slow, relatively steady rebound in global temperatures that has been observed since the end of the Little Ice Age.
If carbon dioxide forcing were a significant factor in this climatic warming, then as the atmospheric content of carbon dioxide isotopically identifiable as resulting from the combustion of fossil petrochemicals has been very rapidly increasing, there really ought to be some proportionality in the rate of increase in average temperature, no?
Am I missing something in Drs. Verburg & Heckey’s paper? If so, I’d ask for a helping hand.
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Silent spring for Mongolians after winter kills herds
The long, cold winter killed an estimated 8 million animals, leaving impoverished herders struggling to survive.
Oops Jesica needs to frame her story to include the planet. He little study 7 years ago has be followed cattle frozenon the hoof.
A real honest scientist needs to take some cores all over the planet.
Good flippin grief. It a lake in a rift that made the news recently when the northern section ruptured for a length of 35 miles near Dabbahu volcano up in Ethiopia. All the talk then was about the “New Ocean” that was just around the corner.
Africa is not well known for it’s extensive seismic network. Just a few days ago it was reported that Mikeno volcano in the Congo had erupted and killed dozens of people. Turns out it was actually a landslide associated with river flooding and that 46 people had died…. the volcano remains quiet. Some of the volcanoes near there erupt and no one knows about it for days or months.
A quick dig around the USGS site at http://earthquake.usgs.gov/earthquakes/eqarchives/epic/epic_circ.php yields at least 12 earthquake following the axis of the lake since 2008. Magnitudes: 3.9, 4.7, 4.2, 5.2, 4.6, 5, 5.5, 5.3, 4.5, 5.2, 4.5, 5.1. And to top that off, a cluster at 2.43S – 28.88E of about 14 with the largest being about Mag 5.9.
Not seismically active… yeah, riight.
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Damn. Mr. Watts, would you please strike that 6:29 PM post of mine? Glitches….
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REPLY: OK feel free to repost -A
Lake Baikal is the largest. Lake Superior is 2nd largest. L.Tan. might be 3rd. By volume. Cheers, gm
BillD
As a lake ecologist perhaps you missed the work done by the FAO’s Lake Tanganyika Framework Fisheries management Plan and the incorporated ecosystem management strategy paper by NKOTAGU, H. H. which states:
“The lake faces a number of threats including excess sedimentation, over – fishing,
pollution and habitat destruction along with climate change.”
As I posted earlier the lake has seen eutophication in the near shore waters and increasing oligotrophy in the pelagic areas (can cause problems with the lipid proxy used for T). Also see: Cohen, A., Bills, R., et al. (1993). “The impact of sediment pollution on biodiversity in Lake Tanganyika” Conservation Biology 7(3) 667-677
And the Lake Tanganyika Regional Fisheries Programme (TREFIP) ENVIRONMENTAL IMPACT ASSESSMENT REPORT -GCP/INT/648/NOR Field report which found “Bottom friction and water temperature play secondary roles in driving the hydrodynamics of the lake. Relatively high temperatures make the viscosity of Tanganyika’s waters low as compared to those in temperate regions.”
Another paper in the FAO document by Sarvala et al cautions “Fish production is ultimately dependent upon food production, and thus subject to climate-induced changes. However, the path from hydrodynamics to fish yields is
long and direct links may be difficult to identify.” Lake Tanganyika’s primary production dynamics may be uniquely complex .
The researchers claiming a CO2 temperature link and implied danger to the fisheries may have also missed Sarvala’s finding that:
“Neither could fish catch changes be linked to long-term trends in copepod zooplankton. Between-region comparisons also failed to show a direct connection between fish catches and food availability.”
Or the findings of Reynolds et al RESEARCH FOR THE MANAGEMENT OF THE FISHERIES ON LAKE TANGANYIKA GCP/RAF/271/FIN-TD/97
“Ecological studies and catch surveys have shown that production rates fall within the average range for deep tropical lakes, and are indeed not particularly high. These studies have also evaluated the vulnerability of the fish stock to increased
fishing pressure and possible over-fishing.”
So it would seem this recent paper highlighting temperature impacts on the fishery production may not have been a proper assumption- (There have been papers by Coenen and by Mannini that show SOME temperature correlation.) This study also found evidence of severe over-exploitation of the fish stocks.
The CO2 as “cause” simplifies the complex and in so doing prevents us from understanding. The Reynolds study concludes with far less hubris:
“Inter-annual, seasonal, and areal variations in yields within
Lake Tanganyika may be linked to the complex relationships
between fish stock fluctuations and migrations and the incidence
of nutrient upwelling and related plankton succession. Yet such
knowledge, even when coupled with findings from the wider set of
hydrophysical, limnological, and related studies that have been
conducted through LTR and other scientific investigations, by no
means allows for close ‘when, where, and how much’ predictions
of ecosystem fluctuation.”
BillD says:
I did both Google and Google Scholar searches on Patrick and did not find anything beyond blog posts. He suggests that adding nutrients might be a simple solution to the reduced productivity of the lake with a volume of over 18,000 cubic km. This solution has worked well in small salmon lakes with on the order of 0.001% of the volume of L. T. but fertilizing such a big lake and deep where nutrients are quickly lost to depth may not be a simple solution IMO.
Your right-I’m no “scholar”-but I had a lot of them that worked for me. I’m just a plain old graduate scientist with 35 years experience that doesn’t know enough to be quiet around my betters. I didn’t write papers- I wrote reports – my career was about trying to understand problems and fix them. If I didn’t fix them- I didn’t get paid or would be open to suit. I’m sure academics would be much more careful with their work if the same applied.
So de-carbonizing the industrialized world and “changing civilization as we know it” is easier than fertilizing Lake Tanganyika? (The salmon projects were demonstrations and showed no limitations as to scale. The real point with the salmon is there are tens of millions to study salmon problems but no money to start full scale fertilization program that is a known fix. A solved problem however has no academic value. There is actually a counter-incentive to fix environmental problems.)
I stand by my comments- the problems faced by the Lake and the people are complex- dismissing what we know about overfishing and trying to simplify the ecosystem dynamics to temperature is counterproductive if not reckless.
Nigel Harris says:
May 19, 2010 at 10:34 am
I’m going to have to try to find another site where I can find genuine, scientific scepticism about AGW, not uninformed knee-jerk condemnation of other peoples’ work.
so because we chuckle at people who still blindly thrash about like Don Quixote De Lamancha against the windmill when their theories have been proven to be full of lies and are ludicrous, we are bad people because we use critical thinking skills and figure out for ourselves rather than following the mantra of the dogmatic liberal?
And they say the skeptics are anal and have no sense of humor.
speaking of humor.
http://www.skepticalscience.com/Unprecedented-Warming-in-Lake-Tanganyika-and-its-impact-on-humanity.html
John Cook from “Skeptical Science” blog was kind enough to give the entire article about Lake Tanganyika and right smack at the top there is a pretty little chart. Does that chart look even vaguely familiar? I looked from top to bottom of this thread and I didn’t see anyone else mention it, so I thought I would.
These people are saying this is unprecedented since the time of the Medevil warming period. Well it was hotter then than now but mysteriously the chart on the right is far higher than the time of the MWP, or even the Holocene optimum several thousand years before then. So what exactly happened to those herring back then? Was there a medevil fish hatchery truck that went around dumping herring back into the lake system after the warming period was over? Did the fish adapt? One would assume so since these lakes have had fish since Biblical times since the Bible talks about large amounts of fish in the seas around Galilee. Did the fish get out and crawl to another body of water then crawl back to the lake when temperatures were more to the scientists liking of the day?
I know these are all things below the lofty mentality of the warmist scientist but they are common everyday things that just make their science look “unbelievable” at best.
I must also say the warmists are a little slow on the uptake of getting the gospel of global warming out… you guys have been talking about it since yesterday, skeptical Science just got it out today.
Mike says:
May 19, 2010 at 11:32 am
Billy Liar said (May 19, 2010 at 10:28 am): “Seems to me that an ill thought out press release can do a lot of harm to your reputation as a scientist (assuming you have/want one).”
Good point. You might be interested in this.
How not to write a press release – gavin @ur momisugly 21 April 2006:
http://www.realclimate.org/index.php/archives/2006/04/how-not-to-write-a-press-release/
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Mike, many thanks for the link. I did find it interesting; I’m reading the comments too.
So if I give her a sample of water from the deep and another 1 cubic meter sample from the surface, she can tell which came from the bottom? Warm water rises. She appparently didn’t test for differences is waves at different temps. You can’t compare fish output with the Great Lakes because they freeze over. Cuts into suface algae there also.
I read so many little comments in her opinion piece that are all about what she feels is going on. If the cores were drawn at the deep part, how do they compare with dozens of cores taken in shallower water? Ooops. She just has 1 core sample?