Moderated Global Warming Discussion
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Speaking of the AGU, have you seen this paper? It's one of the more interesting angles taken to determine the origin of the methane plumes.
EOS, TRANSACTIONS AMERICAN GEOPHYSICAL UNION, VOL. 92, NO. 49, PAGE 464, 2011
doi:10.1029/2011EO490014
RESEARCH SPOTLIGHT
Siberian shelf methane emissions not tied to modern warming
Colin Schultz
American Geophysical Union, Washington, D. C., USA
Eight thousand years ago, a rising sea inundated the vast permafrost regions off the northern coast of Siberia. Comprising the modern east Siberian shelf, the region holds enormous quantities of methane hydrates bottled up in remnant subterranean permafrost zones that are, in turn, trapped beneath the ocean waters. Records of seafloor water temperature showing a 2.1°C rise since 1985, coupled with recent observations of methane emissions from the seabed, have led some scientists to speculate that the rising temperatures have thawed some of the subsurface permafrost, liberating the trapped methane. The connection is compelling, but an investigation by Dmitrenko et al. into the sensitivity of permafrost to rising temperatures suggests the two observations are not connected. Using a permafrost model forced with paleoclimate data to analyze changes in the depth of frozen bottom sediments, the authors found that roughly 1 meter of the subsurface permafrost thawed in the past 25 years, adding to the 25 meters of already thawed soil. Forecasting the expected future permafrost thaw, the authors found that even under the most extreme climatic scenario tested this thawed soil growth will not exceed 10 meters by 2100 or 50 meters by the turn of the next millennium. The authors note that the bulk of the methane stores in the east Siberian shelf are trapped roughly 200 meters below the seafloor, indicating that the recent methane emissions observations were likely not connected to the modest modern permafrost thaw. Instead, they suggest that the current methane emissions are the result of the permafrost's still adjusting to its new aquatic conditions, even after 8000 years. (Journal of Geophysical Research-Oceans, doi:10.1029/2011JC007218, 2011)
aleCcowaN
imperfecto del subjuntivo
cold=death, warmth=life, heat=superpowers,
was it that "the line"?
About Toba's, I'm not going to repeat myself as I have little to add to this post.
A list of things that I think to be inescapable in a GW layman discussion:
-the use of barely known concepts as 'correlation'
-the abuse of adjectives and adverbs to sell the product, for instance, by using "inescapable".
-people who are really worried about their incomes dropping 2% next year owing to recession (so they no longer allow themselves a wax depilatory of their third eyes) are the same people assuring that the planet will manage well ice ages and meteorites crashing, or those not being a real concern.
Furcifer
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Yes, those of us that are familiar with statistical analysis are comfortable calling it an "educated guess".
Neither post supports your false claim.
This is common knowledge.
As I pointed out the well is already poisoned by this cargo cult of climate science.
Nonsense. I've talked numerous times about "calculating trends" like climate sensitivity here in this very forum in this very thread. You know this and continue to say otherwise. It's a complete falsehood.
This is a lie and if you read post #4103 for comprehension you will see why. I really don't know anyone who would claim the recent change isn't rapid.
Correct. These are based on model "approximations". They "confirm" nothing and claiming otherwise is to deliberately misrepresent the science.
Trakar
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Presumably, you do realize that this is an article, not an actual research paper and that it is written by a canadian science journalist, not an actual climate or arctic conditions researcher. But the article in question reviews this paper by Dmitrenko ("Recent changes in shelf hydrography in the Siberian Arctic: Potential for subsea permafrost instability" - http://www.agu.org/pubs/crossref/2011/2011JC007218.shtml) published back at the beginning of Oct. It will be interesting to see how this resolves with a more complete community peer review, that is how science works.
The Semiletov paper has been out for more than a year and a half, and has generally been well received and reviewed amongst the field of researchers specializing in Methane deposits and their reaction to changing environments (cited more than 50 times so far). The Dmitrenko (who specializes in atmospheric and ocean currents and interactions) paper has so far not received much peer comment or reaction, among the researchers who actually specialize in permafrost and methane deposit issues (0 cites).
Personally, I sincerely hope Dmitrenko is more correct than Semiletov, because if the shallow water clathrate deposits are already subject to large scale decomposition things are likely to get a lot worse, a lot faster than many of the researchers being labelled "prophets of Doom" by those seeking "profits from Doom" are projecting.
In science correlation does not equal causation, that much should be obvious to all. I challenge you to find a time when it has been cold and the world did well however. On the other hand the paleo record is very clear that warmth equates to properity. The PETM saw the greatest expansion of terrestrial species the world had seen up to that point according to the fossil record.
I'm curious as to why you hold this belief? The study that this article was based on shows that this process has been going on for at least 8,000 years. Why is this day any different then the 2,920,000 days that came before?
This particular interglacial has been exceptional for one thing and that is the amazing stability of global temps. For the last 10,000 years the globe has held to a one degree band of temperature fairly consistently (the RWP and MWP being the warm exceptions and the 6th Century climate catastrophe and the LIA being the cold exceptions). There has been an approximate rise of .7C over the last 2000 years. That is amazingly stable. That is truly the strange climate we are experiencing! At no time in the history of this planet, that we are able to measure, has it been this stable a temperature.
Trakar
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It isn't the heat or the cold that matters so much as the amount of shift from the existent mean and the rate at which change occurs. For humanity, cold has been more the traditional killer, because we and the majority of the planet's current flora and fauna evolved and adapted to moderately warmer enclaves during the last few million years of planetary ice age and regular cycles of expanding and retreating glaciations. We as a society are currently in the process of ending that ice age and pushing the Earth into planetary climate regimes that haven't existed in tens (if not hundreds) of millions of years. More importantly, we are forcing this change at a pace that is several orders of magnitude faster (globally) than we have yet found good geologic comparisons for. What we know, is that there are several periods of climate change that have occurred at a much slower pace than the one we are pushing presently, that have killed off major proportions of our planet's flora and fauna.
"Causes and consequences of extreme Permo-Triassic warming to globally equable climate and relation to the Permo-Triassic extinction and recovery" - http://www.sciencedirect.com/science/article/pii/S0031018203006679 (abstract)
"Recent ecological responses to climate change support predictions of high extinction risk" - http://anpron.eu/wp-content/uploads...pport-predictions-of-high-extinction-risk.pdf (full pdf)
"Impacts of climate change on the world's most exceptional ecoregions" - http://www.pnas.org/content/108/6/2306.full
(full text)
Trakar
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Please demonstrate the science which indicates that an average global decrease of temperature by 8 degrees C is more dangerous than an average global increase of temperature by 8 degrees C.
Trakar
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Which university would that be?
Trakar
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Please quote the posts to which you are responding. Out of context responses without reference or indication to the discussion and issues being commented upon do not carry well in a moderated thread where they do not well connected to the material being discussed.
Trakar
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Presently? the last 200 years? the last 8000? the last 2 My? Cold? cooler than what hot period? properly frame your challenge and define your terms.
cite or reference?
Cite or reference?
Trakar
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to which belief do you refer?
Please point out in the paper exactly what you are referring to and how you feel this relates to your contentions or my statements.
8,000 years ago, the planet had begun cooling down from an interglacial maximum, headed back towards an eventual glacial expansion a few tens of millenia in our future. Over the last 2 centuries our species has reversed these natural trends and put us back to the point of the Holocene maximum and headed toward surpassing atmospheric compositions and temperatures that our planet has not witnessed in tens (possibly hundreds) of millions of years. And this will happen without including consideration of any of the triggerpoint feedbacks from issues like permafrost clathrate decomposition.
cite or reference?
Actually it's a pretty simple process. Volcanic activity releases enormous quantities of sulfer dioxide and particulate matter into the atmosphere. This cools the planet and reduces the growing time for the plants that are the bottom of the food chain. Starvation ensues.
It's not rocket science. It is the fundamental problem with subsistence level agriculture which has been then norm for most of human existence. You like to harp on about rate of change being the determiner and in a way you are correct, but in an accidental manner.
Rate of change kills because subsistence level agriculture can't prepare for a single years interuption. We can. Our farming technology has increased to the point that when Russia lost most of their wheat crop it wasn't that big a deal. Whaet prices peaked at I think it was 14 bucks for a bushel but that pales in comparison to the 1920's price of 22 dollars a bushel (equivalent) the last time there was a major loss of production.
I will simply let the historical record do that for me. A couple of years ago there was a cold snap that hit the northern hemisphere and 1.6 million animals perished in Mongolia alone. Please show us a time when it was warmer and animals died in those numbers.
Pick any time you wish.
Here is the wikipedia page on the PETM which I am using for brevity due to it being past midnight and I'm tired! If you wish to look there are dozens of papers on Springerlink dealing with the profusion of life during the PETM.
Life
Edited by Gaspode:
Snipped for compliance with rule 4.
The increase in mammalian abundance is intriguing. There is no evidence of any increased extinction rate among the terrestrial biota. Increased CO2 levels may have promoted dwarfing[26] – which may (perhaps?) have encouraged speciation. Many major mammalian orders – including the Artiodactyla, horses, and primates – appeared and spread across the globe 13,000 to 22,000 years after the initiation of the PETM.[26]
http://en.wikipedia.org/wiki/PETM
And here is the link to Paleontology online with their take on the mammalian response to the warmth.
Mammals underwent profound evolutionary and biogeographic changes at the Paleocene–Eocene boundary. Three groups that incorporate many modern mammal species appeared suddenly at this time: Artiodactyla, which includes deer, camels and cows; Perissodactyla, which includes horses and rhinoceroses; and Primates, which includes monkeys, gorillas and humans. These groups probably originated in Asia and then rapidly dispersed to Europe and North America, all within the space of a few thousand years. It seems likely that movement between continents occurred over high-latitude land bridges (such as Greenland or the currently submerged land bridge under the Bering Strait), which only became warm enough to access during the PETM. A number of more ancient Paleocene mammals also went extinct at this time.
Edited by Gaspode:
Snipped for compliance with rule 4.
http://www.palaeontologyonline.com/articles/2011/the-paleocene-eocene-thermal-maximum/
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