Posted on 02/27/2011 1:27:52 PM PST by Ernest_at_the_Beach
Arctic environment during an ancient bout of natural global warming
Scientists are unravelling the environmental changes that took place around the Arctic during an exceptional episode of ancient global warming. Newly published results from a high-resolution study of sediments collected on Spitsbergen represent a significant contribution to this endeavour. The study was led by Dr Ian Harding and Prof John Marshall of the University of Southampton’s School of Ocean and Earth Science (SOES), based at the National Oceanography Centre, Southampton.
Around 56 million years ago there was a period of global warming called the Paleocene–Eocene Thermal Maximum (PETM), during which global sea surface temperatures increased by approximately 5°C.
The warming of the oceans led to profound ecological changes, including the widespread extinction of many types of foraminifera, tiny single-celled organisms with distinctive shells. Plankton that had previously only prospered in tropical and subtropical waters migrated to higher latitudes. Similar changes occurred on the land, with many animals and plants extending their distributions towards the poles.
“Although environmental changes associated with the PETM at low- to mid-latitude settings and high southern latitudes are well documented, we know less about these changes at high northern latitudes,” explained Dr Harding.
Information about the Arctic environment during the PETM has come predominantly from sediment cores drilled from under the pack ice on the Lomonosov Ridge (~ 88°N) by the Integrated Ocean Drilling Program (IODP Site 302-4A). However, these cores do not span the entire PETM and therefore do not provide a complete picture.
“Information from other Arctic sites is needed for a better understanding of PETM environmental conditions, such data can then in turn be used in computer models which will improve our understanding not only of past climatic conditions but also enhance our ability to predict future perturbations,” said Dr Harding.
To help fill this knowledge gap, Dr Harding’s team turned to a site (~78 °N) on Spitsbergen in the high Arctic. Here, 2.5-kilometre-thick sediments span the critical period. During the PETM, the site would have been at around 75 °N, the difference in position being due to the slow movement of tectonic plates over millions of years.
Through analyses of plankton and the chemical and magnetic characteristics of the sediments, they were unambiguously able to identify a 15-metre succession of exposed sediment representing the approximately 170 thousand year PETM event.
At the base of the segment they found the preserved remains of the cyst-forming dinoflagellate Apectodinium augustum, a planktonic species diagnostic of the PETM across the globe. In fact, the species was already present in Spitsbergen before the shift in carbon isotope composition formally marking the onset of the PETM, suggesting that environment change was by then already well underway.
Fieldwork in Spitsbergen
Along with data from other sites, their Arctic evidence suggests not only that sea level began to rise well before the formal onset of the PETM, but also that it peaked about 13,000 years into the period. At the same time, increased surface-water run-off from the land dampened water-column mixing and led to stratification, with an upper freshened layer that overlay denser, more saline seawater beneath.
By carefully comparing their results with those from IODP Site 302-4A to the north, they found evidence for regional differences in the environmental manifestations of the PETM in high northern latitudes. For example, the evidence from the IODP site suggests that the sunlit surface layer of the ocean was often depleted of oxygen, the results from Spitsbergen suggest that oxygen depletion was largely restricted to the bottom waters and sediments. In addition, they found that pollen from flowering plants was scarce, unlike at the IODP site, suggesting that conditions around the Spitsbergen Central Basin may not have been conducive to the growth of flowering plants during the PETM.
“Because this geologically short-lived event is represented by such an expanded section at Spitsbergen by comparison to other deep water sites, this locality has provided us with opportunities for further high-resolution studies of the PETM, which we are currently preparing for publication,” concluded Dr Harding.
The researchers are Ian Harding, Adam Charles , John Marshall, Heiko Pälike, Paul Wilson, Edward Jarvis, Robert Thorne, Emily Morris, Rebecca Moremon, Richard Pearce and Shir Akbari of SOES, and Andrew Roberts of the Australian National University, Canberra.
Preliminary field work was funded by The Millennium Atlas Company Limited, and a second expedition with other members of the palaeo-Arctic Climates and Environments (pACE) group was funded by the Worldwide Universities Network.
Harding, I. C., Charles, A. J., Marshall, J. E. A., Pälike, H., Roberts, A. P., Wilson, P. A., Jarvis, E., Thorne, T., Morris, E., Moremon, R., Pearce, R. B. & Akbari, S. Sea-level and salinity fluctuations during the Paleocene–Eocene thermal maximum in Arctic Spitsbergen. Earth Planet. Sci. Lett. (2011).doi:10.1016/j.epsl.2010.12.043
****************************EXCERPT**********************************
Levi Beckerson (Blog) - July 16, 2009 7:12 AM
Study Rocks Climate Debate! 'Nature not man responsible for recent global warming'
Climate Depot ^ | July 23, 2009 | Marc Morano
“The warming of the oceans led to profound ecological changes, including the widespread extinction of many types of foraminifera, tiny single-celled organisms with distinctive shells.”
The above quote, I believe, is one of the statements in the report with a very large and a most overlooked significance, particularly in the climate of the debates over “man-made” global warming.
Why?
Understand that there IS very large “chains” of some (varying) levels of interdependency of many life forms. Then reread the quoted statement, and then make a mental note of all the other periods of “mass” extinctions that science believes it has evidence for.
Then, remind yourself: LIFE, in the holistic sense WAS NOT EXTINGUISHED, it survived.
And, remind yourself further that if any species has the capability to adapt to “ecological change” it is humanity.
The global warming alarmists are on a political crusade, not a scientific crusade.
*************************************
| Study Finds Even Climate 'Alarmed' Americans Don't Want Cap-and-Trade ^ |
|||||||||||||||||||||||||||||||||
|
05/28/2009 10:44:29 PM PDT · by neverdem · 17 replies · 998+ views American Thinker ^ | May 29, 2009 | Marc Sheppard********************************
|
|||||||||||||||||||||||||||||||||
| Cosmic Rays Do Not Explain Global Warming, Study Finds ^ |
|||||||||||||||||||||||||||||||||
|
12/19/2008 9:38:10 AM PST · by ari-freedom · 36 replies · 958+ views Science Daily ^ | Dec. 17, 2008 | Science Daily******************************************** Thawing permafrost likely will accelerate global warming, study finds ^ |
|||||||||||||||||||||||||||||||||
|
02/16/2011 12:28:02 PM PST · by FreeAtlanta · 46 replies Science Daily ^ | 02/16/2011 | to embarrassed to claim******************************************************UC Berkeley study finds dire warnings on global warming may backfire ^ |
|||||||||||||||||||||||||||||||||
|
11/16/2010 9:53:40 PM PST · by SmithL · 24 replies · 1+ view
***********************************************
|
|||||||||||||||||||||||||||||||||
| A New And Effective Climate Model -- The problem with existing climate models: ^ |
|||||||||||||||||||||||||||||||||
|
********************************************
Wrong but useful (Climate models) ^ |
|||||||||||||||||||||||||||||||||
|
10/01/2009 9:46:13 PM PDT · by neverdem · 16 replies · 640+ views physicsworld.com ^ | Oct 1, 2009 | Gavin Schmidt**************************************************** The Granularity of Climate Models ^ |
|||||||||||||||||||||||||||||||||
|
03/12/2010 10:37:20 PM PST · by neverdem · 16 replies · 815+ views American Thinker ^ | March 13, 2010 | Bruce Thompson***************************************************** Faith-Based (Climate) Models ^ |
|||||||||||||||||||||||||||||||||
|
10/15/2008 1:53:15 PM PDT · by reaganaut1 · 1 reply · 309+ views Forbes ^ | October 2, 2008 | Peter Huber************************************************** It's the Climate Warming Models, Stupid! ^ |
|||||||||||||||||||||||||||||||||
|
03/30/2009 11:05:16 PM PDT · by neverdem · 21 replies · 1,078+ views American Thinker ^ | March 31, 2009 | Gregory Young************************************************************ Podcast: The Belief in Climate Models ^ |
|||||||||||||||||||||||||||||||||
|
wmbriggs.com ^ | William M. Briggs ************************************************** Ocean ridges and climate models ^ |
|||||||||||||||||||||||||||||||||
|
02/04/2011 11:43:56 AM PST · by Ernest_at_the_Beach · 19 replies Watts Up With That? ^ | February 4, 2011 | Anthony Watts*************************************************
|
|||||||||||||||||||||||||||||||||
Nicely said!
And indeed, it already has. The thermal range of human habitation varies from the hottest jungles and deserts to and past the Arctic circle, far greater than any possible proposed thermal change model. And that range was established in far prehistory, without all the technological tools and knowledge we currently have available.
So looked for that and found an entry at Wikipedia....
*********************************************
The Azolla event occurred in the middle Eocene period,[1] around 49 million years ago, when blooms of the freshwater fern Azolla are thought to have happened in the Arctic Ocean. As they sank to the stagnant sea floor, they were incorporated into the sediment; the resulting draw down of carbon dioxide has been speculated to have helped transform the planet from a "greenhouse Earth" state, hot enough for turtles and palm trees to prosper at the poles, to the icehouse Earth it has been since.
*************************************WHAT????*************************
MORE:
*****************************************
Azolla
Azolla has been deemed a "super-plant" as it can draw down as much as a tonne of nitrogen per acre per year[5] (0.25 kg/m²/yr); this is matched by 6 tonnes per acre of carbon drawdown (1.5 kg/m²/yr). Its ability to use atmospheric nitrogen for growth means that the main limit to its growth is usually the availability of phosphorus: carbon, nitrogen and sulphur being three of the key elements of proteins, and phosphorus being required for DNA, RNA and in energy metabolism. The plant can grow at great speed in favourable conditions – modest warmth and 20 hours of sunlight, both of which were in evidence at the poles during the early Eocene – and can double its biomass over two to three days in such a climate.[1]
During the early Eocene, the continental configuration was such that the Arctic sea was almost entirely cut off from the wider oceans. This meant that mixing — provided today by deep water currents such as the Gulf Stream — did not occur, leading to a stratified water column resembling today's Black Sea.[6] High temperatures and winds led to high evaporation, increasing the density of the ocean, and — through an increase in rainfall — high discharge from rivers which fed the basin. This low-density freshwater formed a nepheloid layer, floating on the surface of the dense sea.[7] Even a few centimetres of fresh water would be enough to allow the colonization of Azolla; further, this river water would be rich in minerals such as phosphorus, which it would accumulate from mud and rocks it interacted with as it crossed the continents. To further aid the growth of the plant, concentrations of carbon (in the form of carbon dioxide) and accessible nitrogen in the atmosphere are known to have been high at this time.[4]
Blooms alone are not enough to have any geological impact; to permanently draw down CO2 and cause climate change, the carbon must be sequestered, by the plants being buried and eventually fossilised. The anoxic bottom of the Arctic basin, a result of the stratified water column, permitted just this: the anoxic environment inhibits the activity of decomposing organisms and allows the plants to sit unrotted until they are buried by sediment and incorporated into the fossil record.
With 800,000 years of Azolla bloom episodes and a 4,000,000 km² basin to cover, even by very conservative estimates more than enough carbon could be sequestered by plant burial to account for the observed 80% drop in CO2 by this one phenomenon alone.[8] This drop initiated a global temperature decline which continued for millions of years[citation needed]; the Arctic cooled from an average sea-surface temperature of 13 °C to today's −9 °C,[1] and the rest of the globe underwent a similar change. For perhaps the first time in its history,[9] the planet had ice caps at both of its poles. A geologically rapid decrease in temperature between 49 and 47 million years ago, around the Azolla event, is evident: dropstones — which are taken as evidence for the presence of glaciers — are common in Arctic sediments thereafter. This is set against a backdrop of gradual, long-term cooling: It is not until 15 million years ago that evidence for widespread polar freezing is common.[10]
While a verdant Arctic Ocean is a viable working model, sceptical scientists point out that it would be possible for Azolla colonies in deltas or freshwater lagoons to be swept into the Arctic Ocean by strong currents, removing the necessity for a freshwater layer.[10]
Much of the current interest in oil exploration in the Arctic regions, made possible by global warming, is directed towards the Azolla deposits. The burial of large amounts of organic material provides the source rock for oil, so given the right thermal history, the preserved Azolla blooms might have been converted to oil or gas.[11] This means that much money is available for the study of this event[citation needed] — a centre has been set up in the Netherlands devoted to Azolla.[12]
“The thermal range of human habitation”
It is more than simply the thermal range.
Humans have both “caused” and adapted to changes in the loss and the predominance of various flora and fauna - throughout human history, and still LIFE rit large and humanity and a “habitable” planet have all survived.
Can it be any less now when our technological abilities are so much greater? No, it can’t.
(Earth in Upheaval by Immanuel Velikovsky, pp 41-42)
Corals of the Polar Regions
Spitsbergen in the Arctic Ocean is as far north from Oslo in Norway as Oslo is from Naples. Heer identified 136 species of fossil plants from Spitsbergen (78 56’ north latitude), which he ascribed to the Tertiary Age. Among the plants were pines, firs, spruces, and cypresses, also elms, hazels, and water lilies.
At the northernmost tip of Spitsbergen Archipelago, a bed of black and lustrous coal twenty-five to thirty feet thick was found; it is covered with black shale and sandstone incrusted with fossilized land plants. “When we remember that this vegetation grew luxuriantly within 8 15’ of the North Pole, in a region which is hi darkness for half of the year and is now almost continuously buried under snow and ice, we can realize the difficulty of the problem hi the distribution of climate which these facts present to the geologist.”
There must have been great forests on Spitsbergen to produce a bed of coal thirty feet thick. And even if Spitsbergen, almost one thousand miles inside the Arctic Circle, for some unknown reason had the warm climate of the French Riviera on the Mediterranean, still these thick forests could not have grown there, because the place is six months in continuous night. The rest of the year the sun stands low over the horizon.
Not only fossil trees and coal but corals, too, were found there. Corals grow only in tropical water. In the Mediterranean, in the climate of Egypt or Morocco, it is too cold for them. But they grew in Spitsbergen. Today large formations of coral covered with snow can be seen. It does not solve the problem of their deposition, if they were formed in an older geological epoch.
At some time in the remote past corals grew and are still found on the entire fringe of polar North America in Alaska, Canada, and Greenland. In later times (Tertiary) fig palms bloomed within the Arctic Circle; forests of Sequoia gigantea, the giant tree of California, grew from Bering Strait to north of Labrador. “It is difficult to imagine any possible conditions of climate in which these plants could grow so near the pole, deprived of sunlight for many months of the year.”
It is usually said that in ages past the climate all over the world was the same, or that a characteristic of the “warm periods which have formed the major part of geological time was the small temperature difference between equatorial and polar regions.” To this C. E. P. Brooks, in his book, Climate through the Ages, says: “So long as the axis of rotation remains in nearly its present position relative to the plane of the earth’s orbit around the sun, the outer limit of the atmosphere in tropical regions must receive more of the sun’s heat than [in] the middle latitudes, and [in] the middle latitudes more than [in] the polar regions; this is an invariable law. ... It is much more difficult to think of a cause which will raise the temperature of polar regions by some 30F. or more, while leaving that of equatorial regions almost unchanged.”
The continent of Antarctica is larger than Europe, European Russia included. It has not a single tree, not a single bush, not a single blade of grass. Very few fungi have been found. Reports of polar explorers indicate that no land animals larger than insects have been seen, and these insects are exceedingly few and degenerate. Penguins and sea gulls come from the sea. Storms of great velocity circle the Antarctic most of the year. The greatest part of the continent is covered with ice that in some places descends into the ocean.
E.H. Shackleton, during his expedition to Antarctica in 1907-9, found fossil wood in the sandstone of a moraine at latitude 85 5’. He also found erratic boulders of granite on the slopes of Mount Erebus, a volcano. Then he discovered seven seams of coal, also at about latitude 85. The seams are each between three and seven feet thick. Associated with the coal is sandstone containing coniferous wood. 6
Antarctica, too, must have had great forests in the past.
It often appears that the historian of climate has chosen a field as hard to master as it is to square the circle. It seems sometimes that the history of climate is a collection of unsolved, even unsolvable, questions. Without drastic changes in the position of the terrestrial axis or in the form of the orbit or both, conditions could not have existed in which tropical plants flourished in polar regions. If anyone is not convinced of this, he should try to cultivate coral at the North Pole.
[thanks again Fred Nerks! There were some typos I fixed in this scan, there may be more, I wasn’t all that careful]
Around 56 million years ago there was a period of global warming called the Paleocene-Eocene Thermal Maximum (PETM), during which global sea surface temperatures increased by approximately 5°C.Fossil coral reefs in Spitzbergen were identified a long while ago, and can't be attributed to continental drift under any existing scenario.
 |
||
| · join · view topics · view or post blog · bookmark · post new topic · subscribe · | ||
A damn fern pushed us into our current semi ice age....we need more CO in the atmosphere so we can get back to normal...
I like that closing sentence -- "future decision-making could be made based on scientific data and not on political expediency". I wouldn't count on it, but that would be great.Caves reveal clues to UK weatherAt Pooles Cavern in Derbyshire, it was discovered that the stalagmites grow faster in the winter months when it rains more. Alan Walker, who guides visitors through the caves, says the changes in rainfall are recorded in the stalactites and stalagmites like the growth rings in trees. Stalagmites from a number of caves have now been analysed by Dr Andy Baker at Newcastle University. After splitting and polishing the rock, he can measure its growth precisely and has built up a precipitation history going back thousands of years. His study suggests this autumn's rainfall is not at all unusual when looked at over such a timescale but is well within historic variations. He believes politicians find it expedient to blame a man-made change in our weather rather than addressing the complex scientific picture.
by Tom Heap
Saturday, December 2, 2000
Yeah, well, that’s a nice story. And my proposed lettuce farm is going to cause a pole shift. :’)
“this geologically short lived event” [the 170,000 years of the PETM). And here we are engaged in violent even murderous arguments about whether we have global warming, global cooling, or climate change, based on a few hundred years of kept records. Oh, what a vain creature is man to think any of us have THE answer based on this.
Thanks for your detailed comments and links. :-)
helps to camouflage the polar bears. Seriously though, there is no reason to have ice at the poles, but Antarctica won't melt even in the ridiculous climate models that melt Greenland. So we are talking about 25 or 30 feet sea level rise, in several centuries if you believe ridiculous models, or in many thousands of years if you believe basic thermodynamics (based on the amount of heat required to melt the ice with about 2 degrees of long term warming).
The issue, as with all global warming issues, is not the desirability of some climate or other, but political power and government control.
Note: this topic is from 2/27/2011. Thanks Ernest.
Nearer to our time: There was a show on one of the History channels the other day about the Medieval Warming period in which Europe flourished because of better agricultural conditions.
I think it was followed by the Little Ice Age.
How Climate
Made History
1300-1850
by Brian Fagan
hardcover
Kindle Edition
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
