Another study disproves Penn State's Michael Mann global warming hockey-stick "science"
Read here. With the advancement of paleo-climate science in recent years, the empirical evidence clearly indicates that Penn State's Michael Mann 'hockey stick' temperature graph to be without merit. The hockey-stick scenario was so discredited that even the IPCC eliminated it from their 2007 report.
Yet the hockey-stick myth continues to survive as a green legend despite the mounting empirical evidence that the Medieval Global Warming remains unprecedented.
Indeed, as the adjacent chart indicates, the Medieval Warming was significantly higher than the current warming.
Abrantes et al. just published research revealing the persistent high Medieval temperatures of coastal waters off the Portugal coast. Their analysis (from 900 AD to year 2002) is based on a sediment core from the Atlantic Ocean seabed.
As can be seen, levels of atmospheric CO2 have had little, if any, impact on sea surface temperatures. And this specific research clearly indicates that as CO2 levels rose, the SSTs declined - opposite of IPCC's climate model predictions.
"Abrantes et al. reconstructed a sea surface temperature (SST) history for waters off the coast of Porto, Portugal covering the past thousand years...revealed the occurrence of the Little Ice Age, as well as what they describe as the "persistently higher temperatures registered in the AD 960-1300 interval that we identify as the MWP [ed: Medieval Warming Period]." And from a graph of their SST history, one can see that the peak warmth of the MWP was about 1.2°C greater than the peak warmth of the CWP during the late 20th century." [F. Abrantes, T. Rodrigues, B. Montanari, C. Santos, L. Witt, C. Lopes, A. H. L. Voelker 2011: Climate Research]
Read here. The Climategate scandal was the door opening that revealed a cadre of IPCC "scientists" conspiring to push their rendition of crop circle pseudoscience. A key component of that effort was the infamous "hockey-stick" that purported to show modern era temperatures to be unprecedented, and the climates of the Medieval Warming (MWP) and Little Ice Age (LIA) to be minor blips of no significance. The IPCC's crop circle scientists also claimed that the MWP and LIA only existed in the small regional area of the north Atlantic/European geography. Subsequent studies and a mountain of empirical evidence refutes the IPCC pseudoscience.
A new peer-reviewed paper by Bertler et al., using the latest deuterium and temperature-isotope science, constructed temperatures going back 1,100 years. The new temperature dataset (see adjacent chart - click to enlarge) clearly shows the LIA in Antarctica to be massively cooler than modern temperatures; the dataset establishes that the modern warming is not "unprecedented" as the MWP is slightly warmer.
"The researchers obtained new deuterium (δD) data from the Ross Sea region of Antarctica that they acquired via analysis of the top fifty meters of a 180-meter-long ice core that had been extracted from the ice divide of Victoria Lower Glacier...work revealed three climatically-distinct time periods: the last 150 years of the Medieval Warm Period (MWP, AD 1140 to 1287), the Little Ice Age (LIA, AD 1288 to 1807), and the Modern Era (ME, AD 1808 to 2000)...authors report that "the final 150 yrs of the MWP were ... about 0.35 °C warmer than the ME,"" [N.A.N. Bertler, P.A. Mayewski, L. Carter 2011: Earth and Planetary Science Letters]
Read here. Map source. The Mannian style of climate science was established to fabricate a scenario that the Medieval Warming (MWP) and Little Ice Age (LIA) periods were insignificant weather blips, primarily felt in the northern Atlantic/European region. A vast amount of both anecdotal and paleo-climate empirical evidence refutes Mann's contentions that the MWP and LIA were insignificant and only regional. Another peer reviewed study adds to the refutation.
Researchers Rivera et al. determined that the current terminus position of the Chilean glacier Jorge Montt is the same as the terminus position prior to the onset of the LIA, some 450 years before present (~1550 AD). Dendrochronology analysis established that the maximum extent of the glacier was achieved around 1750 AD.
"A team of scientists studied tree rings...recently exposed by the retreating Patagonian glaciers....trees were dated using radiocarbon methods, yielding burial ages between 460 and 250 years ago...study confirms that the Little Ice Age existed in Chile too. Now remember how the high-sticking hockey team kept trying to have us believe that the Medieval Warm Period-Little Ice Age thing was a local phenomena, and not global?...No misprint there. It’s correct. Before the LIA the Chilean glaciers were at the same spot as the present position. Send a copy of that paper to Michael Mann..." [A. Rivera, M. Koppes, C. Bravo, J. C. Aravena 2011: Climate of the Past]
Read here. Map source. Modern climate alarmists, such as Joe Romm, Michael Mann, Jeff Masters, Al Gore and Kevin Trenberth, commonly deny or lie about significant climate change that took place over the last 5,000 years. Reflecting on their denial of the overwhelming empirical evidence, if they were to admit to the reality of past climate change then that would be a tacit approval that abrupt climate change is natural and does not require high atmospheric levels of CO2. Adding to their woes of gross misrepresentation of past climate history, comes another new study that confirms the reality of past abrupt climate change, further denigrating the position of all past climate change deniers.
Larsen et al. performed multiple analysis of sediment cores of an Iceland glacial lake. The analysis clearly documents the robust climate change during the periods of the Dark Ages,the Medieval Warming and the Little Ice Age. The empirical evidence points to the extreme warmth of Iceland's climate during the MWP and the extreme cold of the LIA.
"A suite of environmental proxies in annually laminated sediments from Hvítárvatn, a proglacial lake in the central highlands of Iceland, are used to reconstruct regional climate variability and glacial activity for the past 3000 years...Varve thickness is controlled by the rate of glacial erosion and efficiency of subglacial discharge from the adjacent Langjökull ice cap...ice-cap expansion is punctuated by notable periods of rapid ice cap growth and/or landscape instability at ca 1000 BC, 600 BC, 550 AD and 1250 AD. The largest perturbation began ca 1250 AD, signaling the onset of the Little Ice Age and the termination of three centuries of relative warmth during Medieval times.Consistent deposition of ice-rafted debris in Hvítárvatn is restricted to the last 250 years, demonstrating that Langjökull only advanced into Hvítárvatn during the coldest centuries of the Little Ice Age." [Darren J. Larsena, Gifford H. Millera, Áslaug Geirsdóttirb, Thorvaldur Thordarsonc 2011: Quaternary Science Reviews]
Read here. The paleo-climate empirical evidence continues to grow that documents the unequivocal, unprecedented warming of pre-industrial periods in many parts of the world. Thousands of researchers have now demonstrably proven that the recent IPCC Climategate science flim-flam and hockey-stick statistical bogosity claims, purporting to prove that higher levels of CO2 during industrial times have led to "unprecedented" warming, are without empirical merit.
The new Stewart et al. research clearly shows (click on image to enlarge) that the Lake Silvaplana, Switzerland region had robustly higher temperatures well prior to the modern industrial/consumer atmospheric levels of high CO2. During Roman and the pre-Roman iron age eras, peak summer temperatures would be considered unnaturally extreme by today's global warming alarmists.
"Working with a piston core that was extracted during the winter of 2005-2006 from Lake Silvaplana in the eastern Swiss Alps, the authors developed a June-July-August (JJA) temperature history of the surrounding region...report that "temperatures reconstructed from ca. 570 BC to AD 120 were warmer than today (AD 1950-2000; 9.8°C)," with the JJA temperatures of the warmest portion of this interval (ca. 570-351 BC) being approximately 11.2°C, after which they say they also "found moderately warm temperatures for the Roman Period (11°C, ca. 15 BC to AD 120)."...which yields a peak Current Warm Period temperature of 10.3°C. And thus we see that the peak temperature of the Roman Warm Period (11°C) was about 0.7°C warmer than the peak temperature of the Current Warm Period, while the peak temperature of the earlier 570-351 BC period (11.2°C) was approximately 0.9°C warmer than the peak temperature of the Current Warm Period." [Monique M. Stewart, Isabelle Larocque-Tobler, Martin Grosjean 2011: Journal of Quaternary]
Read here. The vast majority of new scientific research continues to document that the modern era's warming barely rivals what was experienced during the Medieval Period.
Other than the widely discredited hockey-stick style of temperature reconstructions, the empirical evidence continues to expand, supporting the well known historical anecdotal information about the Medieval Warming.
A new peer-reviewed study by Kaniewski et al. provides important evidence of the Medieval Warming Period (MWP) in the Middle East region of the world. An analysis of pollen from a Syrian sediment core confirms an extended state of higher temperatures during the MWP's low atmospheric CO2 environment.
"Based on analyses of pollen found in a 315-cm-long sediment core retrieved from alluvial deposits within the floodplain of the River Rumailiah in the coastal Syrian lowland, Kaniewski et al. were able to identify key plant functional types that allowed them to construct pollen-derived Biomes (PdBs) similar to those employed by Tarasov et al. after which they were able to relate "the ratio of PdB warm steppe (WAST) divided by PdB cool steppe (COST) to local temperature...The end result of this endeavor was their identification of the timeframe of the MWP (AD 1000-1230) and their finding that at approximately AD 1130, the MWP exhibited "warmer temperatures compared to AD 2000,..." [D. Kaniewskia, E. Van Campoa, E. Paulissend, H. Weisse, J. Bakkerc, I. Rossignola, K. Van Lerberghef 2011: Global and Planetary Change]
Read here. It's been well documented that global warming ideologists will always make every attempt to slant paleo-climate research in such a way that modern warming appears to be "unprecedented." This built-in research bias is very prevalent in tree-ring studies, which the infamous 'hockey-stick' fraud is the classic example - e.g., over-weighting a single tree species by 390 times in the hockey-stick study revealed how desperate researchers have been to create a warming bias.
Despite the efforts of some researchers, more objective and impartial scientists are conducting peer-reviewed studies that avoid the significant problems (flim-flam) of tree-ring analysis. The vast preponderance of these studies reveal the wide natural variations in both temperatures and climates over thousands of years. In addition, most establish that the Medieval Warming Period (MWP) was indeed warmer than our modern warming (but not always).
As an example, the recent Moschen et al. German peat bog research confirms that area of the world had considerably higher temperatures for an extended period during the MWP.
Their research also provided a unique indicator for the extreme temperatures of natural climate - varying without any industrial/consumer CO2 emission impact. As the adjacent chart shows, there is a large, multi-century gap with no peat bog data recorded (where the bold blue curve goes missing). That's when the post-Medieval Warming era became so freaking cold the natives actually dug up (The 'Big Dig') the bog's empirical evidence to burn in their homes to keep warm.
"A new paper by Moschen et al appearing in the journal Climate of the Past presents a high resolution reconstruction of local growing season temperature (GST) anomalies at Dürres Maar, Germany over the last two thousand years...In 2007, a 5.5 m long core was recovered from the centre of Dürres Maar peat bog in the mountainous West Eifel Volcanic Field in southwestern Germany...I got a copy of the paper from a source, who wrote: “The ex-hockey team will hate it”. The paper’s Figure 6 tells quite the story. Indeed there was a lot of climate change in the past when CO2 was more or less stagnant." [R. Moschen, N. Kuhl, S. Peters, H. Vos, A. Lucke 2011: Climate of the Past]
A growing library of peer reviewed studies provides mounting empirical evidence that the medieval warming was also experienced in the Southern Hemisphere. The latest study that discredits the 'hockey stick' bogosity comes from scientists analyzing past climate conditions on New Caledonia.
Wirrmann et al. confirmed that the peak mangrove growth was during the 950 to 1250 AD period, which would conform to the approximate Medieval period in the Northern Hemisphere. The tropical mangrove plant prospers in warmer climates.
"Based on their multi-proxy approach to climate evaluation, the authors determined that between ca. 2640 and 2000 cal yr BP, conditions were "drier and cooler," while subsequent observations linked wetter with warmer. More specifically, they report that "between ca. 1250-500 cal yr BP the higher % of Rhizophoraceae and their peak around ca. 1080-750 cal yr BP underscore a mangrove belt development along the coastline." And they state that this episode must be related to a wetter period and "may be related to a more global phenomenon such as the MWP in the Northern Hemisphere." [Denis Wirrmanna, Anne-Marie Sémaha, Jean-Pierre Debenayb, Magali Chacornac-Raultc 2011: Quaternary Research]
Read here. Another major study affirms that pre-modern temperatures were unprecedented in terms of warming. The widely discredited Mann hockey-stick study, which even the IPCC 2007 report abandoned, has another stake driven through it as more complete research is being accomplished and published.
Scientist Fredrik Ljungqvist analyzed 60 different proxy reconstructions of annual mean temperatures. The reconstructions were from both the Northern and Southern hemispheres, and they represented both marine and terrestrial reconstructions. This is the broadest and largest study of its kind.
Ljungqvist determined that the vast number of reconstructions showed unprecedented warming from the the start of the Mid-Holocene Thermal Maximum period (approximately 8,000 years prior) to the onset of the Little Ice Age. Most of the reconstructions do not have current, modern warming coming close to rivaling the excessive 2°C warming that occurred for thousands of years. His study strongly indicates that this warming took place globally, with the high northern (polar) latitudes experiencing the greatest warming.
"A paper recently published in the journal Geographie examines 60 temperature proxies from around the globe and finds that the vast majority show the Earth was at least 1-2 C hotter than the pre-industrial period during the Holocene Climate Optimum from approximately 9000 to 5000 years ago. The warming of both the Holocene Climate Optimum and the Medieval Warming Period (~1000 years ago) are robust findings from the large number of proxies studied and refutes claims of the IPCC and Mann et al that the Medieval Warming Period was limited to Europe, finding that both were present in the Northern and Southern Hemispheres and were relatively synchronous." [Fredrik C. Ljungqvist 2011: Geograﬁe]
Read here. (h/t Greenie Watch) The Mediterranean Sea basin is considered one ot the more vulnerable to climate change, which is a major concern since the IPCC climate models predict that global warming will result in more frequent storm activity. To test this prediction, EU researchers analyzed 7,000 years of data from sediment cores from southern France's coastal region.
Sabatier et al. analysis establishes the history of severe storm activity, which firmly indicates that severe stroms were more frequent during global cooling (ie. The Little Ice Age) than during global warming spans, such as the Medieval Warming Period.
As is often the case, the empirical evidence refutes the IPCC climate model predictions.
"This paper present a high resolution record of paleostorm events in the French Mediterrannean coast over the past 7000 years based on a long sediment core from lagoonal environment in Gulf of Lions...we have recorded seven periods of increase in storm activity at 6200, 5400, 4600-4200, 3600-3100, 2600, 1900-1500 yr cal B.P. and over the Little Ice Age...Whereas the Medieval Warm Period (1200-700 yr cal B.P.) is characterized by a low storm activity. These evidences of changes in coastal hydrodynamic are in phase with those observed over the North Atlantic and correspond to Holocene cooling evidenced associated to decreases of SST in the North Atlantic." [Pierre Sabatier, Laurent Dezileau, Christophe Colin, Louis Briqueu, Philippe Martinez, Giuseppe Siani, Frédérique Bouchette, Olivier Raynal, Ulrich Von Grafenstein 2011: International Union for Quaternary Research]
Read here. Droughts are a frequent visitor to the southwest U.S. and Mexico regions. The current drought that this area is experiencing is bad but in no way is it as extreme as the droughts that took place during the Medieval era.
As the chart reveals, both the Medieval and modern periods share a characteristic of high incoming solar irradiance. With the increase of incoming solar energy, the result is time spans of frequent and more intense droughts. These more extreme droughts occur naturally and have nothing to do with greenhouse gases, including CO2 emissions.
There are some scientists who predict we are entering a stage where 60-year droughts, like those during the Medieval Period, could occur but no one knows for sure. If solar irradiance falls (as it seems to be doing most recently), the modern drought cycle may end.
Woodhouse et al. published this 1,200 year perspective of Southwestern North America droughts:
"The medieval period was characterized by widespread and regionally severe, sustained drought in western North America. Proxy data documenting drought indicate centuries-long periods of increased aridity across the central and western U.S...The recent drought, thus far, pales hydrologically in comparison... Spatially, the mid-12th century drought covers all of the western U.S. and northern Mexico...whereas the 21st century drought has not impacted parts of the Pacific Northwest...The 21st century drought has lasted about a decade so far, whereas the 12th century medieval drought persisted with an extent and severity...for two decades, 1140–1159 [AD]...In both instrumental and paleoclimatic records, periods of sustained drought in the Southwest have often been concurrent with elevated temperatures. The warmest such episode, in the mid-12th century, was more extensive and much more persistent than any modern drought experienced to date..." [Connie A. Woodhouse, David M. Meko, Glen M. MacDonald, Dave W. Stahle, Edward R. Cooke 2009: Proceedings of the National Academy of Sciences]
Read here. (h/t Tom Nelson) Archeologists are finding human artifacts that were buried under snow and ice hundreds of years ago. The discoveries clearly indicate that temperatures in this region were significantly warmer 1,000 years ago, thus allowing humans to thrive before the Little Ice Age cold made that impossible.
This actual evidence refutes the infamous hockey-stick portrayal that only modern temperatures are "unprecedented."
L. Tan et al. authored a new peer-reviewed study that found higher temperatures existed between 1,000 and 1,200 years ago in the Asian region of north central China. The study also reconstructed precipitation levels for that area over the 1,800 years.
This study's temperature reconstruction shows higher temperatures in the past that can can clearly be labeled as unprecedented. Late 20th century temperatures were well under the Medieval era temperatures.
"A paper published examines the climate of central China over the past 1800 years using two different types of proxies. The paper finds higher temperatures and precipitation were present during the Medieval Warming Period (960-1100 AD) than at the end of the 20th century. This paper adds to the published work of 986 scientists who have documented that the Medieval Warming Period was as hot or hotter than the present and was a global phenomenon. This study also shows both the rate and magnitude of the rise in temperature from the year ~ 700- 880 AD were much greater than over a comparable period including the 20th century." [L.Tan, Y.Cai, Z.An, L.Yi, H.Zhang, Qin 2011: Climate of The Past]
Read here and here. There is an excellent and fascinating post over at Judith Curry's site regarding historical sea levels. It's part 1 of a series by Tony Brown. From one of his linked documents comes the chart on the left, and the chart on the right from a previous C3 post on sea levels. (click on images to enlarge)
Tony does an analyisis of sea levels prior to the pre-Medieval Period, pulling information from a wide assortment of historical resources. Per the documentation he reviewed, there is strong evidence that both the Roman/Byzantine and prior periods had sea levels that exceeded the current level.
"“The North Sea had a nasty little jump between 350 and 550AD, flooding the coasts of northern Europe with an extra 2 feet of water and sending its inhabitants — folk known as Angles and Saxons — fleeing (although “conquering” might be the better word) into ill-prepared Roman territories. At the start of this rise, the areas we know as the Fens were a well-settled part of Roman Britain ruled from the town of Duroliponte (Cambridge) by its native people, the Christianized Romano-Celtic Iceni. Then the sea level rose, and history’s curtain went down for two centuries.”.....At the old shore the Etang of Vendres, near the mouth of the Aude, are the ruins of a Roman Therme of the 1st or 2nd century A.D. (locally called the temple of Venus). There the walls have been washed out by waves so that they now have a deep double notch about 1.80 m above present sea level..."
"So notwithstanding the statements of the IPCC AR4 who assert a sea level status quo from ancient until modern times, there are many studies that point to a picture of relatively static sea levels after the initial Holocene rise. These then show that some 3000 years ago there was a further inundation (think Lyonesse in Cornwall) and in early Roman times levels were somewhere around current levels. Levels then rose significantly through the Roman period peaking around the 700 AD Byzantine period at levels higher than today..."
At the end of part 1 on Curry's site, Tony makes reference to how Science Daily edited out key information from a study they reported on thus leaving their readers with an impression that previous sea levels were not higher. Interesting. Confirms why today's science journalists are no longer easily trusted.
Read here. It has been well established by the left/liberal lamestream media that 97% of "climate scientists" (that's all of 75 people) take their science lessons from Al Gore, the AGW Nobel prize winner. During 2007 Congressional testimony, Al Gore claimed that "droughts are becoming longer and more intense." As a result, a team of scientists decided to do a fact-check on Mr. Gore's (and his renowned 75 disciples) AGW-science claims. (Okay, okay.....probably Stambaugh et al. didn't give a hoot about Al Gore and the 97%-team.)
This new research determined that the 20th and 21st century droughts have been of little significance when compared to both the Medieval Warming and Little Ice Age droughts that were incredibly severe.
"The six scientists report that "20th century droughts, including the Dust Bowl, were relatively unremarkable when compared to drought durations prior to the instrumental record." They note, for example, that the 19th century was the driest of the past millennium, with major drought periods occurring from about 1816 to 1844 and 1849 to 1880, during what they describe as the transition out of the Little Ice Age...write that "the approximately 61-year drought in the late 12th century (ca. AD 1148-1208) appears to be the most significant drought of the entire reconstruction," noting that it "corresponds to the single greatest megadrought in North America during the last 2000 years (Cook et al., 2007), as well as "unmatched persistent low flows in western U.S. river basins (Meko et al., 2007)." And this drought, as they describe it, occurred during the middle of the Medieval Warm Period..." [Michael C. Stambaugh, Richard P. Guyette, Erin R. McMurry, Edward R. Cook, David M. Meko, Anthony R. Lupo 2011: Agricultural and Forest Meteorology]
Read here. Depending on the information source, modern "unprecedented" warming is an increase of +0.5 to 0.7 degrees Celsius. Despite the hysteria expressed about this increase by the media and alarmists, in both the historical and ancient past there have been warmings that exceeded the modern warming.
Recently, a prominent climate scientist came across a long forgotten study published back in 1973 that documents the large warmings and coolings that took place in China thousands of years ago. As an example, the long ago Shang Dynasty, which had its capital approximately at the red spot on the map, experienced extended warming that was found to be 2 degrees higher than modern temperatures. The Shang dynasty existed at this location from 1400 BC to 1050 BC. (map source here)
Other warming/cooling phases affecting the Chinese civilization were documented to range from 2 to 3 degrees over multiple periods.
“The world climate during the historical times fluctuated. The numerous Chinese historical writings provide us excellent references in studying the ancient climate of China. The present author testifies, by the materials got from the histories and excavations, that during Yin-Hsu at Anyang, the annual temperature was about 2℃ higher than that of the, present in most of the time. After that came a series of up and down swings of 2—3℃ with minimum temperatures occurring at approximately 100 B. C. (about the end of the Yin Dynasty and the beginning of the Chou Dynasty), 400 A. D. (the Six Dynasties), 1200 A. D. (the South Snug Dynasty), and 1700 A. D. (about the end of the Ming Dynasty and the beginning of the Ching Dynasty). In the Han and the Tang Dynasties (200 B. C.—220 A. D. and 600—900 A. D.) the climate was rather warm." [Chu Ko-Chen 1973: China National Knowledge Infrastructure]
Read here. The IPCC claims that modern "unprecedented" global warming has caused glaciers and snowpack to shrink, and mountainous areas to become more arid, thus diminishing/eliminating essential alpine river discharges. Whether it's the Himalayas or other mountainous regions though, the empirical evidence does not support the claims of modern warming being "unprecedented," nor the convenient disappearing of the Medieval Warming and Little Ice Age climates of Mann's 'hockey-stick.'
A new peer-reviewed study by Wolfe et al. found that a Canadian lake's modern water level, which is fed from Rocky Mountain water runoff, is significantly higher than during the Medieval Warming Period and higher than lake levels prior to the extended Medieval span. This is an unequivocal indicator that modern warming is not "unprecedented." (click on image to enlarge)
"A peer-reviewed paper published online today in the journal Geophysical Research Letters shows that drought of Western North America was considerably worse during the Medieval Warming Period than at the end of the 20th century. The paper also shows much more variation and extremes in the drought record over the past 5200 years than since the advent of industrialization and rising CO2 levels in the latter 20th century. The proxy records clearly show no correlation of drought with the claimed steady CO2 levels...""a new 5200-year record of Lake Athabasca water-level variations, which serves as a sensitive gauge of past changes in alpine-sourced river discharge, reveals that western Canadian society has developed during a rare period of unusually abundant water ‘subsidized’ by prior glacier expansion.""[Brent B. Wolfe, Thomas W. D. Edwards, Roland I. Hall, John W. Johnston 2011: Geophysical Research Letters]
Read here. Image source here. (click image to enlarge)
The discredited, bogus 'hockey stick' temperature reconstruction has motivated hundreds to conduct new research on the paleo-climate, utilizing valid scientific and statistical methods. The vast majority of these new studies confirm the anecdotal historical evidence that the Medieval Period was the warmest extended time span over the last 2,000 years.
Velle et al. recently published a peer-reviewed analysis of sediment cores from the Svalbard archipelago in the Arctic. The analysis revealed the Medieval Warming in a polar Arctic area to be approximately 0.3°C higher than modern temperatures.
"Working with two short gravity cores and two long piston cores of sediments obtained from the deepest part of Lake Skardtjorna, Velle et al. reconstructed histories of chironomid types and concentrations over the past 2000 years, which they translated into mean July air temperatures based on a modern mean July air temperature calibration data set...in the words of the two researchers, a "warming that occurred at 1000 to 830 BP," where BP = 2003, that "may correspond to what is known as the 'Medieval Warm Period'." And based on their graphical representation of that record, we estimate that the peak warmth of the MWP (~ AD 1000-1170) was about 0.3°C greater than the peak warmth of the Current Warm Period. [Gaute Velle, Katrine Kongshavn, H. John B. Birks 2011: The Holocene]
Read here. The IPCC and climate alarmists have become well known for their hysterical and failed glacier catastrophe prognostications. To add to the IPCC's growing embarrassment, new research indicates that the Rhône Glacier is currently larger than in previous times, which doesn't lend much credence to their claims of the supposed "unprecedented" warming of the 20th/21st centuries.
Interestingly, due to the glacier's melting, it has actually revealed how warm it really was in the not too distant past - under the glacier were remains of human settlements and forests that are now seeing the light of day, again. Obviously, much to the chagrin of the IPCC's Climategate scientists, the human past has experienced a much warmer climate.
Using novel techniques involving measurement of isotopes Carbon 14 and Beryllium 10, Goehring et al. were able to analyze past glacier growth and shrinkage over the past 11,500 years.
"Until now, scientists have had no accurate way of knowing the long-term history of the glacier. Local records of the ice date back to 1602, and it is clear that the Rhone, like other glaciers in the Alps, has retreated dramatically in the past 150 years. This melting has exposed intriguing clues – remnants of trees from once-forested land, and artifacts of human settlements dating back thousands of years, to times when even more of the land was uncovered and green...the researchers said that their more robust history of the Holocene glacier fluctuations reflects how sensitive glaciers are to small changes in climate...said he was surprised by the evidence of exposure revealed by the isotopes. The amount of Beryllium 10 and Carbon 14 they found "told us that not only were the surfaces exposed for significant periods of time, meaning the Rhone Glacier was smaller than today..." [Brent M. Goehring, Joerg M. Schaefer, Christian Schluechter, Nathaniel A. Lifton, Robert C. Finkel, A.J. Timothy Jull, Naki Akçar, Richard B. Alley 2011: Geology]
Magny et al. utilizing advanced scientific techniques, reconstructed 1,000 years of past summer (July) temperatures for the Swiss Jura Mountains region. Unequivocally, they found that July temperatures during the Medieval Period were significantly warmer than modern summer temps.
"Working at Lake Joux in the Swiss Jura Mountains...employed a multi-proxy approach with pollen and lake-level data to develop a 1000-year history of the mean temperature of the warmest month of the year (MTWA), which was July...based on the Modern Analogue Technique. This work revealed what they describe as an "MWP between ca. AD 1100 and 1320," during which time the MTWA at Joux Lake exceeded that of the 1961-1990 reference period by fully 2.0°C....Thus, it would appear that the peak warmth of the MWP at Lake Joux exceeded that of the CWP at that location by something on the order of 0.4-1.0°C." [Michel Magnya, Odile Peyrona, Emilie Gauthiera, Boris Vannièrea, Laurent Milleta, Bruno Vermot-Desroches 2011: Quaternary Research]
Read here. In peer-reviewed research published by the influential Proceedings of the National Academy of Sciences (PNAS), scientists reconstructed 5,600 years of climate conditions in Greenland. This new reconstruction confirmed the warm and optimum climate conditions of the Medieval Warming and the rapid onset of the frigid Little Ice Age.
In the case of Greenland's flourishing Viking settlements, the climate change to a cold phase meant total destruction of their existing society and settlements.
This new PNAS study totally refutes Michael Mann's entirely bogus 'hockey stick' portrayal of climate being benign and unchanging prior to the 20th century.
"What climate scientists have been able to ascertain is that an extended cold snap, called the Little Ice Age, gripped Greenland beginning in the 1400s. This has been cited as a major cause of the Norse’s disappearance. Now researchers led by Brown University show the climate turned colder in an earlier span of several decades, setting in motion the end of the Greenland Norse...The Vikings arrived in Greenland in the 980s...The arrival coincided with a time of relatively mild weather, similar to that in Greenland today. However, beginning around 1100, the climate began an 80-year period in which temperatures dropped 4 degrees Celsius (7 degrees Fahrenheit), the Brown scientists concluded...“You have an interval when the summers are long and balmy [Editor: yes, Greenland summers "long and balmy" during the Medieval period] and you build up the size of your farm, and then suddenly year after year, you go into this cooling trend, and the summers are getting shorter and colder and you can’t make as much hay. You can imagine how that particular lifestyle may not be able to make it,”...[William J. D’Andreaa, Yongsong Huanga, Sherilyn C. Fritz, N. John Anderson 2011:Proceedings of the National Academy of Sciences]
As so many past studies have documented, the Medieval Warming Period was indeed hotter than our current climate, especially in the extreme north and polar regions, such as Greenland and Iceland. The empirical evidence from past research, using a wide variety of scientific techniques, confirms the anecdotal information that was written in the historical past. A newly published study again confirms both the past scientific efforts and historical writings.
Ran et al. performed a diatom-based reconstruction of sea surface temperatures from waters of northern Iceland. Their analysis found that temperatures were approximately 0.6°C higher during the AD 940-1300 period versus modern temperatures. In addition, a strong solar radiation influence was noted in the data. (click on image to enlarge)
"Ran et al. reconstructed summer sea surface temperature (SST) on the North Icelandic shelf for the period AD 940-2006, based on their high-resolution and precisely dated diatom records, along with the help of "a modern diatom-environmental dataset from around Iceland...In the words of the four researchers, their diatom-based SST record indicates that the sea surface on the North Icelandic shelf "was not as warm during the last century as during the Medieval Warm Period (MWP)." More specifically, they write that "warm and stable conditions with relatively strong influence of the Irminger Current on the North Icelandic shelf are indicated during the interval AD 940-1300, corresponding in time to the MWP," and that "a considerable cooling at ~AD 1300 indicates the transition to the Little Ice Age (LIA) with increased influence of Polar and Arctic water masses deriving from the East Greenland and East Icelandic currents."...they end by stating that "the data suggest that solar radiation may be one of the important forcing mechanisms behind the palaeoceanographic changes."" [Lihua Ran, Hui Jiang, Karen Luise Knudsen and Jón Eiríksson 2011: Palaeogeography, Palaeoclimatology, Palaeoecology]
Read here. Map source here. Wet, cold, stormy, miserable, severe weather can be an indicator of a global cooling climate phase. As past empirical evidence well documents, the climate makes swings from warmer to cooler phases, which impacts local and regional weather patterns.
New research (Griessinger et al.) from China confirms that global cooling can cause weather to become wetter and soggier even in semi-arid areas during the hot summer months of the Northern Hemisphere. (click on images to enlarge)
"Based on correlations they exhibited with climate data, tree-ring δ18O measurements of high-elevation Tibetan junipertrees...state that the 800-year annually-resolved oxygen isotope series they developed reflects long-term variations in Asian summer monsoon (ASM) activity in that part of the world. And this history, as they describe it, reveals an "ASM minimum during the Medieval Warm Period (around 1200-1400) and moister conditions during the Little Ice Age (1400-1900),"...This close but inverse correspondence between centennial-scale precipitation anomalies and similar well-known global temperature anomalies (the MWP, LIA and CWP) provides further evidence for the historical reality of the MWP on the Tibetan Plateau,..." [Jussi Grissinger, Achim Bräuning, Gerd Helle, Axel Thomas, Gerhard Schleser 2011: Geophysical Research Letters]
In Europe's past there have been severe superstorms (category 3 intensity or more) that have struck the Mediterranean coast of Europe. By analyzing sediment cores, Dezileau et al. were able to determine that all the catastrophic storms struck before 1900, primarily during the coldest periods of the Little Ice Age and the onset of the cooler Dark Ages.
The evidence shows that periods of global cooling trends, not global warming phases, are when Europe is at its most vulnerable for Mediterranean superstorms striking.
"With respect to extreme weather events, the authors write that the major question of the day is: "are they linked to global warming or are they part of natural climate variability?"...because "these extreme events are inherently rare and therefore difficult to observe in the period of a human life."...Dezileau et al. assessed "the frequency and intensity of these events during the last 1500 years," as well as "links between past climatic conditions and storm activities."...report they found evidence of four "catastrophic storms of category 3 intensity or more," which occurred at approximately AD 455, 1742, 1848 and 1893...all four of the storms "can be called superstorms."...Dezileau et al. suggest that "extreme storm events are associated with a large cooling of Europe,"..." [L. Dezileaua, P. Sabatiera, P. Blanchemanchec, B. Jolyd, D. Swingedouwe, C. Cassoue, J. Castaingsa, P. Martinezf and U. Von Grafensteing 2011: Palaeogeography, Palaeoclimatology, Palaeoecology]
Read here. Map source here. (click on images to enlarge)
Newton et al. analyzed sediment cores from the Makassar Strait between the Indian and Pacific Oceans and confirmed that the hottest sea-surface temperatures took place some 800+ years ago, during the Medieval Period. These scientists noted that Medieval Warming took place during a solar activity maximum.
"Based on Mg/Ca ratios of the planktonic foraminifer Globigerinoides ruber that they obtained from a sediment core that was extracted from the seabed at the southern end (~5.3°S, 117.8°E) of the Makassar Strait...as they describe it, that "the warmest sea surface temperatures of the past 2000 years occurred between 1000 and 800 years ago," which period, they say, "is broadly coincident with the Medieval Warm Period as reflected in Northern Hemisphere temperature anomaly reconstructions."
"...used to reconstruct surface-water temperature (SST), sea-surface salinity (SSS), and seawater density variability over the past 2000 yr. Maximum SST and SSS occurred at both sites between 850 and 700 yr ago, coinciding with the Medieval Solar Maximum and Medieval Warm Period (ca. 1000–700 yr ago). SST and SSS declined at both locations after 700 yr ago and reached minimum values during the Little Ice Age, between 300 and 100 yr ago." [Alicia Newton, Robert Thunell and Lowell Stott 2011: Geology]
Abrupt and massive climate change, as represented by temperatures, has been a natural phenomenon for eons. Despite the claims of IPCC activists, pundits, celebrities, reporters, and some politicians, our current climate change is not unequivocally unprecedented and accelerating faster than previous occurrences. In fact, as the below charts depict, the current climate change is kind of wimpy compared to its ancestors.
It's important to recognize that scientists within the physical science realm concur that the climate can change abruptly with great severity, and that it has taken place with regularity over the last 10,000 years. Their proof? It's the ice cores pulled from the Greenland ice cap, which reveal incredibly large temperature changes as the graph immediately adjacent reveals. (And the Antarctic ice cores provide even more proof.)
As the experts will tell you, there is absolutely no scientific dispute regarding this historical evidence that was laid down by the climate for thousands of years.
While analyzing the ice core data, the scientists additionally determined several undisputed scientific facts:
1. Temperatures have been both hotter and colder than modern temperatures over the last 10,000 years.
2. There has been a cycle of warmer and cooler temperature swings over the last 10,000 years.
3. The modern increase in temperatures since the Little Ice Age represents #19 in the count of climate change swings over the last 10,000 years.
4. Major temperature swings of at least a 1 degree change may take anywhere from 220 years to 1000+ years before ending.
5. The recent past temperature increase has been both modest (below 1 degree) and relatively slow (750+ years) to warm since the initial plunge to the Little Ice Age levels.
These scientific facts are depicted in the visual representation of ice core data below (click on image to enlarge):
The #1 bar is this chart is that of a warming period that started around 10,000 years ago, lasting 840+ years with a temp increase of 1.23 degrees. The #2 bar represents the subsequent cooling period, which lasted some 850 years with temps cooling a huge 3 degrees. The rest of warm/cool climate change swings are represented all the way down to the present period, which is bar #19. (Each bar lists the associated temperature change and the length of the cooling/warming period, from peak to trough or vice versa.)
The modern bar (#19) is especially revealing. Since the initial plunge of the Little Ice Age temperatures about 750 years ago, the natural warming rebound has yet to even cross the 1 degree finish line that would denote this most recent climate change as a major one. Based on historical, natural precedents that the ice core evidence provides, our modern period should be expecting to reach the 1 degree mark in the near term future, regardless of any human influences - that's what nature and the climate does, naturally.
One final note: the ice core data only extends to 1905. To estimate the temperature change from 1905 to 2010, 'C3' used a really useful graphing service provided by Global Warming Science. Using this invaluable service, we found 4 arctic area weather stations (above 65N) that had fairly complete temperature records from 1905. The chart below is the end result, including a linear trend for the 4 stations: 0.55 degrees per 100 years.
Read here. Scientists analyzing maximum latewood density (MXD) datasets from Scandinavia determine that the Medieval Warming was unprecedented in its duration, at least 100 years in length.
In contrast to the modern era, this study, by Gunnarson et al., revealed that there were similar temperature increases from 1910 to 1940's, and one that started in the late 1990's. Neither of these very short-term warmings have MDX temperature reconstructions exceeding the Medieval Period.
"Working in the same general area, researchers combined these older historical MXD data with "recently collected MXD data covering AD 1292-2006 into a single reconstruction of April-September temperatures for the period AD 1107-2006,".....report "there is a steep increase in inferred temperatures at the beginning of the twelfth century, followed by a century of warm temperatures (ca. 1150-1250)," which falls within the temporal confines of the Medieval Warm Period; and they state that "the record ends with a sharp increase in temperatures from around 1910 to the 1940s, followed by decreasing temperatures for a few decades," after which they indicate that "another sharp increase in April-September temperature commenced in the late 1990s," during what is commonly known as the Current Warm Period. Thus, they say that "the two warmest periods are the mid to late twentieth century and the period from AD 1150-1250," and they emphasize that the temperatures of both of these periods have been so similar that "it is not possible to conclude whether the present and relatively recent past are warmer than the 1150-1250 period."" [Björn E. Gunnarson, Hans W. Linderholm, Anders Moberg, 2011: Climate Dynamics]
Read here. Map source here. (click on images to enlarge)
There are multiple factors that affect both regional and global temperatures, but the most important source of long-term temperature change is solar activity. Using data from the Norwegian Sea and multiple solar proxies, the peer-reviewed research by Sejrup et al. confirms a robust and synchronous correlation between solar activity and temperatures.
Note: This research was conducted and completed without the use of magical "hockey stick" science and statistics, perfected by Penn State University personnel.
"...worked with two sediment cores they extracted from the seabed of the eastern Norwegian Sea, developing a 1000-year proxy temperature record "based on measurements of δ18O in Neogloboquadrina pachyderma, a planktonic foraminifer that calcifies at relatively shallow depths within the Atlantic waters of the eastern Norwegian Sea during late summer," which they compared with the temporal histories of various proxies of concomitant solar activity.....This work revealed, as the seven scientists describe it, that "the lowest isotope values (highest temperatures) of the last millennium are seen ~1100-1300 A.D., during the Medieval Climate Anomaly, and again after ~1950 A.D." In between these two warm intervals, of course, were the colder temperatures of the Little Ice Age, when oscillatory thermal minima occurred at the times of the Dalton, Maunder, Sporer and Wolf solar minima, such that the δ18O proxy record of near-surface water temperature was found to be "robustly and near-synchronously correlated with various proxies of solar variability spanning the last millennium," with decade- to century-scale temperature variability of 1 to 2°C magnitude." [Sejrup, H. P., S. J. Lehman, H. Haflidason, D. Noone, R. Muscheler, I. M. Berstad, and J. T. Andrews 2010: J. Geophys. Res]
Read here. Map source here. (click on image to enlarge)
As coastal elites and MSM reporters remain on the 'stuck-on-stupid' belief that current temperatures are"unprecedented," climate researchers continue to establish a scientific database that documents the unprecedented warmth of the Medieval Warming Period.
The newest addition to the database is a peer-reviewed study by Mullins et al. that reveals the New York region being both warmer and wetter than the present climate.
"Working with two sediment cores extracted from the extreme southern end of Cayuga Lake in central New York researchers "found paleolimnological evidence for the Medieval Warm Period (~1.4-0.5 ka), which was warmer and wetter than today." This evidence included weight percent total carbonate, total organic matter, non-carbonate inorganic terrigenous matter, carbonate stable isotopes, carbon isotope values of total organic matter and fossil types (gastropods, ostracods, bivalves, oogonia) and amounts, all of which were used to interpret past climate based on their relationship to modern climate data for the Finger Lakes region of the state. And to make their findings perfectly clear, they repeat that the "data for central New York suggest a warmer, wetter climate than today."" [Henry T. Mullins, William P. Patterson, Mark A. Teece and Adam W. Burnett 2011: Journal of Paleolimnology]
Read here. A new analysis of Greenland ice cores conclusively identifies the extremes of both the Medieval Warming and the Little Ice Age, represented by a 50-year average temperature measurement. This same measurement identifies the 1950's as a modern peak for the 50-year average, with a subsequent cooling through the mid-1990's.
This peer-reviewed analysis, by Kobashi et al., clearly shows that temperatures and climate exhibit a wide variation, regardless of atmospheric CO2 levels. In fact, these scientists state categorically that there are natural, decadal and century-long oscillations that are driving Arctic regional temperature changes over the past, the present and foreseeable future. These decadal/century periodicity events significantly pre-date human CO2 emission influence. (click on image to enlarge)
"Here, we reconstruct the last 1,000 years of central Greenland surface temperature from isotopes of N2 and Ar in air bubbles in an ice core. This technique provides constraints on decadal to centennial temperature fluctuations. We found that northern hemisphere temperature and Greenland temperature changed synchronously at periods of ∼20 years and 40–100 years. This quasi-periodic multi-decadal temperature fluctuation persisted throughout the last millennium, and is likely to continue into the future.....The data show clear evidence of the Medieval Warm Period and Little Ice Age in agreement with documentary evidence." [Takuro Kobashi · Jeffrey P. Severinghaus · Jean-Marc Barnola · Kenji Kawamura · Tara Carter · Tosiyuki Nakaegawa 2010: Climatic Change]
Read here. Paleo-climate and ocean scientists have relied on a theory to explain pre-historical, ancient and historical sea level changes. Now comes actual empirical evidence from the Mediterranean Sea that casts doubt on the "consensus" science.
Dorale et al. using precise measurement techniques determined that the Mediterranean sea level some 81,000 years ago was significantly higher than the current day level, which is counter to past accepted science.
"Precise measurements of sea level from Mediterranean caves have revealed that about 81,000 years ago the seas stood much higher than previously thought — even higher than today's levels.....now suggests that 81,000 years ago the sea level increased sharply to reach a high-point, roughly one metre above today's level. "At face value this is a very beautiful and solid piece of work," says Wallace Broecker, a geologist and climate scientist..."..."It suggests that, for reasons unknown, the sea level which at the time should have been down some 15 metres instead went up one metre, and then went right back down again within just a couple of thousand years." [Jeffrey A. Dorale, Bogdan P. Onac, Joan J. Fornós, Joaquin Ginés, Angel Ginés, Paola Tuccimei, David W. Peate 2010: Science]
Read here. Map source. (click on images to enlarge)
The IPCC and global warming alarmists have attempted to convince policymakers and the public that modern global warming is unprecedented. In addition, the Climategate scientists claimed that prior climate warming periods only took place in North Atlantic/European regions. Peer-reviewed study after study clearly documents that actual empirical evidence does not support the IPCC and alarmist sceintists claims, as this Chinese data reveals.
"Working with a sediment core extracted from the northern East China Sea...the authors [Li et al.] employed the alkenone paleotemperature index Uk'37...to construct a sea surface temperature history of that region covering the past 3600 years..."the highest temperature was 22.7°C which was recorded at 1.01 cal ka BP," about three-fifths of the way through the Medieval Warm Period...calculate that the peak warmth of the MWP was 2.9°C greater than the mean warmth of the first decade of the 21st century..."[GuangXue Li, XiaoYan Sun, Yong Liu, Torsten Bickert, YanYan Ma 2009: Chinese Science Bulletin]
Read here. Map source (click on image to enlarge). The sad record of failed IPCC and Climategate scientist predictions of global-warming caused disasters continues. Climate alarmists have been predicting that a warming climate will provoke increased flooding, due to a warmer atmosphere holding increased water moisture.
Scientists, Czymzik et al., analyzing 450 years of data from Germany, found the IPCC's increased flooding prediction to be the total opposite of reality. Instead, it was determined that colder climates have a greater frequency of floods.
"...the authors write that "assumptions about an increase in extreme flood events due to an intensified hydrological cycle caused by global warming are still under discussion and must be better verified," while noting that some historical flood records indicate that "flood frequencies were higher during colder periods.....The six scientists determined that the flood frequency distribution over the entire 450-year time series "is not stationary but reveals maxima for colder periods of the Little Ice Age when solar activity was reduced," while reporting that "similar observations have been made in historical flood time series of the River Main, located approximately 200 km north.....As time marches on and as ever more studies of this nature are conducted in Europe and elsewhere, it is becoming ever more clear that the climate-alarmist assumption -- as Czymzik et al. describe it -- of "an increase in extreme flood events due to an intensified hydrological cycle caused by global warming" is simply not correct." [Markus Czymzik, Peter Dulski, Birgit Plessen, Ulrich von Grafenstein, Rudolf Naumann, Achim Brauer 2010; Water Resources Research]
Read here. Fabricated claims by global warming alarmists regarding the frequency and intensity of modern severe weather events has recently seen an uptick as idiot-elites do their thing sans empirical evidence. Despite the MSM pundit fabrications, researchers continue to publish their peer-reviewed findings that clearly indicate current severe weather events are not extraordinary per the past.
The newest research by Stambaugh et al. reveals that historical droughts that occurred in America's corn belt were more frequent, more intense and longer than those that have happened since large industrial/consumer CO2 emissions began.
"...[researchers] used a new long tree-ring chronology developed from the central U.S. to reconstruct annual drought and characterize past drought duration, frequency, and cycles in the U.S. Corn Belt region during the last millennium."....."Of great significance is the fact that the new drought reconstruction indicates that "drought conditions over the period of instrumental records (since 1895) do not exhibit the full range of variability, severity, or duration of droughts during the last millennium.""....."that "three of the top ten most severe droughts occurred within a 25-year period corresponding to the late 16th century." Likewise, they state that "the four longest droughts occurred prior to Euro-American settlement of the region (ca. AD 1850)."....."In fact, the longest drought detected by Stambaugh et al. occurred in the middle of the Medieval Warm Period and, as they describe it, "lasted approximately 61 years (AD 1148-1208)."" [Michael C. Stambaugh, Richard P. Guyette, Erin R. McMurry, Edward R. Cook, David M. Meko and Anthony R. Lupo 2011: Agricultural and Forest Meteorology]
Read here. Map source here. A new peer-reviewed study (Clegg et al.) firmly establishes that modern global warming is significantly less than the global warming experienced in the high latitudes, during the summers of multiple periods over the last 3,000 years. Specifically, historical global warming is still unprecedented, and modern warming is a blip in comparison. (click on images to enlarge)
"The authors conducted a high-resolution analysis of midge assemblages found in the sediments of Moose Lake in the Wrangell-St. Elias National Park and Preserve.....The results of the study are portrayed in the accompanying figure, where it can be seen, in the words of Clegg et al., that "a piecewise linear regression analysis identifies a significant change point at ca 4000 years before present (cal BP)," with "a decreasing trend after this point." And from 2500 cal BP to the present, there is a clear multi-centennial oscillation about the declining trend line, with its peaks and valleys defining the temporal locations of the Roman Warm Period, the Dark Ages Cold Period, the Medieval Warm Period, the Little Ice Age.....and, finally, the start of the Current Warm Period, which is still not expressed to any significant degree compared to the Medieval and Roman Warm Periods." [Benjamin F. Clegg, Gina H. Clarke, Melissa L. Chipman, Michael Chou, Ian R. Walker, Willy Tinner, Feng Sheng Hu 2010: Quaternary Science Reviews]
Read here, here and here. The IPCC and Climategate scientists, such as Michael Mann, teamed up to rid the world of the Medieval Warming Period and the Little Ice Age in an effort to convince the world's politicians and mainstream press that the modern warming was "unprecedented." Literally, Mann and his colleges presented a temperature history that had erased the warming and cooling extremes prior to the modern era.
The result of that effort was two fold: one, the infamous 'hockey stick' portrayal of historical temperatures as being a time of little temperature variation was blatantly contrary to known history and evidence; and two, the recognition by other scientists and a minority of the public that climate science had become the complete victim of the governing elites' political agenda.
Subsequent to the 'hockey stick' revelations of politics and fabricated temperature histories, many scientists pushed harder to examine the historical past, in attempts to reconstruct paleo-climate temperatures and climate.
This new study, by Büntgen et al., was able to identify the significant warming periods and the resultant civilization prosperity of a warmer climate, as represented by the known Roman warming and Medieval periods. The tree rings also identified both the Dark ages and Little Ice Age extreme coolings and the associated disease, famine and death of those natural cold periods.
"Climate variations have influenced the agricultural productivity, health risk, and conflict level of preindustrial societies.....Wet and warm summers occurred during periods of Roman and medieval prosperity. Increased climate variability from ~AD 250 to 600 coincided with the demise of the Western Roman Empire and the turmoil of the Migration Period." [Ulf Büntgen, Willy Tegel, Kurt Nicolussi, Michael McCormick, David Frank, Valerie Trouet, Jed O. Kaplan, Franz Herzig, Karl-Uwe Heussner, Heinz Wanner, Jürg Luterbacher and Jan Esper 2010: Science]
"Der Spiegel presents the most important results, which I myself think are not a surprise. The bulk of the Der Spiegel piece focuses on the hunger and misery precipitated by the climatic cold periods throughout the 2500-year period. One really gets a sense of how temperatures in Europe by no means followed the hockey stick shape proposed by Mann, and went from cold to warm, and vice versa. Numerous other proxies show the same applies globally."
Read here. Map source here. The IPCC Climategate scientists and their AGW alarmist brethren at national climate agencies predicted that global warming would increase precipitation in mountainous regions, thus causing more mud/debris slides. Per a peer-reviewed study of an area of the Swiss Alps, this prediction has failed miserably, like so many.
"The authors note that it has been suggested that global warming may increase the frequency of extreme precipitation events and, therefore, that it may enhance the occurrence of natural mass-movement processes such as debris flows in mountainous regions. In fact, they state in regard to this particular phenomenon that there is a "widely accepted assumption that climatic changes will univocally lead to an increase in event frequency."".....The two Swiss scientists found there were peaks in debris-flow activity "toward the end of the Little Ice Age and in the early twentieth century when warm-wet conditions prevailed during summers in the Swiss Alps," but they say they also observed "a considerable decrease in frequency over the past decades which results from a decrease in the frequency of triggering precipitation events.".....they add that their findings "are in concert with data from Jomelli et al. (2007), indicating that the most recent past (2000-2009) represents the period with the lowest frequency of debris-flow events since AD 1900," which latter decade is touted by climate alarmists as having been the warmest such period of the past millennium or more." [Bollschweiler, M. and Stoffel, M. 2010: The Holocene 20: 907-916]
Read here. Another peer-reviewed study proves the IPCC speculative claim that modern temperatures are "unprecedented" is bogus.
Although the infamous Climategate scientists attempted to force the false "hockey stick" caricature of historical temperatures on the public, the on-going scientific research continues to discover that Medieval Period temperatures were, on average, higher than our present temperatures.
Per a new study, a lake in Switzerland provides evidence from sediment cores that refutes IPCC's propaganda that modern temperatures are warmer than past temperatures. (click on image to enlarge)
"Based on their analysis of fossil chironomids that were identified and quantified in four sediment cores extracted from the bed of Lake Silvaplana in the eastern Swiss Alps, plus a previously developed 101-lake transfer function, Larocque-Tobler et al. constructed a detailed history of that region's mean July air temperature over the last millennium.....it can be seen that the peak mean warmth of the Medieval Warm Period exceeded that of the Current Warm Period by approximately 0.5°C in the case of 20-year averages and 1.2°C in the case of 50-year averages." [Larocque-Tobler, I., Grosjean, M., Heiri, O., Trachsel, M. and Kamenik, C. 2010 Quaternary Science Reviews29: 1940-1949]
Read here. Other than the typical lamebrain MSM reporters (scroll down to Arctic temps "reported" by George Monbiot), just about everyone else knows that NASA completely fabricates modern hot Arctic temperatures from wishful alarmist thinking.
NASA's blatantly, bogus temperatures (lies?) are an attempt to scare the public into thinking the ice sheets of Greenland are quickly melting away because of unprecedented "high" temperatures, including those maximum high temperatures forecasted for the ice sheet this week: an average of a -35°F (yes, minus) for the daily high temps. Obviously, the northern ice sheets are safe despite the bogus NASA and Monbiot Arctic alarmism.
While NASA's computer jocks spend their time and our money on fabricating fake temperatures, real scientists continue to conduct expert scientific research on the Arctic. Their latest peer-reviewed findings confirm a previous study that the Medieval Period experienced Arctic temperatures some 2-3°C higher than modern Arctic temps. Map source here.
"We have generated a ~5,000 year long, decadally-resolved record of summer water temperature from the annually-laminated sediments of Lower Murray Lake on Ellesmere Island in the Canadian High Arctic. The varved sediments of Lower Murray Lake allowed high-resolution sampling and excellent chronologic control of the sedimentary record.....Most strikingly, the alkenone record reveals warm lake water temperatures beginning ~800 AD and persisting until ~1200 AD, with temperatures up to 2-3 deg C warmer than the mean temperature for the past 100 years. This dramatic medieval warm period on Ellesmere Island interrupted a distinct (neoglacial) cooling trend that had begun approximately 2000 years earlier." [D'Andrea, W. J.; Bradley, R. S. 2010]
Read here. The 2010 summer Russian heat wave and resulting forest fires have been claimed to be the result of global warming and climate change. Unfortunately for the AGW alarmists and activist scientists, NASA found these claims to be of little merit.
More importantly, modern heat waves and forest fires in Russia are not unprecedented. These severe weather events happen with some frequency, including the documented severe events of these years (link above for more info):
1298, 1364,1431,1735, 1831, 1839-1841, 1868, 1875, 1885 and 1917
Other than a handful of discredited tree-ring studies, the vast accumulation of scientific evidence indicates that modern warming has not been as great as that experienced during the Medieval Warming span.
Another peer-reviewed research study confirms the unprecedented warmth of the MWP from data collected at a lake on Baffin Island, Canada. (click on images to enlarge)
"Sediment cores collected from Donard Lake, Baffin Island, Canada were analyzed to produce a 1240-year record of average summer temperature for this region based on clastic varve thickness..... And in the words of Moore et al. who did the work, "the most prominent feature of the record is a period of elevated summer temperatures from AD 1200-1375," the peak 10-year mean value of which was approximately 0.9°C warmer than the peak 10-year mean value in the vicinity of 1960 (the highest of the last hundred years), 1.2°C warmer than the peak 10-year mean value in the vicinity of 1980, and fully 2.0°C warmer than the last 10-year value of the record, which was centered on approximately 1987." [Moore, J.J., Hughen, K.A., Miller, G.H. and Overpeck, J.T. 2001.]
IPCC Climategate scientists and alarmists claim that modern temperatures are "unprecedented." In another example of just how bogus this claim is, a new peer-reviewed study documents that eastern Finland's temperatures during the Medieval Warming were significantly warmer and extended over a 700-year span, not just a 25-year span that the modern warming represents. (click on images to enlarge)
"Working with a sediment core from Lake Pieni-Kauro in eastern Finland, Luoto and Helama identified and quantified various midge assemblages that were dominated by chironomids, after which they reconstructed a 1500-year history of mean July air temperature from the Finnish multi-lake calibration model of Luoto (2009). The results, shown in the accompanying figure, delineate a Medieval Warm Period stretching from about AD 580 to 1280, the peak temperature of which was approximately 0.3°C greater than the peak temperature at the end of the record, which concludes near the end of 2008. [Luoto, Tomi P. and Helama, Samuli 2010]
'Big Green' and its comrades have proven themselves capable of some the most outlandish lies in their incessant promotion of global governance, regulation and taxation of CO2 emissions. Possibly the biggest of lies is the one that today's modern temperatures are "unprecedented," never before warmer.
This big lie is the linchpin for all the associated hysterical, non-empirical, over-the-top, catastrophic predictions that are made by Big Green. Of course, when the actual, empirical, scientific data is actually considered, the big lie of "unprecedented" is shown to be a blatant falsehood.
As the graphs below reveal, there has been a general decline in polar temperatures over the last 10,000 years. Modern temperatures at both poles are well below their historical peaks.
Simply put, this means both humans and polar bears survived and adapted to warmer temperatures in the recent geological past. In addition, ice sheets outlasted extended periods of significantly higher temperatures in the past. (click on images to enlarge)
The other lie that the empirical evidence exposes as pseudo-science is that CO2 is the primary driving force of climate and temperature change. The ice core evidence is a stunning record of climate and temperature changing regardless of CO2 levels. Obviously, there are other natural forces in play that are the primary "climate disruptors."
That's not to say that human CO2 emissions have no part in modern warming, but it is more likely that a trace gas, like CO2, only has a trace affect on global temperatures and climate.
Notes: The average daily Vostok temperature (1958-2010) is the 2010 data-point for the Antarctica chart. The 2010 Greenland Summit temperature data point is average temperature of recent January through December monthly temperatures (added for modern context). The light gray columns in both charts represent CO2 levels, with 2010 estmated level (added for modern context) being the black column on far right.
YBP (years-before-present) figures were adjusted accordingly with use of year 2010 as end point.
Read here and here. Fredrik Charpentier Ljungqvist, a Stockholm University scientist recently published a peer-reviewed study that found there were previous warming periods that produced a warmer climate than our current climate, over the past 2,000 years . As a followup to that study, Ljungqvist has published additional information for the past 1,200 years that examines paleo-reconstructed temperatures for specific Northern Hemisphere regions.
This new data clearly reveals that both the Medieval Warming and the Little Ice Age cooling were significant climate events across the entire northern portion of the globe. In the majority of regions, modern temperatures are yet to reach the level and extent of the MWP.
"The presently available palaeotemperature proxy data records do not support the assumption that late 20th century temperatures exceeded those of the MWP in most regions.....Previous conclusions (e.g., IPCC, 2007) in the opposite direction have either been based on too few proxy records or been based on instrumental temperatures spliced to the proxy reconstructions. It is also clear that temperature changes, on centennial time-scales, occurred rather coherently in all the investigated regions – Scandinavia, Siberia, Greenland, Central Europe, China, and North America.....Assumptions that, in particular, the MWP was restricted to the North Atlantic region can be rejected."
This new data, combined with his other recent research, establishes without any doubt the existence of substantial climate change prior to 20th century's large emission of CO2. This research completely invalidates the UN's IPCC attempt to falsify historical climate change via the Climategate team of scientists. (click on images to enlarge)
Note: Original graphs had instrumental temperatures superimposed on top of proxy reconstruction during 20th century period. The instrumental data was removed and a reconstruction of the proxy reconstruction was done in order to make them visible - our re-do is close enough for NASA/GISS government work. ;-)
Read here. Map source here. Using sediment cores from lakes, researchers identified distinct periods of climate change, including the Dark Ages, Medieval Warming Period and the Little Ice Age. This peer-reviewed study, like so many, is contrary to the speculative comments by IPCC Climategate scientists who claimed that the MWP was only a northern European phenomenon.
"...the authors measured a number of sediment properties, among which were sulfur content and coarse mineral grains, the former of which served as a proxy for paleo-Asian summer monsoon activity and the latter of which served as a proxy for paleo-Asian winter monsoon activity. This work revealed the presence of a cold/dry interval stretching from AD 1 to 750, a warm/humid interval stretching from AD 750 to 1200, and another cold/dry interval stretching from AD 1200 to the present, which periods they associated, respectively, with "the Dark Ages Cold Period, the Medieval Warm Period and the Little Ice Age ." [Yamada, K., Kamite, M., Saito-Kato, M., Okuno, M., Shinozuka, Y. and Yasuda, Y. 2010]
Read here. Climate alarmist scientists and their computer models have predicted that global warming will cause multiple species to become extinct. Like all global warming predictions emanating from the IPCC Climategate science, this one also does not hold up to actual scientific scrutiny.
Scientists examined past significant global warming periods and discovered that the excessive and extended warmth of those periods did not cause species to die out.
"The first period they examined was the Eocene Climatic Optimum (53-51 million years ago), during which time the atmosphere's CO2 concentration exceeded 1200 ppm and tropical temperatures were 5-10°C warmer than modern values.....The second period they examined consisted of two rapid-change climatic events in the Holocene -- one at 14,700 years ago and one at 11,600 years ago -- during which times temperatures increased in the mid- to high-latitudes of the Northern Hemisphere by up to 10°C over periods of less than 60 years.....the authors note that "at no site yet studied, anywhere in the world, is there evidence in the fossil record for large-scale climate-driven extinction during these intervals of rapid warming." On the other hand, they report that extinctions did occur due to the cold temperatures of the glacial epoch, when subtropical species in southern Europe were driven out of their comfort zone." [Willis, K.J., Bennett, K.D., Bhagwat, S.A. and Birks, H.J.B. 2010]
Read here. Map source here. Numerous temperature reconstructions indicate that during the Medieval centuries, two distinct warming intervals happened. New research from a Scottish loch's sediment core analysis identified the two separate, extended warming periods between 900 and 1600AD.
In addition, the new peer-reviewed research clearly reveals the wide climate variation experienced prior to the large industrial CO2 emissions of the 20th century. The modern warming was found not to be unusual or out of the ordinary. (click on image to enlarge)
"“The Loch Sunart reconstruction for the late MCA suggests temperatures from AD 916 to 1035 were similar to those recorded over the late twentieth century.”..... Cage and Austin [Cage, A.G. and, W.E.N. Austin. 2010] point out “perhaps the most distinctive feature of the Loch Sunart temperature record is the short-lived event between AD 1540 and1600, which is characterized by a very abrupt warming transition at AD 1540. This period had an average temperature anomaly of 1.1ºC above the long-term mean, which is higher than most of the 20th century and the late MCA.”....."“The Loch Sunart temperature reconstruction exhibits a gradual cooling trend that continues from AD 1608 to 1941, with the coldest temperature anomalies (~0.75ºC) of this period occurring between the early 1930s and 1940s.” So in the last 400 years, the sea bottom of Loch Sunart cooled, the coldest period over the past 400 years occurred 70 years ago, and then the water warmed up to levels that were typical during the beginning of the 400-year period."
Read here and here. Map source here. A peer-reviewed study utilizing high resolution data from a peat bog sediment core, analyzes 6,000 years worth of a temperature proxy. The researchers determined that both Roman and Medieval Periods experienced temperatures that were significantly higher than those of the current period. (click on image to enalrge)
"Working with cores extracted from a peat bog west of Jinchuan, China the authors developed "a 6000-year high-resolution δ18O record of peat plant cellulose," which they interpret as "reflecting changes in regional surface air temperature." And from their results, which are depicted in the figure [adjacent], it can be seen that the Medieval Warm Period (which was preceded by the Dark Ages Cold Period and followed by the Little Ice Age) was considerably warmer than the Current Warm Period (which followed the Little Ice Age) has been to date"
Read here. Map source here. Another peer-reviewed study provides high resolution evidence that the world's climate is impacted by an oscillation that occurs approximately every 1,500 years. This oscillation produces rapid climate change, which most likely explains the global warming rebound experienced since the Little Ice Age.
"On the southern coast of the English Channel, Billeaud et al. (2009) studied offshore-derived sediments in the macrotidal setting of Mont-Saint-Michel Bay, France, where they conducted a high-resolution sequence stratigraphy analysis of the intertidal to subtidal wedge, utilizing juvenile shells, peat and organic-rich bulk sediment.....The work revealed that "rapid climate changes, with ~1500-year periodicity, are recorded in the sedimentary successions.....Such results add to the overwhelming evidence provided by other paleoclimate records that have shown, in their words, that "Holocene climate was punctuated by widespread cooling events, recurring every ~1500 ± 500 years (Bond et al., 1997; Bianchi and McCave, 1999; Broecker, 2000; Mayewski et al., 2004; Debret et al., 2007; Allen et al., 2007)."...And since this periodicity suggests that the world was fully ripe for a recovery from the last of these coolings (i.e., the Little Ice Age), 20th-century global warming is seen to be neither unusual, unnatural nor unprecedented..."
Read here. Peer-reviewed research documents the glacier retreat that happened during the Medieval Warming period for the Antarctica peninsula area. Despite Climategate scientists and alarmists claims, this evidence confirms that Antarctica (and the Southern Hemisphere) experienced the climate change of the Medieval era.
"Hall et al. examined organic-rich sediments exposed by recent retreat of the Marr Ice Piedmont on western Anvers Island, where glaciers have been undergoing considerable retreat in response to the well-documented warming of the Antarctic Peninsula..... This work revealed, in their words, that "peat from the overrun sediments dates between 707 ± 36 and 967 ± 47 cal. yr B.P.," which led them to conclude that "ice was at or behind its present position at ca. 700-970 cal. yr B.P," which they interpret as implying that "the present state of reduced ice on the western Antarctic Peninsula is not unprecedented," which means that this period was at least as warm as, or likely even warmer than, the peak warmth of the Current Warm Period."