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Medieval Global Warming: Southern Hemisphere Research Documents Hotter Temps In Uruguay During MWP

A new study analyzing Uruguay's ancient mound settlements reveals the global medieval warming of the Southern Hemisphere - MWP temperatures warmer than those of present

(click on image to enlarge - image source)

Read here. The IPCC and Climategate scientists, such as Michael Mann, attempted to mislead the public and policymakers with claims that the Medieval Warming Period was an insignificant climate event only affecting the northern European areas. However, the empirical evidence continues to grow that the Southern Hemisphere experienced a global medieval warming climate also.

Analyzing sediment cores from the Merín Lagoon Basin, in the region of the ancient Uruguay 'Los Ajos' mound builders, it was determined from opal phytoliths that Uruguay's climate of 750 AD to 1350 AD was warmer and wetter than those of its current modern climate.

"Focusing on coastal lagoons within the Merin Lagoon Basin, which is located between 31-34°S and 52-54°W in the easternmost part of the South American plains, and working with phytoliths found within various sediment cores which they used to create a temperature index indicative of relative warmth, Bracco et al. discovered a period of time straddling the division of the last two millennia (AD 750-1350) that they identified as having "warmer and wetter conditions than those of the present."" [Roberto Bracco, Laura del Puerto, Hugo Inda, Daniel Panario, Carola Castiñeira, Felipe García-Rodríguez 2011: Quaternary International]

Conclusion: Medieval global warming was a significant climate phenomenon that empirically prevailed across the world and not just limited to the northern European/Atlantic region as fabricated by the IPCC.

Previous climate-history and peer-reviewed postings. Historical temperature charts.

Unprecedented Antarctica Climate Change: Polar Experts Document Large Climate Shifts Prior To 1850's

The IPCC and Michael Mann claimed that modern Antarctica climate change is "unprecedented' - new polar research demolishes that myth

Read here. Without doing any scientific field research, the IPCC and Climategate's Michael Mann chose to promulgate a non-scientific position that the Medieval Warming Period and the Little Ice Age were only local European phenomena. Their political agenda was to establish the myth that Antarctica climate change was unaffected by the MWP and the LIA.

That myth is no longer sustainable.

The team of Lu et al. published new research conclusively proving that the Antarctica continent also experienced both the MWP and LIA. In essence, the climate of previous centuries is similar to the climate Antarctica now has (as depicted in the adjacent image) - the modern South Pole climate is not "unprecedented."

"At present the Intergovernmental Panel on Climate Change (IPCC) argues that the Medieval Warm Period was confined to Europe – therefore that the warming we’re experiencing now is a man-made phenomenon...However, Professor Lu has shown that this isn’t true – and the evidence lies with a rare mineral called ikaite, which forms in cold waters...The scientists were particularly interested in crystals found in layers deposited during the ‘Little Ice Age,’ approximately 300 to 500 years ago, and during the Medieval Warm Period before it...‘We showed that the Northern European climate events influenced climate conditions in Antarctica,’...They were able to deduce this by studying the amount of heavy oxygen isotopes found in the crystals." [Zunli Lu, Rosalind E.M. Rickaby, Hilary Kennedy, Paul Kennedy, Richard D. Pancost, Samuel Shaw, Alistair Lennie, Julia Wellner, John B. Anderson 2012: Earth and Planetary Science Letters]

Conclusion: Modern Antarctica climate change is not unusual; is likely to have nothing to do with CO2 emissions; and similar climate variation happened in the past.

Previous climate-history and peer-reviewed postings.

Dust Storm Evidence Documents The Roman & Medieval Unprecedented Warming Scientists Say

The empirical evidence continues to mount that documents the Roman and Medieval unprecedented warming - dust storms from the Aral Sea is the latest empirical evidence

Read here. The adjacent image is a classic example of the extreme environmental devastation produced by progressive / left government regime scientists. Although scientific geo-engineering has destroyed the Aral Sea, its historical evidence still provides further proof that modern global warming is not unprecedented.

The Huang et al. peer reviewed research analyzed 2000 years of dust storm residue and unequivocally determined that both Roman and Medieval minimum temperatures were higher than modern minimum temperatures for this central Asia region - a clear indication of warmer climates during earlier historical periods.

"Noting that dust storms are common features adjacent to the Aral Sea, the authors investigated the grain-size distributions of wind-blown sediments found in a core retrieved from that water body...report that the history of dust deposition in central Asia can be divided into five distinct periods on the basis of their observations: "a remarkably low deposition during AD 1-350, a moderately high value from AD 350-720, a return to a relatively low level between AD 720 and AD 1400 (including the Medieval Warm Period), an exceptionally high deposition from AD 1400 to [the] 1940s and an abnormally low value since [the] 1940s."...coincides with the Roman Warm Period, the second with the Dark Ages Cold Period, the third (as Huang et al. make a point of noting) with the Medieval Warm Period, the fourth with the Little Ice Age, and the fifth with the Current Warm Period...with low/high annual temperature anomalies corresponding to high/low dust supplied in the Aral Sea sediments, respectively...the minimum value of this inverted measure of annual temperature during the Medieval Warm Period was approximately 13% more extreme than the minimum value so far experienced during the Current Warm Period, and that the minimum value during the Roman Warm Period was fully 70% more extreme than that of the present." [Xiangtong Huang, Hedi Oberhänsli, Hans von Suchodoletz, Philippe Sorrel 2011: Quaternary Science Reviews]

Conclusion: Historical climate change, as represented by the Roman and Medieval unprecedented warming documented in central Asia, was a global phenomenon that modern climate change has yet to rival.

Previous climate-history and peer-reviewed postings. Historical and modern temperature charts.

Peer Reviewed Research Confirms That Natural Climate Change Causes Unprecedented Warming

Climate science and consensus evidence is now moving to a position that natural climate change causes unprecedented warming (global and/or regional) - a major refutation of IPCC's denial of natural climate impacts

Read here and here. The IPCC's political agenda requires a denial dogma that is built on the concept that natural climate change is minor, thus the recent warming of the 1980's and 90's is a result of human CO2 emissions.

Of course, the lack of global warming over the last 17 years has made a shambles of the AGW hypothesis, plus new research continues to bolster the climate science thesis that natural climate change actually drives unprecedented temperature change. New research by Chen et al. confirms the power of natural climate forcings.

"...they state, in this regard, that "one of the most intriguing questions within the climate debate is if the present temperature rise is unique in the late Holocene or if there have been pre-industrial time intervals where comparable climatic perturbations occurred," noting that "one of these time intervals where historical records suggest that climate conditions might have been similar to today is the so called 'Roman Warm Period' (~200 BC - AD 400)."...developed high-resolution climatic and environmental reconstructions "based on a dinoflagellate cyst record from a well dated site in the Gulf of Taranto located at the distal end of the Po River discharge plume." ...determined that the dinoflagellate cyst warm/cold ratio suggests that sea surface temperature (SST) was "relatively high and stable between 60 BC and AD 200," which they say is suggestive of "slightly higher SST than today." In fact, they say that the association that is observed between 60 BC and AD 90 is equivalent to modern regions that are characterized by higher SST than those in the present day Gulf of Taranto. And noting that "Versteegh et al. (2007) showed that SST in the region is strongly related to local air temperature," they go on to suggest that the region's air temperature "might have been warmer during the Roman Period as well."" [Liang Chen, Karin A.F. Zonneveld, Gerard J.M. Versteegh 2011: Quaternary Science Reviews]

Conclusion: Paleo-climate empirical evidence from the Roman Period indicates that natural climate change causes unprecedented warming, which also may have been the dominant causal factor the modern warming during the 1980-1990's period.

Previous climate-history, unprecedented-temperatures and peer-reviewed postings. Historical temperature, modern temperature solar-cosmic charts. Source for above map.

Latest Research Shatters Urban Myth of "Unprecedented" Modern Warming: The 'Hockey Stick' Refuted

Climate 'urban myths' have plagued policymakers and the public for years - fortunately Michael Mann's "unprecedented" modern global warming myth is finally dying an empirical-death

(click on image to enlarge)

Read here. Urban myths of Hollywood celebrities, the mainstream press and coastal elites are often foisted on the public and policymakers as "consensus" science.

A recent example was the left/liberal urban legend that vaccines cause autism, which a scientist-fraud perpetrated. (As researchers have amazingly documented, scientific fraud is rampant.)

The classic climate "science" urban myth is that 20th century global warming was "unprecedented" when in fact empirical study after study proves that myth to be without scientific merit. And now a new study demolishes that myth conclusively - will the discredited 'hockey stick' caricature of past temperatures now finally die?

"Working with the GISP2 ice core from the Summit region of central Greenland, Kobashi et al. reconstructed Greenland surface snow temperature variability over the past 4000 years with a method that utilizes nitrogen and argon isotopic ratios..."The estimated average Greenland snow temperature over the past 4000 years was −30.7°C with a standard deviation of 1.0°C and exhibited a long-term decrease of roughly 1.5°C, which is consistent with earlier studies. The current decadal average surface temperature (2001–2010) at the GISP2 site is −29.9°C. The record indicates that warmer temperatures were the norm in the earlier part of the past 4000 years, including century-long intervals nearly 1°C warmer than the present decade (2001–2010). Therefore, we conclude that the current decadal mean temperature in Greenland has not exceeded the envelope of natural variability over the past 4000 years..."" [Takuro Kobashi, Kenji Kawamura, Jeffrey P. Severinghaus, Jean-Marc Barnola, Toshiyuki Nakaegawa, Bo M. Vinther, Sigfús J. Johnsen, Jason E. Box 2011: Geophysical Research Letters]

Conclusions:

• Arctic Greenland was warmer than modern warming during the Bronze, Roman and Medieval periods - ergo, modern warming not unprecedented
• Despite massive industrial/consumer human CO2 emissions, modern warming is easily within natural climate variation
• Scientists claiming that modern warming is "unprecedented" are simply lying (or, amazingly ignorant of the plethora of actual empirical evidence)

Additional peer-reviewed postings. Historical, modern and fabricated-fake temperature charts. Source of above image.

Subarctic Seas: Latest Study Confirms Modern Temperatures Well Below Roman & Medieval Temps

Experts reconstruct sea surface temperatures off of Norway - evidence confirms this subarctic region was warmer during Roman and Medieval times

Read here. It's another peer reviewed study published that refutes Mann's 'hockey stick' caricature of past temperatures over the last 2000 years. (click image to enlarge)

Modern warming is not unprecedented as claimed by the IPCC's Climategate "scientists."

"Sejrup et al established exceptionally accurate chronologies for two marine sediment cores raised from the same location on the Norwegian continental margin...they developed the δ¹⁸O history depicted in the figure [adjacent], which they use as a proxy for what they call "near surface water summer temperature." And as this history clearly shows, the peak warmth of the Medieval Warm Period was significantly greater than the peak warmth of the Current Warm Period has been to date." [H.P. Sejrup, H. Haflidason, J.T. Andrews 2011: Quaternary Science Reviews]

Additional climate-history and peer-reviewed postings. Historical and modern temperature charts.

"Science" By Lubchenco's NOAA: Fake Global Warming, Part III

The NOAA under Lubchenco's control continues to make a mockery of empirical-based science as global warming fabrication continues unchecked

This is an update from the two previous posts, here and here. During the month of December, NOAA / NCDC revised their published historical temperature dataset at least 6 times - affecting monthly historical temperatures going back to 1880. These major revisions were not constrained to just a few recent months or a few recent years, but to all the historical empirical records.

If doing it 6 times in December wasn't bizarre enough, the NOAA "scientists" have already revised the entire dataset 3 times during January (the month isn't even over yet). [Ed. Good news: No new revised datasets in last 2 days, which means the incessant changes may be halted until next month]

Since the Obama administration takeover of NOAA / NCDC, it has been on a tear to fabricate global warming, conducting major temperature fabrication on an almost monthly basis, which has now culminated to producing multiple major revisions per month. (click to enlarge images)

(Above is a sample of revisions, including 2 (of 3) done in January 2012.)

Defenders of Lubchenco's empirical evidence revisionism refer to the constant revisions as "quality control" which is categorically one of the lamest piles of B.S. uttered in the debate on global warming. If the 'QC' defense had even an ounce of truth to it, it would mean every single previous revision had "quality control" issues even though each was a result of the same quality control process.

Plus, in contrast to the 7 major revisions done by NOAA / NCDC over the last 4 weeks, there has been only one major revision by GISS and zero for HadCRUT, UAH and RSS. (These other alphabet climate agencies do not do major revisions every single month, let alone multiple major revisions to the historical record within a month.)

Simply put, the 'big green' activist Lubchenco must have a political agenda that calls for the NCDC dataset exhibiting more "global warming."

Needless to say, her servile puppet-scientists have performed that task since 2008, month-in and month-out, as the change in the global warming trend  exhibits (red is new trend; blue is old) in the adjacent chart.

[Bonus recommendation to NOAA/ NCDC: Publish only one set of numbers per month; avoid changing historical temperatures prior to 1990; and, make future changes random so that they don't appear to be purposefully warming specific periods while cooling others. Food for thought.]

BTW, this Excel chart represents the typical way that alarmists portray "runaway" global warming. That red trend line leaves the impression that global warming will go through the roof by 2100. In fact though, that red trend line indicates a "global warming" of about +0.5°C by year 2100. To mislead the public and policymakers, alarmist scientists and the mainstream press typically avoid putting numeric linear trend information on the chart, for very obvious reasons.

Additional modern, fabricated-fake and historical temperature charts.

Download data file of NOAA's January 2012 revisions (3 so far) of historical temperature dataset.

New Unequivocal Empirical Evidence: Antarctica's Past Climate Warmer Than Modern, Over Last 450 Years

New Antarctica evidence conclusively refutes IPCC global warming scientists' speculation that modern temperatures are "unprecedented" and "accelerating" higher

Read here. The UN's IPCC attempted to convince the public and policymakers that there was a scientific "consensus" that the last 150 years have witnessed "accelerating" global warming that is "unprecedented."

Instead, the evidence now points to the IPCC and its Climategate scientists conspiring to mislead. Thankfully, the vast majority of the world's scientists do not believe in the IPCC's climate political-science proclamations and thus continue performing/producing empirical research to determine the science truth.

The non-IPCC research team of Thamban et al is an example of this and the adjacent chart (click to enlarge) is a product of their research: Antarctica's modern temperatures are not unusual, nor are they rapidly warming versus what has occurred naturally in the historical past. As the evidence clearly shows, a natural warming has been taking place over the last 400+ years.

"Working with an ice core (IND-22/B4) that had been extracted during the austral summer of 2003 from the coastal region of Dronning Maud Land, East Antarctica... -- the authors developed 470-year histories of δ18O and δD that "showed similar down core fluctuations with [an] excellent positive relationship (R2 = 0.9; n = 216) between the two."..."the estimated surface air temperature at the core site revealed a significant warming of 2.7°C with a warming of ~0.6°C per century for the past 470 years."..."...Thamban et al.'s results clearly indicate that all three of these climate-alarmist claims are false in regard to this portion of the planet's southern polar region." [Meloth Thamban, C. M. Laluraj, Sushant S. Naik and Arun Chaturvedi 2011: Journal of the Geological Society of India]

Previous climate-history and peer-reviewed postings. Historical and modern temperature charts.

Current North Atlantic Ocean Temperatures Well Below Those of Medieval Warming Period, New Study Finds

Latest scientific research completely debunks Michael Mann's bogus hockey stick chart - North Atlantic ocean temperatures warmer during Medieval Warming

Read here. As the adjacent chart reveals, both the Roman and Medieval periods included significantly warmer sea surface temperatures in the North Atlantic region.

Around 1250 AD, the Little Ice Age started a cooling process of the sea surface temperatures, which modern warming has yet to recover from.

There is no hockey stick as claimed by Michael Mann. There is no "unprecedented" and "accelerating" warming as claimed by the IPCC. The empirical evidence does not support the left / liberal / progressive / Democrat claim of dangerous climate change due to CO2 warming.

"A paper published today in the journal Paleoceanography finds that Atlantic Ocean surface temperatures have significantly cooled over the past millennium, since the Medieval Warming Period from about 950-1200 AD...Cooling by ∼0.5°C takes place between about AD 1250 and AD 1500; while this corresponds to the inception of the Little Ice Age (LIA), the end of the LIA is not reflected in our record and SST remains relatively low. This transition to cooler SSTs parallels the previously reconstructed shift in the North Atlantic Oscillation toward a low pre-20th century mean state and possibly reflects common solar forcing." [Henning Kuhnert, Stefan Mulitza 2011: Paleoceanography]

Previous climate-history and peer-reviewed postings. Historical and modern temperature charts.

Mann's Discredited Hockey Stick Takes Another Huge Hit: South America's Hot Medieval Temperatures

New research determines that South America did experience the Medieval Warming and temperatures were higher during MWP, contrary to Michael Mann's hockey stick "science"

Read here. As hundreds of scientists have discovered and published, the Medieval Warming (MWP) climate was global in nature, with temperatures that in many areas of the world were higher than today's temperatures.

Contrary to Michael Mann's now widely discredited hockey stick "science," the Neukom et al research found the MWP was a significant high temperature event in South America. This team of 18 highly qualified researchers came from 7 countries; they chose the best 22 climate proxies to reconstruct a thousand+ year temperature series. (click to enlarge chart)

"The international research team — composed of scientists from Argentina, Chile, Germany, Switzerland, The Netherlands, the United Kingdom and the United States — write that their summer temperature reconstruction suggests that “a warm period extended in SSA from 900 (or even earlier) to the mid-fourteenth century,” which they describe as being temporally located “towards the end of the Medieval Climate Anomaly as concluded from Northern Hemisphere temperature reconstructions.” And as can be seen from the figure below, the warmest decade of this Medieval Warm Period was calculated by them to be AD 1079-1088, which as best as can be determined from their graph is about 0.17°C warmer than the peak warmth of the Current Warm Period." [Neukom, R., Luterbacher, J., Villalba, R., Kuttel, M., Frank, D., Jones, P.D., Grosjean, M., Wanner, H., Aravena, J.-C., Black, D.E., Christie, D.A., D'Arrigo, R., Lara, A., Morales, M., Soliz-Gamboa, C., Srur, A., Urritia, R. and von Gunten, L. 2011: Climate Dynamics]

Previous climate-history and peer-reviewed postings. Historical and modern temperature charts.

New Chinese Research: More Proof That Mann's Hockey Stick Was Bogus Science

New research continues to break Michael Mann's discredited hockey stick - individual proxy studies invalidate Mann's claims

Michael Mann concocted the infamous hockey stick temperature chart in an attempt to overturn known, well established paleo-temperature history. His research was soon after discredited by expert statisticians when it was found that Mann had over-weighted a single American tree some 390 times in order to produce his desired result.

The hockey stick was so thoroughly discredited that the IPCC had to quit using it in their PR "science" literature.

Read here. Most individual climate proxy studies are unable to reconstruct a temperature series that resembles the infamous Mann research. The newest study unable to do so is the Liu et al peer-reviewed research.

(click on image to enlarge)

As the 2,485 year old tree ring chart depicts, modern warming is well within the natural variability that the Tibet Plateau has experienced. As with so many independent studies, the hockey stick statistical fabrication is non-repeatable - it solely exists in the bowels of the Climategate conspirators and their bizarre methodologies.

"A blockbuster Chinese study of Tibetan tree rings by Liu et al 2011 shows, with detail, that the modern era is a dog-standard normal climate when compared to the last 2,500 years. The temperature, the rate of change — it’s all been seen before. Nothing about the current period is “abnormal”...these climate cycles have nothing to with human civilization. Their team finds natural cycles of many different lengths are at work: 2-3 years, 100 years, 199 years, 800 years, and 1,324 years. The cold periods are associated with sunspot cycles...The results showed that extreme climatic events on the Plateau, such as the Medieval Warm Period,  Little Ice Age and 20th Century Warming appeared synchronously with those in other places worldwide. The largest amplitude and rate of temperature change occurred during the Eastern Jin Event (343–425 AD), and not in the late 20th century..." [Yu Liu, QiuFang Cai, HuiMing Song, ZhiSheng An, Hans W. Linderholm 2011: Chinese Science Bulletin]

Previous climate-history and peer-reviewed postings. Historical and modern temperature charts.

New EU Research Confirms Roman Warming Period In Arctic Regions Warmer Than Modern

Empirical evidence from Arctic-region waters near Greenland establish robust warming of the Roman Period

Read here. Map source (click to enlarge).

Despite the bogus claims of the UN's bureaucrats and the IPCC Climategate "scientists," the polar areas of the Northern Hemisphere have had warmer climates prior to the 20th and 21st centuries.

There is a vast body of research and empirical evidence confirming that the Arctic regions, and other parts of the globe, were indeed warmer during both the Roman and Medieval eras. In fact, global warming, cooling and climate change are natural events that never cease - that is irrefutable, unequivocal climate reality.

A peer-reviewed study by Perner et al. just added to that mountain of evidence confirming the robust warming of the Greenland area prior to the the modern era.

"The six researchers -- hailing from Denmark, Germany, Norway, Poland and the United Kingdom -- say that their new high-resolution benthic foraminiferal record from Disko Bugt "documents a marked long-term cooling trend over the last 3.6 ka BP," but they state that superimposed on this longer-term late Holocene cooling trend, there is evidence of millennial to centennial scale variability. This variability begins with what they describe as "a pronounced cooling event" at c. 2.5 ka BP, after which "a warm phase in bottom waters is recorded at c. 1.8 ka BP, which corresponds to the 'Roman Warm Period' and is seen to represent the warmest bottom water conditions recorded in Disko Bugt during the last 3.6 ka BP." This unique warm period was in turn followed by a cooler period (which would obviously be the Dark Ages Cold Period), after which they identify a warming of the subsurface waters during the 'Medieval Climate Anomaly'," which was followed (from 0.9 ka BP) by "pervasive and even harsher environmental conditions" that ultimately culminate at 0.3 ka BP in what they say is the Little Ice Age, and from which the region has yet to recover to Medieval Warm Period conditions." [K. Perner, M. Moros, J.M. Lloyd, A. Kuijpers, R.J. Telford, J. Harff 2011: Quaternary Science Reviews]

Previous peer-reviewed postings.

New EU Research: Medieval Unprecedented Warming Period Temps Robustly Higher - By 1.2 Degrees

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]

Previous unprecedented-warming, climate-history and peer-reviewed postings. Additional Medieval unprecedented warming graphs.

Latest Research Disproves IPCC's Climategate Hockey-Stick: Antarctica Was Warmer During Medieval Period

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]

Additional climate-history and peer-reviewed postings. Historical and modern temperature charts.

Southern Hemisphere Glaciers Provide Proof That Medieval Warming & Little Ice Age Were Global

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]

Additional climate-history and peer-reviewed postings. Historical and modern temperature charts.

Abrupt, Severe Climate Change Over Past 3,000 Years Recorded By Iceland Glacier Lake, Scientists Discover

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]

Additional climate-history and peer-reviewed postings. Historical and modern temperature charts.

Swiss Alps: Latest Study Confirms Pre-Medieval's Unprecedented Warming - Modern Temps Pale In Comparison

Note: Additional historical temperature charts

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]

Additional climate-history and peer-reviewed postings. Historical and modern temperature charts.

New Research From Middle East: Scientists Confirm Medieval Period Temperatures Were Warmer Than Current Temps

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]

Additional climate-history and peer-reviewed postings.

German Peat Bog Study Verifies Extreme Warm Temperatures of Medieval Period - Modern Warming Less

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]

Additional climate-history and peer-reviewed psotings. Historical and modern temperature charts.

Peer Reviewed Study Establishes Unprecedented Medieval Warming On Tropical Island In Southern Hemisphere

Read here. Map source.

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]

Additional climate-history and peer-reviewed postings. Historical temperature charts.

Mann's Discredited 'Hockey Stick' Suffers Another Major Blow: New Study Confirms Unprecedented Warming Pre-20th Century

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]

Previous climate-history, unprecedented-temperatures and peer-reviewed postings. Additional historical and modern temperature charts.

Vostok, Antarctica Current Temperatures Still Significantly Below Roman & Medieval Peaks

As the empirical evidence keeps mounting, the climate alarmist claim of a catastrophic Antarctica ice sheet melt event from "global" warming is entirely without merit.

One, as global warming alarmist scientists are finally admitting in the scientific literature, there has been no warming since 1998. Two, the average surface temperature at Vostok, Antarctica over the last two decades is a minus 55.1C degrees - that's 55 degrees below melting temperature. (click on image to enlarge)

The Vostok ice core temperature chart reveals the following essential points about this frozen region of the world:

• The 2010 annual temperature was below both the long-term and short-term averages
• The temperature average since 1990 is significantly below the peaks of the Medieval and Roman eras, and even below those prior to the Roman peak
• For the 5,000+ year period, the linear trend (aqua line) indicates overall cooling
• The green polynomial fitted curve to the data shows temperatures heading in a warming direction over the past 1,300 years, prior to modern era consumer/industrial CO2 emissions.

It should be noted that although the two polar regions both have a lot of ice, snow and cold, they are entirely different climates. These polar extremes experience warning and cooling periods at different times and at different rates/levels of change. As a result, the historical temperature regimes, commonly referred to as the 'Roman' and the 'Medieval', happened differently at the geographical opposites.

Additional historical temperature charts.

Asian Temperatures During Medieval Period Were Unprecedented New Research Determines

Read here. (click on image to enlarge)

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]

Additional climate-history and peer-reviewed postings. Other historical temperature charts.

Sea Levels Higher During Medieval Warming Period - Research Shows Current Sea Level Rise Began By 1750 AD

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.

Additional sea level postings. Sea level charts here.

NOAA Temperature Data Rebuts IPCC's Climate Model Predictions of Global Warming

The UN's political and propaganda climate agency, commonly known as the IPCC, has made an ongoing, multi-decadal effort to convince both policymakers and the public that global warming was relentless, unprecedented and accelerating. The well publicized IPCC climate predictions even went as far as to claim winters would be wamer with an associated disappearance of snowfall throughout the Northern Hemisphere.

Unfortunately for the IPCC though, and its climate model predictions, and its "consensus" science, natural climate forces made a mockery of the exhibited arrogance and hubris embodied within the United Nations climate propaganda agency.

As fate would have it, large expanses of global geography have experienced colder and snowier conditions during many of the last ten years, totally contradicting the "settled" science of politicians and bureaucrats. Case in point is the vast area of the U.S. and its various regional areas. (click on image to enlarge)

The U.S. has been cooling overall for the past 15 years, and as the chart above depicts, its winters, as reported by the NOAA climate services, have contributed to that trend. This happened despite the IPCC claim that increased CO2 emissions results in global warming, not hemispheric cooling. And let there be no doubt, annual CO2 emissions continue to be large and growing.

h/t: Steve Goddard

Additional failed-prediction postings. Modern temperature charts.

Canadian Lake's Past Water Levels Refutes Both Mann's 'Hockey-Stick' Climate & IPCC's "Unprecedented" Modern Warming

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]

Additonal climate-history and peer-reviewed postings. Historical temperature charts.

Analysis of Sediment Cores From Arctic Circle Region Determines Medieval Era Warmer Than Modern Period

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]

Additonal climate-history and peer-reviewed postings. Historical temperature charts.

Peer-Research Establishes That Temperatures In China Were Warmer In 1920-40s Versus Modern Temperatures

Read here.  (click on image to enlarge)

Global warming alarmists, such as Al Gore and Mitt Romney, who advocate for more government spending, regulations and taxes to make a gallon of gas even more expensive, claim that current global temperatures are "unprecedented." Nothing could be more scientific-nonsense when, clearly, peer-reviewed study after study shows that current modern warming is lukewarm versus previous periods.

The Gore-Romney-Obama nonsense about "unprecedented" warming can't even hold its own during the 20th century, as a new study by Yi et al. establishes without a reasonable doubt. Early 20th century temperatures prior to large human CO2 emissions were hotter than temperatures in the 1990s and early 21st century.

And to emphasize the anti-science hysteria from Democrat/Republican big government liberals/leftists/progressives, this study shows how absurd their claim is that climate change is only due to recent human CO2 emissions.

"In the ongoing global warming debate there is often a significant difference between the perception of what is going on with the Earth’s climate when compared to what is actually going on.  There is no greater example of this than the summer temperatures in the Northern Hemisphere...A recent study is probably the highest resolution reconstruction using temperature and precipitation records from the region and then correlating to tree-ring data to create a high resolution reconstruction of the summer temperatures for North-Central China...it is clear that the peak of the modern warming cycle for the summer months took place 70-80 years ago.  It should be noted that the United States set the all time temperature record for 50% of the states back in the 1930′s."

"We concluded that (1) the droughts, occurred during the years of 1484 AD, 1585–1587 AD, 1689–1691 AD, 1784–1786 AD and 1876–1878 AD, were the results of rainless and torrid combination; (2) the droughts, occurred during the years of 1560–1561 AD, 1599–1601 AD, 1609 AD, 1615–1617 AD, 1638–1641 AD and 1899–1901 AD, were first caused by rainless summer, and then controlled by low precipitation and/or high temperature; (3) the droughts, occurred during the years of 1527–1529 AD, 1720–1722 AD, 1813–1814 AD, 1856–1857 AD and 1926–1930 AD, were first caused by torrid summer, and then controlled by both low precipitation and high temperature; (4) the dominant climate pattern within the study area consisted of warm–dry and cold–wet alternations, and the recessive pattern consisted of cold–dry and warm–wet alternations. We also showed that the drought/flood index is a valuable climate proxy in quantitative reconstructions, especially in places where tree-ring data is not available." [Liang Yi, Hongjun Yu, Junyi Ge, Zhongping Lai, Xingyong Xu, Li Qin and Shuzhen Peng 2011: Climatic Change]

Additional "unprecedented"-warming and peer-reviewed postings. Modern temperature charts.

Algae Research Confirms That North Atlantic During The 1990s Was Cooler Than 1920s-1930s

Read here. There is an abundance of both empirical and anecdotal evidence that the Arctic and sub-Arctic regions were warmer during the early 20th century than the more recent recorded temperatures. (For an indication of the anecdotal evidence about the 1920s and 1930s go here and scroll down to those decades.)

Scientists and Arctic experts now believe that the early 20th century saw exceptional polar and Northern Hemisphere warming that is yet to be adequately explained since atmospheric CO2 levels were so low at the time.

Now a new study by Halfar et al. adds to growing empirical evidence that indeed the North Atlantic area may have been warmer during the 1920s and 1930s.

"The authors write that "mid- and high-latitude crustose coralline algae are an emerging extra-tropical marine climate archive," as was demonstrated during a field calibration study (Halfar et al., 2008), since "they are amongst the longest-lived shallow marine organisms," and since "they show constant growth over their lifespan...Using a regional network of specimens of the coralline alga Clathromorphum compactum spanning portions of the Labrador Current inshore branch from the Gulf of St. Lawrence to both latitudinal extremes of the eastern Newfoundland shelf,...The new temperature reconstruction revealed "the well-documented regime shift and warming in the northwestern Atlantic during the 1990s." But in addition, the eight researchers report that "large positive changes in algal growth anomalies were also present in the 1920s and 1930s, indicating that the impact of a concurrent large-scale regime shift throughout the North Atlantic was more strongly felt in the subarctic Northwestern Atlantic than previously thought." And they specifically state that this regime shift "may have even exceeded the 1990s event with respect to the magnitude of the warming," as "has recently been suggested for the central and eastern North Atlantic," citing the study of Drinkwater (2006)." [Halfar, J., Hetzinger, S., Adey, W., Zack, T., Gamboa, G., Kunz, B., Williams, B. and Jacob, D.E. 2011: Palaeogeography, Palaeoclimatology, Palaeoecology]

Additional modern-temperature and peer-reviewed postings.

Latest Data From EU Scientists: Medieval Warming In Switzerland Was Unprecedented Versus The Current Lukewarm Temperatures

Read here. Map source here.

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]

Additonal climate-history and peer-reviewed postings. Historical temperature charts.

New Refutation of Mann's 'Hockey Stick' Science: Medieval Warming Prosperity Collapsed Due To Devastation of Rapid Climate Cooling

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]

Additonal climate-history and peer-reviewed postings. Historical temperature charts.

2011 Icelandic Study Refutes Bogus "Unprecedented" Modern Temperature Claim: Medieval Warming Was Hotter

Read here. Map source here.

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]

Additional climate-history and peer-reviewed postings. Historical temperature charts.

When Did Hottest Sea-Surface Temperatures Occur? Newest Research Says During Medieval Period

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]

Additional climate-history and peer-reviewed postings. Historical temperature charts.

Been There, Done That: Unequivocal, Unprecedented & Accelerating Climate Change Prior To The IPCC

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.

Additional historical and modern temperature charts.

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.

Latest Peer-Reviewed Research: The Warming of The Medieval Period Remains Unprecedented

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]

Additional climate-history and peer-reviewed postings. Historical temperature charts.

Scientists Say Norwegian Sea Research Confirms Large, Robust Solar Impact On Temperatures

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]

Additional solar, climate-history and peer-reviewed postings.

Unprecedented Warming Strikes New York, Prior To Modern CO2 Levels: New Study Finds Medieval Period Warmer

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]

Additional climate-history and peer-reviewed postings. Historical temperature charts.

Chinese Study Finds Medieval Period Sea Surface Temperatures Hotter Than Modern Temperatures

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]

Additional climate-history postings. More peer-reviewed postings. Historical and modern temperature charts.

New Research From Alaska Determines That Modern Global Warming Is Well Below Past Warming Periods

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]

Additional climate-history postings. More peer-reviewed postings. Historical and modern temperature charts.

Latest In-Depth Tree Ring Analysis Refutes The Infamous Mann/IPCC 'Hockey Stick'

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."

Additional peer-reviewed and climate-history postings.

Modern Swiss Precision Determines Medieval Period Temperatures Robustly Warmer Than Modern Temps

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 Reviews 29: 1940-1949]

Read about other peer-reviewed studies. Additional climate history postings and historical temperature charts.

Empirical Evidence From Canada's High North: Medieval Period Summers Robustly Warmer Than Modern Summers

Read here. Map source here.

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.]

Read about other peer-reviewed studies. Additional climate history postings and historical temperature charts.

Climate Experts Discover Finland's Medieval Warming Was Longer & Hotter Than Modern "Unprecedented" Warming

Read here. Map source here.

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]

Read about other peer-reviewed studies. Additional climate history postings and charts.

Memo To New, Incoming Republicans Re: 'Big Green' Lies: Their Biggest Whopper - Modern Temperatures Are "Unprecedented"

'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.
  
Historical temperature charts. Other climate history postings. Modern temperature charts. List of peer-reviewed study postings.

Paleo-Climate Scientist Examines Recent Peer-Research, Determines All N. Hemisphere Regions Had Large Medieval Warming

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. ;-)

Historical temperature charts. Other climate history postings. Modern temperature charts. List of peer-reviewed study postings.

New Peer-Reviewed Evidence Documents Medieval Climate Change In Northern Japan

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]

Other climate history postings. List of peer-reviewed study postings. Historical temperature charts.

Paleo-Climate Experts Reject Mann's "Hockey Stick" Hypothesis, Embrace The McIntyre/McKitrick Results

Read here and here. As is well known by now, the IPCC, the MSM and Hollywood wildly (and foolishly) celebrated the "Hockey Stick" caricature of past temperatures when it was first introduced, which portrayed the Medieval Warming and Little Ice Age as non-existent. Subsequent expert analysis by McIntyre and McKitrick found the hockey stick portrayal of past temperatures to be bogus and without scientific merit.

Recently, paleo-climate experts from around the world confirmed that the hockey stick caricature was dead by holding a major Medieval Warming Period (MWP) symposium in Lisbon, Portugal titled "The Medieval Warm Period - Where and when was it warm?". [Archived home web page here.]

Obviously, holding a MWP conference means there is no MWP "consensus" yet, and the IPCC Climategate-style of science is definitely not "settled." Additional confirmation of the MWP existence (pouring salt into Michael Mann's wound) is the symposium's prominent use of a graph from a peer-reviewed study that depicts MWP temperatures matching or exceeding modern warming temperatures. The symposium graph is an ensemble of paleo proxy reconstructions [Jansen et al., 2007]; and, by focusing solely on the ensemble's temperature ranges of the proxies, as depicted in the 'C3' chart below, the Jansen et al. research clearly is more supportive of, and similar to, the McIntyre & McKitrick results instead of the infamous hockey stick results. (click on image to enlarge)

This range of ensemble temperatures is also very similar to the results of multiple other peer-reviewed studies in the paleo-climate science field.

A Scottish Loch's Evidence Substantiates Two Significant Medieval Warming Intervals, Study Shows

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."

Additional climate history postings. Historical temperature charts.

Scientists Determine That China's Roman & Medieval Temperatures Significantly Warmer Than Present

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"

Additional climate history postings. Historical temperature charts.

French Data Confirms 1,500 Year Climate Cycle: Global Cooling/Warming Phases Natural, Not Man-Made

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..."

Additional climate history postings. Historical temperature charts.