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Medieval Warm Period (MWP)

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Also check out the Paleoclimate section, which includes references to the MWP.

Medieval Warm Period. Documenting the Global Extent of the Medieval Warm Period. By Angus McFarlane Introduction In this article I pose the following questions: Was the Medieval Warm Period (MWP) a global event?

Documenting the Global Extent of the Medieval Warm Period

Where the MWP temperatures higher than recent times? The reasons for asking these questions are that climate establishment have tried to sideline the MWP as a purely local North Atlantic event. Study: Ammonium as ice core proxy shows strong Medieval Warm Period in the tropics. The MWP has been vigorously argued to be a regional northern hemisphere phenomenon only, but this new study finds it in South America.

Study: Ammonium as ice core proxy shows strong Medieval Warm Period in the tropics

In this new paper they write: “The most striking features in the reconstruction are the warm temperatures from ∼1050 to ∼1300 AD compared to the preceding and following centuries, the persistent cooler temperatures from ∼1400 to ∼1800 AD, and the subsequent rise to warmer temperatures which eventually seem to exceed in the last decades of the 20th century the range of past variation. While the onset of the warm period around 1050 AD is almost consistent within the dating error (±60 years at 1000 AD) with the perception of a Northern Hemisphere (NH) MWP from 950 to 1100 AD, it is remarkable to note that it seems to have lasted about 200 years longer in the tropics.” Figure 7. A review of temperature reconstructions. Guest essay by Andy May In previous posts (here and here), I’ve compared historical events to the Alley and KobashiGISP2 Central Greenland Temperature reconstructions for the past 4,000 years.

A review of temperature reconstructions

Unfortunately, these two reconstructions are very different. Recently Steve McIntyre has suggested a third reconstruction by Bo Vinther. Vinther’s data can be found here. Unfortunately, Vinther is often significantly different from the other two. Body Of Proof: Large Number Of Studies Show Medieval Warm Period “Prominent In Southern Hemisphere” Remember how in the late 1990s/early 2000s the Medieval Warm Period (MWP) was made to disappear, and it was claimed that it was mainly a local, North Atlantic phenomenon.

Body Of Proof: Large Number Of Studies Show Medieval Warm Period “Prominent In Southern Hemisphere”

Unfortunately for those trumpeting this claim, a comprehensive worldwide survey of scientific literature is now showing that the MWP was in fact a global phenomenon, suggesting large-scale natural cycles are what is really driving the climate. ================================= Charting the Medieval Warm Period In The Southern Hemisphere By Dr. The Medieval Warm Period – a global phenomenon, unprecedented warming, or unprecedented data manipulation? Originally in German here, with some portions translated to English using the Google translator below.

The Medieval Warm Period – a global phenomenon, unprecedented warming, or unprecedented data manipulation?

Google translator is largely imperfect, but to read the Google translation in English go here. If anyone wishes to do a personal translation for the entire article, please leave a note in comments and I will replace it. Of great interest is the global graphic below, which shows that the MWP is a worldwide event, not just limited to portions of the Northern Hemisphere. “ “Who controls the past controls the future: who controls the present controls the past.” – George Orwell, 1984.

18 New Papers Link High Solar Activity To Medieval And Modern Warmth, Low Solar Activity To Little Ice Age Cooling. “It is generally accepted that the climate warms during periods of strong solar activity (e.g., the Medieval Warm Period) and cools during periods of low solar activity (e.g., the Little Ice Age).”

18 New Papers Link High Solar Activity To Medieval And Modern Warmth, Low Solar Activity To Little Ice Age Cooling

—Lyu et al., 2016 Within the last 1,000 years, global-scale surface temperatures underwent a warm period during Medieval times, centennial-scale cooling during the 14th to 19th centuries, and another warm period since the early 20th century. Loehle: Vindication. Guest Post by Craig Loehle (cloehle -at- ncasi.org) When I published my 2000 year reconstruction (Loehle, C. 2007.

Loehle: Vindication

A 2000 Year Global Temperature Reconstruction based on Non-Treering Proxy Data. Study shows they are still trying to erase the ‘Medieval Warm Period’ From the THE EARTH INSTITUTE AT COLUMBIA UNIVERSITY and the “must make the blade of the hockey stick flat” department comes this claim: Study undercuts idea that ‘Medieval Warm Period’ was global Vikings may not have colonized Greenland in nice weather.

Study shows they are still trying to erase the ‘Medieval Warm Period’

Medieval Warm Period confirmed via cave study of 3000 years of climatic variations. Remote cave study reveals 3000 years of European climate variation Roaring Cave in Scotland.

Medieval Warm Period confirmed via cave study of 3000 years of climatic variations

A study of its limestone has produced a unique 3000-year-long record of climatic variations that may have influenced historical events including the fall of the Roman Empire and the Viking Age of expansion. Credit: Courtesy of UNSW SYDNEY — University of New South Wales Australia-led research on limestone formations in a remote Scottish cave has produced a unique 3000-year-long record of climatic variations that may have influenced historical events including the fall of the Roman Empire and the Viking Age of expansion. Historical Grape Harvest Dates Show Modern Temperatures No Warmer Now Than Most Of The Last 1,000 Years.

Public domain photo.

Historical Grape Harvest Dates Show Modern Temperatures No Warmer Now Than Most Of The Last 1,000 Years

Source here In a late February (2017) interview on a U.S. news program, mechanical engineer Bill Nye claimed that the settled science says humans have been warming the planet at a rate that is unnaturally and “catastrophically” fast since the year 1750 . Hottest year ever? Giant clam reveals Middle Ages were warmer than today.

While government science and media begin the ramp-up to claim 2014 as the “hottest year ever” China’s Sea’s biggest bivalve shows that the Middle Ages were warmer than today, when Carbon Dioxide was lower. From the Chinese Academy of Sciences: Two recent papers, one is in Earth-Science Reviews and the other is in Chinese Science Bulletin, have studied key chemical contents in micro-drilled giant clams shells and coral samples to demonstrate that in the South China Sea the warm period of the Middle Ages was warmer than the present. The scientists examined surveys of the ratio of strontium to calcium content and heavy oxygen isotopes, both are sensitive recorders of sea surface temperatures past and present.

Tibetan Temperature Reconstruction Shows Medieval Warm Period Was Warmer Than Today! A team of scientists led by HE YuXin of the Department of Earth Sciences at the University of Hong Kong examined two lake cores extracted from the Tibetan Plateau in order to reconstruct the past temperature development. Source: East_Asia_topographic_map.png: Ksiom, the GNU Free Documentation License, Version 1.2 The two cores coming from two different lakes go back 2600 and 2200 years respectively. Here’s the paper’s abstract (my emphasis): Considerable efforts have been made to extend temperature records beyond the instrumental period through proxy reconstructions, in order to further understand the mechanisms of past climate variability. Yet, the global coverage of existing temperature records is still limited, especially for some key regions like the Tibetan Plateau and for earlier times including the Medieval Warm Period (MWP).

Evidence of the Medieval Warm Period in Australia, New Zealand and Oceania. By Sebastian LüningGeoscientist and co-author of ‘The neglected Sun’ The climate of the pre-industrial past is of greatest importance to the ongoing climate discussion. Current climate can only be understood when interpreting it in the paleoclimatological context of the past few thousand years.

Until not too long ago it was thought that the pre-industrial climate was monotonous and constant. This idea was e.g. promoted by Mann et al. whose famous hockey stick curve featured prominently in the IPCC report of 2001. Over the last 15 years, however, a large number of studies changed this view by providing robust evidence for the existence of significant natural climate variability. Medieval Warm Period And Little Ice Age Show Up In South America Too – Far Far Away From North Atlantic. Dr. Michael-Shawn Fletcher Based on data from a few carefully selected tree rings, dogmatic warmist scientists like to insist that the Medieval Warm Period really did not exist globally and was only a local North Atlantic phenomenon. The climate, they tell us, was pretty much steady over the last couple thousand years – until man began to prosper a hundred years ago. However, yet another new study, one by Michael Shawn Fletcher and Patricio Iván Moreno, has been published and adds more to the growing mountain of evidence that the Medieval Warm Period was indeed a global phenomenon.

AGU: Lowell et al on Greenland Organics « Climate Audit. Ray PH reported at RC an AGU session describing the very interesting recent discovery of organic material disgorged from a retreating glacier N of 70N on the east coast of Greenland, with radiocarbon dates around the MWP. To put things in perspective, I should first mention the talk by Tom Lowell, on work in collaboration with about a dozen other authors, concerning organic remains from the Istorvet Ice Cap in East Greenland. These are organic remains recently uncovered by the retreating glacier. Dating them tells you when the glacier had last retreated that far. Carbon-14 dates put the date of this earlier glacial retreat to between AD 800 and 1014, bracketing the time of the Norse colonization. Insofar as glaciers are primarily sensitive to temperature, that does indicate that in the Middle Ages this particular place, at least, was probably as warm as at present.

Greenland much warmer in the past - Once boasted butterflies & lush forests. Scientists drill through 2 kilometers of Greenland ice, find butterflies & lush forests. Arctic Was An Open Sea In The Year 1122. Evidence for the Medieval Warm Period on the SE Greenland Shelf. Another paper refutes the Mann made hockey stick – MWP was ≈1°C warmer than current temperatures. Debunking the “Vikings weren’t victims of climate” myth.

Vikings arrived in Greenland during warm period like today's. During the MWP Glaciers In the Antarctica Retreated Further and Faster Than Today - Principia Scientific International. The Medieval Warm Period in Antarctica: How two one-data-point studies missed the target. Baffin Island study disappoints: The illusive ‘coup de grace’ on the Medieval Warm Period.