by Lüning et al., July 6, 2019 in NoTricksZone
For a long time it has been said that the Medieval Warm Period was a purely North Atlantic phenomenon. This has proved to be wrong.
On 29 June 2019, a paper by Lüning et al. 2019 on the Medieval Warm Period in Antarctica appeared in the trade journal Palaeogeography, Palaeoclimatology, Palaeoecology. Here is the abstract:
With the publication of this paper, the Medieval Climate Anomaly (MCA) has now been confirmed on all four continents of the southern hemisphere.
While the largest part of the southern hemisphere apparently experienced a warm phase during the MCA, there were also isolated areas that cooled down. To the latter regions belong, for example, coasts, where cold water from the depth rose increasingly. In other areas so-called climate seesaws or dipoles were active, as we know them from today’s climate. One end of the “seesaw” heats up, the other end cools down.
Another result of the studies is that the medieval climate history of huge areas in the southern hemisphere is simply unknown. A task force urgently needs to be set up to fill in this climatic “empty space” with information on pre-industrial temperature development. This information is urgently needed to calibrate the climate models on the basis of which far-reaching socio-political planning is currently taking place.
What follows are publications on the Medieval Period climate of the southern hemisphere as an overview:
Lüning, S., M. Gałka, F. Vahrenholt (2019): The Medieval Climate Anomaly in Antarctica. Palaeogeogr., Palaeoclimatol., Palaeoecol., doi: 10.1016/j.palaeo.2019.109251
by P. Gosselin, June 19, 2019 in NoTricksZone
Dry summers were not rare 1000 years ago. Researchers from the University of Greifswald’s research group ‘Landscape Ecology and Ecosystem Dynamics’ have been able to reconstruct 1000 years of the dry summer period in northern Germany.
Beech forest – photo: Dr. Tobias Scharnweber
The article ‘Removing the no-analogue bias in modern accelerated tree growth leads to stronger medieval drought’ was published in 2019’s February edition of the journal Scientific Reports.
As part of the current collaborative research project BaltRap (The Baltic Sea and its Southern Lowlands: Proxy-Environment interactions in times of rapid changes), the researchers investigated growth rings in nearly 2000 living beech trees – including some from the university’s own Elisenhain forest – and archaeological wood used for construction from around 1000 A.D. The growth rings found in this wood are a unique archive of previous environmental conditions. If the climatic conditions are good, growth rings are wide; in unfavourable years, like in dry 2018, there is little growth. Dendroclimatology uses this correlation to reconstruct past environmental conditions.
by Marcia Wendorf, May 15, 2019 in InterestingEngineering
Between 1300 and 1850, the Earth experienced a Little Ice Age whose cause to this day is not known.
During the period 950 CE to 1250 CE, the earth experienced an unusually warm period, which became known as the Medieval Warm Period (MWP) or the Medieval Climatic Anomaly. At their height, temperatures during that period were similar to those experienced during earth’s mid-20th-century warming period.
Following the Medieval Warm Period came a period of intense cold, which has become known as the Little Ice Age (LIA). The term “Little Ice Age” was coined by Dutch-born American geologist F.E. Matthes in 1939. The LIA began around 1300 CE and lasted until about 1850 CE.
Within that stretch, NASA’s Earth Observatory has described three particularly cold periods: one around 1650, a second around 1770, and the third around 1850.
by Don J. Easterbrook, 2011 in ScienceDirect
The Medieval Warm Period (MWP) was a time of warm climate from about 900 A.D. to 1300 A.D. when global temperatures were apparently somewhat warmer than at present. Its effects were evident in Europe where grain crops flourished, alpine tree lines rose, many new cities arose, and the population more than doubled. The Vikings took advantage of the climatic amelioration to colonize Greenland, and wine grapes were grown as far north as England where growing grapes is now not feasible and about 500 km north of present vineyards in France and Germany. Grapes are presently grown in Germany up to elevations of about 560 m, but from about 1100 A.D. to 1300 A.D., vineyards extended up to 780 m, implying temperatures warmer by about 1.0–1.4 °C (Oliver, 1973).
by I.B. Bauhi & S. Akçer-Ön, August 30, 2018 in QuaternaryInternational
by Lüning et al., 2018 in NoTricksZone
Global warming alarmist scientists like claiming that the well documented Medieval Warm Period (MWP) was merely a regional phenomenon, and not global. However a new publication by Lüning et al adds yet another study that shows the warm period from 1000 years ago was indeed global.
by Kirye, October 23, 2048 in NoTricksZone
Dr. Fukai also points out that global vegetation coverage increased by 11% in 29 years, from 1982 to 2010, as increasing CO2 has helped the greening of the Sahel and Sahara Desert. He contradicts the often heard media claims that drought is spreading globally, writing: “The media spread the word that desertification is progressing globally, but practically the desert is greening through CO2.” […] “Everyone should be aware that increasing CO2 concentrations in atmosphere is not in itself harmful, but it’s a good thing.”
Dr. Fukai also shows that the earth’s temperature change is not simple and does not correlate at all with CO2. He shows graphs from D. M. Etheridge et al., Mauna Loa Observatory and the temperature data from Moberg et al. (2005).
The retired Japanese professor writes that at around 1000 A.D. — the Medieval Warm Period — there were no signs showing CO2 concentration was higher. A temperature graph using data from Moberg et al. (2005) shows the Medieval Warm Period appears clearly and that CO2 was in fact around 280 ppm at that time.
by S. Lüning, January 9, 2018 in WUWT
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. Of particular interest are the past 1000 years which commenced with the generally warm ‘Medieval Climate Anomaly’ (MCA, aka ‘Medieval Warm Period’, MWP), that eventually passed into the ‘Little Ice Age’ (LIA), before returning to the warm climate of the current ‘Modern Warm Period’ of the 20th and early 21st centuries.
There have been controversial debates about the existence of the MWP, …
by K. Richard, April 2, 2018
Canada’s stable-to-increasing polar bear population extends its range slightly further south of the 55th parallel (York et al., 2016).
According to published geological evidence from the 1950s, remnants of wine grape vineyards have been unearthed in regions as far north as the polar-bear-inhabiting 55th parallel during the Medieval Warm Period (~800s to 1300s AD).