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 Willis Eschenbach, March 17, 2019 inWUWT
People often say that we’re heading into the unknown with regards to CO2 and the planet. They say we can’t know, for example, what a 2°C warming will do because we can’t do the experiment. This is seen as important because for unknown reasons, people have battened on to “2°C” as being the scary temperature rise that we’re told we have to avoid at all costs.
But actually, as it turns out, we have already done the experiment. Below I show the Berkeley Earth average surface temperature record for Europe. Europe is a good location to analyze, because some of the longest continuous temperature records are from Europe. In addition, there are a lot of stations in Europe that have been taking record for a long time. This gives us lots of good data.
So without further ado, here’s the record of the average European temperature.
by K. Richard, March 7, 2019 in NoTrickszone
Yet another scientific paper presents evidence that the Arctic region was warmer than recent decades during the 1930s, leading scientists to conclude there is “still-insufficient knowledge of the mechanisms governing the Arctic Climate System.”
by Y, S., Zheng et al., 2018, Marine Micropaleontology, in CO2Science
According to Yuan et al. (2018), “studies examining sea surface temperature variability over the past one century and their influence on climate change in China are seriously lacking.” And therefore, in an effort to remedy this information void, the team of eight Chinese scientists developed “the first tree-ring-based dendroclimatic sea surface temperature (SST) reconstruction for the South China Sea.”
In accomplishing their objective Yuan et al. cored 22 Pinus massoniana trees in the Changting Region of the Fujian Province, China. Analysis of the cores revealed a statistically significant relationship between the tree-ring series and gridded March SSTs (1°C resolution) of the South China Sea (16-20°N, 112-116°E). Ultimately, this relationship enabled them to produce a proxy temperature reconstruction over the period 1893-2011, which reconstruction is shown below.
by Charles the moderator, February 7, 2019 in WUWT
Study shows that Vikings enjoyed a warmer Greenland
Chemistry of bugs trapped in ancient lake sediment shows a warm climate at a key time in Greenland’s history
Although TV and movies paint Vikings as robust souls, braving subzero temperatures in fur pelts and iron helmets, new evidence indicates they might have been basking in 50-degree summer weather when they settled in Greenland.
After reconstructing southern Greenland’s climate record over the past 3,000 years, a Northwestern University team found that it was relatively warm when the Norse lived there between 985 and 1450 C.E., compared to the previous and following centuries.
by P. Gosselin, January 29, 2019 in NoTricksZone
A paper very worth reading from the USA from January 2019 in Science (Geoffrey Gebbie of the Woods Hole Oceanographic Institution/Peter Huybers of Harvard University, hereinafter GH19) is titled “The Little Ice Age and 20th-century deep Pacific cooling”.
It shows fascinating science.
The authors evaluated temperature measurements made in the deep sea by the famous expedition of the “HMS Challenger” in the 1870s. The ship sailed the Atlantic and Pacific, and probably provided the first data on the oceans down to depths of over 2000 meters. The recalibration of the old data alone is a work of art! What the paper found: The Pacific down in depths has cooled from 1870 to today, the Atlantic not.
by Scott St. George Jan Esper, December 19, 2018 in WUWT
Tree rings are the backbone of most last millennium temperature reconstructions.
Maximum density is a superior temperature proxy than ring-width but is less available.
The newest tree-ring reconstructions agree better with instrumental temperatures.
They also fit the memory structure of instrumental temperatures more closely.
It is imperative to develop new, long and up-to-date maximum density chronologies.
by K. Richard, November 22, 2018 in NoTricksZone
The evidence that “global” warming has not been global in scale continues to accumulate. Two more new reconstructions from the Western Pacific (He et al., 2018) and subpolar North Atlantic (Orme et al., 2018) indicate that modern temperatures have continued to decline since the onset of the Little Ice Age.
These add to the nearly 300 graphs published in the scientific literature since 2017 showing that there is nothing unusual, unprecedented, or remarkable about the temperatures changes in the last 150 years.
by David Middleton, November 17, 2018 in WUWT
Why 536 was ‘the worst year to be alive’
By Ann Gibbons Nov. 15, 2018
Ask medieval historian Michael McCormick what year was the worst to be alive, and he’s got an answer: “536.” Not 1349, when the Black Death wiped out half of Europe. Not 1918, when the flu killed 50 million to 100 million people, mostly young adults. But 536. In Europe, “It was the beginning of one of the worst periods to be alive, if not the worst year,” says McCormick, a historian and archaeologist who chairs the Harvard University Initiative for the Science of the Human Past.
A mysterious fog plunged Europe, the Middle East, and parts of Asia into darkness, day and night—for 18 months. “For the sun gave forth its light without brightness, like the moon, during the whole year,” wrote Byzantine historian Procopius. Temperatures in the summer of 536 fell 1.5°C to 2.5°C, initiating the coldest decade in the past 2300 years. Snow fell that summer in China; crops failed; people starved. The Irish chronicles record “a failure of bread from the years 536–539.” Then, in 541, bubonic plague struck the Roman port of Pelusium, in Egypt. What came to be called the Plague of Justinian spread rapidly, wiping out one-third to one-half of the population of the eastern Roman Empire and hastening its collapse, McCormick says.
by P. Homewood, November 8, 2018 in NotaLotofPeopleKnowThat
My very first foray into climate blogging was an analysis of extreme weather events in 1971. (I wrote it in 2011, so it was not a cherrypicked year, merely a nice round 40 years before.)
I won’t bore you with it again, as it was basically just a very long list. You can see it here though.
But here is a summary, which goes to show that extreme weather is the norm, not the exception:
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 John Moreau, 20 octobre 2018 in Belgotopia
« Le contenu de la mémoire est fonction de la vitesse de l’oubli »
Désormais, chaque inondation quelque peu catastrophique, chaque tornade, chaque anomalie météorologique est rattachée au réchauffement climatique qui parait-il nous menace, mais dont en plus l’homme serait responsable !
Pourtant, la consultation de chroniques ou récits anciens est révélatrice de précédents tout aussi apocalyptiques, et relativise la notion même de « changements climatiques », ainsi que la définition d’un « climat stable » qui n’a jamais existé mais qu’on voudrait instaurer à tout prix.
AUX ENVIRONS DE 1850, FIN DU « PETIT AGE GLACIAIRE » et début d’un réchauffement du climat, surtout perceptible en hiver.
Pour l’ensemble des épisodes :
by P. Homewood, October 12, 2018 in NotaLotofPeopleKnowThat
The significance of course is that the warming of the oceans began long before any impact from CO2 emissions.
HH Lamb has written extensively about how sea temperatures in the Atlantic fell radically during the LIA. Is the warming trend since then merely a return to earlier conditions?
by Indriani Roy, September28, 2018 in FrontiersinEarthScience
College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
The puzzle of recent global warming trend slowdown has captured enough attention, though the underlying cause is still unexplained. This study addresses that area segregating the role of natural factors (the sun and volcano) to that from CO2 led linear anthropogenic contributions. It separates out a period 1976–1996 that covers two full solar cycles, where two explosive volcanos erupted during active phases of strong solar cycles. The similar period also matched the duration of abrupt global warming. It identifies that dominance of Central Pacific (CP) ENSO and associated water vapor feedback during that period play an important role. The possible mechanism could be initiated via a preferential alignment of NAO phase, generated by explosive volcanos. Inciting extratropical Rossby wave to influence the Aleutian Low, it has a modulating effect on CP ENSO. Disruption of Indian Summer Monsoon and ENSO during the abrupt warming period and a subsequent recovery thereafter can also be explained from that angle. Interestingly, CMIP5 model ensemble, and also individual models, fails to comply with such observation. It also explores possible areas where models miss important contributions due to natural drivers.
by Anthony Watts, August 30, 2018 in WUWT
Earth’s surface has undergone unprecedented warming over the last century, and especially in this century.
Every single year since 1977 has been warmer than the 20th century average, with 16 of the 17 warmest years on record occurring since 2001, and 2016 being the warmest year on recorded history. A study from 2016 found that without the emissions from burning coal and oil, there is very little likelihood that 13 out of the 15 warmest years on record would all have happened.
First a definition of the word “unprecedented”:
Note that “in this century” isn’t part of the definition. it says “never done or known before”
So in that spirit, here’s some other “unprecedented” warming in Earth’s history, via the Vostok Ice Core dataset: