Purer Zufall: Solares Minimum soll angeblich nichts mit den Kältewintern der 1430er Jahre zu tun haben

Am 21. Dezember 2016 konnte man bei Radio SRF wieder einmal einen klimawandlerischen Lückentext bestaunen. Durch gezieltes Weglassen wichtiger Informationen wurde der Zuhörer effektiv in die Irre geleitet. Dritter Beitrag vom “Echo der Zeit”:

Klimaforscher in den USA bringen ihre Daten in Sicherheit

In den USA demonstrieren Wissenschaftler auf der Strasse für die Klimaforschung. Einige von ihnen sichern sogar ihre Forschungsdaten auf externen Rechnern, Weil sie befürchten, dass Klimaforschungsdaten unter der Regierung Trump als missliebig gelöscht werden könnten.

Begegnung mit Ray Bradley in Bern.

Welche Mechanismen greifen, wenn Menschen leugnen, worüber in der Wissenschaft Konsens herrscht – dass der Klimawandel vom Menschen gemacht ist? Klaus Oberauer, Professor für Psychologie an der Universität Zürich, hat dazu geforscht. Das Gespräch.

Ray Bradley, einer der Co-Autoren der berühmt-berüchtigten “Hockey-Stick-Kurve” von Michael E. Mann, darf sich im Beitrag als ungerecht verfolgtes Opfer von angeblich durch “Big Oil” gekaufte US-Politiker darstellen. Leider haben die SRF-Journalisten “rein zufällig” vergessen, die andere Seite der Story zu berichten, dass nämlich die “Hockey-Stick-Kurve” wissenschaftlich längst widerlegt ist und deren Autoren völlig zurecht für grobe Verstöße gegen wissenschaftliche Standards kritisiert wurden, siehe z.B. hier.

Gleich im Anschluss darf dann “Klima-Experte” und Psychologie-Prof. Klaus Oberauer die Skeptiker des überzogenen IPCC-Klima-Alarmismus, als “Verschwörungstheorie-Trottel” oder konservativ verbohrte “Wissenschaftsleugner” abkanzeln. Schade, dass die SRF-Zuhörer auch hier nicht die volle Wahrheit über den Hintergrund von Oberauer erfahren dürfen. Er ist nämlich Co-Autor von einschlägig bekannten Aktivistenartikeln zusammen mit seinem Mitstreiter Stephan Lewandowski, in welchen IPCC-Skeptiker unter krasser Verdrehung der realen Datenbasis als irre Verschwörungstheoretiker dargestellt werden (siehe z.B. hier). Ausserdem ist es mehr als fragwürdig, dass sich Oberauer im SRF-Radio-Interview als scheinbar neutraler Beobachter inszenieren darf, obwohl er in Wirklichkeit ein lupenreiner Öko-Aktivist ist.

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Beitrag zur Kleinen Eiszeit auf BBC Radio “Science in Action” am 16. Dezember 2016:

Europe’s Coldest Decade
In the midst of the Little Ice Age, winter temperatures plummeted even lower in the extraordinary decade of 1430-1440. Rivers, lakes and coastlines froze over year after year. Seeds perished, flocks dwindled, famine ensued, and soon minorities and witches were being blamed for the miserable conditions. Historian Chantal Camenisch and Kathrin Keller of Bern University look into what may have been the worst decade in European weather in almost a millennium.

Es geht um eine Arbeit von Chantal Camenisch und Kollegen in Climate of the Past, in der die kalten Winter der 1430er Jahre als zufällige Laune der Natur beschrieben werden, die angeblich nichts mit dem zeitgleichen solaren Spörer-Minimum zu tun haben sollen. Kurios: Unmittelbar nach dem Interview mit den beiden Schweizer Autorinnen wird unter Hinweis auf andere Arbeiten von der BBC eingeräumt, dass kalte Winter sehr wohl mit geringer Sonnenaktivität verbunden wären.

Hier die dazugehörige Pressemitteilung zum Paper, die am 1. Dezember 2016 von der European Geosciences Union herausgegeben wurde:

The Coldest Decade of the Millennium? How the cold 1430s led to famine and disease

While searching through historical archives to find out more about the 15th-century climate of what is now Belgium, northern France, Luxembourg, and the Netherlands, Chantal Camenisch noticed something odd. “I realised that there was something extraordinary going on regarding the climate during the 1430s,” says the historian from the University of Bern in Switzerland.

Compared with other decades of the last millennium, many of the 1430s’ winters and some springs were extremely cold in the Low Countries, as well as in other parts of Europe. In the winter of 1432–33, people in Scotland had to use fire to melt wine in bottles before drinking it. In central Europe, many rivers and lakes froze over. In the usually mild regions of southern France, northern and central Italy, some winters lasted until April, often with late frosts. This affected food production and food prices in many parts of Europe. “For the people, it meant that they were suffering from hunger, they were sick and many of them died,” says Camenisch.

She joined forces with Kathrin Keller, a climate modeller at the Oeschger Centre for Climate Change Research in Bern, and other researchers, to find out more about the 1430s climate and how it impacted societies in northwestern and central Europe. Their results are published today in Climate of the Past, a journal of the European Geosciences Union.

They looked into climate archives, data such as tree rings, ice cores, lake sediments and historical documents, to reconstruct the climate of the time. “The reconstructions show that the climatic conditions during the 1430s were very special. With its very cold winters and normal to warm summers, this decade is a one of a kind in the 400 years of data we were investigating, from 1300 to 1700 CE,” says Keller. “What cannot be answered by the reconstructions alone, however, is its origin – was the anomalous climate forced by external influences, such as volcanism or changes in solar activity, or was it simply the random result of natural variability inherent to the climate system?”

There have been other cold periods in Europe’s history. In 1815, Mount Tambora – a volcano in Indonesia – spewed large quantities of ash and particles into the atmosphere, blocking enough sunlight to significantly reduce temperatures in Europe and other parts of the world. But the 1430s were different, not only in what caused the cooling but also because they hadn’t been studied in detail until now.

The climate simulations ran by Keller and her team showed that, while there were some volcanic eruptions and changes in solar activity around that time, these could not explain the climate pattern of the 1430s. The climate models showed instead that these conditions were due to natural variations in the climate system, a combination of natural factors that occurred by chance and meant Europe had very cold winters and normal to warm summers. [See note]

Regardless of the underlying causes of the odd climate, the 1430s were “a cruel period” for those who lived through those years, says Camenisch. “Due to this cluster of extremely cold winters with low temperatures lasting until April and May, the growing grain was damaged, as well as the vineyards and other agricultural production. Therefore, there were considerable harvest failures in many places in northwestern and central Europe. These harvest failures led to rising food prices and consequently subsistence crisis and famine. Furthermore, epidemic diseases raged in many places. Famine and epidemics led to an increase of the mortality rate.” In the paper, the authors also mention other impacts: “In the context of the crisis, minorities were blamed for harsh climatic conditions, rising food prices, famine and plague.” However, in some cities, such as Basel, Strasbourg, Cologne or London, societies adapted more constructively to the crisis by building communal granaries that made them more resilient to future food shortages.

Keller says another decade of very cold winters could happen again. “However, such temperature variations have to be seen in the context of the state of the climate system. Compared to the 15th century we live in a distinctly warmer world. As a consequence, we are affected by climate extremes in a different way – cold extremes are less cold, hot extremes are even hotter.”

The team says their Climate of the Past study could help people today by showing how societies can be affected by extreme climate conditions, and how they should take precautions to make themselves less vulnerable to them. In the 1430s, people had not been exposed to such extreme conditions before and were unprepared to deal with the consequences.

“Our example of a climate-induced challenge to society shows the need to prepare for extreme climate conditions that might be coming sooner or later,” says Camenisch. “It also shows that, to avoid similar or even larger crises to that of the 1430s, societies today need to take measures to avoid dangerous anthropogenic climate interference.”

Note:
Even without the influence of external factors, the climate can vary naturally because of the way the different components of the climate system (such as atmosphere, oceans or land) interact with each other. El Niño, a warming of the eastern equatorial Pacific Ocean, is an example of natural variability. This phenomenon happens every 2 to 7 years and causes changes in temperature and rainfall also in other parts of the world for months. The type of natural variability responsible for the 1430s climate conditions is another, much less common, example.