Dr. Sebastian Lünning’s and Prof. Fritz Vahrenholt’s climate website Die kalte Sonne, has a report on a paper on the Maunder Minimum in the Journal The Holocene. What follows is a translation in English:
Study by Diodato and Bellocchi show that Little Ice Age was not restricted to North Atlantic region (Painting by Hendrick Barentsz)
The climate of the last 10,000 years has been everything except stable, and global mean temperatures fluctuated by more than 1°C. Today’s “Modern Warm Period” was preceded by the Little Ice Age (LIA), which lasted from 1300 to 1850.
The high point of the Little Ice Age occurred during a period of weak solar activity from 1645-1715, called the Maunder Minimum. During this time, Central Europe turned bitter cold, glaciers grew and the Thames River even froze over in the wintertime. During the cold winter of 1683/1684, the ground froze more than a meter deep in Southern England.
The Little Ice Age is widely known for the North Atlantic region of Northern Europe, and for this reason some scientists falsely assumed that it had been a regional phenomenon and it was balanced out by other areas on the planet being warmer. However, this hypothesis has not been confirmed as a growing body of scientific literature shows that all continents were hit by the LIA.
In the Mediterranean region there have been no reliable temperature reconstructions from during this period. The existing tree-ring temperature reconstructions for the last 500 years have been regarded as riddled with problems as tree rings in some cases in the Alps and upper northern latitudes are turning out to be an unsuitable method for climate reconstructions.
An Italian team of scientists led by Nazzareno Diodato and Gianni Bellocchi of the Met European Research Observatory has analyzed historical climate records from the Mediterranean region of Italy to see how temperatures developed in southern Europe during the Little Ice Age. In their study they reconstructed the temperatures for the winter months December-February . The Moio and Susanna Manuscript as well as the Corradi-Annals made up the core of their study. The chronicles of Giovanni Battista Moio and Gregorio Susanna contained a list of extreme weather events and famine in the region of Calabria. The Corradi-Annals consist of a collection of reports on climate extremes and their impacts on the environment from 5 AD to 1850. In addition the researchers used other data sources such as a catalogue of the Italian Agency for New technologies on environmental events. Indices were calculated based on historical information and were converted into temperatures.
In their study, the Italian scientists discovered that the winters in the Mediterranean area of study were several degrees colder than what had been earlier assumed by coarser simulations for Europe. The scientists were able to show that the known cold phase of the Maunder Minimums was also prevalent in the Mediterranean region.
Extreme cold with snow occurred in 16 of 25 winters between 1675 and 1700. Especially the years 1665, 1677, 1684, 1687 and 1692 temperatures fell sharply and rivers on the Italian peninsula froze. From 1682 to 1707 a number of flooding catastrophes occurred in Northern Italy. Extremely cold winters struck between 1684 and 1694 and an especially cold winter in 1709. The Venetian Lagoon froze over in 1684 and 1709. The lowest temperature was measured in 1684. In Sicily a series of catastrophic harvests hit in the 1690s. For the cold of the 1683/1684 winter, a statistical period of repetition of 1000 years was calculated.
The study’s authors say that the cold at the peak of the Little Ice Age was mainly due to the low solar activity of the Maunder Minimum. However they do point out that there was large regional variability for climate development during this phase of solar inactivity in the Mediterranean region due to below average atmospheric air pressure. An important atmospheric element during this period was a high pressure zone over Northern Europe while low pressure dominated the Central Mediterranean region. This resulted in protracted weather blocking in the winter and associated cold snaps striking Central and Southern Europe.
The study impressively shows that the Little Ice Age was much more than an event restricted to the North Atlantic region. The Holocene.