From Klimanachrichten

By KlimaNachrichten Editor

The period between 1250 and 1860 is also known as the Little Ice Age. We have already reported on them here a few times. The Little Ice Age was the undoing of the Franklin Expedition, among others. In the search for the Northwest Passage, the crew failed on the ice, although they had set off in the summer. Franklin was in the wrong place at the wrong time. He paid with his death.

But what was the climate like at that time and what were the climate drivers? Volcanoes played a major role, but also a minimum of solar activity. However, the summers were by no means consistently wet and cool.

A 2022 study addresses this topic. From the translated summary.

The Little Ice Age (LIA), which lasted from about 1250 to 1860 AD, was probably the coldest period of the last 8000 years. Using new documentary data and analyses of alpine glacier fluctuations, the complex transition from the medieval climate anomaly to the LIA and the resulting high variability of seasonal temperatures for Europe are described and interpreted.
The onset of LIA was likely different in both hemispheres. The low average temperature of the LIA is primarily due to the high number of cold winters. Conversely, many summers were warm and dry.

Important triggers of the lower temperatures were primarily the numerous clusters of volcanic eruptions and the weak solar radiation during the four prominent Great Solar Minima: Wolf, Spörer, Maunder and Dalton.
The temperature drop triggered the sea-ice-albedo feedback and led to a weakening of the Atlantic orbital circulation, possibly associated with a trend towards negative North Atlantic Oscillation indices.

The statistics of extreme events show a mixed picture. Correlations with forcing factors are weak and can only be found in the context of the “years without a summer”, which very often occurred after large volcanic eruptions.

We must always keep in mind that in the middle of the 19th century, several factors came together. After one of the coldest periods of the last 8,000 years, a climatic countermovement followed. In addition, the industrialization of the world and the massive use of coal began. Landmasses were reshaped on a large scale, such as during the settlement of North America.
In addition, the time was also the birth of modern meteorology. In the Crimean War, France had lost large parts of its fleet due to a storm for which it was not prepared. As a lesson from this, weather forecasts were made on the basis of data, of course in no comparison to today. However, warnings of severe weather were still possible at that time due to the use of telegraphy. So a lot came together.

A recent study on the topic finds volcanism “responsible” (51% involved), but also a participation of the “North Atlantic Oscillation” (NAO), which particularly influences the winters in Europe and even a participation of the “IPO” (Interdecadal Pacific Oscillation at the other end of the world) to 28%. In any case, we would do well to remember that nothing in nature is constant and romanticized images from the period before the middle of the 19th century are to be viewed critically. So the next time we hear the phrase “before industrialization”, please remember this article.