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E - 188: Sugar Cane and the Medieval Warm Period

Updated: Apr 16, 2021

A few days ago I came across the fact that the Arabs successfully introduced sugar cane to Sicily when they conquered the island in 831 AD. But then it disappeared again 300 years later. The plant was also introduced to Al-Andalus (Spain) where it also did not survive. I started to wonder how sugar cane could be cultivated in Sicily which I know for its arid summers.

Sugar cane plants

Sugar cane came from India to Europe and requires a sub-tropical climate with a minimum of 60 cm of rain p.a. Trouble is that Sicily receives only 50 cm a year these days. Not enough for sugar cane. Have to admit that I love Google – whatever else we think about its privacy policy. The search question “how warm was Europe in 900 AD” resulted in a few interesting leads. Apparently, Europe was about 1 C warmer and enjoyed 300 years of a climate called the Medieval Warm Period – which means warmer summers with moderate rain thus higher agricultural yields.

The origin of sugar cane

But sugar cane’s impact did not end there. Refining it is not an easy task and requires a lot of energy. Vaporizing the juice, crystallizing the sugar and drying the crystals requires vast amounts of fuel. Where did the wood – the only source of heat energy at the time - come from? In the absence of big forests in Sicily, it had to be imported from further north. Have not found a source about this wood trade. Probably too trivial at the time and deemed not worthy of recording. The wood could have travelled as ballast in the hulls of ships from Genoa, Pisa and Amalfi. It would have provided these merchants with a currency to pay for the luxury goods they were sailing south for.

The Medieval Warm Period not only affected Sicily. It also meant that Northern Europe enjoyed favorable climatic conditions. The better weather allowed people to expand the arable land available. They moved into Europe’s central woodlands, the coastal plains bordering the North Sea, settled the Alps and re-opened mountain passes which were not in use since Roman times. At the same time, a new type of plow was making its way from China to Europe. The iron tiller allowed the plowing of heavy soil – something impossible for its wooden predecessors.

Both the increase of productivity and expansion of arable land meant that towns started to grow again and new towns were established. There was finally enough agricultural surplus to support more people living in towns. From 1’000 to 1’300 AD, Europe’s population increased by 40% (56m to 79m). A big change for Medieval times! Larger towns allowed for a higher division of labor. Specialized craftsmen and guilts started to appear and began to dominate city life. A high degree of division of labor also resulted in competitive advantages and thus incentivized long-distance trade. Last but not least, the nobles’ tax revenue increased which triggered higher demand for luxury goods. After centuries of lackluster demand people asked for spices, silk and medical products (sugar was classified as a drug in its early days) again. In the history books all this is called the 10th century economic revival – I guess it was the 10th century climate change instead.

Fatimid Empire at its peak in the 10th century

The Fatimid Empire was perfectly positioned to take advantage of the new demand from Europe. Its mostly Muslim and Jewish traders were happy to supply the goods sourced in India and China. There were again intensive trade relations between the Fatimids and the Tang dynasty in China, as there had been between the Roman Empire and the Han dynasty.

Thanks to its excellent geographical position, Sicily became a vibrant trading hub in the Mediterranean with Palermo at its center. The island could produce textiles (cotton and silk), sugar and its traditional products. As first port of call, it was far closer for the Christian traders from Amalfi, Genoa and Pisa than the Levant. The new wealth of the island did not remain unnoticed. The Byzantine Empire wanted the island back and almost succeeded in 1040 had it not for internal strife that ruined the campaign.

Sicily in 1588 - the shape to Palermo had not changed much since it was retaken by the Normans from the Muslim in 1071

The appearance of sugar cane in Sicily in the 9th century signaled the economic awakening Europe was going to see in a century later. And the commercial rise of Palermo as Arab trading center financed the university and the transfer of culture from the Arab world to Europe which just got out of the dark ages. An amazing transformation due to climate change.

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