In the history of world medicine, theach dai dich outbreak in the 14th century, also known as the Black Death, is always mentioned as a major event that caused a serious decline in the European population.
Previously, analysis often focused on the role of rat and insect species and limited hygiene conditions in the Middle Ages. However, a new study published in the journal Communications Earth & Environment has shown that the picture of this disaster is much more complicated, with the participation of a surprise factor: Nature.
The team of scientists analyzed wood samples from the growth rings of ancient trees in Europe and the eternal ice core taken from the Southern pole.
Data collected shows that around 1345 and 1346, the Earth's atmosphere contained a large amount of sulfur and ash. This is a clear sign of large-scale volcanic explosions. This layer of dust has blocked the sunlight, causing summer temperatures in Europe to drop unusually low for two consecutive years.
Sudden changes in the climate have caused a chain reaction on the food system. The crop season in the Mediterranean region has been severely unstable, pushing the trading powers of the time such as Venice and Genoa into a serious food shortage.
Faced with the pressure to ensure food supply for people, these countries are forced to seek goods from outside. They decided to resume routes to import grains from the Black Sea area, despite the fact that this area is rumored to be affected by the epidemic.
It is the urgent need for food that has unintentionally created a path for pathogens to move.
Researchers argue that when ships carrying wheat from the Black Sea docked at Italian seaports, they not only brought food but also parasites containing epidemic bacteria hidden in the grain shipments.
From busy seaports, pathogens quickly entered the mainland and spread throughout the continent.
Historical data also shows a remarkable coincidence: Cities that rely heavily on imported grains were the first to record an outbreak, while autonomous inland areas were affected by food later.
This research result provides an important lesson on the close connection between the environment and society. It shows that the epidemic is not simply a health problem, but is also deeply affected by climate change and disruptions in the global supply chain.
