Researchers at MARUM – Center for Marine Environmental Sciences, University of Bremen, have posited that historical episodes of climate change triggered ancient pandemics. I found this fascinating as we are still feeling the effects of COVID-19.
The team reconstructed temperatures and precipitation data from 200 BC to 600 AD with a resolution of three years, an extremely high resolution for paleoclimate scientists. This period of history includes three major pandemics recorded by historians: the Antonine Plage (around 165 – 180 AD), the Cyprian Plague (around 251 – 266 AD), and the Justinian Plague (around 540 AD), each following a change in climate.
The researchers measured deposits of dinoflagellates on the ocean floor to reconstruct temperature and precipitation patterns during that time. Dinoflagellates are single-celled algae living in the ocean’s upper waters. They have preferences regarding where they live; some like it cold, some like it hot, some like it nutrient-dense, while others like it nutrient-sparse. Scientists can use the accumulations of the unicellular algae on the ocean floor to track changes at the ocean’s surface.
“If the conditions in the upper waters change, the composition of the cyst species that accumulate on the seabed also changes,” said first author Professor Karin Zonneveld from MARUM and the Department of Geosciences at the University of Bremen.
With the help of Bremen volcanologist Andreas Klügel, Zonneveld dated core samples from the Gulf of Taranto by tracking volcanic ash deposits also on the sea bed. They worked with University of Oklahoma professor Kyle Harper to precisely date and compare the climate data with historical events, concluding that climate-related stress can trigger pandemics or intensify disease outbreaks into pandemics.
Harper and Zonneveld believe this could hold important information for the future: “…Studying the resilience of ancient societies to climate change and exploring how climate change and the incidence of infectious diseases are linked could give us a better insight into the climate change-related challenges we face today.”
They published their study in Science Advances.