News - Nature Communications: Epidemics have caused sharp drop in CO2 levels in Earth's atmosphere, study finds

Researchers at the University of Cambridge in the UK have found out that epidemics of plague and other diseases in the distant past affected the Earth's atmosphere. This is evidenced by the results of the study of Antarctic ice, which were published in the science journal Nature Communications. The specialists studied the gas bubbles in the ice and formed an idea about the composition of the earth's air in the last 2000 years. Data on carbon dioxide (CO2) in the Earth's atmosphere correlates with some historical events. For example, at the “border” between the 16th and the 17th centuries, there was a rapid decrease in the concentration of CO2, reaching a minimum in the year 1610. That period coincides with the campaigns between the Old and New Worlds, when the natives of North and South America became victims of diseases brought from Europe. And when the pioneers returned home, the Europeans suffered the same fate due to encountering unfamiliar pathogens. According to scientists, the rampant epidemics reduced the population to such an extent that the surviving people had to flee the disease-ridden regions. And the desolated areas were gradually covered by forests, which absorbed more CO2 from the atmosphere. "Our analysis supports a more gradual decrease in CO2 of 0.5 ppm [parts per million] per decade from 1516 to 1670 CE,” paleoclimatologist Amy King, the paper's first author, and colleagues  write in their paper, adding that roughly 2.6 gigatons of CO2 were absorbed per decade as human population numbers dwindled and forests regrew. "This corroborates modeled scenarios of large-scale reorganization of land use in the Americas following New World-Old World contact," they added.