Death toll from WWI and 1918 flu pandemic may have spiraled due to abnormally cold and wet seasons: Study
World War I and the 1918 flu pandemic that followed are considered one of the darkest periods on Earth. The former killed close to 10 million military personnel, while the latter is thought to have wiped out an estimated 50 to 100 million people worldwide. Now, scientists suspect that abnormal climate conditions likely contributed to the high death toll, a new study suggests.
Here, scientists have spotted a once-in-a-century climate that saw torrential rains and unusually cold temperatures between 1914 and 1918. It also likely played a role in creating the right conditions for the Spanish flu pandemic. Though abnormal weather conditions are well-documented, previous studies have not linked them with death rates, the researchers said.
“I’m not saying that this was ‘the’ cause of the pandemic, but it was certainly a potentiator, an added exacerbating factor to an already explosive situation,” Alexander More, a climate scientist and the lead author of the new study.
“It’s interesting to think that very heavy rainfall may have accelerated the spread of the virus,” said Philip Landrigan, director of the Global Public Health Program at Boston College, who was not connected to the new study. “One of the things we’ve learned in the Covid pandemic is that some viruses seem to stay viable for longer time periods in humid air than in dry air. So it makes sense that if the air in Europe were unusually wet and humid during the years of World War I, the transmission of the virus might have been accelerated.”
In this study, more and his colleagues studied a 72-meter-long ice core from the Colle Gnifetti glacier in the Swiss-Italian Alps, which holds a 2000-year-old record of climate history. Their analysis showed an inflow of cold ocean air swept over to the Alps during that period, possibly triggering heavy rainfall and cold temperatures.
The abnormal climate also provided the perfect conditions for the flu virus to propagate. The researchers explain that allied troops from East Asia carried a less dangerous virus strain to northern France. The virus likely became deadly due to mutations caused by chlorine gas used in the war, previous studies have suggested. In this study, the team provided the first real evidence of a climate anomaly, thanks to the ice core.
The death toll in Europe peaked three times during the war. More explained that these peaks clashed with periods of cold temperatures and heavy rain caused by extremely unusual influxes of ocean air in the winters of 1914-15, 1915-16 and 1917-18 -- together providing a once in a 100-year anomaly.
Following the bad weather events was the 1918 Spanish flu, which broke out in the autumn of 1918. Damp conditions help the virus spread at faster rates. It may have also affected bird migrations, bringing humans and animals closer in unhygienic conditions.
The researches said that history has a lesson to offer. "Indeed, the pandemic development history of the Spanish Influenza from 1917 to 1919 sends a warning into our own time, a century later, of the ongoing risks of war zones (including the use of chemical weapons), wildlife trade, unsanitary conditions, and humanitarian crises as incubators of disease, assisted by climate‐change triggers," they wrote in their study.
The study is published in GeoHealth.