Bad Weather During WWI Made the Spanish Flu Deadlier

Caroline Delbert
·3 min read
Photo credit: Universal History Archive - Getty Images
Photo credit: Universal History Archive - Getty Images

From Popular Mechanics

  • Researchers analyzing gases in glacial cores have corroborated historical record of the 1918 pandemic.

  • Ice cores trap environmental factors, viruses, bacteria, and more that illustrates conditions at the time.

  • Terrible weather could have worsened the pandemic by trapping disease-spreading ducks, for example.

New research suggests the deadly Spanish flu pandemic of 1918 was worsened by climate anomaly factors that also made key World War I battles bloodier. The research uses ice cores from a European glacier to reverse engineer factors like precipitation and overall air temperatures at the time.

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By measuring presence of chemical markers of marine gases, for example, scientists can analyze ice cores for evidence of large-scale storms and more. “Later peaks in marine air proxies in 1921–1922 and 1926 are connected to documented residual activity from North Atlantic hurricanes, particularly severe in those years, but not approximating the extremes of 1914–1918,” the researchers explain in their paper.

“Well-documented torrential rains and unusually cold temperatures affected the outcomes of many major battles on the Western Front during the war years of 1914 to 1918,” the American Geophysical Union (AGU) wrote in a statement. “The new ice core record corroborates historical accounts of torrential rain on battlefields of the Western Front, which caused many soldiers to die from drowning, exposure, pneumonia, and other infections.”

Wartime conditions are well-studied overall, but these researchers say the way the same climate events affected the subsequent Spanish flu pandemic isn't fully understood. Much is already being made of how the 1918 pandemic and the current COVID-19 pandemic resemble each other. This year, severe heat waves and wildfires have combined to worsen air conditions for people in the western U.S., for example.

But the climate events in 1917 and 1918 were the opposite: extreme cold and heavy rain. This, the researchers say, likely affected a major disease vector at the time. “Mallard ducks are the main animal reservoir of H1N1 flu viruses and as many as 60 percent of mallard ducks can be infected with H1N1 every year,” the AGU explains.

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And when once-in-a-century cold strikes an entire continent, migratory birds are a very commonly affected group. They rely on weather factors to cue their migrations, and when their plans are foiled by unseasonable factors, they also must adapt to survive in unplanned circumstances.

In this case, that could mean staying around and even mingling closer with humans in order to survive. “The transfer of H1N1 influenza virus from animals (avian and mammals) to humans (zoonosis) occurs primarily via water sources contaminated with fecal droppings from infected birds,” the researchers explain.

“These atmospheric reorganizations happen and they affect people. They affect how we move, how much water is available, what animals are around,” researcher Alexander More said in the AGU statement. “Animals bring their own diseases with them in their movements, and their migrations are due to the environment and how it changes, or how we change it.”

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