Study says genocide triggered Little Ice Age

The “Little Ice Age” of the 16th and 17th centuries was triggered by the genocide of indigenous people in the Americas by European settlers, new research suggests.

Scientists have long wondered what caused the drop in temperatures so severe that it caused the River Thames to freeze over.

New analysis by University College London (UCL) argues that so many people were slaughtered or died of disease that the amount of agricultural land dramatically reduced, which in turn sucked carbon dioxide (CO2) from the atmosphere.

Known as the “Great Dying”, the upheavals following the first contact with Europeans in 1492 is thought to have cut the population of 60 million living across the Americas to five or six million within just 100 years.

Published in Quaternary Science Reviews, the study found that much of the land previously cultivated by indigenous civilisations would have fallen into disuse, becoming swallowed up by forest and grassland.

It estimates that an area of 56 million hectares, roughly the size of France, would have been “rewilded” in this way. The scale of the change is believed to have drawn an amount of CO2 from the atmosphere equivalent to two years of fossil fuel emissions at the present rate.

Professor Mark Maslin, from UCL’s School of Geography, said: “There is a marked cooling around that time which is called the Little Ice Age, and what’s interesting is that we can see natural processes giving a bit of cooling, but to actually get the full cooling — double the natural processes — you have to have this genocide-generated drop in CO2.”

The research team examined historical population data, using it to model the reduction of land devoted to agriculture.

Ed Hawkins, professor of climate science at Reading University, said: “Scientists understand that the socalled Little Ice Age was caused by several factors — a drop in atmospheric carbon dioxide levels, a series of large volcanic eruptions, changes in land use and a temporary decline in solar activity. The drop in CO2 is itself partly due the settlement of the Americas and the resulting collapse of the indigenous population.

“It demonstrates that human activities affected the climate well before the industrial revolution began.”