News & Opinion | February 1, 2019 2:30 pm

European Colonizers Killed Enough Natives to Change Global Climate

The effect was so profound, it's now known as the Little Ice Age.

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Christopher Columbus showing objects to Native Americans upon landing. (Library of Congress)

When Europeans arrived in the Americas, they caused so much death and brought with them so many diseases that they were able to change the global climate, a new study finds.

Over about 100 years in South, Central and North America, Europeans killed 56 million indigenous people, causing large areas of farmland to be abandoned and then reforested, researchers at University College London, or UCL, estimate. That increase in trees and vegetation across what is roughly the size of France resulted in a massive carbon dioxide decrease in the atmosphere, CNN reported, and a temperature shift.

Carbon levels changed enough to cool the Earth by 1610, researchers found, a period that was so profound that it was known as the “Little Ice Age.”

Columbus arrived in 1492.

“CO2 and climate had been relatively stable until this point,” UCL Geography Professor Mark Maslin, one of the study’s co-authors, told CNN. “So, this is the first major change we see in the Earth’s greenhouse gases.”

By combining archaeological evidence, historical data and analysis of carbon found in Antarctic ice, the UCL researchers showed how the reforestation — directly caused by the Europeans’ arrival — was a key component of the global chill, they said.

“For once, we’ve been able to balance all the boxes and realize that the only way the Little Ice Age was so intense is because of the genocide of millions of people,” Maslin said.