Earth system impacts of the European arrival to the Americas after 1492

The study investigates the environmental impacts of European colonization and the subsequent depopulation of Indigenous peoples in the Americas after 1492. It estimates that the European arrival led to the deaths of approximately 56 million Indigenous people by 1600, primarily due to epidemics. This drastic population decline resulted in the reforestation of about 55.8 million hectares of land, which sequestered approximately 7.4 petagrams of carbon, contributing to a significant drop in atmospheric CO2 levels. The research highlights that the decline in CO2 concentration by 7-10 ppm in the late 1500s and early 1600s, which lowered global surface temperatures by 0.15°C, was largely driven by human activities rather than natural factors. The findings suggest that the Great Dying had profound effects on the Earth System, indicating that human impacts on the environment were significant even before the Industrial Revolution. The study emphasizes the importance of including large-scale vegetation regeneration in the Americas to understand the global carbon budget of the 1500s.

- European arrival in the Americas led to an estimated 56 million Indigenous deaths by 1600.

- The population decline resulted in the reforestation of 55.8 million hectares, sequestering 7.4 petagrams of carbon.

- The atmospheric CO2 drop of 7-10 ppm in the late 1500s was significantly influenced by human-induced land use changes.

- The study highlights the substantial human impact on the Earth System prior to the Industrial Revolution.

- Understanding these historical changes is crucial for assessing the global carbon budget of the 1500s.