Genghis Khan and his empire, which lasted nearly two centuries, actually cooled the Earth.
told in one word: reforestation. When the Mongol hordes invaded
Asia, the Middle East, and Europe they left behind a massive body count,
depopulating many regions. With less people, large swathes of
cultivated fields eventually returned to forests, absorbing carbon
dioxide from the atmosphere.
the conquest of the Americas
(killing of 95% of First Nations) there was enough time for the forests
to re-grow and absorb significant amounts of carbon.
Recovery of forests following the collapse of human populations in the
Americas after the arrival of Europeans may have driven the period of
global cooling from 1500-1750 known as the Little Ice Age,
humans started to influence the environment thousands of years ago by
changing the vegetation cover of the Earth‘s landscapes when we cleared
forests for agriculture.