Ancient farmers spared us from glaciers but profoundly changed Earth's climate

Millenia ago, ancient farmers cleared land to plant wheat and maize, potatoes and squash. They flooded fields to grow rice. They began to raise livestock. And unknowingly, they may have been fundamentally altering the climate of the Earth.
Read more: https://phys.org/news/2018-09-ancient-farmers-glaciers-profoundly-earth.html?source=Snapzu