Humans were changing the environment even 11,250 years ago

Men-made environmental change was happening even 11,250 years ago. Scientists from Tel Aviv University took a sample under the Dead Sea (a cylindrical section of rock and dirt) which gave a sediment record of the past 220 centuries. The Dead Sea area is an excellent natural laboratory for studying geology and climatology, because it offers "a rare combination of well-documented substantial climate change, intense tectonics and abundant archaeological evidence for past human activity,  the study said.
"Natural vegetation was replaced by crops, animals were domesticated, grazing reduced the natural plant cover, and deforestation provided more area for grazing," said geologist Shmuel Marco, who led the study.