When did the Anthropocene, the current geological epoch, actually begin? In research published in Science in August 2019, Australian social scientists say humans have been the main influence on the Earth’s climate and environment since 2000 BCE. “The activities of farmers, pastoralists and hunter-gatherers had significantly changed the planet four millennia ago,” writes co-author Andrea Kay from the University of Queensland. “The long-term cumulative changes that early food producers wrought on Earth are greater than many people realise.”