Humans substantially altered the planet much earlier than previously thought, a worldwide collection of archaeological experts reported Thursday. By 3,000 years ago, the experts wrote in Science magazine, the planet had been “largely transformed by hunter-gatherers, farmers, and pastoralists.”

People farmed, burned forests and grazed their goats, sheep and cattle. By about 1,000 BCE, with Mayan civilization on the rise in Mesoamerica and the Zhou dynasty beginning in China, what the authors describe as intensive agriculture, or continuous cultivation of the land, was “common in most regions where it is still practiced today.”

The results vary for different farming practices and different regions, said Erle Ellis, a geographer and environmental scientist at the University of Maryland, Baltimore County, and a designer of the ArchaeoGLOBE project, as the research effort is called. But, he said, it is clear that the information pushes back the onset and spread of major human change to the global environment earlier than previously thought, sometimes by 1,000 years or more.

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“What we’re showing,” said Lucas Stephens, who helped design and administer the survey of 250 or so archaeologists on which the report is based, “is that there is a deep history of this, going back further than what earth scientists currently recognize.” Dr. Stephens, now at the Environmental Law and Policy Center in Chicago, organized the survey while he was at the University of Pennsylvania and the University of Maryland, Baltimore County.