Early anthropocene
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The early anthropocene hypothesis (sometimes called Early Anthropogenic) is a theory proposed by William Ruddiman. The Anthropocene era, as some scientists call the most recent period in the Earth's history when the activities of the human race first began to have a significant global impact on the Earth's climate and ecosystems, did not begin in the eighteenth century with advent of coal-burning factories and power plants of the industrial era, as was commonly assumed, but dates back to 8000 years ago, triggered by intense farming activities of our early agrarian ancestors. It was at that time that atmospheric greenhouse gas concentrations stopped following the periodic pattern of rises and falls that had accurately characterized their past long-term behavior, a pattern which is explained by natural variations in the earth's orbit known as Milankovitch cycles. In his overdue-glaciation hypothesis Ruddiman claims that an incipient ice age would probably have begun several thousand years ago, but the arrival of that scheduled ice age was forestalled by the activities of early farmers.
The early anthropocene hypothesis has been challenged on the grounds that comparison with an earlier interglaciation ("Stage 11", around 400,000 years ago) suggest that 16,000 more years must elapse before the current Holocene interglaciation comes to an end, and that thus the early anthropogenic hypothesis is invalid. But Ruddiman argues that this results from a false alignment of recent insolation maxima with insolation minima from the past, among other irregularities which invalidate the criticism. (See external links)
