Here’s a new article in The Economist showing evidence of climate change in the ice polars caps at the same time agrarian societies emerged.
The ice-core record shows that the level of carbon dioxide in the atmosphere made an anomalous upturn about 7,000 years ago, and that methane levels, which were also falling, began to increase about 5,000 years ago. These numbers correspond well with the rise of farming in Europe and Asia.
It appears that the extensive farming method used by early farmers was responsible of a more than proportional increase in methane, a greenhouse gas. Yet another point for Georgescu-Roegen and thermoeconomics.