Israeli study finds burst of fires 8,000 years ago forced humans to become farmers

Catastrophic fires and soil erosion fueled by climate changes more than 8,000 years ago probably pushed early humans to settle and take up farming, a new study shows.

Prof. Amos Frumkin of Jerusalem’s Hebrew University reached the conclusion after reviewing charcoal, soil, and mineral deposits from different environments and climatic regions across Israel.

His research, which provides fresh insight into why humans in the regions may have abandoned their hunter-gatherer lifestyle, was published this month in the Journal of Soils and Sediments.

Frumkin found extensive evidence of fire activity spiking sharply, around 8,200 years ago, likely caused by intense lightning storms, which may have resulted from high solar radiation stemming from the Earth’s position in its orbit around the sun at that time.

The fires, the study suggests, cleared large areas of vegetation where early humans would have hunted and foraged. The soil, no longer held together by plant roots, was washed or blown off mountainsides into water-retaining valleys or natural depressions, providing the perfect conditions for hungry humans to begin agricultural cultivation.

The locations of the accumulated soil, known as sediment, correspond to some of the largest Neolithic settlements from the period, according to the study. Among them are Jericho, Gilgal, and Netiv Hagdud in the southern Jordan Valley, as well as Sha’ar Hagolan, further north, just below the Sea of Galilee.

On the hills, where the soil was mostly eroded, large Neolithic settlements were mainly concentrated in areas of thick sediment buildup, as at the site of Motza, just west of Jerusalem.

An exposed rock face showing layers of soil washed down from surrounding slopes into the Jordan Valley, accumulating atop sediments of Lake Lisan, an ancient lake that once stretched from the Sea of Galilee in northern Israel to south of the Dead Sea. (Amos Frumkin)

In the paper, Frumkin rules out volcanic activity as a cause for the fires and argues that human-caused fires on this scale were improbable.

“An anthropogenic fire ignition is possible, but it seems improbable that humans, concentrated locally, ignited large fires for a fraction of the entire Neolithic period, causing major environmental collapse, including the loss of most vegetation and hillslope soils,” he writes.

The Levant is believed to be one of the first areas of the world where humans began farming and developing sedentary cultures some 8,000 years ago.

“This wasn’t a gradual cultural shift — it was a response to environmental collapse. Agriculture and settlement patterns were likely shaped by necessity, not just innovation,” Frumkin writes.

Rocks in the area of Ofra in the West Bank that have eroded material between them. (Amos Frumkin)

The study relied on existing data of charcoal particles (showing fire history) from Lake Hula in northern Israel, mineral formations in caves in and around Jerusalem, and soil deposits in the area around the Dead Sea.

“The various records infer that the environmental catastrophes resulted from a climatic shift, rather than an anthropogenic cause, such as intentional burning,” the study concludes. “Increased lightning intensity promoted an intensive fire regime, which caused major loss of vegetation and soil degradation, enhancing and possibly causing the Neolithic revolution. Unprecedented human behavior, such as farming and domestication of plants and animals, could be influenced by the severe environmental deterioration.”