TEL AVIV — More than 3,200 years ago, life was abuzz in and around what is now this modern-day Israeli metropolis on the shimmering Mediterranean shore.

To the north lay the mighty Hittite empire; to the south, Egypt was thriving under the reign of the great Pharaoh Ramses II. Cyprus was a copper emporium. Greece basked in the opulence of its elite Mycenaean culture, and Ugarit was a bustling port city on the Syrian coast. In the land of Canaan, city states like Hazor and Megiddo flourished under Egyptian hegemony. Vibrant trade along the coast of the eastern Mediterranean connected it all.

Yet within 150 years, according to experts, the old world lay in ruins.

Experts have long pondered the cause of the crisis that led to the collapse of civilization in the Late Bronze Age, and now believe that by studying grains of fossilized pollen they have uncovered the cause....