About fifteen thousand years before Hurricane Katrina, the planet started to warm up again, entering another interglacial period, with the most intense and rapid warming happening around 11,000 BCE. Humans began developing villages, basic animal husbandry, and more deliberate systems of gathering. A brief, localized cold snap called the Younger Dryas, caused by glacial meltwater spilling into the Atlantic Ocean and shutting off the Gulf Stream, brought frigid temperatures to Europe and drought to southwest Asia for a thousand years. 34 According to archaeologist Brian Fagan, it was almost certainly this drought that drove the people in a small village on the Euphrates, who had until then depended for their sustenance on hunting desert gazelles, harvesting nuts, and gathering wild grasses, to begin deliberately cultivating rye, lentils, and a grain called einkorn. 35 By 9000 BCE, after the Younger Dryas had ended and the Gulf Stream had switched back on, the agricultural revolution had begun. Neolithic humans hunted, herded, gathered, and farmed from Europe to South America, thriving in the warm and mild climate of what is now called the Holocene.

About fifteen thousand years before Hurricane Katrina, the planet started to warm up again, entering another interglacial period, with the most intense and rapid warming happening around 11,000 BCE. Humans began developing villages, basic animal husbandry, and more deliberate systems of gathering. A brief, localized cold snap called the Younger Dryas, caused by glacial meltwater spilling into the Atlantic Ocean and shutting off the Gulf Stream, brought frigid temperatures to Europe and drought to southwest Asia for a thousand years. 34 According to archaeologist Brian Fagan, it was almost certainly this drought that drove the people in a small village on the Euphrates, who had until then depended for their sustenance on hunting desert gazelles, harvesting nuts, and gathering wild grasses, to begin deliberately cultivating rye, lentils, and a grain called einkorn. 35 By 9000 BCE, after the Younger Dryas had ended and the Gulf Stream had switched back on, the agricultural revolution had begun. Neolithic humans hunted, herded, gathered, and farmed from Europe to South America, thriving in the warm and mild climate of what is now called the Holocene.