Before our current, carbon-fueled global warming trend took off during the 20th century, the most consequential temperature bump in recorded history was the Medieval Warm Period.
Recently, scientists announced in the journal Nature that they’ve found a new way to decipher the climate of this period — and their findings match with current climate models in a way that gives researchers more confidence in their ability to predict the future.
Scientists don’t know exactly what caused the Medieval Warm Period, which lasted from about 800 to 1400, though they agree it was the result of natural fluctuations in Earth’s climate. Whatever the exact cause, the warming — probably less than 1 degree Celsius at the peak — changed human affairs for better and for worse. Wine grapes grew prolifically in England and citrus fruits thrived in China. Throughout northern Europe, grazing lands and farms spread northward and up mountains, into the once-forbidding islands of Iceland and Greenland. But in the American Southwest and in Central America, repeated megadroughts contributed to the collapse of civilizations.