Old climate clues reveal history

This story was originally Appear in Yale Environment 360 and is climate desk cooperate.

Joseph Manning, a professor of ancient history at Yale University, likes to recall the moment he saw an advance copy of an academic paper that pinpointed the timing of major volcanic eruptions over the past 2,500 years.When he read the paper, “I literally fell out of my chair,” he said recently.

Relying on new geochemical techniques for analyzing ice core sediments to date ancient volcanic activity down to year and even season, Paper, published in nature A 2015 study shows that major eruptions worldwide have caused a decade-long Global temperatures are dropping. post-study Hold these droplets at 13 degrees Fahrenheit.

To Egyptologist Manning’s surprise, the paper recalibrated the earlier chronology by seven to eight years, so that the date of the eruption matched the well-documented political, social and military upheaval of ancient Egypt’s three centuries of history. time coincides. The paper also links volcanic eruptions to major 6th Pandemics, famines and socioeconomic upheavals of the century in Europe, Asia and Central America. The inevitable conclusion, the paper argues, is that volcanic soot — which cools the planet by protecting its surface from sunlight, adversely affecting growing seasons and causing crop failures — helped drive these crises.

Since then, other academic papers relying on paleoclimate data—most of them using state-of-the-art techniques originally designed to understand climate change—have found countless instances in which climate change helps trigger social and political unrest, and often cause crashes. The latest is a Paper Posted last month exist Communication Earth and Environment This postulates “a systematic link between volcanic eruptions and dynastic collapses in China’s two-thousand-year history”.

62 of 68 dynasties fell, study finds Occurs shortly after the eruption in the northern hemisphere, and if the eruption and collapse were unrelated, there is only a 1 in 2000 chance of this outcome happening. The Chinese traditionally cite the revocation of the “mandate of heaven” to explain the cold weather, droughts, floods and agricultural failures that seemed to accompany the demise of dynasties. The paper argues that there is a climate explanation for these phenomena.

All of these papers have been driven by a nearly decade-long revolution in climate science and technology. A flood of quantitative data from “climate proxies”—ice cores, tree rings, cave stalagmites and stalactites, and lake, swamp and seafloor sediments—has upended the way some historians work.

Joe McConnell, pioneering Ice Core Analysis Laboratory The Desert Research Institute in Reno, Nevada, argues that climate data gives historians what DNA evidence offers the justice system: an indisputable, objective source of vital information. McConnell said that, like DNA evidence to overturn a guilty verdict, climate data is “information that historians have to accept.”

To mine this data, some historians are crossing broad barriers within their disciplines, collaborating with biologists, geologists, geographers, paleoclimatologists, climate modelers, anthropologists, and more. These unconventional historians are studying geochemistry and climatology; the scientists working with them are reading history.

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