SOCIETY × ENVIRONMENT

An Empire Read in the Ice

~100 CE

History · Antiquity · Holocene · Meghalayan

Snow that fell on Greenland two thousand years ago carries lead smelted from Spanish ore. Read year by year, the ice records Carthaginian and Roman mining as hemispheric air pollution, rising with imperial expansion, peaking under the early Empire, plunging with the plagues of the second and third centuries. The isotopes name the source, the mining districts of southern Spain and above all Rio Tinto.

Why it matters

Rome kept no economic statistics, so its GDP is argued from shipwrecks and potsherds; the ice offers what no text can, a continuous annual gauge of ancient industry that no chronicler could flatter. It also pushes the Anthropocene question further back: an empire polluted the air of half the planet two millennia before coal. History and geochemistry audit each other here.

Dating & uncertainty

The Greenland record is dated layer by layer to the year, from 1100 BCE to 800 CE; the date shown here falls in the early Roman Empire, when emissions peaked. Atmospheric transport modelling turns ice concentrations into European emissions; reading those emissions as mining output, coinage or the economy at large is a further step, supported here by the parallel decline of bullion in silver coinage.

Sources

1. McConnell et al. (2018), PNAS · Lead pollution recorded in Greenland ice indicates European emissions tracked plagues, wars, and imperial expansion during antiquitydoi:10.1073/pnas.1721818115
2. Hong et al. (1994), Science · Greenland ice evidence of hemispheric lead pollution two millennia ago by Greek and Roman civilizationsdoi:10.1126/science.265.5180.1841
3. Rosman et al. (1997), Environmental Science & Technology · Lead from Carthaginian and Roman Spanish mines isotopically identified in Greenland ice dated from 600 B.C. to 300 A.D.doi:10.1021/es970038k

Our species’ history as one day

23:51:118 min 48 s before midnight

if the 315,000 years of Homo sapiens were compressed into a single day