Just like old times (Image: Reuters/Reinhard Krause)

CHINA now consumes nearly as much coal as the rest of the world combined. And perhaps it always did: it seems coal was routinely burned 3500 years ago in what is now China – the earliest evidence we have for the practice.

John Dodson at the Australian Nuclear Science and Technology Organisation in Sydney, and his colleagues in China, were examining early evidence of bronze casting in northern China when they found chunks of burned coal in the ancient slag piles instead of the charcoal they expected. “We got one of the guys to take samples and he sieved out some seeds, which we radiocarbon dated in Sydney,” says Dodson. The seeds were chosen because they formed at the time the coal was burned, whereas the coal formed millions of years earlier. “You can’t just radiocarbon date the coal because it is already ancient carbon,” he says.

The results confirmed that coal had been burned in the area around 3500 years ago. The team also found coal at four more sites, dating back 3500 to 3700 years – with one of them dating back even further, to about 4600 years ago (The Holocene, doi.org/rw8).


“We have been looking at vegetation change in the landscape and it seems the coal appears in the archaeological sites just as the evidence for ancient forests in the region disappeared,” says Dodson. He thinks the locals switched to coal once they had burned all the wood in the forests for fuel.

“With no other energy supply you would be forced to move on. But here, coal was lying around on the surface – you don’t even have to mine it – and life could continue,” says Dodson.

The finding is remarkable because it is practically the only evidence of coal burning in the archaeological record. One rare exception is a study from the 1990s, which reported limited evidence that lignite (brown coal) was used for fuel around 73,000 years ago in ice age Europe – but not on a routine basis as seems to be the case in Bronze-Age China.

Early coal use could imply that the climate change associated with burning fossil fuels may have begun long before the industrial revolution in the 18th century. “Maybe things were set in train thousands of years ago,” says Dodson.

William Ruddiman at the University of Virginia in Charlottesville has long argued so. His “early Anthropocene” hypothesis suggests human-induced climate change may have begun 8000 years ago. Ruddiman thinks the latest study is consistent with his idea, “because people would have only turned to coal when wood became unavailable because deforestation was nearly complete”, he says.

Jennifer Marlon at Yale University thinks it is unlikely that the coal combustion in China had much of a global climatic impact. “Emissions would have been way too small still,” she says.

This article appeared in print under the headline “Earliest coal fuelled China 3500 years ago”