Original URL: http://www.theregister.co.uk/2012/10/04/romans_started_climate_change/
Romans, Han Dynasty, kick-started climate change
What have the Romans ever done for us?
Posted in Science, 4th October 2012 07:34 GMT
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Anthropogenic climate change may not be a recent phenomenon, with researchers reporting ice cores from the first two centuries AD show big spikes in methane prevalence.
Those two centuries, the researchers note, co-incide with the most prosperous periods for the Roman Empire and Han Dynasty.
A Nature paper, Natural and anthropogenic variations in methane sources during the past two millennia [1], speculates that deforestation and use of charcoal as a fuel made for increases in methane emissions.
The methane was detected in ice cores from Greelanand. The cores also show methane levels tailed off around 200 AD, a time at which deforestation slowed as Rome declined and the Han Dynasty collapsed.
Lead author Celia Sapart of Utrecht University told Reuters [2] the team behind the paper say they have spotted a spike in methane emissions that corresponds roughly to the end of the dark ages, and a dip not longer after the Black Death.
One possible fly in the ointment is a rise in methane prevalence before the Little Ice Age.
Sapart feels the results mean climate scientists need to rethink what is a "normal" state for Earth's climate.
"The pre-industrial time was not a natural time for the climate - it was already influenced by human activity," she told Reuters, adding that "When we do future climate predictions we have to think about what is natural and what did we add." ®