‘It's a common misconception that the human impact on climate began with the large-scale burning of coal and oil in the industrial era,’ said Julia Pongratz, who headed the research by the Carnegie Institution's Department of Global Ecology.‘Actually, humans started to influence the environment thousands of years ago by changing the vegetation cover of the Earth's landscapes when we cleared forests for agriculture,’ she told
Post bomb carbon dating
From the most brutal beginning possible, Genghis survived to unite the Mongolian tribes and conquer territories as far apart as Afghanistan and northern China.
He left a mountain of skulls that remained for years in China.
Genghis Khan has been branded the greenest invader in history - after his murderous conquests killed so many people that huge swathes of cultivated land returned to forest.
The Mongol leader, who established a vast empire between the 13th and 14th centuries, helped remove nearly 700million tons of carbon from the atmosphere, claims a new study.
Time periods also looked at included the Black Death in Europe, the fall of China's Ming Dynasty and the conquest of the Americas.
All of these events share a widespread return of forests after a period of massive depopulation.
This plot shows the level of carbon-14 in the atmosphere as measured in New Zealand (red) and Austria (green), representing the Southern and Northern Hemispheres, respectively.
Aboveground nuclear testing almost doubled the amount of carbon-14 in the atmosphere. The black arrow shows when the Partial Test Ban Treaty was enacted that banned aboveground nuclear tests. A special kind of radiocarbon dating: Bomb radiocarbon dating.
‘We found that during the short events such as the Black Death and the Ming Dynasty collapse, the forest re-growth wasn't enough to overcome the emissions from decaying material in the soil,’ explained Pongratz.
‘But during the longer-lasting ones like the Mongol invasion...
there was enough time for the forests to re-grow and absorb significant amounts of carbon.’Though the Khan will remain known as Genghis the Destroyer and not Genghis the Green, Dr Pongratz hopes that her research will lead to future historians examining environmental impact as well as the more traditional aspects of study.