Mongol conquests (1200-1380) and the conquest of America by Europeans (1519-1700) had the same effect on the global carbon cycle, as well as the modern demand for fuel. But the "Black Death" (1347-1400) and the fall of China's Ming Dynasty (1600-1650) proved to be too short events to the global carbon budget noticed them.
But both — nothing compared to the deforestation!
"The common belief is that the human impact on climate began with the large-scale use of fossil fuels in the era of the industrial revolution is wrong," — emphasizes the study's author Julia Pongratz of the Carnegie Institution (USA).
Increasing levels of carbon dioxide in the atmosphere, recorded in the analysis of Greenland and Antarctic ice coincides with the emergence of agriculture: as soil depletion and population growth, people are moving to a new place, gaining territory from the primeval forests. On the contrary, during the sharp reduction of the human population as a result of wars and epidemics of arable land and pastures were dropped, and the forests began to counterattack.
In collaboration with Ken Caldeira of the Carnegie Institution, and colleagues from the Meteorological Institute of the Max Planck (Germany), Ms. Pongratz tried to estimate the area of vegetation of the planet in its dynamics with a 800, and compare these data with the results of modeling of the carbon cycle. It turned out that even long cataclysms could not offset continuing in other parts of the world uncontrolled logging. Only one Mongol invasion was so terrible catastrophe that came to the empty space of the forest for a half-century, Dr. wa able to reduce the concentration of carbon dioxide in the atmosphere by 700 million tons
About the same today humanity emit from burning fuel.
Results of the study are published in the journal Holocene.