The above popular quote, also used in the 2007 Will Smith starrer movie, Hitch, is widely credited to Genghis Khan, the great 12th century Mongol warlord, whose empire (his sons helped in rapid expansion of his empire) according to http://en.wikipedia.org/wiki/Genghis_Khan stretched from modern day China to Central Asia encompassing most of China, Tibet, Afghanistan and most of the Central Asian republics.
He is naturally revered in Mongolia with the Mongol’s considering him as the founding father of the Great Mongol empire and modern day Mongolia. Incidentally, Mongolia’s international airport in the capital city of Ulaanbaatar has been renamed ‘Chinggis Khan International Airport’.
In the Middle East, Iran, Afghanistan and countries like Ukraine, people view him negatively.
In China he evokes mixed reactions, whereby people in some provinces viewing him positively and in others he is seen as a barbarian invader.
Incidentally, North China suffered a drastic population decline with the census in 1195 showing a population of 5 Cr people in north China and the first Mongol census in 1235 – 36 showing just about 85 lakh people, thus registering a 75 % decline in population. Although some of the decline in the population can be attributed to natural death, migration to Southern China but the rest is attributed to the large scale death and destruction caused by him.
This and other death toll’s cumulatively, according to a research conducted by the Carnegie Institution’s Department of Global Ecology, caused by the Mongol warrior ‘s conquests helped remove nearly 700 MT of carbon from the atmosphere, which is roughly about the same produced in a year from the global use of petrol. Such depopulation meant that large tracts of cultivated land became afforested once again leading to absorption of carbon – dioxide from the atmosphere.
The study basically measured and compared the carbon impact of this event to a number of other historical events like the Black Death in Europe (10 – 15 Cr deaths due to plague around 14 th Century which reduced Europe’s population by ~ 50%), the fall of China’s Ming Dynasty and the conquest of the Americas that involved a large number of deaths. These events too caused massive depopulation resulting in a large scale return of forests. But what separates the Mongol conquests was its longevity, as it lasted for more than a century and the sheer size, almost 4x the size of the land conquered by Alexander the Great.
This makes him the greenest one amongst the legendary invaders of the world..