26. Genghis Khan Gave Us an Unintended Case Study on the Potential of Reforestation to Reduce Atmospheric Carbon
The Mongols killed a whole lot of people and depopulated vast regions. Without people to keep cultivated areas clear, nature took over and those lands reverted to forests. Enough forest cover to absorb 700 million tons of carbon dioxide from the atmosphere. That is the equivalent of what people today – twenty times more numerous than in the days of Genghis Khan – pump into the atmosphere from gasoline in a year. It is relevant as a case study of what significant reforestation (hopefully, without the Mongols’ massive slaughter) could do to reduce atmospheric carbon. As a study author put it:
“Today about a quarter of the net primary production on the Earth’s land surface is used by humans in some way, mostly through agriculture. […]. In the past, we have had a substantial impact on global climate and the carbon cycle, but it was all unintentional. Based on the knowledge we have gained from the past, we are now in a position to make land-use decisions that will diminish our impact on climate and the carbon cycle. We cannot ignore the knowledge we have gained”. Of course, before we get started on global reforestation, we have to first stop the ongoing massive global deforestation that is clearing out the Amazon and other natural carbon sinks around the world.