If you had to guess, which of these would you think would be a better control for global warming: Genghis Khan or the Black Death? Before answering, consider that both were responsible for removing a significant chunk of humanity from the surface of the planet (and interning it underground). The logic is that since it is people who cause global warming, fewer of these pests means less global warming.
Most ordinary citizens pick the Black Death, if only because of the name, which is scarier than the Great Khan’s. And when it was in its youth, the infamous disease wiped out nearly a third of Europe plus a significant chunk of the Asian Subcontinent. Altogether, the Bubonic plague, the official alias of Black Death, killed about 100 million, a toll which rivals even militant socialism (a.k.a. communism).
But Julia Pongratz of the Carnegie Institution’s Department of Global Ecology compared the bodies piled up by the Black Death with those massacred by Genghis Khan and found that those who fell by the sword took more carbon with them than those who met their demise by disease. Why?
Genghis Khan and his Mongol hordes had an impact on the global carbon cycle as big as today’s annual demand for gasoline. The Black Death, on the other hand, came and went too quickly for it to cause much of a blip in the global carbon budget.
More particularly, “During high-mortality events, such as wars and plagues, large areas of croplands and pastures have been abandoned and forests have re-grown, absorbing carbon dioxide from the atmosphere.” Stated less euphemistically, fewer people means less carbon dioxide injected into the atmosphere, the poisonous gas responsible for climate chaos.
What made the Mongol invasion so great wasn’t just that it killed so many net-carbon increasers, but that it lasted so long, more than time enough to allow trees to take the place of the slaughtered. Khan himself didn’t live forever, of course, but his well-trained hordes pushed on towards Europe for just over a century. A healthy forest can be grown in that time.
The Black Death also lasted about a century, and while it killed twice as many people as did Genghis and his followers, it didn’t kill with the same efficiency as the Mongols. The plague would wander into a populated area and, depending on its mood, would take a out a few here, a few there. It was picky, choosing its victims haphazardly, almost as if it didn’t take itself seriously. The problem was that it left too many alive in any one spot, and those survivors, being only human, decided to celebrate their success of not being killed by engaging in some vigorous breeding by the warm glow of fireplaces. Fireplaces using wood from—you guessed it—nearby forests.
Contrast that with Khanian behavior. The Mongols would ride to town, surround it, encourage its occupants to surrender and be killed in an organized, efficient manner. Or, if the town’s occupants were recalcitrant, the Mongols would lay siege and then kill everybody in a sloppy, disorganized way. It was a take-no-prisoners, kill-everything-in-site attitude either way.
The good thing about this, according to Pongratz, was that when the hordes pushed on towards their next set of victims, they left only silence behind. And barren (freshly fertilized) ground covered in tree seeds—seeds which were able to grow into forests which sucked CO2 from the air, thus cooling the planet.
According to a summary of Pongratz’s work, “Genghis Khan’s bloody conquests scrubbed 700million tons of carbon from the atmosphere as depopulated land returned to forest.” Al Gore was the Nobel Peace Prize for a lot less than that!
The Mongols killed only half as many as the Black Death, but by removing these folks contiguously, “there was enough time for the forests to re-grow and absorb significant amounts of carbon.” In fact, the amount of carbon socked away on the “re-growth on depopulated lands” was “equivalent to the world’s total annual demand for gasoline today.”
The potential uses for Pongratz’s research are obvious. “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 now know that we can’t rely on disease to solve our global warming problems. Other solutions must be explored.