One of the critical raw materials on which our world depends is natural rubber. Almost all the natural rubber we consume is produced in tropical Southeast Asia, which seems natural - after all, the tropical belt is its natural habitat. Except that nothing could be further from the truth. The primary source of natural rubber today is Hevea brasiliensis which, as the name suggests, is native to the Amazon basin in Brazil. Yet, Brazil and the Amazon basin are a small and economically unimportant producer of natural rubber today.
The reason for this anomaly is that within its natural habitat, the rubber tree faces a multitude of diseases and pests that were adapted to the same environment and to the rubber tree itself. The most important of these adversaries is the South American leaf blight (SALB) disease which “is responsible for the very small share of world natural rubber production from America (3.2%), because most of the large plantations have been destroyed by the disease”. James Scott explains the adaptive dynamic behind this1:
In their natural habitat in the Amazon basin, rubber trees grow here and there among mixed stands of great diversity. They thrive amid this variety in part because they are far enough apart to minimize the buildup of diseases and pests that favor them in this, their native habitat. Transplanted to Southeast Asia by the Dutch and the British, rubber trees did relatively well in plantation stands precisely because they did not bring with them the full complement of pests and enemies. But concentrated as row crops in the Amazon, they succumbed in a few years to a variety of diseases and blights that even heroic and expensive efforts at triple grafting (one canopy stock grafted to another trunk stock, and both grafted to a different root stock) could not overcome.
In an environment free of its natural adversaries (Southeast Asia), the rubber plant thrived, and researchers were able to focus all their efforts on maximising productivity. For example, “the Malaysian program by the Rubber Research Institute Malaysia (RRIM) focused only on obtaining H. brasiliensis clones of high productivity since the disease was not a concern because the pathogen was absent”. In sharp contrast, rubber is grown in Latin America under severe constraints and sub-optimal growing conditions in an effort that has not yet succeeded due to the considerable adaptability of the fungus that causes leaf blight disease.
The success of the rubber plant outside its natural habitat mirrors the story of humanity itself. As I have explained in a previous essay, civilisation arose after homo sapiens left Africa and left behind the disease burden within the African environment. The great William McNeill summarised this dynamic in human history in his book ‘Plagues and Peoples’:
Risk of macro-parasitism that we call civilisation is reduced in places like Africa and India where micro-parasitism rules.
The Amazon basin is unsuitable for the industrial production of natural rubber precisely because it is the natural habitat for the plant, just as the African savannah was inimical to human civilisation because it was our natural habitat. The natural habitat for rubber resists simplification just like Africa resisted the most important components of the civilisational suite of ecosystem simplification (such as large-scale irrigated agriculture). And like civilisation thrived after homo sapiens left the competitive disease landscape of Africa and the ecological web of microbes and parasites that constrained us, rubber plantations thrived in places like Asia where the South American leaf blight (SALB) disease was not present.
The story of industrial rubber and the journey of our own species out of Africa illustrate that human civilisation is a radical simplification of the environment. Human civilisation is also an entirely artificial construct with very little relation to what is “natural”. However, this is not a bug; it is a feature.
James Scott in ‘Two Cheers for Anarchism’