Current conventional wisdom points to Central Asia as the origin of cannabis before being introduced to Europe and the rest of the world—"current" being the key word. That's because a recent study examining fossil pollen studies (FPSs) from the European Pollen Database showed that Europe may actually be cannabis' origin source.
The analysis determined that the oldest pollen consistent with cannabis was first present in Europe during the Olduvai cold stage beginning 1.8 million years ago—not the Holocene era as usually suggested. The analysis also found that cannabis cultivation in Europe began in Bulgaria during the late Miocene period—roughly 1,000 years earlier than the currently accepted timeline.
The study also notes that its research was limited by several factors. First, the algorithm used in the study is challenged by "inherent assumptions and biases" that all pollen-based methods face. Additionally, the shifting of the ice sheets during the Pliocene Epoch and subsequent refugia prior to the Holocene came with the loss of history in the soil and beyond. As such, niches of cannabis and other pollens were given assumed trends based off statistical data available. Other limitations in the study included a lack of FPS to study in key regions, including Southeast Russia and Ukraine. Conversely, analysis was conducted in FPS-dense nations such as the United Kingdom, Switzerland and the Czech Republic.
In all, the study falls short of providing a concrete determination on the origin of cannabis. However, the findings could open the door for additional research into the subject. If more of these results prove true, “conventional wisdom” may soon have to change.