The article suggests that Agriculture began around 10,000 BP. From my previous studies as an archaeologist, in the New World we understand a slightly different chronology. But caveat, I've been out of the field for quite awhile and not familiar with most recent research.

Sometime before 10,000 BP peopes entered the Americas for the first time (multiple points of entrance, not just Bering Straight). They were large game hunters (Mammoth, Mastadon, Athabascan bison) as identified by the tool assemblage they left behind. This period lasted between 12000 BP and 9000 BP.

By 9000 BP the large Pleotocene mammals had disappeard (became extinct) from the Americas. Between 9000 BP and 7000 BP the environment became warmer and drier as is known in the American SW as the Holocene. Subsistance strategies changed from large game exploitation to new strategy that emphasized a greater reliance on hunting smaller game and a greater reliance on exploiting local plant resourses. This is reflected in the tool assemblage by smaller, less elaborate projectile points, and the first appearance and reliance on grinding stones to process plant resources

The Holocene ended (by some scientists) by 7000 BP. The temperatures became cooler worldwide. It is around this transition time that agriculture arose. It began as "insipient agriculture" whereby hunter and gatherer groups collected seeds from the plants they ate. They would "plant" the seeds along the migration routes they followed. As they followed game and the seasonal changes, they would return to the areas where they planted seeds (mostly likely began during the middle of the Holocene). The success of these planted plots encouraged increasing the practice. In the process they selectively changed the plant itself by selective selection of better seeds, leading to the domestication of crops. As the cooler temperatures made hunting and gathering more difficult, subsistance made another shift to a greater reliance on crop rearing and year round habitation in one area. Birth of agriculture.

As a subscript, some scientist call the entire period beginning at the end of the last ice age (Pleistocene) to the present as the Holocene. However, a new movement among geologists is to label the end of the Holocene to the present as the "Anthropocene". Meaning the period of time geologic time that humans permanently changed the face of the Earth in a identifiable way (cities, agricultural, mining, etc).

It is ridiculously arrogant to believe humans are the most intelligent life form in the universe - so the possibility of some extra terrestrial visitors is at least possible, if not probable

Sceptical about any of this actually holding up to scrutiny. 13000 years ago is a stretch.