The Rise of Agriculture

Agriculture [noun]: the science or practice of farming, including cultivation of the soil for the growing of crops and the rearing of animals to provide food, wool, and other products.

                                                                                                        (Oxford University Press 2015)

The main themes of my blog that I will use to explore to the effects of feeding us is how agriculture causes global environmental change through: 

                - the conversion of land 

                - the production methods used

First I thought to find out how agriculture started...

As we are delving back into time, key geological epochs to know about are the Pleistocene — which began roughly 2.58 million years ago (Gibbard and Head 2010) to roughly 11,700 years ago (Walker et al., 2009)  — and the Holocene which directly followed it. When exactly the Holocene finished (and the Anthropocene which we are in now began) is one of much debate, some interesting articles on the subject are available here and here. But for us the end of the Pleistocene and beginning of the Holocene are the most importance for agricultural origins.

From hunter-gatherers to agriculturists

Why we moved from hunter-gatherers to an agricultural society is intriguing, it is thought to be due to climatic change at the end of the Pleistocene. Through studying ice cores we can see the climate of the Pleistocene went through periods of abrupt warming and cooling (Cummings et al., 2006), and this unreliable climate is thought to have made agriculture pretty much impossible for our ancestors (Richardson et al., 2001). As the last ice age of the Pleistocene came to an end the earth entered a new epoch, the Holocene, which had a much warmer and more stable yearly climate. We can see this change in the ice cores as demonstrate in figure 1. below:

Figure 1: Graph showing isotope levels of oxygen from ice-cores, which reflect temperature changes. (Cummings et al., 2006)   

This new climate allowed agriculture to be a feasible long term option (Richardson et al., 2001), and using radiocarbon dating we can see that agriculture appeared during this time. Adapting to this changing climate, agriculture seems to have developed separately in about 9 locations (Diamond and Bellwood 2003) and then spread globally as, compared to hunting and gathering, agriculture could support larger populations. (Richardson et al., 2001, Diamond and Bellwood 2003):

Figure 2. Archeological map of agriculture homelands and spread of associated cultures, with approximate radiocarbon dates  (Diamond and Bellwood 2003). 

Exactly how those hunter-gatherers began agriculture appears to have been a fairly gradual process incorporating a combination social and technological factors (Cummings et al., 2006). Many groups already had an agricultural element to their societies from which they expanded upon and Roth (2006) provides interesting evidence for women driving the adoption of agriculture, and how it began as an extension of their 'gathering' role (girl power eh!). 

So that's how we became an agrarian society. I hope you found out something new and i''ll leave you here with this interesting tidbit:

Though agriculture dominates the globe hunter-gatherer societies still remain out there, one such example is the Sentinelese people living on North Sentinel Island in the Bay of Bengal. They are one of the last ‘un-contacted' tribes and have been able to remain this way for so long due to being incredibly hostile to any outsider contact. If you are interested in learning more about them click here.

Credit: North Sentinel Island 2015

Till next time!