Formerly, all people on Earth were hunter-gatherers. Over the last 10,000 years, human started to realise the favourable factors of food production and the balance tipped away from hunting-gathering to food production. Around 8500 B.C. people in the Fertile Crescent started to produce food by themselves and population boom and spread of food production slowly begins (Diamond. J, 1998)
Breasted's 1916 map of the Fertile Crescent (Wikipedia)
Food production exemplifies the autocatalyrics process of population boom. Nowadays, 40% of the terrestrial ecosystem have been transformed into agricultural land. (Barnosky. A et. al, 2012). Theoretically, the physical transformation threshold of land of the last critical transition(~30% glacial ice to ice-free), from Earth land to agricultural, has been exceeded. According to Treehugger, 20% of the U.S. CO2 emission comes from the food system. On a global scale, agricultural land contributes 12% of the world's green house gas emission (IPCC).
Apart from green house gas emission, deforestation for agriculture contributes to the warming of land surface and directly leads to loss of biodiversity. Over 4000 plants and animal species are threatened by agricultural intensification; more than 1000 threatened bird species are affected during food production process (GRIDA).
Ceasing food production is surely not a solution to the problem. To strike the balance between food production and its negative impact on the ecosystem is essential in combating climate change. Ecosystem is the life support system of the Earth. If human continues to exploit lands and natural resources unsustainably, the consequences of decrease in overall net primarily productivity and biodiversity may contributes to the possible 6th mass extinction.
