Pessimists/Malthusians:  people who worrying about the population growing could bring problems to the world like outstrip
food supply, leading to famine, disease, and social disorder.

Neo Malthusians: Those people are the thinker that think disease will take over the developing countries in next  50 years by increasing global warming, shortages of arable land, conflicts
over fresh water, declining fish stocks, and the spread of
AIDS or other diseases.

Optimists/cornucopians: Those are the people think that with the development of solar and wind energy, the earth’s carrying capacity would increasing so they have a optimist idea about population growing.

Unreported World: Kenya’s Human Time Bomb: This video fit into the Pessimists/Malthusians category, one time the local people in Kenya talked about the lack of land and resources cause the war in Kenya, the 18 – 35 years old age group don’t satisfied with what they get right now, instead, they ask for more resources but they can’t get that, so they start the war for resources.

Hans Rosling’s TED Talk: Global population growth, box by box: This video fit into Optimists/cornucopians category. Hans Rosling’s ideas are all base on when poorest group of people get enough things they ask for, the population growth will comes to a stop or even decrease, tho, he thinks the west world will still be a lead position with the improvement of the quality of the life for those poorest population groups.