The Human Population and Its ImpactChapter 6

C.O. You’ll know how human population has changed over time and if the Earth can sustain our rapidly growing population.L.O. You’ll get into small groups after taking some notes and discuss ramifications of current human population and if you agree or disagree with Malthus’ assertions.

1. Clarify weebly stuff2. Finish 1-3 Notes3. Introduce Shoe Project

Due next Friday4. Start Chapter 6 –

History of human population5. HW read 6-2 to 6-4 tonight6. Quiz tomorrow7. TEST Thursday, I think

Are There Too Many of Us? Estimated 2.4 billion more people by 2050 Currently 7+ Billion people living • Earth reached that milestone October 31st,

2011. Are there too many people already? Will technological advances overcome

environmental resistance that populations face Should populations be controlled?

Are There Too Many of Us?

The World’s Most Typical Person (video)https://www.youtube.com/watch?v=4B2xOvKFFz4

Core Case Study: Are There Too Many of Us?

Will growing populations cause increased environmental stresses?

Quick Group Discussion & Share-out. What environmental stresses might an increasing human populations cause?• Infectious diseases• Biodiversity losses• Water shortages• Traffic congestion• Pollution of the seas• Climate change

6-1 How Many People Can the Earth Support? We don’t know. But….• how long can we continue increasing the earth’s

carrying capacity for humans?• without seriously degrading the life-support system for

humans and many other species?

Vegas, Baby, Vegas

Early Human Population• Anatomically Modern Humans appear in fossil record

~200,000 years ago in Africa

http://6000generations.wordpress.com/2012/11/09/out-of-africa-is-morphing-into-out-of-africarabia-as-genetic-and-archaeological-time-lines-converge/

Early Human Population• About 70,000 yrs ago Toba Volcano erupted in Indonesia. • Ash limited sun for nearly 6yrs• Genetic Bottleneck suggests humans almost wiped out – DNA

suggests we owe our existence to 40 breeding pairs!

http://www.npr.org/blogs/krulwich/2012/10/22/163397584/how-human-beings-almost-vanished-from-earth-in-70-000-b-c

Early Human Population Mostly hunter/gather populations existed before 10

KYA. • Populations were very small and had very little population

growth.• Death rates and birth rates were both very high.• Catastrophic population crashes were also possible.

At about 10 kya – 8 kya, the population growth rate increased, why?

Early Human Population “Neolithic Revolution”

• Transition from hunter/gather to agrarian (farming) societies• With ag comes the end of nomadism.

Occurred through the development of cultivation of animals and plants

Occurred in many different regions of the World• Asia, Africa, North America, Melanesia, etc

Early Human Population – • The Fertile Crescent (Birthplace of Ag)

Early Human Population – • The Fertile Crescent of North America• The Four Corners (AZ, NM, CO, UT)

Human Population Growth Continues but It Is Unevenly Distributed

Reasons for human population increase• Movement into new habitats and climate zones• Early and modern agriculture methods• Control of infectious diseases through• Sanitation systems• Antibiotics• Vaccines

Human Population Growth Continues but It Is Unevenly Distributed

Year Human PopulationYrs to an Additional

Billion People1AD-1750 800,000

1830 1,000,000,0001930 2,000,000,000 100yrs1960 3,000,000,000 30yrs1975 4,000,000,000 15yrs1987 5,000,000,000 12yrs1999 6,000,000,000 12yrs2011 7,000,000,000 12yrs

(2050) 8,900,000,000

Human Population Growth Continues but It Is Unevenly Distributed

Population growth in developing countries is increasing 15 times faster than developed countries

By 2050, 97% of growth will be in developing countries

Should the optimum sustainable population be based on cultural carrying capacity?

Global Connections: UN World Population Projections by 2050

Science Focus: How Long Can the Human Population Keep Growing?

Thomas Malthus (economist) and his take on population growth: 1798• Proposed humans growing exponentially & food couldn’t

keep up.• Proven wrong… so far

Humans have altered 83% of the earth’s land surface Can the human population grow indefinitely?

Science Focus: How Long Can the Human Population Keep Growing?

Thomas Malthus’ beliefs – Continued Population growth leads to poverty when the population increases faster than the food

supply. Overpopulation leads to lower wages and a labor surplus, further exasperating poverty Malthus believed that the Poor should incorporate “moral restraint” to curve their high

reproductive habits. Poverty is to be blamed on the Poor. It’s the Poor's own fault that they are poor. Malthus was skeptical that the Poor where capable of doing this (Social Darwinism), and thus the Poor would remain poor. He was opposed to welfare because it might encourage more poverty.

Science Focus: How Long Can the Human Population Keep Growing?

Neo-MalthusiansTwo of the more outspoken, and controversial Neo-Malthusians are Paul Ehrlich: The Population Bomb Seen as a “Doomsdayer” , proposes that unless immediate action is taken to control overpopulation, series

crisis's will ensue. “We can no longer afford merely to treat the symptoms of the cancer of population growth; the cancer

itself must be cut out. Population control is the only answer. The operation will demand many apparently brutal and heartless decisions. The pain may be intense. But the disease is so far advanced that only with radical surgery does the patient have a chance of survival”, quote in Schmidtz and Willott (2002), Environmental Ethics; What Really Matters, What Really Works, Oxford University Press, New York, pg 265.

Garrett Hardin: “The Tragedy of the Commons” Author of the “Lifeboat Ethics. Quoting Goldfarb (2000) in his book Notable Selections in Environmental

Studies, Second Edition, Dushkin-McGraw Hill, Guilford, CN,) • “[Lifeboat ethics is] a world model in which the developed, affluent nations that control and use most of the

world’s resources are in a lifeboat while the struggling developed nations are floundering in the surrounding ocean. He concludes that it is folly to try to rescue all the swimmers and suggests that the ethically appropriate strategy is one of triage, by which the ‘haves’ permit the poorest and least developed of the ‘have nots’ to drown in order to prevent the entire boat from sinking” (pp. 39-40).

Science Focus: How Long Can the Human Population Keep Growing? A contrasting academic camp to the Neo-Matlhusians are the

Cornucopians.• Technological advances (e.g. in agriculture) and expansion of the market

economy will mitigate any problems presented by overpopulation. • If there are more people, then we will discover/invent new ways to feed them.

Technology will help us better utilize our resources, cure diseases, etc. – Prominent among the Cornucopians is Bjørn Lomborg.

Fig. 6-A, p. 124

NATURAL CAPITAL DEGRADATION

Altering Nature to Meet Our Needs

Reduction of biodiversity

Increasing use of the earth's net primary productivity

Increasing genetic resistance of pest species and disease-causing bacteria

Elimination of many natural predators

Introduction of potentially harmful species into communities

Using some renewable resources faster than they can be replenished

Interfering with the earth's chemical cycling and energy flow processes

Relying mostly on polluting and climate-changing fossil fuels