Lecture OutlinesNatural Disasters, 5th edition

Patrick L. Abbott

Christiane Stidham, Stonybrook University

Natural Disasters and the Human Population

Natural Disasters, 5th edition, Chapter 1

2003 Natural Disasters• More than 83,000 people killed by natural disasters

in 2003• Bam, Iran earthquake: 41,000 people

– Gujarat, India (2001): 20,000 people

– Izmit, Turkey (1999): 19,000 people

– Tangshan, China (1976): 240,000 people

• European heat wave: more than 35,000 people– Unique event

– Unprecedented temperatures, but probably more frequent with global warming

Human Fatalities in Natural Disasters• Sawtooth-shaped curve caused by largest natural disasters

• Biggest killers (in order): hurricanes, earthquakes, floods, severe weather, landslides, volcanic eruptions, tornadoes and tsunami

• Most mega-killer disasters occur in densely populated belt through Asia, along Indian Ocean – number of fatalities is proportional to density of population

• Effects on survivors

– Increase in suicides

– Increase in altruism

Economic Losses from Natural Disasters

• Destruction and damage to structures, loss of productivity and wages

• Increase in economic losses over time is result of increase in human population and urbanization

• Most expensive events caused by storms and occurred in U.S., Europe and Japan

Natural Hazards• Hazard exists even where disasters are infrequent• Evaluate site risk• Mitigation prior to event

– Engineering, physical, social and political plans and actions to reduce death and destruction from natural hazards

• Mitigation after event– Rebuilding and re-inhabiting same site

– Case history: Popocatepetl Volcano, Mexico• Eruptions in 822, 1519 and beginning again in 1994

• Currently 100,000 people living at base

Magnitude, Frequency, and Return Period• Inverse correlation between frequency (how often it occurs) and

magnitude (how big it is) of a process

– Frequent occurrences are low in magnitude, rare occurrences are high in magnitude

– Small-scale activity is common, big events are rare

– Larger the event, longer the return-period (recurrence interval)

• Cost-benefit ratio can be considered in conjunction with return-period of given magnitude event

The 20th Century Was Unique

• Population growth at unprecedented and breathtaking rate, doubling twice

• Increased numbers of people in hazardous settings

Overview of Human Population History• Difficult to assess early human population growth• Human species ‘began’ approximately 160,000 years

ago, with a few thousand people• Human population has grown to 6.3 billion people in

2003• Growth rate is exponential

The Power of an Exponent of Growth• Visualize in terms of doubling time

– Number of years for population to double in size, given annual percentage growth rate

– Doubling time = 70 % growth rate/year

– Example of interest paid on money• Linear growth: $1000 + $100 / year

• Exponential growth: $1000 + 7% / year

– Example of water lily plant in pond• Doubles in size every day

• Covers half the pond the day before it covers the whole pond

The Last 10,000 Years of Human History• Flat population growth curve until 8,000

years ago

– Agriculture established

– Domestication of animals

– Growth rate increased to 0.036%/year

• By 2,000 years ago, population ~200 million people

– Better shelter, food and water supplies faster population growth

– Growth rate of 0.056%/year

• By 1750, population ~800 million people

The Last 10,000 Years of Human History

• By 1750, population ~800 million people– Establishment of public health principles, causes of disease

recognized

– Birth rates soared, death rates dropped• By 1810, population ~1 billion• By 1925, population ~2 billion• By 1960, population ~3 billion• By 1974, population ~4 billion• By 1987, population ~5 billion• By 1999, population ~6 billion• By 2012, projected population ~7 billion

The Human Population Today

• Present population: (insert number)– Growth rate = 1.3%/year

– Doubling time = 53 years

• Growth rate =

fertility (birth) rate – mortality (death) rate

Future World Population

• Demographic transition theory:– Mortality and fertility rates decline from high to low levels

because of economic and social development

• Population Reference Bureau estimates world population growth rates are dropping– From 1.8% in 1990 to 1.3% in 2003

– Due to urbanization and increased opportunities for women

Future World Population

• BUT population explosion continues– From 1950 to 2000 population grew from 2.5 billion to 6 billion

– Growth rate of 1.3%/year means population of 9 billion in 2050

• Consider no. of births / woman to predict 2150 population– Average 1.6 children/woman: 3.6 billion

– Average 2 children/woman: 10.8 billion

– Average 2.6 children/woman (current average): 27 billion

Mathematical Extrapolation

• Too many people?– Crowding in cities

– Crime

– Pollution

– Illegal migration

– Disease

• Room for more people?– Entire world population could fit inside 42 km x 42 km square

• Consider carrying capacitycarrying capacity

Carrying Capacity

• How many people can Earth support?– Calculations of carrying capacitycarrying capacity vary considerably

– Increasing amounts of food can be produced

– People can migrate from areas of famine or poverty to less crowded or wealthier areas

– BUT Earth’s resources are finite, so solutions are temporary

Carrying Capacity• Example of Rapa NuiRapa Nui (Easter Island)

– Isolated Pacific island with poor soil and little water

– Settled by 25-50 Polynesians in 5th century• Survived easily on chickens and yams, plenty of free time

• Developed elaborate competition between clans with moai (statues)

– Civilization peaked at 1550, with population of about 7,000

Carrying Capacity

• Example of Rapa NuiRapa Nui (Easter Island)– Reached by a Dutch ship in 1722

• Found about 2,000 people living in caves

• Primitive society, constant warfare

– Rapa Nui’s carrying capacity had been drastically lowered by society’s actions:

• Transportation of moai had required cutting down trees

• Erosion of soil made yams scarce

• Lack of canoes made fishing difficult and escape impossible

End of Chapter 1