Biophysical Hazards

Reading

• Smith Ch 10

Biophysical Hazards

• “dustbin” category for various assorted hazards– disease– extremes of

temperature– wildfire

Disease organisms

• Microbes: Bacteria, viruses, prions

• Parasites

• can affect people directly

• can affect crops

Infectious Disease

• Interaction between – population of disease organism– population of host organism– often complex transgenic relationships

• Lyme disease

Infectious Disease

• Endemic: always present

• Epidemic: periodically active– Major Epidemics: Pandemics

Infectious Disease

• Epidemic/endemic depends on size of host population– Too small: tendency toward epidemics– Large enough: tends to be endemic

Flu in Manitoba

Infectious Disease

• Tendency for ecological balance between disease organisms and their hosts

• Very deadly diseases– kill their hosts too quickly to spread efficiently– but modern communications can change that …

• Fighting flu in Hong Kong

Anthropological speculation

• Humans evolved in Africa

• Human population designed to be naturally regulated by the diseases of Africa

• Take humans out of Africa:– Epidemic growth of human population

• Humans as an epidemic?

Black Death Pandemic 1347-1350

• Bubonic plague

• Killed 50 million Europeans in 3 years – 1/3 of European population

• Severe social disruption– Weakened the feudal system

Black Death Pandemic 1347-1350

• Losses of urban populations:– London: 50% loss – Beijing: 40% loss

Population of London, England

0

100000

200000

300000

400000

500000

600000

700000

1000 1100 1200 1300 1400 1500 1600 1700

Black Death Pandemic 1347-1350

• Western Europe in population crisis by 1347– war, famine, disease, harvest failure– soil exhaustion

• Black Death the latest of a series of calamities

• Population took until 1600s to rebuild

1918-19 Influenza Pandemic

• WW1: killed 9 million in 4 years

• Influenza: killed 25-37 million in 2 years– 16 million killed in India

Sydney NSW

• Ann Arbor MI Fall 1918

• High River Alberta, Fall 1918

• Potential public enemy #1

Plague in the USA

• San Francisco 1909

• New Orleans 1914

• Now endemic in California– transgenic shift from

rats to ground squirrels

Bubonic Plague in CA

Promoting/Discouraging Disease

• Increase probability of infection– population builds resistance– example of Tuberculosis in Victorian England

• Decrease probability of infection– population does not get the exposure to build

resistance– example of Polio

Polio in LA, 1950s

Biological limits

• People suffer irreversible deterioration and death if internal body temperature– falls below 26 degrees C– rises above 40 degrees C

Extreme Cold

• Windchill, hypothermia– severe high-latitude/high-altitude weather

conditions– cold water exposure

Extreme temperatures

• Cold weather kills fewer than hot weather– easier to keep warm than keep cool– body designed to survive cooling better than

overheating

The Humidex Chart

• US OSHA heat chart

Extreme temperatures

• Dec 1983 cold snap kills 150 in USA

• 1979-80 5000 heat deaths in USA

• 1936-75 20,000 died in USA from heat & humidity

Extreme temperatures

• Kills the elderly, those with compromised circulatory & respiratory systems

• Urban areas worse: heat island effect, worse in inner city

• Set to worsen with global warming

Extreme temperatures

• 1955 heat-wave in LA killed 946 people– twice as deadly as 1906 San Francisco

earthquake

• Toronto Telegram June 1959

Frost Hazards

• Bad for agriculture, especially tender crops close to harvest time

• Various devices to reduce frost risk

• Locate farms to avoid frost

The Niagara Fruit Belt

• Mainly on the Lake Ontario plain, N of the Escarpment

• Cooler temperatures here retard fruit growth, reducing risk of a spring frost

• Or make ice wine

Wildfire Hazards

• Promoted when fuel accumulates (dry vegetation) and meets dry, windy, warm weather

October 1871 USA

• Wildfire in Michigan & Wisconsin

• Follows 14 week drought

• Land-clearance fires whipped up by strong winds

• Burns 1.7 M hectares

• Kills 1500

• World’s greatest wildfire disaster?

Ash Wednesday 1983

• Victoria & South Australia

• 1983 El Nino drought & heatwave

• Strong winds (70 km/h+)

• Killed 76, 8000 homeless

• Ash Wednesday fires 1983 NSW

• 6 firefighters died here

Macedon NSW

Brushfires, 1983 drought Australia

1983 El Nino drought fires, Australia

NSW Fires Dec 1993-Jan 1994

• 1992-3 El Nino

• Affected 1 M Hectares

• 300+ fires along 1100 km coastline fanned by strong winds

• Destroyed 200 buildings

• Killed 4

Jan 1994 NSW

• Jan 1994

Australian Fires

• Burn faster than other people’s fires– 800 Hectares/hour in Australia– 1 Hectare/hour in Northern USA

Dandenong NSW 1997

Dandenong NSW 1997

• Engadin NSW 1997 controlled burn

Engadin NSW 1997

Pillaga NSW 1997

Lithgow NSW Dec 1997

• Lost home, Sydney NSW Dec 1997

Heathcote NSW Dec 1997

• Mt Martha NSW Jan 1998

Icon in the smoke, Jan 1998

Smoky Sydney Dec 1997

Sussex Inlet NSW Jan ‘02

Toomerong NSW Xmas 2001

Causes of “Wildfires”

• Lightning strikes

• Human carelessness– rubbish that burning gets out of control– car exhausts, discarded glass containers etc.,

• Fires maliciously set

• Effects of urban growth

Grass & Brush Fires, Brampton ON

0

10

20

30

40

50

60

1935 1940 1945 1950 1955 1960 1965 1970

An

nu

al #

of

Fir

es

Fuel Issues

• Fire is part of the natural ecology

• Controls fuel accumulation

• Requires fuel accumulation– tends to be seasonal– Toronto area:

• first warm weekend (usually April)

New Jersey

New Jersey brushfire

Northern Quebec

Effects of Fire Prevention

• May cause fuel to accumulate to dangerous levels

• Pre-emptive burns, controlled burns required

Some areas fire-prone

• Malibu California– Seasonally-dry Chaparral vegetation which

burns hot and fast– Seasonally strong Santa Ana winds can whip up

fires into a conflagration– Inhabited by the rich, dislike restrictions on

their lifestyle– Demand good fire protection

• Before & after 1993 canyon fire, Malibu CA

• Ventura Co. California 4 July 1985

Arizona wildfires June 2002

El Dorado CO June 2002

• Missionary Ridge fire CO June 02

Oroville CA June 2002

• Smoky skies

Valley View CO June ‘02

Hayman CO fire 16hrs old June ‘02

Glenwood CO June ‘02

Sacramento Mtns NM June ‘02

Shaw St Toronto May ‘02

• Windy evening, flames spread through garages at rear

Biophysical Hazards

• Bit of a mixture

• But includes major killers– infectious disease– antibiotics ceasing to be effective