Transcript Biophysical Hazards

Biophysical Hazards
Reading
• Smith Ch 10
Biophysical
Hazards
• “dustbin”
category for
various assorted
hazards
– disease
– extremes of
temperature
– wildfire
Disease organisms
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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
700000
600000
500000
400000
300000
200000
100000
0
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
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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
Annual # of Fires
60
50
40
30
20
10
0
1935
1940
1945
1950
1955
1960
1965
1970
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