Parts 1,2,3,4 Geography AS Unit 1 Global Challenges World at Risk

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1. Global Hazards Definitions

Hazard: A potential threat to human life or property.

Hydro-meteorological Hazards -  (caused by climatic processes) = droughts, floods, tropical cyclones, and storms.

Geophysical  Hazards -  (caused by land processes) = earthquakes, volcanic eruptions, and landslides.

Disaster:  When the hazard actually seriously affects humans.

Risk: The likelihood that humans will be seriously affected by a hazard.

Vulnerability: How susceptible a population is to the damage potentially caused by a hazard.

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1. Disaster Risk Equation

Risk =Hazard x Vulnerability

Capacity to Cope

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1. Why are some people vulnerable to hazards?

  •  State of human development - inequalities in income, political power, is development controlled? - e.g.dangerous buildings
  • Population in developing locations often depend on local land for food, live in poor eco-systems, and have poor health.
  • Population densities - rapid urbanisation - higher=increased vulnerability
  • Location- e.g. hurricane belt/plate boundaries - poorer people forced to live in dangerous places where others don't want to... 
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1. Why is global warming a major hazard?

  • Has the potential to trigger more hazards and increase severity
  • It is chronic (long term) - constant threat,can't be solved quickly/easily
  • It is GLOBAL - will effect entire world
  • Solutions are complex and require international cooperation - of governments, businesses, and individuals
  • Increases in HYDRO-METEOROLOGICAL hazards 
  • Rapid pop growth+urbanisation = increasing no.people vulnerable to hazards
  • Increasing world poverty = more people vulnerable
  • Exploitation of resources --> increased risk - e.g. deforestation > flooding 
  • Affecting El Nino=unpredictable global weather change > affect HYDMET
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1. Differing Vulnerability Examples

Bam, Iran

  • 2003
  •  6.6
  •  90% housing = mud, brick, no frame 
  • = 25,000 deaths

Hawaii

  • 2006
  • 6.6
  • 0 deaths, few minor injuries
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2. Hazard trends- magnitude & frequency, why incre

  • Climate change increasing severity and frequency is weather-related hazards  (hydro-meteorological)  + expanding range of disease carriers
  • No. reported natural disasters dramatically increasing each year since 60's - some argue due to technology improvements & better recording, and some argue severity is a result of rising world pop = increasing no. pop in poverty, pressure on land
  • Environmental damage makes effects worse
  • El Nino Southern oscillation impact on hydro-meteorological 
  • Geophysical disasters fluctuating >no overall rising trend- remain huge killer
  • Disasters cause more damage in countries with low and medium development levels
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2. Impacts from disasters on lives, infrastructure

Lives

  • No. deaths caused by disasters decreasing
  • Recent levelling off - improved risk management strategies in developed countries - PPP (Prediction, Preparedness, Prevention) /// Increasing no. vulnerable people in poor countries = more affected= more deaths.

Economy & Infrastructure 

  • Economic losses growing disproportionally to rate of disaster (rapidly).
  • Economic damage appears greater in high-income countries, in relative terms, more devastating in poorer countries = account for a far greater proportion of their GDP.
  • Many developing countries depend on crops & tourism for income - both can be devastated by natural disasters.
  • E.g UK insurance covers flood damaged house/Bangladesh lose everything
  • New infrastructure tends to be rebuilt to higher standard = greater cost
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3. How to assess local hazard risk (using disaster

- Research past events, e.g. rivers that have flooded

- Likely future events, e.g. landslides caused by coastal erosion

- Impacts of these on people, property and the environment.

ALSO RESEARCH HAZARD PATTERNS + RISK POTENTIAL

- OS maps > locations of rivers, pop ar risk if flood

                 > particularly vulnerable pops, e.g. housing estate nr river

- GIS - overlay local maps, e.g. tectonic plate boundaries, and river flood plains -     show where the hazards coincide

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3. Global distribution of major natural hazards

Geophysical Hazards - usually occur near plate boundaries.

Constructive = Volcanoes and Earthquakes - Moving apart, pressure released at boundary, magma less dense= rises, e.g. N.America + Eurasion plates forming mid atlantic ridge- formed Iceland.

Destructive = Volcanoes (*80%)  and Earthquakes - plates moving together, more dense oceanic subducts - plates stuck =pressure = earthquake, e.g. Kashmir e.quake 2005, friction = crust to magma, then rises (volcano) 

Conservative = Earthquakes- two plates locked together, pressure builds up >> jerk past, e.g. Pacific moving past N.America - San Andreas fault, California

Volcanoes can also occur away from plate boundaries, e.g. Hawaii, caused by large magma chambers beneath crust.

Landlides - most vulnerable areas are mountainous, esp after seismic activity + heavy rain

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3. Global distribution of major natural hazards

Hydro-Meteorological Hazards - widespread in their distribution, increasingly unpredictable in their location.

Floods - Coastlines, rivers -  when excessive rainfall related to atmospheric processes, e.g. cyclones, El Nino Southern Oscillation, e.g. S.America, rapid snow/ice melt

Droughts - + 1 third of the world's land surface has a level of drought exposure - variations in the movement of the inter-tropical convergence zone = delayed rainy season, El Nino affecting rainfall patterns, e.g. Australia. Also create forest fires

Tropical Cyclones/Storms - Cyclones occur in latitude 5-20 degrees north and south of the equator, over warm ocean (+26.5 C) of at least 70m in depth - Coriolis affect = rotation of air.

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3. Disaster Hotspots: California

-California is one of the most desiable places to live in America due to it's high wealth, warm climate, and sandy beaches but is also the USA's most hazardous state. This is due down to plate tectonics and and climatic patterns - inc El Nino affects

-San Andreas fault (conservative plate boundary) runs the length of the state. This plate boundary has caused many earthquakes. - Pacific plate moves north-westwards past N.American plate (sam direction, but Pacific moves 6x speed)

-San Andreas is the fault between them - runs along Californian coast, from LA down to San Francisco.

Main Disasters = EQuakes, droughts, tsunamis, landslides + volcanoes BUT ALSO

-Hurricanes - trade winds blow hurricanes formed in the Pacific towards California and flooding - result of El Nino & limited city drainage

Vulnerable? > 70% pop within 50km fault line, buildings along coast, massive economy = huge economic loss, highly populated. Economy 6th highest in world

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3. Disaster Hotspots: California Facts & Figures

-Earthquakes in California have high liquefaction rate (strength of soil decreases and, reducing ability to support foundations -for infrastructure) and high magnitude risk. E.g.Loma Prieta, Oct 1989, 7.1 magnitude, Epicentre - Loma Prieta, San Francisco Bay area, 63 deaths, +13,000 injured, +23,000 homes damaged, +1000 destroyed, 366 businesses, cost $6BN

- Landslides-El Nino + deforestation+ building on Coastal land e.g. La Conchita, 2005, 10 deaths

- La Nina years & anticyclones = Drought + forest fires - edge of LA moving into Sierra Nevada mountains, e.g. S.Cali Oct 2007 killed 22, destroyed 1300 homes

- Tsunami risk - Pacific Ocean prone to tsunamis, e.g. EQ off Alaska, 1964 struck Crescent City, N. Cali, killed 12.

-Volcanoes - not been one since 1915 (Lassen Peak), however some being  monitored - e.g Lassen Peak, around Mammoth Lakes

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3. Disaster Hotspots: The Philippines

Cluster of just over 7,000 islands situated directly south of the eastern edge of china, the Philippines consist of micro plates that lie between convergent (destructive) plates - Eurasian + Pacific.positioned along western edge ring of fire. 

  • Northern and Eastern coasts face the Pacific which is the world's most tsunami-prone ocean.
  • It lies within the South-East Asia's major typhoon belts.
  • Landslides are common in the mountainous district.
  • GDP: $4,111 USD

Main Disasters = EQuakes, volcanoes, tsunamis, landslides, typhoons, drought, flooding. Vulnerable? > densely populated area = high population density - esp around Manilla, pop pressures > deforestation of upland areas for agriculture *landslides, flooding, fast growing economy//many below poverty line, people living in unstable locations, e.g. Aeta tribe on slopes of Mt.Pinatubo (erupted 1991)

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3. Disaster Hotspots: The Philippines Facts & Figu

-Earthquakes: Philippine & Eurasian plate lock together, jerk. E.g. Luzon Island, 1990, 7.8 magnitude, +1,600 deaths, +3,500 injured, 100,000 homes destroyed, cost $300 Million

- Landslides: lots rain in short space time, mountainous areas e.g. Leyte island, 2006, after rained for 10 days, whole village burried - inc school, hundreds deaths

Drought: distinct wet and dry seasons, e.g Manilla = wet Nov-Apr & dry May-Oct, if dry season particularly harsh/wet comes late e.g. Luzon Island- reduced river flow > power production hydroelectric plants, many without power for long period= reduced social & economic activity 

- Tsunami: earthquakes in any of surrounding oceans, e.g. EQ 7.9 hit Moro Gulf, 1976, thousands killed, several cities devastated

-Volcanoes: destructive plate boundary - Philippine plate being subducted below Eurasian. E.g. June 1991, Mt.Pinatubo, many evacuated, 350 died - some from disease in Evac Camps, 80,000 hectares farmland buried in ash, 500,000 farmers lost livelihoods, $710 million economic loss.

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3. Disaster Hotspots: The Philippines Facts & Figu

- Flooding: heavy monsoon rain,imact of typhoon rains, squatter settlements vulnerable, e.g. July 1972, Central + Southern Luzon, most of Manila underwater, 600 dead, 370,000 homeless, 250,000 hectares rice damaged.

- Typhoons: have around 10 a year, develop in Pacific & blow westwards over islands, e.g. 2006, Typhoon Xangsane across Manilla & surrounding densely populated area in North, destroyed homes, high winds and torrential rain, landslides, loss of power and water.


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4. Global warming is part of on-going climate chan

Climate change: Any significant change in the weather of a region over a period of several decades.

There is much evidence to support the fact the climate has changed & always will.

Long Term:

  • Temperature have been higher & lower in the past than today
  • Datafrom the last 400,000 years shows this fluctuation
  • The climate shifted between cold glacial periods (100,000 years) and warmer interglacial periods (10,000 years). <<<<We are currently in this

Medium Term:

  • Last glacial period ended 18,000 years ago
  • The warming of the climate after this was warm but not constant
  • Around 5000 years ago temperatures were 1-2 C higher than today
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4. Global warming is part of on-going climate chan

Short Term:

  • Has been a noticeably sharp rise in temperature over the last 100 years
  • Overall pattern of increase but not constant - global temps rose steadily from 20th century until 40's then dropped back down, scientists thought = another glacial period, but temp rose rapidly since 1970's (global warming)
  • Current changes are unprecedented = worrying(http://static.guim.co.uk/sys-images/Guardian/Pix/pictures/2010/2/4/1265282134205/TempChart.gif)
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4. On-going climate change evidence

Long Term:

  • Ice cores - scientists extract cores if ice from ice sheets - analyse gasses trapped in layers - one layer formed each year. - data for 400,000 years
  • Pollen - preserved in sediment, can be identified & dated to show when released - indicated conditions of time produced.
  • Sea level change - affected by volume stored as ice, rased beaches dated.

Medium Term:

  • Historical records - indirectly indicate conditions, e.g. agriculture reports
  • Tree Rings - a new ring formed each year, good conditions = thick ring- date back 10,000 years
  • Retreating glaciers - size & how far they extended by looking at position of rocks deposited nearby, greater distance of rocks indicates temp increase.
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