The world at risk

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Global Hazards

Hydrometeorological (Cyclones, Floods) Geophysical (Earthquakes, Volcanoes)

When human life is in danger it is considered a hazard. Natural hazards only turn into natural disasters if there is a sever loss of life and injury.

Measuring a disaster risk is summarised by the disaster equation: R= (H X V) / C

H= Size/scale/probability   V= Vulnerability    C= capacity to cope

Risk is directly proportional to: size and severity, number of people, vulnerability of the people living in the area

Global warming is the greatest problem currently facing humankind

- Rising sea level threatening large cities

- Higher temperatures could spread to temperate latitudes

- Global warming likely to increase the frequency of hydrometeorological events

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Global hazard trends

El Nino and La Nina (changes in ocean oscillation causing cyclones and hurricanes)

Global warming and population growth causing more sever floods

Abnormally low rainfall leading to droughts impacts activities most dependant on rainfall

Factors driving the increase of natural disasters

GLOBAL WARMING

EL NINO / LA NINA

WORLD POPULATION GROWTH

URBANISATION

POVERTY

OVEREXPLOITATION OF NATURAL RESOURCES


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Global hazard patterns

Cyclones: high humidity and plent of water vapour, light winds, sea surface temperatures of 26-27

Droughts: More widespread, found worldwide

River floods: low lying valley floors, floodplains, little river regulation, deforestation

Earthquakes and volcanoes: interplate movement, plate tectonics (destructive, constructive, conservative)

Landslides: mass movement caused by steeping and undercutting, deforestation, heavy rainfall

DISASTER HOTSPOT- geographic areas where multiple hazard risks are found (California and the Philippines)

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Climate change and its causes

Long-term and medium-term climate change- global temperatures have fluctuated over the past 500,000 years

Interglacial/glacial periods

currently in a Interglacial period

Evidence for long term climate change- Ice cores, sea floor sediment, Tree ring analysis

Evidence for short term climate change- Weather forecasts, studying ice shelf, Coral bleaching

Natural causes: Astronomical events (Milankovitch Cycles- tilt, orbit) Ocean currents (North atlantic current) Volcanic eruptions (Large scale eruptions like Mount Pinatubo) Global warming and enhanced greenhouse effect

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Impacts of global warming

Direct impacts

Cold regions (Arctic): permafrost melts, Albedo increases, Food webs effected, Economic impacts for local Inuits

Hot regions (Africa): Droughts, Food supplies down, Desertification, Diseases sprends easily

Indirect impacts

Eustatic sea level rise due to melting ice sheets and thermal expansion

BANGLADESH- most of the country occupies floodplains, 15-20 million live just 1m above sea level, rising levels will destroy coasta mangroves which provide protection

Predicting climate change can be done with computer models

some scientist believe that increase in atmospheric CO2 will reach a tipping point and create irreversible change

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Coping with climate change

International strategies (Kyoto Protocol 1997, Carbon crediting)

National strategies (Promoting cleaner technologies, Carbon taxes on activities)

Local strategies (Carbon footprint reduction, congestion charges, bicycle hire)

MITIGATION- reducing the output of greenhouse gases and gas sinks

ADAPTATION- Changing our lifestyle to cope with a new environment rather than preventing

Adaptation- drought resistant crops, flood barriers, coastal management strategies

Mitigation- low emission zones, reducing urban heat island, (strategues above)

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The challenge of global hazards for the future

Risks from natural hazards are increasing due to several factors:

- more frequent and higher intensity hazards

- rapid world population growth

- increased number of people living in poverty

(water shortages, Food insecurity)

Meeting the challenges

Reducing carbon emissions

renewable energy

Energy efficiency

Reafforestation

Carbon capture

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