The world at risk
- Created by: rebecca crombie
- Created on: 20-03-14 16:24
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
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
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)
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
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
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)
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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