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Geography – Edexcel AS World at risk.

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Presentation on theme: "Geography – Edexcel AS World at risk."— Presentation transcript:

1 Geography – Edexcel AS World at risk

2 Hazards: Contents Types of hazards Key Terms Risks and Vulnerability
Natural Hazard or Disaster? Is the world becoming more hazardous? Human factors Falling Deaths Increasing Numbers of people affected El Nino & La Nina Distributions: Earthquakes, Volcanoes, Slides, Drought, Storms Hazard Hotspots: California, Philippines - Compared

3 What is a hazard? Every year many events around the world happen that may be described as natural hazards For a natural event or phenomena to become a hazard it has to involve people It is the way that social systems and environments link together that determines whether an event becomes a hazard What is a natural event in an uninhabited location can be a severe hazard in another place where people are involved Definition? A natural hazard is a natural event or process which affects people eg causing loss of life or injury, economic damage, disruption to peoples’ lives or environmental degradation.

4 Hazards: Two Types of hazards
Hydro-meteorological Geophysical Caused by running water and its processes (hydro) and those associated with weather patterns (meteorological) Includes floods, debris and mudflows Tropical cyclone/hurricane, storm surges, thunder and hail storms, tornadoes, blizzards and other sever storm Droughts , bush fires temperature extremes, sand and dust storms Read p 6-8 Pearson Caused by earth processes. They can be caused by either internal earth processes of tectonic activity eg volcanoes, earthquakes, tsunamis Or by external processes of geomorphological origin involving mass movement eg landslides, rockfalls, rockslides Read P 9-11 Pearson

5 Both geophysical and hydro-meteorological?
These two types of hazard sometimes overlap Eg a snow avalanche may be hydro-meteorological(snow-ice) in origin, but geophysical as an event (mass movement) Eg a landslide CAN GLOBAL WARMING BE SEEN AS A NATURAL HAZARD?

6 a)Which of these ten are hazards then
a)Which of these ten are hazards then? b)Are they hydrological, meteorological, geomorphological or tectonic? 1. A cyclone affecting Hong Kong 2. A hurricane passing over a remote unpopulated island 3. A flood in a rural area which floods the roads, but does not affect any houses 4. A volcano erupting in isolation in the middles of the Pacific ocean 5. An avalanche in a ski resort 6. An avalanche high on the mountain slopes remote from any settlement 7. A tsunami wave 50cm high off the coast of Japan 8. An earthquake in Kashmir, Northern Pakistan 9. A drought in Australia’s outback 10. A landslide in a favela in Rio

7 Na-tech or quasi-natural hazards- where natural hazards trigger a technological hazard eg flooding causes a dam to burst Techno hazards – technological hazards such as Chernobyl power plant exploding Chronic hazards – such as global warming and el-nino/la nina may increase the threat of other environmental hazards eg sea level rise increases the risk of coastal floods Super hazards – catastrophic Earth changes from super volcanoes, tsunamis and asteroid strikes Context hazards – widespread (global) threat due to environmental factors such as climate change or a super volcano.

8 Environmental and context hazards

9 Hazards: Key Terms Disasters: are the ‘realisation’ of the hazard to cause social impacts such as loss of livelihoods, lives and economic impact such as damage to goods and property. It especially occurs in areas where environments and people are vulnerable. Vulnerability: is a high risk combined with an inability of individuals and communities to cope.

10 How a hazard becomes a disaster – Dregg’s model


12 Dregg’s model shows how some kind of overlap is needed for a hazard to become a disaster.
A disaster is a matter of scale – it is simply bigger than a natural hazard. In 1990 Swiss Re insurance defined a disaster as an event that where at least 20 people died, or insured damage of over 16 million US dollars was caused. But values and currencies change all the time! It depends on how vulnerable the people are that are exposed to it. More of the world’s population are living in areas where they are exposed to hazards eg Bangladesh ( to floods and cyclones), favelas in Brazil (to landslides) The greater the scale of the natural hazard and the more exposed the people are, the greater the disaster is likely to be.

13 How a disaster becomes a hazard (Philip Allan)



16 Hazards: Vulnerability
Shaped by underlying state of human development, includes inequalities in income, opportunity and political power. Poverty stricken people often depend upon the land for food, live in poor eco-systems and have poor health. The result of this is that high risk is combined with inability to cope with the adverse impact of natural hazards and climate change.

17 Hazards: Natural Hazard or Disaster?
A natural disaster is the effect of a natural hazard (e.g., flood, tornado, hur ricane, volcanic eruption, earthquake, or landslide). It leads to financial, environmental or human losses. The resulting loss depends on the vulnerability of the affected population to resist the hazard, also called their resilience The actual or potential interaction between extreme natural events and human activities that may result in damage, disruption, death or injury

18 Risk Risk is the exposure of people to a hazardous event and the process of establishing the probability that a hazard event of a particular magnitude will occur within a given period. The types of risk in order of reduced severity are: Hazards to people – death, severe injury, disease, stress Hazards to goods – economic losses, infrastructure damage, property damage Hazards to environment – pollution, loss of flora and fauna, loss of amenity Exposure to a hazard is not always avoidable. People may place themselves at risk! See p. 5 Philip Allan

19 Risk: why do people remain exposed to hazards?
UNPREDICTABILITY: Not always predictable when or where an event will take place. Also difficult to know the likely magnitude of the event. Human activity and physical changes also mean that for example sea level is rising giving a greater chance of lowlands flooding. Moreover deforestation of drainage basins increase the frequency and magnitude of flooding. LACK OF ALTERNATIVES: Difficult to uproot and move to another location giving up homes, land and employment. Often the world’s most vulnerable are the poor who are forced to live on unsafe floodplains or steep hillsides. CHANGING LEVELS OF RISK: Deforestation can make an area once safe from flooding more susceptible. As can the effects of global warming eg sea level rise RUSSIAN ROULETTE: Optimism, turning a ‘blind eye’, ‘acts of god’, part of the living process. People are comforted by the statistics which show that the risk of death is lower than that from influenza or car accidents. They also believe that if a high magnitude event occurs then it may be safe for a few years, this is not always true. COST V. BENEFIT: Many hazardous areas offer advantages that in people’s minds outweigh the risk. Flood plains for example have very fertile soils and rich volcanic soils are also attractive.

20 The risk perception process

21 Vulnerability quadrant (Philip Allan)

22 Hazards: Measuring Risk (p 7 Philip Allan and p 12 Pearson)
Frequency or magnitude of hazard (H) x vulnerability (V) Risk (R)= Capacity to cope or adapt (C)

23 The risks are getting worse in some countries because:
1. the frequency is increasing with climate change. 2. Vulnerability is increasing as a result of unsustainable development leading to poor land use and environmental degradation. 3. The capacity to cope is decreasing owing to poverty and urbanisation. Risks are lower in more developed countries because they have resources and technology to provide protection.



26 A year of wild weather:2011 or 2010
1. Redo the hazards diary case study, updating it for either 2011 or You should try to extend the columns to include geophysical hazards, and if you want the higher grades, Na-tech, techno and chronic hazards as well. 2. Overall – what’s the worst hazard and why? 3. Crucially, make sure you include the basic impacts and death tolls if appropriate to help back- up your point for the previous question. You can then refer to these in preparation for the June exams.

27 Use the case study example (p11 Philip Allan) as a guide for what you need to do here.
MunichRe Reports will help you, as will bits of other research on the BBC News website (e.g. type in volcano / earthquake etc), or GoogleNews.

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