Transcript World at Risk 1 - SLC Geog A Level Blog

Geography – Edexcel AS
World at risk
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
What is a hazard?
 Every year many events around the world happen that may be
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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.
Hazards: Two Types of hazards
Hydro-meteorological
Geophysical
 Caused by earth processes.
 Caused by running water and its
 They can be caused by either
internal earth processes of
tectonic activity eg volcanoes,
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earthquakes, tsunamis
 Or by external processes of
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geomorphological origin involving
mass movement eg landslides,
rockfalls, rockslides
 Read P 9-11 Pearson
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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
Both geophysical and hydrometeorological?
 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?
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
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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
 Na-tech or quasi-natural hazards- where natural hazards trigger a
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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.
Environmental and context hazards
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.
How a hazard becomes a disaster
– Dregg’s model
 Dregg’s model shows how some kind of overlap is needed for a
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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.
How a disaster becomes a hazard
(Philip Allan)
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.
Hazards: Natural Hazard or Disaster?
Hazard
Disaster
 A natural disaster is the
 The actual or potential
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
interaction between
extreme natural events and
human activities that may
result in damage,
disruption, death or injury
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
Risk: why do people remain
exposed to hazards?
 UNPREDICTABILITY:
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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.
The risk perception process
Vulnerability quadrant (Philip Allan)
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)
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.
A year of wild weather:2011 or
2010
 1. Redo the hazards diary case study, updating it for
either 2011 or 2010. 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 backup your point for the previous question. You can
then refer to these in preparation for the June
exams.
 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.