Test on global hazards

Use this test to make sure you know about global hazards. In addition, please look at the different ways of presenting hazard profiles.

  1. Define a natural hazard. (2)
  2. Identify and define with examples the four types of hazards. (8)
  3. State whether each of the events below is a hazard, if so what type and why is it/is it not   a hazard;
  • A drought in the South East of England. (3)
  • A flood in a rural area which floods the roads, but doesn’t affect any houses.(3)
  • An avalanche, high on mountain slopes, remote from any settlement. (3)
  • A tsunami 50 cm high off the coast of Japan. (3)
  • A volcano erupting on a remote unpopulated island. (3)
  1. Define a windstorm. (2)
  2. Name two case studies of each type of hazard;
  • Flood (2)
  • Earthquake (2)
  • Windstorm (2)
  1. How would Swiss Re define a disaster? (3)
  2.  What is a vulnerable population? (2)
  3. What is a quasi-natural hazard? Give an example with it. (3)
  4. What are the six indicators used to assess the impact of a hazard? (6)
  5. What is the risk equation? (3)

_______________________________________________________________________________________

Answers

  1. A natural hazard is a natural event or process, which involves people. (2)

Candidates may also give example e.g. loss of life, injury, disruption, economic damage or environmental degradation.

  1. Hydro-meteorological (1) — these are hazards caused by weather conditions & water (1)

Geo-physical (1) — these are hazards caused by processes of the earth. (1)

Geomorphic (1) — these are hazards caused by external earth processes involving mass movement (1)

Tectonic (1) — these are hazards caused by tectonic activity; earthquakes, volcanoes and tsunamis. (1) (to get 1 mark for tectonic hazards candidate is not required to give examples)

  1. a) It is a hydro-meteorlogical hazard (2) Chose one from the following 3 reasons;

– Because it will affect the agricultural yield for England. (1)

– Extreme heat may affect some people’s health. (1)

– There may also be concerns with water supply. (1)

b) Hydro-Meteorlogical hazard (2)-because it affects roads which affects people because they may be blocked from going to work or school and residents experience general disruption (1)

c) It is not a hazard because being remote it affects no one. (3)

d) Tectonic hazard (2) because it affects people living on the coast of Japan e.g. injury, loss of lives, economic damage etc (1) Candidates do not need to give an example to get one mark

e) It is not a hazard because there are no people involved. (3) It is just a natural event.

A storm with high or violent winds (1) with no or a little precipitation (1)

(a) (i) Boscastle August 2004 (ii) Mississippi flood 1993 (2)

(b) (i) Kobe earthquake January 1995 (ii) California earthquake 1989 (2)

(c) (i) Lady Lake tornado 2007 (ii) Windstorm Klaus January 2009 (2)

Candidates may pick other examples e.g. Haiti earthquake Jan 2010 – year it happened is required but month isn’t.

  1. A disaster, which caused at least 20 people to die (1), or insurance damage (1) of over US $16 million. (1)
  1. A vulnerable population is one that is susceptible to human or economic loss (1) because of the geography of where they live. (1)
  1. A quasi-natural hazard is a hazard, which is caused by a bi-product of human activity (especially while using natural resources) (2) . For example, in Indonesia (2006) a mud volcano erupted killing and disrupting many lives. It is claimed that a company called Lapindo Brantas caused it. (1) Candidates may use other examples.
  1. i) Duration (1) — Period of time over which it occurs
  2. ii) Area reliability (1) – Could you predict the area that was affected e.g. you can predict where a volcano will reach but you can’t for a

iii) Magnitude (1) — How big is it compared to the average

iv) Frequency (1) – How often-on average does the even happen?

v) Speed of onset (1) – Length of time between first appearance and peak e.g. lag time in flooding

vi) Area extent (1) – How big is the region affected?

(Note: Candidate do not need to give explanation to get the mark, the indicator on its own is fine)

10. Disaster risk = (Hazard x Vulnerability) / Capacity

A mark each for each part being in the right space.

Rising Sea Levels & Bangladesh

RISE IN SEA LEVELS 

AIM:  To investigate how sea level rise may have a disproportionately bigger effect on some countries like Bangladesh.

Modelling the rise in sea levels 

There are various predictions for sea level rise for the future. The mode extreme one predicts a rise in sea level by 15m by 2100. This puts many places including London in peril. But how is this 15m going to be achieved?

  1. Melting of West Arctic ice sheet = 5m rise
  2. Complete melting of Greenland ice sheet  =  7m
  3. Collapse and melting of world’s glacier system = 2m
  4. Continual thermal expansion of oceans = 1m

So all four event equal a 15m rise in sea level.However, most models produce a rise of 1m. Nevertheless, it is important that we act fast because even if the probability is small the risk of sea levels rising is so great. There are 3 key fundamental reasons why it is so difficult to model sea level rise hence the vast set of results.

The first reason is that it is difficult to predict the quantity of future greenhouse gas emissions especially as that isn’t just based on us it is based on nature e.g. volcanic eruptions. The second is based on the concept of ceteris paribus which is the concept that all other things remain the same i.e. ‘business as usual’. Finally, it is difficult to predict the actual impacts of a rise in sea levels.

There are two types of changes involved when we are discussing sea level changes: EUSTATIC & ISOSTATIC. Eustatic changes involve changes in sea level due to the amount of water in oceans and isostatic changes involves movements of land in response to changes in sea levels.

So where are the most vulnerable places?

There are three types of area which are most vulnerable to changes in sea level rise.

  1. Land on river deltas e.g. Bangladesh
  2. Areas that lie close to sea level e.g. Netherlands, Eastern Britain
  3. Small low lying islands in the Pacific oceans e.g. Tebua

CASE STUDY: Bangladesh

Background

  • 70% of the country lies on flood plains, less than 6m above sea level
  • Faced by multiple varieties of hazards
  • Has a growing population 
  • It is an LEDC
  • It is the world’s most densely populated area
  • It is a mega-delta filtering 57 river including Ganges, Meghna and Brahmaputra. In addition it filters snowmelt from Himalayas, monsoon rains and high tides.

What happens if sea levels rise

  • It could loose up to 20% of its land
  • Displace 40 million people
  • Threaten food supply, drinking water and agricultural land
  • Increasing water temperatures can lead to increased number of water borne diseases such as Cholera
  • The biggest risk is being lost like Tebue which means that tens of millions of environmental refugees will have to seek livelihood in other countries.
  • Damage to coral reefs 
  • More risk of cyclones
  • Malnutrition
  • Child development and education will be negatively affected 
  • Loss of properties 

So how are Bangladesh acting right now?

  1. Technological solutions – In the 1990s, Dhaka the capital city – cleared 102km of drains and constructed 144km of drains. They also opened 633 channels to improve drainage
  2. Early warning/ flood predictions – This includes preparing people especially the vulnerable of floods e.g. allowing people to be evacuated to safer grounds quickly and effectively
  3. Behavioural – Changing land uses and food choices e.g. increase fishing more than arable farming. Bans have also been put in place to slow down urbanisation
  4. Managerial – e.g. improve sanitation and water management to prevent water-borne diseases.

The solutions presented in this post are one thing but Bangladesh only has limited funds and there is a limit to how much they can borrow or rely on international aid. They also have a large vulnerable population and protecting every single citizen isn’t easy. Bangladesh has to think ahead as climate change provide more extreme situations of flooding etc then they have prepared for.

REVIEW QUESTIONS

  1. Define Eustatic changes.
  2. Define Isostatic changes.
  3. What are the three reasons that make modelling difficult?
  4. What is extreme quantity of sea level rise predicted?
  5. What are three most vulnerable places in regards to rising sea levels
  6. State two facts about Bangladesh
  7. Name three impacts of rising sea levels in Bangladesh
  8. Name two solutions Bangladesh plans
  9. What are the two fundamental  problems with these solutions?
  10. What are the three main rivers of the 57 that make Bangladesh a mega-delta?

Suggested Answers

  1. Eustatic changes are changes caused by changes in the amount of water in oceans
  2. Isostatic changes are the responses of land to changes in sea levels
  3. It is based on the concept of ceteris paribus, it is hard to predict future greenhouse gas emissions and we do not accurately know the impacts of rising sea levels
  4. 15m 
  5. Large river delta e.g. Bangladesh, the Nile, places with low lying land such as Netherlands or Eastern Britain, small low lying islands in the Pacific or Indian ocean
  6. Almost 70% is a flood plain which lies on less than 6m above sea level and  has the world’s most densely populated area
  7. 40 million people will have to be displaced, risk of water borne diseases such as Cholera and risk to properties and livelihoods 
  8. Technological 633 channels to improve drainage and managerial improve sanitation and waste management
  9. Bangladesh does not have the funds and has a large vulnerable population
  10. Ganges, Meghna and Brahmaputra