Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

“Natural Disaster, its causes & effects.”


Published on

Sayef Amin
Southeast University
LLBH Program

Published in: Education, Technology

“Natural Disaster, its causes & effects.”

  1. 1. Assignment on –“Natural Disaster, its causes & effects.” 1
  2. 2. Introduction of Natural Disaster:A natural disaster is a disaster caused by nature, such as floods, volcanic eruptions,earthquakes, tsunamis, avalanches, lahars (volcanic mudslides), landslides,sinkholes, blizzards, drought, hailstorms, heat waves, hurricanes, tropical storms,typhoons, Ice Ages, tornadoes, and wildfires. Epidemics caused by bacteria orviruses are sometimes considered natural disasters, but sometimes put into adifferent category. A biological threat such as locusts or toxic fungi could also beconsidered a natural disaster.Some disasters are on the edge of natural and non-natural. Famines, the chroniclack of food, may be caused by a combination of natural and human factors. Twospace-originating categories of natural disaster, both of which rarely effect humanson the surface, include asteroid impacts and solar flares. Although the risk ofasteroid impact in the short term may be low, some scientists argue that in the longterm, the likelihood of death by asteroid is similar to that of death by traditionalnatural disasters such as disease.The deadliest natural disasters are famines, which claimed 70 million peopleduring the 20th century alone, with 30 million dying during the famine of 1958–61in China. In the Soviet Union there were several man-made famines that killedmillions, blamed on the collectivist policies of Stalin, the leader of the country atthe time. Famines have a history of bringing out the worst in people, includingatrocities and cannibalism.Another of the deadliest natural disasters is epidemics, most notably the Spanishflu of 1918-1919, which killed 50 million — more than World War I, which hadoccurred just before. Rather than killing infants or the aged, the Spanish flu struckdown people in the prime of life. Having a good immune system was no protectionagainst this virus — in fact, it was a liability. The virus is believed to have killedits victims primarily through over activating the immune system in a process calleda cytokine storm.Historically, volcanoes may have been the biggest type of natural disaster. Somescientists believe that the eruption of Mt. Toba in Indonesia over 73,000 years agomay have killed off most of the human species, leaving behind only 1,000 - 10,000breeding pairs. This phenomenon, called a population bottleneck, has beenconfirmed through genetic analysis. 2
  3. 3. Definition of Natural Disaster:A natural disaster is the effect of earth’s natural hazards, for example flood,tornado, hurricane, volcanic eruption, earthquake, heat wave, or landslide. Theycan lead to financial, environmental or human losses. The resulting loss dependson the vulnerability of the affected population to resist the hazard, also called theirresilience. If these disasters continue it would be a great danger for the earth. Thisunderstanding is concentrated in the formulation: "disasters occur when hazardsmeet vulnerability."[Thus a natural hazard will not result in a natural disaster inareas without vulnerability, e.g. strong earthquakes in uninhabited areas. The termnatural has consequently been disputed because the events simply are not hazardsor disasters without human involvement. A concrete example of the divisionbetween a natural hazard and a natural disaster is that the 1906 San Franciscoearthquake was a disaster, whereas earthquakes are a hazard. This article gives anintroduction to notable natural disasters; refer to the list of natural disasters for acomprehensive listing.Natural disasters are cataclysmic events that can have a direct or indirect impact onthe publics health and well-being, according to the United States Department ofHealth and Human Services. Natural disasters can include weather phenomena aswell as landslides and avalanches, which occur as a result of erosion or severeweather patterns.Natural disaster of a different kind: Cold Spell in Bangladesh:Being a Bangladeshi, it is never a pleasant experience to talk about the periodicnatural disasters, mainly floods and cyclones that ravage the country every nowand then. To increase the sufferings of the poor disaster vulnerable people of thecountry, recently there has been a new addition to the list of regular naturaldisasters of Bangladesh named Cold Spell, thanks to the global climate change.The impact of Cold Spell is as notorious as other regular natural calamities ofBangladesh as far as the death toll is in concern. The recent Cold Spell thatappeared on the 7th January in Bangladesh has already taken sixteen lives, out ofwhich are 9 children and made most of the population of the northern Bangladeshto suffer with pneumonia, cold diarrhea, cough, fever, asthma and other cold-related diseases. 3
  4. 4. During a Cold Spell, gusty extreme cold wind coupled with heavy fog covers thewhole area of Bangladesh. Historically the average winter temperature inBangladesh is within 15 to 20 degree Celsius. However, in recent Cold Spells thisaverage temperature has dropped to as low as 4 degree Celsius, a new record forthe country. The most affected area during this calamity is the northern part of theBangladesh which is closer to the Himalayas. Northern Bangladesh is the mostpoverty stricken area of the country where people have year round income povertyand seasonal food poverty during the time of agricultural lean seasons. The recentcatastrophe of Cold Spell has magnified their sufferings to a severe extent,shortage of warm clothing and shelter has caused them even their lives.The sufferings of poor people of northern Bangladesh reached to an untold terriblestage especially for those who live in the remote island areas of river Tista, whichis locally known as Char. Some places in the northern part had not seen the sun forthe last 3 to 4 days due to the extreme fog and clouds. Most places of the char areasin the river basins remained covered with fog, reducing the visibility till noonalmost every day. In such situations, poor cannot join their regular work because ofthe unfavorable weather condition as well as due to sickness. As a result, they losea significant share of their regular income which further reduces their ability totake proper action against the shock.Also the daily transportation of food items from all parts of the country has beendangerously interrupted. Basic road and water transportation has been delayed foran indefinite time, causing major physical communication to an almost completehalt. Needless to say, such physical communication chaos has triggered the price ofcommon household commodities to a seasonal extreme, causing the sufferings ofthe poor even more severe. People who took desperate attempt to hit the roadignoring such bad driving conditions have already paid the price with roadaccidents if not heavy traffic congestions in the highways.The main reason for such calamity is the constant and consistent blow of chillywind from the northwest blowing at a speed of 10-15 kms per hour which made theweather further cooler during the typical winter season. As there is no rain, pollencount in the air is relatively high in this season making the air full of dust andcausing respiratory problem and allergic infections along with asthma, pneumonia,chronic bronchitis, respiratory problem, chronic obstructive pulmonary disease.Hospitals, especially those in the northern part of the country, are experiencing 4
  5. 5. massive admission of patients suffering from cold related illnesses for the last fewdays. Reports received from different sources mentioned seriously sufferings ofthousands and millions people living in the sandy char areas in Kurigram,Lalmonirhat, Gaibandha, Rangpur, Nilphamari, Bogra and Sirajganj districts on theBrahmaputra basin.Effects of Natural Disasters:Natural disasters have become so commonplace that they hardly receive passingnotice on the news unless there have been a large number of casualties. Volcanoes,mudslides, tsunamis and floods are just a few of the ways nature strikes on a dailybasis, leaving behind destruction and heartache. Humans have learned to preparefor the possibility of tornadoes, earthquakes, hurricanes and wildfires, but noamount of preparation can lessen the impact that natural disasters have on everyaspect of society.Physical Destruction:The biggest visible effect of naturaldisasters is the physical ruin theyleave behind. Homes, vehicles andpersonal possessions are often destroyed within a short period of time, leavingfamilies homeless and shutting some businesses down permanently. Tornadoesdestroy structures at whim, earthquakes cancause structural damage that might not beapparent at first glance, and tsunamis andfloods sweep homes off their foundations.Emotional Toll:Possessions are not hard to replace, as manypeople keep insurance on their property andtangible goods. The emotional toll of naturaldisasters is much more devastating. The death of a loved one may be the worst-case scenario but its not the only lasting emotional effect victims experience.Whole communities may be displaced, separating friends and neighbors; victimsface anxiety and depression as they wonder if it could happen again. In extremecases, they may experience post traumatic stress disorder (PTSD).Economic Concerns:According to the National Hurricane Center, Hurricane Katrina cost the U.S. $75billion when it slammed into New Orleans in August 2005. That doesnt include 5
  6. 6. the damage caused in the Florida counties of Miami-Dade and Broward by thesame storm. While destruction of this magnitude is not commonplace, even aminor storm can cause considerable damage. At the very least, the local economymust be able to absorb the cost of cleanup and repairs.Indirect Effects:While the visible effects of natural disasters areimmediate and strongly felt, communities thatsurround ground zero can be indirectly affected bythem as well. Natural disasters almost always lead toa disruption in utility services around the areaimpacted. This can mean life or death for those who rely on dialysis or oxygen tolive. Medical assistance is also often slowed, as emergency crews must focus onthe victims of the disaster. Banks and other businesses might be closed, affecting afamilys ability to withdraw money to pay bills and buy groceries.Geography:Geography plays a large role in how natural disasters affect an area. In rural orisolated communities, natural disasters can thrust families into a situation wherethey must do without modern conveniences like electric and running water. Theymay not be able to get to town to buy necessities and have to rely on what theyhave stocked up. Densely populated areas face their own unique problems fromnatural disasters. Hygiene becomes a concern, as people crowd into temporaryrelief centers and competes for limited resources.Environment:Humans arent the only living things affected by natural disasters. As is the casewith humans, animals can be displaced from their homes. Sometimes they have noalternative but to leave the area and try to fit into a new habitat. Volcanoes,earthquakes, floods, wildfires and mudslides often permanently alter an areasLandscape, leading in some cases to the destruction of a local speciesDisruption of UtilitiesCommunities that surround areas affected by natural disasters are seriouslyaffected by the disruption caused to utility services. Generally, power is the firstthing to go when theres a natural disaster. This can literally mean life or death tothe people who are on life support systems such as oxygen and dialysis. Medicalassistance becomes hard to get since the crews are busy helping the victims of thedisaster. Banks can be shut down, causing a shortage of cash circulation that 6
  7. 7. prevents people from accessing funds for much needed provisions for babies and small children. Emotional Damage When a natural disaster strikes, the emotional toll on the people affected is quite devastating. While possessions can be replaced eventually through insurance, the emotional damage can take a long while to heal. People lose loved ones in natural disasters; deaths of people and precious pets, serious injury and people missing all add up to severe emotional trauma. Communities get displaced meaning separation from family and friends. Victims face stress, trauma, anxiety and depression as a result of natural disasters. Social Consequences The social consequences of natural disasters in the short and long term are wide ranging. The disasters affect housing; people are left homeless and rebuilding a home takes a long time and a lot of money. Health care infrastructure is affected; the impacts are worse in developing countries that already have poor facilities to begin with. Disease starts spreading and, without proper medical attention, makes a bad situation worse. Education is a big loser when a natural disaster happens, schools are often closed, teachers are unable to come in to work and children are displaced and unable to attend school. Transportation capacity is reduced hindering relief efforts and disrupting normal life. What Are the Different Types of Natural Disasters? Tornado A tornado occurs on the surface of the earths land as a result of humidity in the lower atmosphere combining with wind shears. The spinning comes by way of downdrafts and updrafts, but the violent speed is usually due to rapid changes in the air (such as dry air suddenly becoming very cool). When air mass is unstable and storms come through an area, a tornado often results. The reason most tornadoes occur in the Midwest of the United States is because tropical winds from the south Gulf move up to meet the cool winds of Canadas north. When they collide in the middle, its usually somewhere around Kansas or Nebraska (though tornadoes can occur anywhere if the conditions are right, theyre usually not as severe in other regions). 7
  8. 8.  Earthquake Violent tremors of the earths surface are the result of earthquakes, which are caused by the shifting of the earths tectonic plates and fault lines below the surface. When the earths temperature changes, this causes movement of rock and plates in the earths mantle. This happens all over the globe, but some stresses are more severe in some areas. Parts of the world that experience more earthquakes usually do so because the plates below them are more brittle and weak. In the Pacific Ocean, there is the Ring of Fire that stretches up and down the coasts of North America and South America and continues across to Japan and down to east of Australia. Volcanic eruption occurs for similar reasons, in that activity occurs below the surface of the earth causing stress and sudden release of molten rock. Hurricane Also known as a tropical cyclone or typhoon, hurricanes are violent storms that occur off of ocean shores. High winds are produced by water that has evaporated from an ocean surface in a low pressure area. This also causes a spiraling effect, which gains momentum the more condensation it collects. Minimal hurricanes have winds of about 75 mph (Category 1), but the most catastrophic storms will blow more than 155 mph (Category 5). Once a hurricane hits land, it begins to cool and slow, but this is the point at which a hurricane does its most damage. Destruction of trees, cars and buildings is likely in the event of a hurricane. Causes of Natural Disasters: Floods: According to the U.S. Environmental Protection Agency (EPA), barring fire, floods are the most common natural disaster affecting Americans. Floods are a factor in 90 percent of natural disasters. Flood events have both natural and man- made causes. Storm events can create flood waters that exceed the capacity of the environment or man-made structures. Levees and dams provide a false sense of security as became evident during the Great Flood of 1993 in the Upper Mississippi River valley. A painful lesson was learned. Wetlands destruction removed a natural means to absorb floodwaters. Fires: Fires are natures environmental managers. They create and maintain ecosystems such as prairies and pine forests. In fact, prairies evolved with the presence of fire. The health of the ecosystem is dependent on this disturbance. Fires remove a buildup of litter on the soil surface, allowing nutrients to be released into the environment. It also creates favorable conditions for seed germination. Suppression of fire allows litter to accumulate, setting the stage for catastrophic fires. Plants and trees have adapted to the presence of fire. However, the higher temperatures of crown fires can kill plants entirely. These fires are more difficult to control. 8
  9. 9. Suppression of fires is expensive, upward of $1 billion annually, according to the U.S. Forest Service. Drought: Drought has had more widespread effects than any other natural disaster. Each year, drought costs the United States more than $6 billion. Its safe to say that droughts have greater impacts in modern times. More people are affected by loss of land and food crops as well as environmental damage. The immediate effects are overshadowed by secondary issues. Compacted, dry soils are vulnerable to topsoil loss and erosion. Dry conditions make fires more common. Evidence suggests global warming may be the cause for an increase in drought frequency and changes in the global climate. Weather Events: Like drought, an increase in severe weather events has been recorded in the last 100 years by the National Climatic Data Center. While notification systems are in place, vulnerabilities still exist for property damage and crop loss. Development has also complicated the effects of such events. An increase in development leads to a decrease in wetlands and an increase in impervious surfaces such as roads and driveways. This creates a scenario for floods and flash flooding. As with drought, scientists believe a link between global warming and climate changes exists. Prevention/Solution: Not all natural disasters can be prevented. Each natural disaster has its own factors and complications. Understanding the basic principles of ecology can provide keys to lessening their effects. Nature evolved with natural disasters and disturbance. The best prevention is looking at the strategies found in nature. What Is Natural Disaster Management? Significance Effective natural disaster management saves lives. Procedures set in place before a catastrophe occurs ensure a speedier and more effective response. A preventative measure, such as strengthening the infrastructure of buildings in earthquake regions, minimizes the risk of injuries and helps people to resume normal life more quickly. Features Governments and some large corporations in developed countries designate aid money for natural disasters before they happen. They also liaise with the governments of affected regions and aid workers on the ground when a disaster occurs to determine the extent of medical aid and supplies needed. Aid workers are trained to assess the scale of the disaster. Non-government overseas aid workers may already be based in the region and have a good understanding of the local 9
  10. 10. culture, which can be invaluable in advising how to administer help effectively,according to the Global Education website.ConsiderationsGovernments and aid organizations, such as the Red Cross, and representatives ofthe affected region usually work together to save lives and restore order after adisaster occurs. Natural disaster management continues long after the initial crisishas passed. Funds, for example, may be allocated to rebuild homes destroyed by aflood. 10