Urban disasters

URBAN DISASTER

An urban area can be defined as an area with large population and high density. An urban disaster occurs mainly due to urbanization. Urban cities have lifelines like electricity line, water line, sewage
line, telephone line etc.
Urbanization of the world's population is accelerating. More than 50% of the global population is already urban with more than one billion people living in slums. This trend continues and it is estimated that by 2050 more than 67% of the world's population will be living in cities.

Based on the damage caused, urban disasters are classified into:

1. Urbanizing natural disaster is seen mostly in the developing world where substantial natural environment is not affected by human activities. It mainly occurs when residential areas and urban infrastructure are developed in rural areas.
2. Pseudo-urban natural disasters are disasters where there is little or no damage to human life whereas urban infrastructure and lifeline systems are completely destroyed. In such type of disasters, population density is not large and only property damages are prevalent.
3. Urban natural disasters are disasters that are largely amplified due to overpopulation and socioeconomic activities.

Urbanization is a major cause of concern in the current time due to the following reasons:

1. The marginalized rural populace invariably lives a nomadic life, constantly on the move, in search of a better life. They live as workers in rural areas toiling in agricultural fields or performing menial jobs
2. Upon arrival in urban cities, they are attracted to the luxurious and comfortable lifestyle preferring to stay back and work as unskilled laborers in the organized as well as unorganized job sector. This leads to formation of slums that lack sanitation services, supply of clean water, reliable electricity, law enforcement and other basic services.
3. Hence, slums in urban cities are a major centres of crime. Lack of healthy environment contributes to vector borne diseases that become the epicenter of epidemics
4. Statistics indicate that crimes originate in slums and spread across entire metropolitan cities making it an unsafe place to stay

EFFECT OF POPULATION ON URBAN NATURAL DISASTER

1. Ratio of amplification
2. Effect of population density on disasters

Urban natural disasters are characterized by catastrophe due to overpopulation and dense concentration of social capital which has not invested enough for disaster prevention. Highly populated cities amplifies the injury to its inhabitants and damage to property.

Other type of urban disasters include:

1.  Chernobyl nuclear disaster that devastated Pripyat city that was a major bustling center of activity
2. 1926 Miami hurricane, Hurricane of 1900 in Galveston, TX, 1994 Earthquake in Northridge, CA, Kanto Earthquake in 1923, Earthquake in San Francisco in 1906, Hwang He floods in 1931 in China, Tropical cyclone in Bangladesh in 1998.
3. The great Chicago fire in1871, Starvation in Bengal in 1943,

Higher losses of life and property in a given hazard intensity in urban areas are due to:

1. Increasing urbanization
2. Expansion of habitat into unsuitable vulnerable areas
3. Higher population densities
4. Vulnerable construction due to loss of traditional skills 
5. Ignorance, apathy and the false belief that disaster will not occur in the area
6. Complacency due to long gap between two events
7. Non-engineered unsafe construction
8. Structurally unsound and unauthorized vertical constructions and additions to houses

ASSIGNMENT QUESTIONS

ASSIGNMENT QUESTIONS

1. Define and discuss risk and capacity with respect to disasters
2. What is mitigation and discuss the structural measures to mitigate the effect of floods

1. Discuss with the help of an example, artificial floods in urban areas
2. Discuss forest fires as natural and man made disaster with the help of an example

1. Discuss the ecological impacts of various types of disasters with examples
2. Discuss climate change as a disaster

1. Write short notes on climate change adaptation
2. List the local resources that can be used in disaster management

 

1. Briefly explain sanitation and shelter as components of disaster relief
2. List the salient features of DM act and DM policy

Classification, causes and impacts (social, economic, political, environmental, health and psychosocial) of disasters

Classification of disasters:
Disasters are primarily classified as:

1. Natural disasters and
2. Man-made disasters

Natural disasters are caused due to natural phenomena. Examples are:

• Floods
• Droughts
• Cyclones
• Earthquakes
• Tsunamis
• Volcanoes
• Landslides
• Avalanche
• Blizzard (Snow storm)
• Wind chill
• Sand storms

Man-made disasters are caused primarily due to human negligence. Examples are:

• Explosions
• Leakage of toxic chemicals
• Pollution
• Deforestation, Forest fires
• Dam failure
• Wars, Weapons of mass destruction (WMD), Biological weapons, Chemical weapons, etc.

Natural disasters can further be divided into 

• Hydrometeorological based disasters and
• Geological based disasters

Hydrometeorology is the study of exchange of energy and water between the lower atmosphere and Earth's surface. Examples of hydrometeorological disasters are:

• Cyclone
• Flood
• Drought
• Wind chill
• Snow storm
• Sand storms. etc

Geology is the science of study of the Earth. Examples of geological based disasters are:

• Earthquake
• Volcano
• Landslide
• Tsunami, etc

Earthquake:

The Earth is made-up of rocks, tectonic plates and molten magma at the core. The tectonic plates are in constant motion relative to each other. As the plates move against each other, any irregularity causes an abrupt jerk resulting in tremendous energy being released which is experienced on the surface as an Earthquake.

Volcano:
The Earth's core is made up of molten magma under pressure. When this molten magma finds its way to the surface of the Earth through cracks or fissures it erupts with great force spewing red hot lava. Volcanoes occur under the oceans on the sea bed also. They cause severe damage to life and property. Sometimes volcanoes remain dormant for several years before becoming active again. In the past, volcanoes have occurred in Italy(Mount Etna), Indonesia(Mount Merapi), Japan(Sakurajima), United States(Mount St. Helens), Ethiopia(Erta Ale), etc.

Landslide:
Landslide refers to a type of mass wasting. Examples include:

• Rock falls
• Deep seated slope failures
• Mud flow and
• Debris flow

Tsunami:
Tsunami is Japanese meaning tidal wave or  a  harbour wave. It occurs due to disturbances in the sea floor. It is a series of waves in a water body caused by displacement of large volume of water in an ocean.

Disasters are also classified as:

• Extraterrestrial disasters: These types of disasters are caused by collision of celestial bodies. Space telescope data reveals 4700 potentially hazardous asteroids with diameter greater than 330 feet are present near the Earth. Other types of extraterrestrial hazards are:
• Magnetic storms
• Catastrophic Earth changes
• Meteorite Impacts and
• Impacts from near-earth objects

Man-made disasters:

• These hazards man-made or human induced disasters. They are caused primarily due to human activities leading to loss of life and property along with causing damage to the regions economy and productive capacity. Examples of these disasters are:
• Environmental pollution
• Terrorism
• Destruction of property
• Road & rail accidents
• Explosions
• Chemical spills
• Industrial accidents
• Nuclear accidents, etc.
• Physical hazards that are caused due to developmental activities. Examples include:
• Deforestation
• Desertification
• Loss of natural resources
•  Pollution
• Waste disposal, etc.
• Technological hazards that are caused due to interaction of society, technology and the natural environment. Examples include:
• Explosions
• Wars
• Release of  toxic substances into the environment
• Oil spills, etc

Environmentalists have further categorized technological hazards into:

• Industrial Hazards
• Structural collapse hazards
• Nuclear hazards
• Computer hazards and
• Transportation hazards

Biological hazards or biohazards:

• These type of hazards originate from biological sources. Examples are:
• AIDS
• Malaria
• Severe epidemics in plants and animals (SARS)

Biohazards are further categorised into:

• Pathogens (Example: Anthrax, Small Pox, Influenza, Plague etc)
• Toxins 

Social hazards originate from social systems such as:

• Population explosion
• Famine
• Warfare
• Conflict
• Terror attacks
• Holding people hostage etc

Causes of disasters:

• Earthquakes are mainly caused by slippage within geological faults but also due to volcanic activity, landslides, mine blasts and nuclear tests.
• Landslide is a geological phenomenon that includes a wide range of ground movements like rock falls, deep failure of slopes and shallow debris flow that occurs offshore, coastal and onshore environments.Gravity is the primary driving force along with contributing factors like slope stability.
• Tsunami is a series of water waves caused by displacement of large body of water. The 2004 Indian ocean tsunami was the deadliest in human history causing the death of 2,30,000 people in the countries surrounding the Indian ocean.
• A volcano is a rupture in the Earth's crust that allows hot magma and volcanic ash from the Earth's interior to erupt on the Earth's surface.
• A flood is an overflow of water that submerges vast areas of land. Floods occur in rivers when flow capacity exceeds the capacity of the channel
• Landslides also called a landslip or mudslide occurs when the slope changes from a stable to an unstable condition due to groundwater pressure, weakening of a slope due to saturation from snow melt or heavy rainfall. Landslides are also caused due to deforestation, mining at the foot of the slope, excess withdrawal of ground water, construction activity and explosive activity in the vicinity
• Droughts are caused due to less or no rainfall combined with excessive withdrawal of groundwater.
• Snow storms and sand storms occur in cold and desert regions respectively. Snow storms occur in the cold mountainous regions and consist of freezing winds combined with snow reducing visibility and related hazardous conditions. Sand storm is a meteorological phenomena in arid and semi-arid regions. Sand storms may cause asthma and other related respiratory problems. Sand storms or dust storms involve transport of fine sand particles from one place to another. A sand storm can transport and carry large volumes of sand unexpectedly.

Impacts of disasters:
Disasters may have the following effects on communities as listed below.

1. Social impacts: The social impacts of a disaster refer to the tangible and intangible effects on a society and the expenses to rebuild the society to the stage that existed before the disaster occurred. The most common social impacts on a community involve:
1. increased mental health issues
2. alcohol misuse
3. domestic violence
4. chronic diseases and
5. short-term unemployment
2. Economic impacts: Any disaster destroys tangible assets such as buildings and equipment. Disasters have severe short-term economic impacts. The costs of disasters rise exponentially with economic development. Disasters affect the infrastructure of a community in a manner that all other projects requiring funds are stopped and diverted to reconstruction and rehabilitation work
3. Political Impacts: Disasters fundamentally test a government's preparedness and capacity to deal with a disaster. Government's should be aware of natural disaster risks in their region and set regulatory measures in place before the disaster occurs. If a government has done a poor job responding to a disaster they may be voted out or political unrest may occur in response to a disaster.
4. Environmental impacts: Disasters have a profound effect on the environment. They cause a temporary or permanent effect on the environment depending the type of disaster. Earthquakes modify the topography of the terrain, Volcanoes release several tons of carbon-dioxide and other toxic gases. In addition, they destroy the local landscape and anything that comes in contact. Floods cause widespread destruction of the local region and habitat. They also cause loss of life and severe erosion.
5. Health impacts: Disasters impact the health of affected people in several ways. People may suffer from physical injuries that may be temporary or permanent. Affected people may suffer psychologically and suffer from mental illnesses. The health effects may last much longer than the disaster itself. The health effects of a disaster are unavoidably linked to the social and economical effects of any disaster.
6. Psychosocial impacts: Psychosocial impacts refers to the effect caused by the environment on the social and or psychological aspect on an individual or community due to a disaster. Several psychiatric disorders may affect psychological and social aspect of the affected individual's life. Disasters may diseases such as PTSD, depression, extreme stress, anxiety and a range of mental diseases.

Review of past disasters and drought in India

REVIEW OF PAST DISASTERS IN INDIA

The Indian subcontinent is highly vulnerable to cyclones, droughts, earthquakes and floods. Avalanches, forest fire and landslides occur frequently in the Himalayan region of northern India. On an average, about 50 million people in the country are affected by one or the other disaster every year, besides loss of property worth several million.

In the 1970s and the 80s, droughts and famines were the biggest killers in India. Floods, high winds and earthquakes dominate the reported injuries, with increasing numbers in the last ten years. The period from 2001 to 2011 has been associated with a large number of earthquakes. Floods, droughts, cyclones, earthquakes, landslides and avalanches are some of the major natural disasters that repeatedly and increasingly affect India. The natural disasters directly impact economies, agriculture, food security, water, sanitation, the environment and health each year.

 Different natural hazards because varying levels of physical damage to infrastructure and agriculture with implications for their indirect and secondary impacts. Drought causes heavy Crop and Livestock losses over wide areas of land.  Floods and Cyclones cause extensive whereas damage to both infrastructure and agriculture, depending on their timing relative to the agricultural cycle. Earthquakes can cause wide spread devastation of infrastructure and other productive capacity over relatively large areas.

During the period 1980 - 2010 India faced disasters in the form of floods (in 1980, 1982, 1993, 1994, 1995, 1998, 2002, 2004, 2005, 2006 and 2009), drought (in 1982, 1987, 2000 and 2002), earthquake (in 1993, 2001 and 2004), epidemics (in 1984 & 1988), storm (in 1990, 1996, 1998 & 1999)

India is a country highly vulnerable to natural disasters. Enormous population pressures and urbanization have forced people to live on marginal lands or in cities where they are at greater risk to disasters and the damage they can cause. Each time a flood, a regional drought or a devastating earthquake occurs, millions of Indians are affected. In addition to large-scale displacement and the loss of life, these events result in the loss of property and agricultural crops worth millions.

In India, 68 percent of the land is drought prone, 60 percent is prone to earthquake, 12 percent is prone to floods and 8 percent to cyclones. This amounts to almost 85 percent of the land area in India  vulnerable to natural hazards. The main natural disasters in India includes floods, earthquakes, droughts, and cyclones while the minor natural hazards in India are landslides, avalanches, hailstorms, forest fires and bush fires.

These disasters have been categorized into following five sub-groups depending on origin. They are:

1. Water and Climate Related Disasters Ex:Floods and Drainage Management, Cyclones, Tornadoes and Hurricanes, Hailstorm, Cloud Burst, Heat Wave and Cold Wave, Snow Avalanches, Droughts, Sea Erosion and Thunder and Lightning. 
2. Geologically related disasters Ex:Landslides and Mudflows, Earthquakes, Dam Failures/Dam bursts and mine fires
3. Chemical , Industrial & Nuclear related disasters Ex: Bhopal gas tragedy
4. Accident related disasters Ex:Forest Fires, Urban Fires, Mines Flooding Oil Spill, Major Building Collapse, Serial Bomb Blasts, Festival related disasters, Electrical disasters and Fires, Air, Road and Rail Accidents, Boat Capsizing and Village Fire.
5. Biologically related disasters Ex:Epidemics, Pest Attacks, Cattle epidemics and Food poisoning.

DROUGHT IN INDIA

India has a largely monsoon dependent irrigation network. An erratic pattern, both low (less than 750 mm) and medium (750 - 1125 mm) makes 68 percent of the total sown area vulnerable to periodic droughts. Severe and rare droughts occur in arid and semi-arid zones once in almost every 8-9 years. Drought is a perennial feature in some states of India. 16 percent of the country’s total area is drought prone and approximately 50 million people are annually affected by droughts. In fact, persistent drought with less than average rainfall over a long period of time gives rise to serious environmental problems.

Drought in India has resulted in millions of deaths in the past three centuries. Indian agriculture is heavily dependent on climate to irrigate crops. The southwest monsoon is essential for crops and its failure results in below average crop yields.

Sometimes, droughts have led to major famines for example:

1. The Bengal famine of 1770 (one third of population in affected area dead)
2. The famine in 1876-1877 (five million people dead)
3. The 1899 famine (4.5 million people dead)

Drought strikes India every eight to nine years. Drought impacts the poorest the hardest. 

Classification and characteristics of disasters in India

CLASSIFICATION OF DISASTERS IN INDIA

The Indian subcontinent is among the world’s most disaster prone areas.

It is vulnerable to wind storms spawned in the Bay of Bengal and the Arabian Sea, earthquakes caused by active crustal movement in the Himalayan mountains, floods brought by monsoons, and droughts in the country’s arid and semi-arid areas.

Most of the frequently occurring disasters in India fall in two categories.

1. Hydro-meteorological disasters and 
2. Geological disasters

Hydro-meteorology refers to the transfer of water and energy between land surface and the lower atmosphere. 

Examples of hydro-meteorological disasters are:

1. Floods
2. Tropical cyclones
3. Drought and
4. Desertification

Geological disasters are also called geophysical disasters that originate from the solid Earth. They are interchangeably used with the term geophysical hazard. Examples of geological hazards are:

1. Earthquakes
2. Mass movements and
3. Volcanic activity

Other types of disasters are:

1. Meteorological disasters are short lived and caused by micro to meso-scale extreme weather and atmospheric conditions that last from minutes to days for example:
1. Extreme temperature
2. Fog
3. Storm
2. Hydrological disasters that are caused by occurrence, movement and distribution of surface and sub-surface freshwater and saltwater.
3. Climatological disasters are caused by long-lived meso to macro-scale atmospheric processes ranging from intra-seasonal to multi-decadal climate variability for example:
1. Drought
2. Glacial lake outburst
3. Wildfires
4. Biological hazards are caused due to exposure to living organisms and their toxic substances (Ex: venom)
5. Extraterrestrial hazards caused by extra-terrestrial objects as they pass near the Earth, strike the Earth and affect the Earth's Ionosphere, magnetosphere and thermosphere. Ex: Meteorites and asteroids. Another example of extraterrestrial hazard is "Magnetic storms" that are caused by solar flares from the sun or Coronal Mass Ejections (CME). This causes disruption of communication and navigation systems, damage to communication satellites, power outages, radiation poisoning in human beings leading to chromosomal damage, cancer and other health problems.

Characteristics of disasters in India

The most common natural disasters occurring in India are:

1. Earthquakes
2. Cyclones
3. Floods and
4. Famine

The characteristics of the above listed natural disasters are discussed  with regard to the following parameters.

1. Predictability
2. Initial lethality
3. Scope and
4. Onset delay

Among the above listed natural disasters, Earthquakes cannot be predicted while cyclones can be predicted with reasonable accuracy. However, cyclones give a very small window of opportunity (time) to people so that they can escape. Floods can be predicted well in advance so that necessary measures for mitigation can be put into place thereby preventing loss to life and property. Famine is a natural disaster that can be predicted accurately with modern computer modelling and simulation techniques.

Owing to the destructive nature of Earthquakes, it is considered to have the highest initial lethality among the natural hazards being discussed. Next comes cyclones followed by floods. Cyclones have a higher destructive potential than floods as they comprise of very fast winds that move in a circular fashion destroying everything coming in their way. A flood is defined as land that is normally dry being inundated due to excessive rains leading to disruption in daily activities. 

Earthquakes affect a relatively small region and hence the scope of damage caused is relatively low. Cyclones occur mainly along coasts. Hence, the scope of the damage caused is greater than Earthquakes. Floods occur over a large area and hence they have a relatively greater scope for damage than cyclones. A famine refers to an extended period of drought. Lack of water for an extended duration causes severe destruction in the community

The term 'on-set delay' refers to the time lag before the occurrence of a disaster. This short time should be used as a window of opportunity to rescue people from the potentially dangerous situation. As Earthquakes occur at any random instant, the on-set delay is low in this case. In case of cyclones, the on-set delay is greater than that mentioned in the case of Earthquake as they can be predicted a few days in advance with the help of satellite images. Floods have greater on-set delay (except in case of FLASH FLOODS) than cyclones as flooding of any area takes place gradually and provides sufficient time for evacuation operations. Famine is a disaster with the greatest 
on-set delay as it develops extremely slowly and provides several indicators well in advance.

Classification, causes and impacts of drought

DROUGHT

Drought is a weather-related natural disaster. It affects vast regions for months or years. It has an impact on food production and it reduces life expectancy and the economic performance of large regions or entire countries.
Drought is a recurrent feature of the climate. It occurs in virtually all climatic zones, and its characteristics vary significantly among regions. Drought differs from aridity in that drought is temporary; aridity is a permanent characteristic of regions with low rainfall.
Drought is a gradual hazard of nature that has a cumulative effect. It is related to a deficiency of precipitation over an extended period of time, usually for a season or more. This deficiency results in a water shortage for some activity, group, or environmental sector. Drought is also related to the timing of precipitation. Other climatic factors such as high temperature, high wind, and low relative humidity are often associated with drought.

Drought may be defined conceptually or operationally.
Conceptually, drought may be defined as a protracted period of deficient precipitation that causes extensive damage to crops, resulting in loss of yield.
Operational definition of drought helps to identify the beginning, end and degree of severity. In this case, the beginning of drought is identified by considering the degree of departure from the precipitation average over a specified time period. Usually, a historical average is considered as a threshold to identify the beginning of the drought. Operational definitions are used to analyze drought frequency, severity, and duration for a given historical period. A climatology of drought for a given region provides a greater understanding of its characteristics and the probability of recurrence at various levels of severity. Information of this type is beneficial in the formulation of mitigation strategies.

Types of drought

1. Meteorological drought: Meteorological drought is defined on the basis of the degree of dryness, in comparison to a normal or average amount, and the duration of the dry period. Definitions of meteorological drought must be region-specific, since the atmospheric conditions that result in deficiencies of precipitation are highly region-specific. Data sets required to assess meteorological drought are daily rainfall information, temperature, humidity, wind velocity and pressure, and evaporation.
2. Agricultural drought: Agricultural drought links various characteristics of meteorological drought to agricultural impacts, focusing on precipitation shortages, differences between actual and potential evapo-transpiration, soil-water deficits, reduced groundwater or reservoir levels, and so on. Plant water demand depends on prevailing weather conditions, biological characteristics of the specific plant, its stage of growth, and the physical and biological properties of the soil. A good definition of agricultural drought should account for the susceptibility of crops during different stages of crop development. Deficient topsoil moisture at planting may hinder germination, leading to low plant populations per hectare and a reduction of yield. Data sets required to assess agricultural drought are soil texture, fertility and soil moisture, crop type and area, crop water requirements, pests and climate.
3. Hydrological drought: Hydrological drought refers to a persistently low discharge and/or volume of water in streams and reservoirs, lasting months or years. Hydrological drought is a natural phenomenon, but it may be exacerbated by human activities. Hydrological droughts are usually related to meteorological droughts, and their recurrence interval varies accordingly. Changes in land use and land degradation can affect the magnitude and frequency of hydrological droughts.Data sets required to assess hydrological drought are surface-water area and volume, surface runoff, streamflow measurements, infiltration, water-table fluctuations, and aquifer parameters.
4. Socioeconomic drought: Socioeconomic definitions of drought associate the supply and demand of some economic good with elements of meteorological, hydrological, and agricultural drought. It differs from the other types of drought in the sense that its occurrence depends on the processes of supply and demand. The supply of many economic goods, such as water, forage, food grains, fish, and hydroelectric power, depends on the weather. Due to the natural variability of climate, water supply is ample in some years, but insufficient to meet human and environmental needs in other years.   Socioeconomic drought occurs when the demand for an economic good exceeds the supply as a result of a weather-related shortfall in water supply.Data sets required to assess socioeconomic drought are human and animal population and growth rate, water and fodder requirements, severity of crop failure, and industry type and water requirements

 Causes of drought

1. Land and water temperatures cause drought. As overall temperatures increase more water evaporates and severe weather conditions increase. Landscapes and crops need more water to survive and overall the demand for water increases.
2. Air circulation and weather patterns also cause drought. Key events like     El-Nino or La-Nina help contribute to drought in areas
3. Soil moisture levels also contribute to drought. When soil moisture is depleted there is less evaporation of water to create clouds. Surface temperatures rise, more water is needed and less is available which contributes to a more severe drought.
4. Drought can also be a supply and demand of water issue. When a region is growing rapidly the demand for water can exceed the supply. When weather conditions, temperatures or air patterns push a region toward a drought the demand for water by people can offset or worsen the situation depending on how the region reacts. Excessive irrigation contributes to a drought. 
5. If the timing of water doesn’t match the agricultural season there may be too much water when it is not needed it and too little when it is actually needed. Proper storage and collection of water is key to counter balancing this cycle and clearly in the scope of human management.

Impact of drought
Drought produces a complex web of impacts that spans many sectors of the economy and extends beyond the area experiencing physical drought. This complexity exists because water is integral to society's ability to produce goods and provide services.
Impacts are commonly referred to as direct and indirect.
Direct impacts include:

1. reduced crop, range land, and forest productivity, 
2. increased fire hazard
3. reduced water levels
4. increased livestock and wildlife mortality rates and 
5. damage to wildlife and fish habitat.

The direct impacts influence:

1. crop productivity
2.  income for farmers and agribusiness
3. prices for food and timber
4. unemployment
5. exemption to farmers who borrowed heavily from banks
6. migration

Types of drought impacts are:

1. Economic impacts: The economic impacts of drought are listed below:

1. Droughts destroy growth of crops resulting in poor yields and poor quality crops. Excessive funds are used to provide sufficient water to crops
2. Death of livestock due to lack of food and water
3. Reduced timber production due to wild fires, low productivity of forest land and  and loss of young trees.
4. Loss of fishery production due to damaged fish habitat due to drought.
5. Loss of recreation and tourism
6. Loss to industries manufacturing farm equipment.
7. Loss to hydroelectric power generating companies
8. Loss of revenue to water supply companies
9. Loss to inland river navigation based transport companies
10. Increased cost due to import of food.

      2. Environmental impacts: The environmental impacts of drought are listed below:

1. Environmental impact includes forest fires, soil erosion, damage to life forms and their habitat coupled with decline in air and water quality.
2. Wildlife may migrate to other areas.
3. Increased stress to endangered species
4. Decrease in water level in reservoirs, ponds, lakes and loss of wetlands
5. Dry top soil becomes prone to erosion by wind leading to reduced soil quality and low biological productivity of landscape.
6. Loss of biodiversity and extinction of species

      3.Social impacts: The social impacts of drought are listed below:

1. Disputes due to water shortage and lifestyle changes
2. Revenue loss due to drought causes physical, mental stresses that contribute to loss of human lives due to suicidal tendencies
3. Reduction in recreational activities
4. Mass migration of communities
5. Reduced fire fighting ability
6. Sustenance on basic food leading to malnutrition and high infant mortality rate
7. Steeply declining quality of life in the affected community

Differential impacts of disasters

DIFFERENTIAL IMPACTS OF DISASTERS

The phrase, 'differential impacts of disasters' is discussed below:

• Susceptibility to disasters is governed by the following factors:

1. If the population of the community consists of primarily young people, the impact would be low. Young people are generally healthy, active and can respond well to any event with negative consequences. 
2. Children, the elderly and women in the community are extremely susceptible and require assistance to handle any negative situation.
3. At times, religion also plays a significant role on the impact of a disaster.
4. Education plays a major role during disasters and the educated prove to be an extremely valuable resource as they respond to any emergency with the knowledge previously gained. Differential impacts of disasters are clearly seen in this case.
5. Economic standing of people plays a clear role in case of disasters. While the affluent can effectively respond to a disaster on their own, the economically weaker sections depend on the government for their evacuation, resettlement and rehabilitation.
6. Disasters and poverty are inextricably linked. The poor are the worst affected during any disaster.

Change in demographic patterns combined with mounting disaster losses have brought a focus on the manner in which changing demographic patterns shape vulnerability and resiliency of social systems.

Global trends in disasters

GLOBAL TRENDS IN DISASTERS

Data and statistics are important in understanding the impacts and costs of disasters. Systematic disaster data collection and analysis can be used to inform policy decisions to help reduce disaster risks and build resilience. The term, "Global Trends" refers to a change in the situation that affects many countries of the world. Generally, the world has been witness to an increasing in the number of disasters as listed below-

1. According to statistics from United Nations International Strategy for Disaster Reduction (UNISDR), the number of disasters has increased significantly in recent years. This has been possible due to accurate recordings and better communication technology.
2. Population growth has led to more people living in potentially hazardous locations.
3. Countries in the developing world are more vulnerable because of their low coping capacity.
4. The number of Earthquake events has not increased in the past decades and is fairly stable.
5. An increase in number of floods and wind storms has is seen. This may be due to global environmental changes or climate change.
6. Around fifty to seventy volcanoes erupt every year. Eruptions of a very large magnitude are rare. The trend also shows an increase in the number of people affected indicating the growing population density in the developing world.
7. An increase in the hurricane activity in the Atlantic has been linked to global warming.
8. It has also been proposed that a natural cycle in the Atlantic called Atlantic Multi-decadal Oscillation (AMO) to explain the high number of major hurricanes.
9. The USA has a long term trend of falling hurricane related deaths and increasing economic costs
10. People living along the coast are at risk from hurricanes.
11. Increasing coastal populations causes increased risk from hurricanes
12. Scientists believe that increased global warming will lead to more unpredictable weather and an increase in weather events.
13. Hazards associated with El-Nino are well known such as drought in Indonesia and flood in Peru
14. Summer of 2007 witnessed wide spread flooding in the UK. This was linked to La Nina conditions in the pacific.

However, with respect to specific disasters, the global trend observed is discussed below

Urban disasters

The term 'urban disaster' is misleading. It could refer to a natural disaster like flood or earthquake occurring in an urban area or man-made disaster like overpopulation in an urban area or an industrial accident like an explosion or chemical leakage seiously affecting an urban area. Whichever the case, the impact is loss of economy, loss of jobs and destruction of natural resources. There has been a steady increase in the number of urban disasters leading to destruction of infrastructure. Unplanned and unscientific methods of mining and construction has led to sporadic but steady increase in number of Earthquakes, landslides and land subsidence incidents throughout the world. Overpopulation has led to conflicts and wars between countries over natural resources. Global environmental issues like global warming and sea level rise are primarily affecting urban areas resulting in them being termed as urban disasters. Spread of urban areas causing 'urban sprawl' and 'heat island effect' are primarily environmental issues of concern and if these issues are not addresses in time before they will actually become 'urban disasters'. Hence the global trend concerning urban disasters is steadily increasing.

Pandemics 
 A pandemic is defined as a sudden outbreak that very widespread and affects a whole region, a continent, or world due to a susceptible population. A pandemic causes a high degree of mortality. Ex- small pox and tubeculosis. A pandemic is basically a global epidmeic. It is an epidemic that spreads to more than one continent. A pandemic is a global disease outbreak. HIV/AIDS is an example of one of the most destructive global pandemics in history. Influenza pandemics occurred in-
-Spanish influenza (1918) killed 40 - 50 million people
-Asian influenza (1957) killed 2 million people
-Hongkong influenza (1968) killed 1 million people
Evidence suggests that the possibility of pansemics has increased over the past century because of increased global travel and integration, urbanization, changes in land use and greater exploitation of the natural environment. It is predicted that these trends will continue and intensify in future. A few pandemics in the recent past were malaria, HIV/AIDS, Tuberculosis, SARS in 2003, Ebola virus in 2013 and avian flu pandemics has seen sporadic outbursts in the past. Pandemics appear to be increasing in frequency because of increasing emergence of viral disease from animals. Some geographic regions with a high risk of origin  of a pandemic (sprak risk) lack in preparedness to handle the disease. Influenza is the most likely pathogen to cause a severe pandemic.

Global emergencies 
The term 'complex emergency' has no clear definition. It is often the result of a combination of political instability, conflict, social inequity, underlying poverty and violence. Complex emergencies are essentially political in nature and erode cultural, civil, political and economic stabilities of society. They can be worsened by natural hazards. Cities in the developing world exhibit the characteristics of complex emergencies. Complex emergencies have been defined as crises resulting from a combination of instabilities interacting with each other. Complex emergencies combine internal conflict with large scale displacement of people, mass famine and food shortage and fragile or failing economic, political and social institutions. Complex emergencies display four main types of instability-

1. Political instability
2. Economic instability
3. Environmental instability and
4. Demographic instability

Complex emergencies are present virtually in every part of the world. However, they are prevelant in areas without proper governance, poverty, lack of education in the community, unhygenic living conditions, etc.
Armed conflicts have been a major cause of disruption in the last decade. There has been an increase in the number of political conflicts has increased from 2006 to 2016 as per statistics published by United Nations Office for the Coordination of Human Affairs (UNOCHA).

Climate change 
Climate change refers to a change in the global or regional climate patterns.
A direct relationship exists between climate and health. Climate change will be responsible for almost 250,000 additional deaths due to malnutrition, malaria, diarrhea and heat stress. Climate change has also contributed to increased frequency of natural disasters. The current warming trend is of the human activity since the mid 20th century. The increased levels of green house gases has caused the Earth to warm up in response. The current warming is occurring around ten times faster than the rate of ice-age-recovery warming. Rapid climate change is evident through
-Global temperature rise
-Warming oceans
-Shrinking ice sheets
-Glacial retreat
-Decreased snow cover
-Sea level rise
-Declining arctic sea ice
-Extreme events and
-Ocean acidification
Trends show an increase in warming of the world's climate. This temperature will not be uniform across the globe over time. This implies a shorter and milder winter followed by longer and hotter summers. This adversely affects agriculture and ecosystems. Climate change also results in an increase in frequncy and duration in rainfall. Increasing frequency and intensity of heat waves result in drought. Climate change also causes frequent intense storms (cyclone).

Cyclones and floods

CYCLONES AND FLOODS

CYCLONE:

1. A cyclone begins when air heated by the sun rises very swiftly which creates areas of very low pressure.
2. As the warm air rises, it becomes loaded with moisture and condenses into clouds.
3. Cool air moves in quickly to fill the void but because of the constant rotation of the Earth, the air is bent inwards and then spirals upwards with great force.
4. At the center of the storm is a calm, cloudless area called the 'eye' where there is no rain and winds are light.
5. The cyclone is sustained by a steady flow of moist air.
6. Winds around the 'eye' reach speeds upto 200 kmph and a fully developed cyclone pumps two million tonnes of air per second.
7. Formation of a cyclone depends on conditions mostly found in the tropical convergence zone (ocean surface temperature > 26C, humid unstable atmosphere. 

Causes of floods

FLOODS

 

Among all the disasters that occur in India, floods are the most commonly occurring natural disasters due to the irregularities of the Indian monsoon. About 75% of the annual rainfall in India is concentrated in 3-4 months of the monsoon season. As a result there is very heavy discharge from rivers during the period causing widespread floods.

Flood is a state of higher water level along a river channel or on coast leading to inundation of land that is not normally submerge. Flood therefore is a natural disaster which causes considerable damage to the crops, livestock and human life.

The major floods are mainly caused in the Ganges-Brahmaputra-Meghna basin which carries 60% of the total river flow of the country. According to National Flood Commission about 40 million hectares of land area is prone to flood in the country. On an average, the area affected by floods annually is about 8 million hectare, out of which the cropped area affected is about 3.7 million hectare.

Floods are caused by natural, ecological or anthropogenic factors either individually or as a combined result. The various causes of floods in India are as follows:

• Heavy precipitation: Rainfall of about 15 cm or more in single day may be beyond the carrying capacity of the river and this causes the spilling of river over natural banks. Areas affected include west coast of Western Ghats, Assam and sub-Himalayan West Bengal and Indo-Gangetic plains

• Rise in river bed: Due to large gradients the Himalayan rivers carry a large amount of silt and sand which are ultimately deposited in the catchment area, and on the river bed. Siltation reduces the carrying capacity of river.

• Meandering tendency of river-flow: In the flat terrain rivers have the tendency to meander or change the course within a specific boundary. Lower reaches of Gangetic plains and Brahmaputra.
   
• Cyclones: Tropical cyclones accompanied by strong winds, high tidal bores causing inundation of coastal regions. Floods due to cyclone are common in the East coast of Tamil Nadu, Andhra Pradesh, Odisha and West Bengal.
   
• Silting in Delta areas: Sea tides deposit silt on the river-mouths and discharge channels leading to steady deterioration of their discharge capacity.
   
• Obstruction of free-flow of rivers: Embankments, railways, canals etc. obstruct the free flow of rivers leading to flood.
   
• Inadequate drainage arrangement: After introduction of irrigation in some areas, the sub-soil water table rises fast unless adequate arrangement are simultaneously made for both surface and sub-surface drainage. Punjab, Haryana and Uttar Pradesh.
   
• Earthquake and Landslide: These natural disaster change the river course and consequently cause flood.
   
• Deforestation: Deforestation causes the acceleration of runoff and lowering of infiltration. Deforestation of hill slopes leads to greater run-off which raises the water level in rivers. Western Ghats, Siwaliks and Chotanagpur plateau region.
   
• Cloud burst: Cloud bursts leads to high amount of rainfall within a short time leading to flash floods. Flash flood generally occurs in Himalayan region.
  
  
  A sudden violent flood caused by exceptionally heavy rain in a normally dry valley in a semi-arid area, the torrential stream sometimes being laden with debris. Flash floods are often caused by:
  
  
  1. Cloud burst / heavy downpour in the mountain areas 
  2. Rapid melting of snow and ice in mountain areas. 
  3. Glacial lake outburst in the high Himalayas and 
  4.  Failure of landslide / debris flow dams in high and rugged mountain areas.
   

The flood prone regions of India are listed below:

• The basin of the Himalayan rivers covering a part of Punjab, Haryana, Himachal Pradesh, Delhi, Rajasthan, Uttar Pradesh, Bihar and West Bengal. The Kosi and the Damodar are the main rivers causing floods.
• The North-Western river basin covering the states of Jammu and Kashmir, parts of Punjab, Haryana, Western Uttar Pradesh and Himachal Pradesh. The Jhelum, the Sutluj, the Beas the Ravi and the Chenab are the rivers causing floods in this region. 
• The Central and Peninsular river basins covering Madhya Pradesh, Odisha, Andhra Pradesh and Maharashtra, contain the Narmada the Tapi, the Chambal and the Mahanadi. Heavy floods occur in the Godavari, the Krishna the Pennar and the Cauvery at long intervals and flood problem is generally serious.

Road disasters in India

Definition of traffic accident
A traffic accident, motor vehicle collision, motor vehicle accident, car accident, automobile accident, road traffic collision, road traffic accident, occurs when a vehicle collides with another vehicle,
pedestrian, animal, road debris, or other stationary obstruction, such as a tree or utility pole. Traffic collisions may result in injury, death, vehicle damage, and property damage.

Causes
A number of factors contribute to a traffic accident. For example:

1. vehicle design, 
2. speed of operation, 
3. road design, 
4. road environment,
5. driver skill and/or impairment, and 
6. driver behaviour.

Types of traffic accidents
Traffic collisions can be classified by type of collision. For example,

1. head-on, 
2. road departure, 
3. rear-end, 
4. side collisions, and
5. rollovers.

The main elements of good driving are:

1. controlling a car including a good awareness of the car's size and capabilities
2. reading and reacting to road conditions, weather, road signs and the environment and
3. alertness, reading and anticipating the behavior of other drivers.

In order to minimise accidents, several measures have been taken-up including:

1. law enforcement policies (drink-driving laws, setting of speed limits, and speed enforcement systems such as speed cameras & use of seat belts)

Effects
Impacts due to traffic accidents:

1. Loss of life or injury or life-long disability
2. Loss of property
3. Psychological stress (PTSD)
4. Increased insurance costs
5. Associated social discrimination