Drought

 Drought

• Drought is a prolonged dry period in the natural climate cycle that can occur anywhere in the world. 
• It is a slow-onset disaster characterized by the lack of precipitation, resulting in a water shortage. 
• Drought can have a serious impact on health, agriculture, economies, energy and the environment.
• Rising temperatures caused by climate change are making already dry regions drier and wet regions wetter. 
• In dry regions, this means that when temperatures rise, water evaporates more quickly, and thus increases the risk of drought or prolongs periods of drought.
• Drought is termed as any lack of water to satisfy the normal needs of agriculture, livestock, industry or human population. It is shaded in red/yellow on the given maps.
• The main types of drought are as follows:
1. Meteorological Drought: Reduction in rainfall for a specific period below a specific amount
2. Hydrological Drought: Drying up of water sources – both surface and groundwater (together or individually)
3. Soil Moisture Drought: Unavailability of adequate moisture to support the standing crop.
4. Ecological Drought: Productivity of a natural ecosystem falls significantly as a consequence of distress induced environmental damage.
• In India, since 60% of the agriculture is still rainfed, meteorological drought is an important cause of drought conditions. Thus, any deficit in monsoon rains is felt to a large extent especially in areas that have large rain variability – leeward side of Western Ghats (Marathwada and Vidarbha) and North-west extremities of the country.

Heat wave and cold wave

Heat wave

Heat wave is a prolonged period of extremely high temperatures that typically lasts for several days to weeks and can have significant impacts on human health, the environment, and the economy. Heat waves are often associated with stagnant air masses and high humidity, which can exacerbate the impacts of high temperatures.

Effects of Heat Wave:

Heat-related illnesses: Heat waves can lead to a range of heat-related illnesses, including heat exhaustion, heatstroke, and dehydration.

Poor air quality: High temperatures can increase the formation of ground-level ozone and other air pollutants, which can have significant impacts on respiratory health.

Crop failure and water shortages: Heat waves can lead to crop failure, water shortages, and other impacts on agricultural productivity and food security.

Power outages and infrastructure failure: High demand for electricity during heat waves can lead to power outages and infrastructure failure.

Control Measures:

Affected individuals should drink plenty of water and avoid alcohol and caffeine, which can dehydrate the body.

Affected individuals should spend time in air-conditioned buildings or use fans and other cooling devices to lower body temperature.

Populations should avoid outdoor activities during peak hours and limit outdoor activities during the hottest parts of the day and schedule activities for early morning or evening when temperatures are cooler.

It is recommended to wear lightweight, light-colored, loose-fitting clothing to stay cool and protect skin from the sun.

Regular and frequent monitoring of the elderly, sick, or other vulnerable populations who may be at greater risk during heat waves.

It is generally recommended to reduce energy use during peak hours by turning off non-essential appliances and using energy-efficient cooling devices.

It is advisable to invest in infrastructure and community resilience to prevent and mitigate the impacts of heat waves, such as green roofs, heat-resistant building materials, and early warning systems.

Effective management of heat waves requires a coordinated response across multiple sectors, including public health, emergency management, and infrastructure planning and management.

Cold wave

A cold wave is a prolonged period of extremely cold temperatures, often accompanied by strong winds and/or precipitation, that can have significant impacts on human health, the environment, and the economy. Cold waves can be caused by a variety of factors, including changes in weather patterns and atmospheric conditions.

Effects of Cold Wave:

Hypothermia and frostbite: Cold waves can lead to hypothermia and frostbite, which can cause permanent damage to the body and even be life-threatening.

Poor air quality: Cold waves can lead to the formation of air pollutants, including particulate matter and carbon monoxide, which can have significant impacts on respiratory health.

Infrastructure failure: Cold waves can cause infrastructure failure, including power outages and water supply disruptions.

Reduced agricultural productivity: Cold waves can reduce agricultural productivity and increase the risk of crop failure, leading to food shortages and increased food prices.

Control Measures:

Dress warmly: Wear warm, layered clothing to protect the body from the cold and wind.

Stay indoors: Limit outdoor activities during the coldest parts of the day and spend time indoors in heated buildings.

Keep home warm: Maintain indoor temperatures at or above 18°C (65°F) and ensure that homes are properly insulated to conserve heat.

Use safe heating devices: Use safe heating devices, such as electric heaters or wood stoves, and follow manufacturer's instructions to prevent carbon monoxide poisoning and other hazards.

Check on vulnerable populations: Check on elderly, sick, or other vulnerable populations who may be at greater risk during cold waves.

Reduce energy use: Reduce energy use by turning off non-essential appliances and using energy-efficient heating devices.

Build resilience: Invest in infrastructure and community resilience to prevent and mitigate the impacts of cold waves, such as emergency heating centers and early warning systems.

Effective management of cold waves requires a coordinated response across multiple sectors, including public health, emergency management, and infrastructure planning and management.

Biological disasters

Biological disasters

Biological disasters refer to catastrophic events caused by infectious diseases or biological agents that pose a significant threat to human health and the environment. Some examples of biological disasters include:

COVID-19 pandemic: A global pandemic caused by the SARS-CoV-2 virus, which emerged in 2019 and has caused millions of deaths and significant economic and social disruption.

Ebola outbreak: An outbreak of Ebola virus in West Africa in 2014-2016 that caused over 11,000 deaths and had significant impacts on public health and the economy.

Anthrax attacks: In 2001, a series of attacks using anthrax spores sent through the mail in the United States resulted in several deaths and widespread fear.

Bovine spongiform encephalopathy (BSE) or mad cow disease: A prion disease that affects cows and can be transmitted to humans, causing variant Creutzfeldt-Jakob disease, which has significant impacts on human health.

Avian influenza (bird flu): An infectious disease caused by the H5N1 virus that can infect birds and humans, with significant impacts on public health and the economy.

Foot-and-mouth disease (FMD): A highly contagious viral disease that affects livestock and can cause significant economic impacts in the agricultural sector.

Malaria outbreak: A mosquito-borne infectious disease that affects millions of people worldwide, particularly in developing countries with limited access to healthcare.

Biological disasters can have significant impacts on public health, the economy, and the environment, and can be challenging to prevent and control. Effective prevention and management of biological disasters require early detection and rapid response, effective risk communication, investment in research and development, and building resilience in health systems and communities.

Technological disasters

Technological disasters

Technological disasters refer to catastrophic events that are caused by failures or accidents in technology-related systems, such as industrial facilities, transportation networks, energy infrastructure, and communication systems. Some examples of technological disasters include:

Chernobyl nuclear disaster: In 1986, a reactor at the Chernobyl nuclear power plant in Ukraine exploded, releasing radioactive material into the environment and causing significant health and environmental impacts.

Deepwater Horizon oil spill: In 2010, an explosion on the Deepwater Horizon oil rig in the Gulf of Mexico caused a massive oil spill that lasted for months, damaging marine ecosystems and coastal communities.

Fukushima nuclear disaster: In 2011, an earthquake and tsunami in Japan caused a meltdown at the Fukushima Daiichi nuclear power plant, resulting in the release of radioactive materials and long-term environmental and health impacts.

Bhopal gas tragedy: In 1984, a gas leak at a pesticide plant in Bhopal, India, released toxic gas into the surrounding community, resulting in thousands of deaths and long-term health impacts.

Space shuttle disasters: In 1986 and 2003, two separate disasters involving the space shuttle program resulted in the deaths of all crew members and significant impacts on the space program.

Flint water crisis: In 2014, the city of Flint, Michigan, switched its water supply to a contaminated source, resulting in a public health crisis and long-term impacts on the community.

The Three Mile Island nuclear accident: In 1979, a partial meltdown of a nuclear reactor at the Three Mile Island power plant in Pennsylvania resulted in a significant release of radioactive material and long-term environmental and health impacts.

Technological disasters can have significant impacts on human health, the environment, and the economy, and can take years or decades to recover from. Preventing technological disasters requires effective risk assessment and management, regulation and oversight, and investment in technology and infrastructure that is resilient and designed to prevent failures and accidents.

Global disaster trends

Global disaster trends

Changing risks are becoming increasingly important due to various factors, such as rapid urbanization, globalization, climate change, and technological advancements. Some examples of emerging risks of disasters include:

1. Cybersecurity threats: As more critical infrastructure and services become digitized, there is an increasing risk of cyber-attacks that can disrupt essential services and cause significant economic and social damage.

2. Pandemics: The emergence and rapid spread of infectious diseases, such as the COVID-19 pandemic, can cause widespread illness, death, and economic disruption.

3. Urbanization: As more people move to urban areas, there is an increased risk of disasters related to population density, such as heatwaves, urban flooding, and building collapses.

4. Climate change: Rising global temperatures, sea level rise, and extreme weather events are increasing the frequency and intensity of disasters, such as hurricanes, wildfires, and droughts.

5. Social and political instability: Political conflicts, social unrest, and economic crises can exacerbate the impacts of disasters, particularly in vulnerable and marginalized communities.

6. Technological hazards: The increasing use of hazardous materials and technologies, such as nuclear power and genetically modified organisms, can pose significant risks to human health and the environment in the event of a disaster.

7. Financial risks: The increasing interconnectedness of global financial systems can amplify the economic impacts of disasters and create systemic risks to the global economy.

Addressing emerging risks of disasters requires a proactive and multidisciplinary approach that involves stakeholders from various sectors and levels of society. This includes developing risk assessments and early warning systems, investing in disaster preparedness and response, promoting sustainable development and resilience-building measures, and addressing the root causes of vulnerability and risk.

Emerging risks of disasters

 Emerging risks of disasters

Emerging risks of disasters refer to new or changing risks that are becoming increasingly important due to various factors, such as rapid urbanization, globalization, climate change, and technological advancements. Some examples of emerging risks of disasters include:

Cybersecurity threats: As more critical infrastructure and services become digitized, there is an increasing risk of cyber-attacks that can disrupt essential services and cause significant economic and social damage.

Pandemics: The emergence and rapid spread of infectious diseases, such as the COVID-19 pandemic, can cause widespread illness, death, and economic disruption.

Urbanization: As more people move to urban areas, there is an increased risk of disasters related to population density, such as heatwaves, urban flooding, and building collapses.

Climate change: Rising global temperatures, sea level rise, and extreme weather events are increasing the frequency and intensity of disasters, such as hurricanes, wildfires, and droughts.

Social and political instability: Political conflicts, social unrest, and economic crises can exacerbate the impacts of disasters, particularly in vulnerable and marginalized communities.

Technological hazards: The increasing use of hazardous materials and technologies, such as nuclear power and genetically modified organisms, can pose significant risks to human health and the environment in the event of a disaster.

Financial risks: The increasing interconnectedness of global financial systems can amplify the economic impacts of disasters and create systemic risks to the global economy.

Addressing emerging risks of disasters requires a proactive and multidisciplinary approach that involves stakeholders from various sectors and levels of society. This includes developing risk assessments and early warning systems, investing in disaster preparedness and response, promoting sustainable development and resilience-building measures, and addressing the root causes of vulnerability and risk.

Climate change and urban disasters

CLIMATE CHANGE

Climate change refers to a long-term shift in the Earth's climate system, including changes in temperature, precipitation patterns, and extreme weather events, that are primarily driven by human activity, particularly the emission of greenhouse gases into the atmosphere.

The Earth's climate has always undergone natural variations over time, but the current changes are occurring at an unprecedented rate and are largely attributed to the increase in atmospheric concentrations of carbon dioxide and other greenhouse gases due to the burning of fossil fuels, deforestation, and other human activities.

The effects of climate change are far-reaching and include rising sea levels, more frequent and severe heat waves, droughts, floods, and storms, as well as changes in ecosystem dynamics and the distribution of plant and animal species. These impacts have significant consequences for human societies and economies, affecting food and water security, human health, infrastructure, and energy systems, among other areas.

Mitigating and adapting to the impacts of climate change require a collective effort by individuals, communities, governments, and businesses, including reducing greenhouse gas emissions, transitioning to cleaner and more sustainable energy systems, protecting and restoring ecosystems, and developing adaptive strategies to reduce vulnerability to climate impacts.

URBAN DISASTER

An urban disaster is an unexpected event or series of events that disrupts the normal functioning of a city or urban area, resulting in significant human, material, economic, or environmental losses. Urban disasters can be caused by a variety of factors, including natural hazards such as earthquakes, floods, hurricanes, and wildfires, as well as human-made hazards such as terrorist attacks, industrial accidents, and civil unrest.

Urban disasters can have a significant impact on the people living in affected areas, as well as on the infrastructure, institutions, and systems that support the functioning of cities. In addition to causing physical damage and loss of life, urban disasters can also result in social and economic disruption, displacement of populations, and long-term effects on public health, the environment, and the economy.

Effective disaster management and preparedness strategies can help mitigate the impact of urban disasters by improving risk reduction, emergency response, and post-disaster recovery and reconstruction efforts. These strategies involve a wide range of stakeholders, including government agencies, non-governmental organizations, communities, and individuals, and require a multidisciplinary approach that integrates social, economic, environmental, and technological factors.

Man-made disasters

TSUNAMI

TSUNAMI

The term ‘Tsunami’ has been coined from the Japanese term Tsu meaning ‘harbour’ and nami meaning ‘waves’. Tsunamis are waves generated by earthquakes, volcanic eruptions, or underwater landslides and can reach 15m or more in height devastating coastal communities. Tsunamis caused by nearby earthquakes may reach the coast within minutes. When the waves enter shallow water, they may rise to several feet or, in rare cases, tens of feet, striking the coast with devastating force. The Tsunami danger period can continue for many hours after a major earthquake.

 

Tsunamis are nearly always created by movement of the sea floor associated with earthquakes which occur beneath the sea floor or near the ocean. Tsunamis may also be generated by very large earthquakes far away in other areas of the Ocean. Waves caused by these travel at hundreds of kilometers per hour, reaching the coast several hours after the earthquake. Unlike ordinary tides, which are short, frequent and surface level, tsunami, are barely noticeable in their deep-sea formation stage. At this point despite a wavelength up to 100 km, they are shallow in depth and move at hundreds of
 Kilometer per hour.

Tsunamis can be very large. In coastal areas their height can be as great as 10m or more (30m in extreme cases), and they can move inland several hundred meters.All low-lying coastal areas can be struck by tsunamis.

A tsunami consists of a series of waves. Often the first wave may not be the largest. The danger from subsequent tsunami waves can last for several hours after the arrival of the first wave.

Sometimes a tsunami causes the water near the shore to recede, exposing the ocean floor. This is nature’s Tsunami warning.

The force of some tsunamis is enormous. Large rocks weighing several tons along with boats and other debris can be moved inland several meters by tsunami wave activity. Homes and other buildings are destroyed. All floating material and water move with great force and causing mortality or injuries to people.

Tsunamis can occur at any time of day or night.

Tsunamis can travel up rivers and streams that lead to the ocean thereby polluting them.

Tsunamis may also be generated by very large earthquakes far away in other areas of the Ocean. Waves caused by these travel at hundreds of kilometers per hour, reaching the coast several hours after the earthquake. Unlike ordinary tides, which are short, frequent and surface level, tsunami, are barely noticeable in their deep-sea formation stage. At this point despite a wavelength up to 100 km, they are shallow in depth and move at hundreds of kilometer per hour.

landslides

LANDSIDES

Landslides
Landslides are among the major natural disasters or calamities in the world. In hilly terrains of India, including Himalayan mountains landslides have been a major and widely spread natural disasters that strike life and property almost perennially and occupy a position of major concern. These landslides, year after year, bring about untold misery to human settlements apart from causing devastating damages to transportation and communication network. Landslides, debris fall, debris slide, debris flow, rock toppling etc. cause destruction of slope and ground surface, initiating the change of uncontrolled erosion in the mountain terrains.

FACTORS THAT CAUSE LANDSLIDES
Landslides occur because of the interplay of several factors.
Natural factors
★ Intensity of rainfall
★ Steep slopes
★ Stiffness of slopes
★ Highly weathered rock layers
★ Soil layers formed under gravity
★ Seismic activity
★ Poor drainage
Man made factors
★ Deforestation leading to soil erosion
★ Non-engineered excavation
★ Mining and quarrying
★ Non-engineered construction
★ Land use pattern

Vulnerable houses are those which are situated on:

• Existing landslides area.
• Steep natural slopes.
• Areas in or at the mouths of drainages (such as canyons).
• Houses constructed near foothills.

PROTECTION MEASURES FROM DAMAGE TO BUILDINGS
Site Selection
Landslides generally happen where they have occurred in the past, and in identifiable hazard locations. Areas that are typically considered safe from landslides include areas that have not moved in the past; relatively flat areas away from sudden changes in slope; and areas at the top of or along ridges. Houses built at the toe of steep slopes are often vulnerable to slides and debris flows.
Signs and Warnings
A house located on a hill can detect possible slope failure by watching for these signs:
Doors or windows stick or jam for the first time.
New Cracks appear on plaster, tile, brick or foundations.
Outside walls, walks or stairs begin pulling away from the building.
Slowly developing, widening cracks appear on the ground or on paved areas such as streets or driveways.
Underground utility lines break.
Fences, retaining walls, utility poles or trees tilt or move.
Water or bulging ground appears at the base of a slope.

The potential for landslides and destructive erosion can be greatly reduced or prevented with proper development, sound construction techniques, seasonal inspections and regular maintenance of drainage facilities.

Earthquake

 EARTHQUAKE

"An earthquake is a sudden motion or trembling of the ground produced by the abrupt displacement of rock masses".

• Most earthquakes result from the movement of one rock mass past another in response to tectonic forces.
• The focus is the point where the earthquake's motion starts.
• The epicenter is the point on the earth's surface that is directly above the focus.
• Earthquake Magnitude is a measure of the strength of an earthquake as calculated from records of the event made on a calibrated seismograph.
• In 1935, Charles Richter first defined local magnitude, and the Richter scale is commonly used today to describe an earthquake's magnitude.
• Earthquake Intensity.  is a measure of the effects of an earthquake at a particular place. It is determined from observations of the earthquake's effects on people, structures and the earth's surface.
• Among the many existing scales, the Modified Mercalli Intensity Scale of 12 degrees, symbolized as MM, is frequently used
  

Earthquake Hazards
Earthquake hazards can be categorized as either direct hazards or indirect hazards.
Direct Hazards

• Ground shaking
• Differential ground settlement
• Soil liquefaction
• Immediate landslides or mud slides, ground lurching and avalanches
• Permanent ground displacement along faults
• Floods from tidal waves, Sea Surges & Tsunamis
  

Indirect Hazards

• Dam failures
• Pollution from damage to industrial plants
• Delayed landslides.

Most of the damage due to earthquakes is the result of strong ground shaking. For large magnitude events, trembling has been felt over more than 5 million sq. km.

Site Risks
Some common site risks are:

• Slope Risks - Slope instability, triggered by strong shaking may cause landslides. Rocks or boulders can roll considerable distances.
• Natural Dams - Landslides in irregular topographic areas may create natural dams which may collapse when they are filled. This can lead to potentially catastrophic avalanches after strong seismic shaking.
• Volcanic Activity - Earthquakes may be associated with potential volcanic activity and may occasionally be considered as precursory phenomena.
• Explosive eruptions are normally followed by ash falls and/or pyroclastic flows, volcanic lava or mud flows, and volcanic gases.