Environmental concerns and natural disasters
Environmental problems come from natural disasters and human activity. Floods, cyclones, earthquakes, tsunamis, forest fires, landslides and cloudbursts cannot always be stopped, but early warning and planning save lives.
Why we should be concerned
Human development has degraded and polluted the environment. A large population, fast-changing technology and lack of respect for nature have added to problems such as pollution and the using up of natural resources. Environmental problems are of two kinds: natural (disasters) and human-made. A disaster causes large-scale damage to life and property, felt locally or across the world. Nature can recover from many natural events, but every citizen needs to understand these problems to help protect the environment.
Natural disasters: causes and management
| Disaster | Main causes | Management and safety |
|---|---|---|
| Flood | Heavy monsoon rain brings more water than river banks can hold; poor drainage; people blocking the natural flow of rivers | No building in river beds; desilt drains and reservoirs; build schools, offices and homes above past flood levels; flood-proof buildings; a known evacuation centre; drink boiled water and eat cooked food to stop epidemics (fast-spreading diseases) |
| Cyclone | Intense low-pressure storms over the Bay of Bengal and the Arabian Sea; seasons April to May and October to December; the coasts of West Bengal, Odisha, Andhra Pradesh and Tamil Nadu suffer most | Cyclone-safe buildings; remove decaying trees and unsafe structures; store food, drinking water, a lantern, torch and matches; go to a shelter, stay calm, ignore rumours; get vaccinated afterwards |
| Earthquake | Sudden shaking of the ground when rocks give way to forces inside the Earth | Earthquake-resistant buildings, roads, dams and bridges; safety steps below |
| Tsunami | Earthquakes under the ocean, and sometimes undersea landslides or volcanic eruptions, push huge amounts of water | Early warning from the tsunami warning centre at INCOIS, Hyderabad; tree cover along the shore reduces the impact |
| Forest fire | Lightning striking dry trees; heat building up in dry litter in summer; human carelessness with matchsticks, bidis or cigarettes | Clear dry litter in summer; call the fire brigade; spray water or dig a trench around the fire; move animals to safety; never enter a burning forest |
| Landslide | Rock, earth or debris sliding down an unstable slope; mostly set off by heavy or long rain; made worse by deforestation, dynamite blasting and construction on slopes | Keep tree cover on slopes, whose roots hold the soil; avoid blasting and careless cutting of slopes; early warning |
| Cloudburst | An extreme burst of rain in a few minutes, sometimes with hail and thunder | Causes flash floods and landslides; cannot be prevented, so rely on early warning and a ready home plan |
What to do in an earthquake
- 1★Stay indoors until the shaking stops. Get under a strong table or bed, or shield your head with your arms or a pillow.
- 2Keep away from glass, windows, outside walls and anything that can fall, such as lights, mirrors and cupboards.
- 3In a tall building, do not change floors. Avoid the lift, and do not rush to the stairs.Power may fail and trap you in a lift.
- 4If driving, stop away from buildings, walls, slopes, trees and electric poles, and move into the open.
- 5Afterwards, be ready for aftershocks; keep away from beaches and low river banks; listen to radio or TV; give first aid; tell rescue teams if people are trapped.
★ key step
Richter scale and damage (as given in your NIOS lesson)
| Reading on the Richter scale | Likely damage |
|---|---|
| Up to 3 | No damage; most such earthquakes pass unnoticed |
| 5 | Old buildings develop cracks |
| 7 | Roads crack |
| Above 8 | Buildings collapse |
Disasters India remembers
The Odisha super cyclone of October 1999 brought very strong winds, rain for three days and sea water far inland. The Indian Ocean tsunami of 26 December 2004 was set off by an earthquake near Sumatra in Indonesia. It struck Tamil Nadu, Puducherry, Andhra Pradesh, Kerala and the Andaman and Nicobar Islands. After it, India set up its tsunami early warning centre. Earthquakes have hit Latur in Maharashtra (30 September 1993) and Bhuj in Gujarat (26 January 2001; your NIOS lesson prints 2002), and a cloudburst caused flash floods in Leh in August 2010. In March 2011 an earthquake and tsunami in Japan damaged the Fukushima nuclear plant. In most earthquakes, people are hurt by falling buildings and debris, not by the ground movement itself.
Activity: a newspaper report on a natural disaster
- 1Collect news reports and pictures of any natural disaster from old newspapers or magazines.
- 2Note what happened, where and when, and its causes.
- 3List the damage to people, animals, homes, crops and roads.
- 4Note how human actions made it worse, such as cutting trees on slopes or building on river beds.
- 5★Write a report of about 70 words, ending with how people could reduce the damage next time.
★ key step
Before a cyclone reaches the coast of Odisha or Andhra Pradesh, warnings on radio, TV and mobile phones help families move to cyclone shelters in time. A torch, dry food, drinking water and medicines kept ready make a simple home plan.
2 marks: “A news report says an earthquake measured 6.9 on the Richter scale. What does this number tell us, and which instrument recorded the shaking?” It gives the size (magnitude) of the earthquake, that is, how much energy was released. A seismograph recorded it.
2 marks: “Give two steps that reduce the damage caused by floods.” Any two: no building in river beds; desilting drains and reservoirs; building above past flood levels; flood-proof buildings; a ready evacuation centre.
3 marks: “What is a natural disaster? Explain the causes of landslides, and name two human activities that make them worse.” A natural event causing large-scale damage to life and property. Landslides: unstable slopes, heavy or long rain, earthquakes, erosion, groundwater pressure. Made worse by deforestation and dynamite blasting (or construction on slopes).
Warn, Plan, Shelter: disasters cannot always be stopped, but early warning and a ready plan save lives. Earthquake: Drop, Cover, Hold.