There is a difference between natural catastrophes-those extreme events in nature, such as earthquakes, that cause widespread damage- and man-made environmental catastrophes, for which we, human beings, are responsible. Man-made disasters pollute huge areas and cause extensive damage to animals, plants, and even to human beings. Examples include oil and chemical spills, accidents in nuclear power plants, overfishing in seas, and large-scale destruction of forests. The increased greenhouse effect also belongs to the category of man-made environmental catastrophes.
How are oil and chemical spills caused?
Chemical accidents are caused by technical problems, human negligence, and errors committed by people employed in chemical factories or the transportation of chemicals. This happens time and again, but luckily very big accidents occur only rarely. An example would be the big chemical accident that took place in the Indian city of Bhopal in 1984. Oil spills happen mostly in the seas when oil tankers accidentally overturn in the water. An overturned oil tanker pours out copious amounts of oil that flows through the water surface and submerges plants, animals, and water birds, causing many of them to die wretchedly.
What happens in an accident in a nuclear power plant?
The reactor of a nuclear power plant (NPP) contains radioactive substances that are very dangerous for human beings. Such plants are monitored very carefully. If a technical fault goes unnoticed there can be uncontrolled chain reactions (page 137) in the reactor. The internal pressure rises enormously within a few minutes and there is an explosion. This is exactly what happened in 1986 in Chornobyl, an NPP in Ukraine. A huge cloud of radioactive substances formed over Europe; it first settled over the Scandinavian countries and then traveled to the Mediterranean countries via Poland and Germany. The radioactive substances reached the soil through rain. People, who switched off the reactor and later cleaned up the area, died from the effects of radiation.
What are the consequences of overfishing?
Overfishing means the practice of catching fish faster than they can reproduce through natural processes. Overfishing inevitably leads to the depletion of other marine species including birds and mammals. As a result, the food chain (page 59) gets disturbed and animals and plants start reproducing in an uncontrolled way. The natural equilibrium between the living communities in a marine ecosystem gets disturbed-and this is a serious environmental catastrophe.
In what way is the destruction of forests an environmental catastrophe?
Forests are our ‘green lungs’. They consume the greenhouse gas carbon dioxide (CO2) during photosynthesis and release oxygen, which we need for breathing. Clearing forests not only destroys precious natural resources but also drastically cuts down our supply of oxygen. Rainforests are also important for preserving the Earth’s climate. They accumulate moisture, release a part of it into the air, and thus control the movement of air masses.
What is the greenhouse effect?
In a greenhouse, the air gets heated up because the warm rays of the sun get trapped by the roof and the walls and are not reflected outwards completely. This situation is comparable to the conditions currently prevailing on the Earth. The layer of the atmosphere, which acts like the glass roof, contains greenhouse gases, such as water vapor, carbon dioxide (CO₂), methane, nitrous oxide, and ozone, in appropriate amounts to keep the Earth comfortably warm. Due to irresponsible human activities, the carbon dioxide content has increased by 20% and methane content by 90%. As a result, more heat is getting trapped and making the Earth warmer than usual. The increased temperature is causing the ice of the polar caps and glaciers to melt; this has led to a rise in sea levels and drastic climate changes all over the world.
