is a home to millions of different kinds of living things which are linked in
many ways. Together they make up the complex world of nature. Some are rivals
or enemies, while the others depend on each for survival.
and animals live in a particular set of surroundings, called their habitat.
Nowadays people are in a hurry to change habitats to suit their own needs - to
create farmlands or build cities, for exam- pie. The way people live threatens
the delicate balance between living things and their habitats.
create pollution which travels through the air and water from one habitat to
certain things to stay alive and healthy. We need clean air to breathe and pure
water to drink. We need also food that is safe to eat and housing to shelter
us. But we can't get all these things by ourselves. We live in a large
community, so we can solve health problems only working together.
air is a community problem. Air becomes polluted in many ways. Cars, trucks,
buses and airplanes are among the worst polluters. They send partly burned
gases into the air. Air can be also polluted by smoke and gases from factories.
Dirt, smoke and gases in the air can be carried away by wind, by air currents
or settle over as a blanket of smog.
pollution can cause diseases. But everyone may feel uncomfortable and suffer
from lack of energy when air isn't clean.
people do to cut down on air pollution? Today many factories use devices to
reduce the smoke, dust or gases. Special kinds of gasoline for cars can help to
reduce air pollution. More efficient engines can help too.
Water pollution is caused by dumping wastes into
lakes, rivers and other bodies of water. Harmful wastes may also soak into the
soil, or drain or run off from fields that have been sprayed with pesticides.
Pesticides are often used to kill insects and weeds in cities or on farms.
Polluted water can spread many diseases.
people throw away amazing amounts of garbage and trash. What happens to these
wastes after they are picked up by garbage trucks? Trucks take the garbage to
out-of-the-way places, called garbage dumps. Sometimes the trash is burned,
causing air pollution. But the more healthy way to get rid of solid wastes is
to spread them over the land and pack them down. After that a thick layer of
earth can be put down over the garbage and trees and grass can be planted.
rise in the human population and the corresponding demand for resources have
had a dramatic impact on the natural world. While global
warming, acid rain and holes in the ozone layer affect the whole planet, other
changes threaten individual species.
temperatures are currently rising every year. This is called global warming. It
is caused by the buildup of gases and water vapour in the atmosphere. These
gases form a layer that reflects the heat back to Earth, rather than allowing
it to escape into the outer atmosphere. As the planet warms up, the water in
the oceans will take up more space and water locked up in glaciers and the
polar ice caps will start to melt. This could cause sea levels to rise and many
habitats will disappear under water.
fall when poisonous gases from power stations and vehicle exhausts mix with
oxygen and moisture in the air. These gases become a part of the water cycle
and may be carried a long way by the wind before they fall as acid rain or
snow. Acid rains poison or kill wildlife in lakes, rivers and forests, and
damage the surrounding plant life. The problem could be controlled by reducing
vehicle emissions and limiting the gases released from power stations.
layer of ozone gas high in the atmosphere provides protection against the
Sun's harmful rays. However, certain pollutant gases are now destroying the
ozone. Since 1979 "holes" have appeared in the ozone layer first
over the Antarctic, then over the Arctic.
Damaging ultraviolet rays from the Sun penetrate these "holes", slowing
the growth of plants.
is our home but much of it is dirty and dying. By the year 2030 scientists
report that 25% of all animals, birds, fish and insects may be extinct. Every
year man cuts down more trees to provide paper, wood, medicines, and mineral
fuel. But it isn't only trees and forests which are disappearing. Every rain
forest contains millions of animals, insects and flowers. These are destroyed
too. Governments in rain forests countries need to plan and work together. They
should protect certain areas and plant new forests.
Today many scientists and world leaders
realize that the Earth is in danger. It's really very simple. Either we stop
killing the Earth, or we kill ourselves. We need a cleaner, healthier planet.
Millions of ordinary people understand this too. Some of them belong to the
so-called "Green" or earth-friendly organizations in countries all
over the world. Groups, like "Green Peace", have already helped to
stop the hunting of some animals, such as whales. What else can be done? I
think that everyone should decide for himself how he or she can help our
planet. And it is important not only to decide but also to carry out the