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Humans and the Environment

Swathing Machine on a FarmFire was one way that early humans changed their environment.  Fire was a good way to drive animals into places where they could be killed for food and skins.  Burning dead grass puts nutrients into the soil so that new grass will grow more quickly.  Grazing animals will come to this rich grass and can easily be hunted.  When humans began herding animals and farming, they made great changes in their environment.  They cleared forests and tilled the soil to kill "weeds" and make a good place for seeds to grow.  They put animals on pastures in greater numbers than would occur naturally and changed the earth forever.  The Sahara Desert has grown in size because humans tried to farm and herd cattle and goats close to its edge.  When drought came, the topsoil blew away and the land could not recover.

Humans have had the ability to change their environment for thousands of years.  Today this ability is greater than ever.  This is because there are more people living now than ever before and human activity is concentrated in huge cities.  Also, science and technology allow us to interfere with natural processes in more direct ways.

We now understand more about the environment and how it works.  Sometimes this understanding came about after  a problem had surfaced.  The story of DDT is a good example.  DDT was introduced after World War II as a very effective pesticide.  DDT is broken down slowly through natural processes.  The DDT was washed into the soil and into rivers where animals and plants absorbed small amounts of it.  Birds, which are at the top of the food chain, were greatly affected.  The DDT caused them to lay eggs with very thin shells.  The eggs did not survive.  Ospreys, eagles and falcons were particularly affected by DDT.  When DDT was banned, these birds made a dramatic recovery but DDT residue is still found in every environment on earth.

Pollution ClipartPollution problems are not just problems of the air, water, or soil.  Pollution affects all parts of the environment.  When we put something into the environment, it doesn't just go away.  The pollutant eventually becomes part of the environment.  When a toxic chemical enters our lakes and rivers, it doesn't just stay there.  It enters the plants and animals that live in the water.  It may enter drinking water that people use.  It may get into the soil through irrigation.  Eventually it is washed into the ocean where fish and other creatures may become contaminated.  If we eat these fish, we too become contaminated.  Serious diseases, like cancer, could be associated with pollution.

Some environmental problems are not easy to see.  Not all pollutants cause immediate or short-term problems.  It may take years of exposure or build-up before any effects are seen.  A good example is the accumulation of carbon dioxide in the air.  One of the by-products of combustion is carbon dioxide.  For over a century man has been burning huge amounts of coal, oil and gas.  Research suggests that we have burned so much that we have increased the amount of carbon dioxide in the air.  Carbon dioxide absorbs heat.  A small increase in the amount of carbon dioxide will increase the temperature of the earth.  This is called the "enhanced greenhouse effect".  A rise of the average annual temperature of 3 degrees Celsius would make most of the prairies unsuitable for agriculture.  It would be too dry.  This same rise in temperature would start melting the polar ice caps.  The world's sea coasts could be flooded by several metres of water.

Earth clipartThe better we understand the earth, the better we can understand the problems that face us.  An environmental viewpoint is one way of looking at the earth.  This way of looking at problems goes beyond immediate questions and looks at how they affect the whole environment.  A functioning, well balanced environment is important humans.  We need clean air to breathe, clean water to drink, food to eat, and shelter.  All these things are part of our environment and are interconnected.  We now know that if we pollute our air we may be affecting our food and water supply.

Governments, industry, and public groups all recognize the need to manage and protect the environment so that it continues to provide the necessities of life.  Scientists in government and industry research environmental problems.  New information is used to make new regulations or devise new processes which improve environmental quality.  Public groups tell government and industry of their concerns and interests.  Each of us has a part to play in this process.

The planet Earth is the only place we know of in the whole universe where mankind can live.  We need to take care of it.

Reprinted from Focus On Environment (1993) with permission of Alberta Environment.

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