CHAPTER 1 PoLLUTION A GLOBAL CRISIS E fforts to improve the standard of liv ing for humans through the control of nature and the development of new products have also resulted in the pollu tion or contamination of the environment Much of the world's air water and land is now partially poisoned by chemical wastes Some places have become uninhabitable This pollution exposes people all around the globe to new risks from disease Many species of plants and animals have become endangered or are now extinct As a result of these developments governments have passed laws to limit or reverse the threat of environmental pollution All living things exert some pressure on the environment Predatory animals for example reduce the population of their prey and animal herds may trample vast stretches of prairie or tundra The weather could be said to cause pollution when a hurricane deposits tons of silt from flooded rivers into an estu ary or bay These are temporary dislocations IO
PoLLUTION A GLOBAL CRISIS that nature balances and accommodates to Modern economic development however Sometimes disrupts nature's delicate bal ance The extent of environmental pollution caused by humans is already so great that Some scientists question whether Earth can continue to support life unless immediate corrective action is taken EcoLoGr AND ENVIRONMENTAL DETERIORATION The branch of science that deals with how living things including humans are related to their surroundings is called ecology Earth supports some 5 million species of plants animals and microorganisms These interact and influence their surroundings forming a vast network of interrelated envi ronmental systems called ecosystems The arctic tundra is an ecosystem and so is a Brazilian rainforest The islands of Hawaii are a relatively isolated ecosystem If left undisturbed natural environmental sys tems tend to achieve balance or stability among the various species of plants and animals Complex ecosystems are able to compensate for changes caused by weather or intrusions from migrating animals and II
PoISONING PLANET EARTH PoLLUTION AND OTHER ENVIRONMENTAL HAZARDS A farmer in Vaudreuil Haiti works in a cornfield on June 30 2009 Thony Belizaire AFP Getty Images are therefore usually said to be more stable than simple ecosystems A field of corn has only one dominant species the corn plant and is a very simple ecosystem It is easily destroyed by drought insects disease or overuse A forest may remain relatively unchanged by weather that would destroy a nearby field of corn because I2
PoLLUTION A GLOBAL CRISIS OL These passenger pigeons were painted by the famous American natu ralist and bird expert John James Audubon 1985 1851 before they became extinct Buyenlarge Archive Photos Getty Images 13
