PoisoNING PLANET EARTH PoLLUTION AND OTHER ENVIRONMENTAL HAZARDS monuments Like smog coal emissions can harm lung and heart tissue in humans Fossil fuels also emit carbon dioxide and other so called greenhouse gases gases that in excessive amounts heat up the planet to unhealthy levels You will also learn how fertilizers contain ing chemicals like nitrogen which plants use for growth can end up in waterways if farmers have poor soil conservation techniques This nitrogen can make so much algae blossom that it chokes out all other life in the water And then there is the problem of what to do with the ever increasing mountains of garbage that pile up in landfills One solution is recycling The United States recycles about 30 percent of its solid waste for instance But it also makes more trash than many other nations approximately 4 5 pounds 2 kilograms of garbage per per son are generated each day in the United States significantly more than the 2 5 to 4 pounds 1 1 to 1 8 kilograms per person that many European nations and Japan make Radioactive pollutants have become a major concern since the first atomic bomb was dropped on Hiroshima Japan in 1945 Nuclear power plants generate hard to store waste and occasionally disasters have
INTRODUCTION occurred most notably the 1986 catastro phe at the Chernobyl nuclear power plant in the Soviet Union Exposure to radiation can cause cancer and numerous other illnesses though it may take years for the effects of such exposure to become apparent About 620 000 square miles 1 6 million square kilometers of tropical rainforest are cleared each decade If deforestation con tinues at that rate all tropical forests on Earth which make up the habitat of two thirds of the planet s species will be gone in less than a century Overpopulation in the Sahel region of Africa has forced hun gry people to farm increasingly fragile land bordering the Sahara contributing to the problem of desertification In 2006 the UN warned that desertification threatened the livelihoods of about one billion people What s next Individuals can make a dif ference by consuming less taking fewer car trips and recycling Perhaps most impor tantly however governments businesses and environmental organizations need to work together to find large scale solutions to these problems To do this will take much political will But this volume will show why it's so important for us not to foul the nest we rely on for our very
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
