Waste and Pollution

Humans have not always been careful with natural resources. For example, we waste water by letting faucets run and by watering lawns. We pollute rivers, streams, and groundwater with garbage and toxic wastes. Fumes from our vehicles and factories pollute the air. High levels of these fumes in the atmosphere may be changing the climate of the entire planet. Earth’s temperature may be rising. This “global warming” can create many problems. For instance,

glaciers are shrinking, and the polar ice caps are melting. Rising sea levels may eventually flood coastal areas. Floods, drought, hurricanes, and tornadoes are among the natural disasters that can be caused by changes in the earth’s climate. Toxins in the air and other chemicals may be damaging the ozone layer. The ozone layer of the atmosphere protects living things from the

sun’s harmful rays. Without this protection, many life-forms—including humans—are in danger.

In the name of progress, we have changed the landscape. We have cut down whole forests for lumber and to create farmland. This action destroys wildlife habitat. It causes erosion and flooding. We have dammed rivers to produce electricity. Lakes formed by dams have flooded

huge areas. Fish stopped by the dams can’t reach their breeding grounds. We have changed the course of rivers to water farmland. This has formed deserts where the water used to flow. It has added salt to the soil, making the land barren. We have filled in swamps and built malls. The many animals and plants that lived in the swamps are gone. Why have we been so careless? Part of the problem is that we often don’t know the harm we are doing until it is too late. Two examples are the building of the Aswan Dam and the clearing of the Amazon rain forest.    

In the 1960s, President Nasser of Egypt dammed the Nile River. The reason was to control its yearly flooding and to produce electricity. “The miracle has been wrought,” he said. The dam did stop the floods. However, it also blocked the flow of silt that enriched the soil of farms along the Nile. This meant that farmers had to start using chemical fertilizers. The lack of the silt that flowed from the Nile into the Mediterranean Sea caused many problems. It increased erosion along the coast and it harmed wildlife. Sardines and shrimp were two species that lived in the

sea. After the dam was built, they could not get their normal food— organic matter in the silt. As a result, the fish died. Egypt’s sardine industry failed.

Rodents that had been kept in control by the yearly floods increased in numbers. Sewage systems that were cleansed by the floods became clogged. Farmland below the dam no longer drained properly. It became salty and useless. Farm production was cut in half. The “miracle” turned

out to be a disaster for Egypt.