20.3 The environment and society  (Page 2/21)

Pollution

Pollution describes when contaminants are introduced into an environment (water, air, land) at levels that are damaging. Directly related to carrying capacity, environments can often sustain a limited amount of contaminants without marked change, and water, air, and soil can “heal” themselves to a certain degree. However, once contaminant levels reach a certain point, the results can be catastrophic.

Water

Look at your watch. Wait 15 seconds. Then another 15. In that time, two children have died from lack of access to clean drinking water. Access to safe water is one of the most basic human needs, and it is woefully out of reach for millions of people on the planet. Many of the major diseases that peripheral countries battle, such as diarrhea, cholera, and typhoid, are caused by contaminated water. Often, young children are unable to go to school because they must instead walk several hours a day just to collect potable water for their family. The situation is only getting more dire as the global population increases. Water is a key resource battleground in the 21st century.

As every child learns in school, 70 percent of Earth is made of water. Despite that figure, there is a finite amount of water usable by humans and it is constantly used and reused in a sustainable water cycle. The way that humans use this abundant natural resource, however, renders much of it unsuitable for consumption and unable to sustain life. For instance, it takes two and a half liters of water to produce a single liter of Coca-Cola. The company and its bottlers use close to 300 billion liters of water a year, often in locales that are short of useable water (Blanchard 2007).

As a consequence of population concentrations, water close to human settlements is frequently polluted with untreated or partially treated human waste (sewage), chemicals, radioactivity, and levels of heat sufficient to create large “dead zones” incapable of supporting aquatic life. The methods of food production used by many core nations rely on liberal doses of nitrogen and pesticides, which end up back in the water supply. In some cases, water pollution affects the quality of the aquatic life consumed by water and land animals. As we move along the food chain, the pollutants travel from prey to predator. Since humans consume at all levels of the food chain, we ultimately consume the carcinogens, such as mercury, accumulated through several branches of the food web.

Soil

Some of you might have read The Grapes of Wrath in English class years ago. Steinbeck’s tale of the Joads, driven out of their home by the Dust Bowl, is still playing out today. In China, as in Depression-era Oklahoma, over-tilling soil in an attempt to expand agriculture has resulted in the disappearance of large patches of topsoil.

Soil erosion and desertification are just two of the many forms of soil pollution. In addition, all of the chemicals and pollutants that harm our water supplies can also leach into soil with similar effects. Brown zones where nothing can grow are common results of soil pollution. One demand of the population boom on the planet is an attendant requirement for more food to be produced. The so-called “Green Revolution” in the 1960s saw chemists and world aid organizations working together to bring modern farming methods, complete with pesticides, to developing countries. The immediate result was positive: food yields went up and burgeoning populations were fed. But as time has gone on, these areas have fallen into even more difficult straits as the damage done by modern methods leave traditional farmers with less than they had to start.