We have not inherited the Earth from our fathers. We are borrowing it from our children. —Native American saying Photographs from outer space impress on the world that humankind shares one planet, and a small one at that. (See Figure 1.1.) Earth is one ecosystem. There may be differences in race, nationality, religion, and language, but everyone resides on the same orbiting planet. General …
Earth scientists are in the midst of a revolution in their understanding of how climate change occurred in the past. Researchers are discovering the geological and astronomical forces that have changed the planet's environment from hot to cold, wet to dry, and back again, over hundreds of millions of years. Dramatic climate change is nothing new for planet Earth. The climate of the past 10,000 years, during which civilization developed, is a mere blip in a much bigger history of climate c…
Ozone is a gas naturally present in Earth's atmosphere. Unlike regular oxygen, which contains two oxygen atoms (O2), ozone contains three oxygen atoms (O3). A molecule of regular oxygen can be converted to ozone by ultraviolet (UV) radiation, electrical discharge (such as from lightning), or complex chemical reactions. These processes split apart the two oxygen atoms, which are then free to bind with other loose oxygen atoms to form ozone.…
One of the consequences of a modern society is the generation of enormous amounts of waste. The scale of materials use by industrialized countries dwarfs that of a century ago. By 2000 the stock of materials drew from all ninety-two naturally occurring elements in the periodic table compared with just twenty in 1900. The U.S. Geological Survey (USGS) estimates that, in the United States alone, con…
According to the Environmental Protection Agency (EPA), the average person breathes in 3,400 gallons of air each day. Because air is so essential to life, it is important that it be free of pollutants. Throughout the world poor air quality contributes to hundreds of thousands of deaths and diseases each year, not to mention dying forests and lakes and the corrosion of stone buildings and monuments. Air quality is also important to the quality of life and recreation because air pollution causes h…
Water is precious for many reasons. It is an essential resource for sustaining human, animal, and vegetative life. A living cell is mostly water. An adult human's body is about 65 percent water; blood is 90 percent water. Agriculture is absolutely dependent on water to produce food crops and livestock. Water is crucial to tourism, navigation, and industry. Enormous amounts are used to gener…
Acid rain is the common name for acidic deposits that fall to Earth from the atmosphere. The term was coined in 1872 by English chemist Robert Angus Smith to describe the acidic precipitation in Manchester, England. Today scientists study both wet and dry acidic deposits. Although there are natural sources of acid in the atmosphere, acid rain is primarily caused by emissions of sulfur dioxide (SO2) and nitrous oxide (N2O) from electric utilities burning fossil fuels, especi…
Many of the substances naturally found in the environment or released by modern, industrialized society are harmful to humans and other living creatures. Common toxins include heavy metals (lead, cadmium, aluminum, mercury, and manganese), chlorine, organic chemicals (such as pesticides and herbicides), and radiation. These substances may be found in the home, workplace, or backyard, in the food a…
Human activity on Earth has always altered the land. When populations were small enough, and productive and accessible land was abundant, people could abandon land that had been damaged by overuse and move on. While some countries still have excess land available, if population growth continues at the expected rate, virtually all arable (fit for cultivation) land will be in use. …
Imagine an energy source that uses no oil, produces no pollution, cannot be affected by political events and cartels, creates no radioactive waste, and yet is economical. Although that might sound impossible, some experts claim that technological advances could make a renewable energy-based economy achievable by the mid-twenty-first century.…