Global Warming

Two issues that worry many geologists are global warming and the greenhouse effect. The greenhouse effect is a natural process that keeps the earth at temperatures that are livable. What does the greenhouse effect have to do with global warming? When humans release gases into the air, the greenhouse effect will alter the temperature of the earth. More gases in the atmosphere means the earth will start to get warmer, and the result is global warming. On the other hand, if there was no greenhouse effect, the earth would be too cold for humans to comfortably exist.

In order to talk about global warming, we must first learn what causes the greenhouse effect. The three most common greenhouse gases are water vapor, carbon dioxide, and methane. Many of the sun's rays are absorbed by water vapor. Water vapor is a natural atmospheric gas and it accounts for "80 percent of natural greenhouse warming; the remaining 20 percent is due to other gasses that are present in very small amounts" (Murck, Skinner, and Porter 488).

A greenhouse gas known as carbon dioxide is the second biggest absorber of the sun's heat rays. Humans affect the amount of carbon dioxide in the atmosphere in many ways. Every time fossil fuels are burned, more carbon dioxide is released into the air. Car exhaust emissions also increase the amount of carbon dioxide in the air, and more carbon dioxide means more heat rays being absorbed. This will cause the earth's temperature to warm.

Another greenhouse gas is methane. "Methane absorbs infrared radiation 25 times more effectively than carbon dioxide, making it an important greenhouse gas despite its relatively low concentration" (Murck, Skinner, and Porter 490). Many studies have been performed on how methane is released into the atmosphere. Results have shown that methane is "generated by biological activity related to rice cultivation, leaks in domestic and industrial gas lines, and the digestive process of domestic livestock, especially cattle" (Murck, Skinner, and Porter 490).

The Environmental Media Services Organization has found that the greenhouse effect "could drive temperatures up as much as 6 degrees by the year 2100 - an increase in heat comparable to the 10 degree warming that ended the last ice age" (Fast Facts). If a 10-degree warming was the factor that ended the last ice age, imagine what another warming could do. "Consider hydrology, for instance. Warm air holds more water vapor than cold air, so there is an increase in evaporation in dry areas, and hence more drought - something that has been documented on every continent. Once that water is in the atmosphere, it's going to come down somewhere - and, indeed, we have seen the most dramatic flooding ever recorded in recent years. In 1998, 300 million humans, 1 in 20 of us, had to leave their homes for a week, a month, a year, or forever because of rising waters" (The Planet Speaks 124). Much of the gained water would be from melting icecaps in the ocean and melting glaciers on land. Coastal cities and islands could be wiped out.

Global warming would not affect only humans; it would also affect sea life. This would happen because water temperatures would rise. "Corals are intolerant of temperatures just a few degrees warmer than usual" (Fast Facts). There have been problems with corals dying out in the past few years because of increased water temperatures. Other marine life would probably migrate to warmer waters. The warm water would make them think they were in their natural habitat. A downfall to this unknown migration would be that food would become scarce in their new, unadapted habitat. An example is salmon; salmon are also sensitive to the temperature of the water. During the summer when the water is warm, salmon have a high metabolic rate. During the winter months, their metabolism slows down, which is good because less food is available at this time. With global warming and increased water temperatures, salmon would have a high metabolic rate longer each year. They would possibly eat all the available food and many salmon would die as a result.

Global warming is already disturbing patterns of the circulation of seawater. Cold water moves along the sea floor toward the equator and warm water around the equator moves toward the poles across the surface of the ocean. This process is very important to the living of ocean species. This circulation process brings oxygenated water to the sea floor. If this process no longer happened, water along the sea floor would become depleted of the oxygen organisms need to survive" (Fast Facts). The resulting factor would be more death among deep-sea organisms.

There are many negative environmental effects of global warming. Another effect is the fact that higher temperatures will lead to a change in the water cycle. Warmer temperatures will cause a greater amount of evaporation from lakes, rivers, streams, and oceans. In some areas this could be good, but in other areas it could be bad. In northern regions of the U.S., where we live, an increase in the temperature and the amount of rain could extend the growing season of crops. In turn, the farmers could make more money. It could also hurt some farmers though. There is a possibility that crops could get too much rain and crops could be killed. Certain areas would actually get less rain, which would lead to more droughts. Warm temperatures and wet weather would be the main result of global warming in certain areas, and warm temperatures and wet weather are factors that promote tropical storms. Thus, tropical storms would appear more often and with greater frequencies.

More rain as a result of global warming will also force plant life and its species to adjust their location. Species migrate naturally, but scientists ay that global warming would cause them to migrate at a much faster rate. If the climate changes, "some forest species in North America will shift by as much as 300 miles to the north" (Campaign to Stop Global Warming). Plants will also be forced to migrate. If one region is getting more rain than another, plants that need more