Greenhouse Effect

HUMAN ACTIVITIES CAN disrupt the balance of the natural system that regulates the temperature on [Page 470]Earth. This natural regulating system is known as the greenhouse effect. As human societies burn fossil fuels, and adopt it to increasingly sophisticated and mechanized lifestyles in the developed world, the amount of heat-trapping CO2 and CH4 in the atmosphere has increased. By increasing the amount of these heat-trapping gases in the atmosphere, humankind has enhanced the warming capability of the natural greenhouse effect.

Most of Earth's heat is re-radiated toward space, but some is trapped by greenhouse gases in the atmosphere. This is a natural effect that keeps Earth's temperature at a level necessary to support life.

This human influence (in addition to the natural release of these gases) on the natural warming function of the greenhouse effect has become known as the enhanced greenhouse effect. It is this human-induced enhanced greenhouse effect that causes environmental concern. This enhanced greenhouse effect has the potential to warm the planet at a rate that is unprecedented. Greenhouse gas effects due to natural phenomena have existed from the very beginning of the Earth. The rate has increased over time due to increased human activity such as industrialization, deforestation, increased fossil-fuel-based transportation, and increased agriculture to satisfy the increased population.

Human activity—particularly burning fossil fuels (coal, oil, and natural gas) and land clearing—is generating more greenhouse gases. Scientists are convinced that this will trap more heat and raise Earth's surface temperature.

Another factor that is causing significant change in the atmosphere is the rising levels of carbon dioxide, due to increased burning of coal and oil, which traps more heat in the atmosphere, thus warming the Earth. This phenomenon began with the advent of the Industrial Revolution of 1800s, and has been increasing ever since. Work was done by hand and by animal power before the Industrial Revolution, but was done by fossil-fuel burning machines since the Industrial Revolution, resulting in generation of higher amounts of CO2 and its subsequent release to the environment. It is difficult to predict the precise effects of doubling the concentration of CO2 in [Page 471]the atmosphere, but doubling CO2 should increase global temperatures.

Also, increased production of rice and growing numbers of domestic animals to feed the increasing population have resulted in increased emissions of CH4. During the last two centuries, the concentrations of CO2 and CH4 (both greenhouse gases) have increased faster than at any other time in the recorded history of mankind, leading to enhanced greenhouse effect.