Greenhouse Effect Essay ⋆ Environment Essay Examples ⋆ EssayEmpire

This Greenhouse Effect Essay example is published for educational and informational purposes only. If you need a custom essay or research paper on this topic, please use our writing services. EssayEmpire.com offers reliable custom essay writing services that can help you to receive high grades and impress your professors with the quality of each essay or research paper you hand in.

The greenhouse effect is a natural phenomenon of the earth atmosphere. Gases, in particular carbon dioxide, methane, and ozone, are present in the atmosphere in small quantities. They have the capacity to retain energy in a manner analogous to a greenhouse. However, the comparison is not exact because greenhouses and the atmosphere use different trapping mechanisms.

Greenhouses are made of clear translucent material such as glass or plastic that allows sunlight to enter. The ambient temperature outside of the greenhouse can be many degrees colder, but the temperature inside of the greenhouse will be much warmer. This happens because the sun’s rays warm the atmosphere of the closed greenhouse, causing its indoor temperature to rise. Because the glass panes of the greenhouse act as insulating material, heat is not easily transferred from inside of the greenhouse to the colder air outside. In the earth’s atmosphere, greenhouse gases create a similar warming effect, but it is not exactly the same as the warming that occurs in a greenhouse.

Earth, Venus, and Mars also have atmospheres, and a greenhouse effect as well. In the case of Mars, the effect is insufficient to warm the planet. For Venus, it is too much of a good thing. Because Venus is rich in carbon dioxide, it retains heat, producing an inhabitable surface temperature of around 850 degrees F. In the case of Earth, its atmospheric greenhouse effect has been just right, with an average global temperature of 59 degrees F, until recently.

A Natural Process

The greenhouse effect is a complicated natural process that occurs in the earth’s atmosphere, which has four major layers. The Troposphere is the thick layer extending from the surface of the earth to about 7 miles (11.3 kilometers). It holds the air life on earth breathes and most of the clouds. The Stratosphere extends from the top of the troposphere to about 30 miles (48 kilometers) above the surface of the earth. It has some high flying clouds, but its upper portion is the location of the ozone layer. The Mesosphere is the third layer of the earth’s atmosphere. It extends to about 50 miles (80 kilometers). The final layer is the Thermosphere. The atmosphere is extremely thin, and extends to about 600 miles (965 kilometers) above the surface of the earth. Beyond is empty space.

Solar energy striking the earth is composed of more than just visible light. In the electromagnetic spectrum, the radiation leaving the surface of the sun is composed of short-wave X-rays and gamma rays. Gamma rays are deadly to humans for even a short period of time. However, these forms of radiation are absorbed in the Thermosphere by the time they have penetrated the atmosphere to a depth of about 100 miles (160 kilometers) above the earth’s surface.

Ultraviolet (UV) waves are next to X-rays and gamma rays in wavelength. These wavelengths extend across the electromagnetic spectrum to violet light in the visible spectrum. UV waves are dangerous to living things. They cause sunburn and can kill plankton in the oceans. They are absorbed in the top of the Mesosphere by ozone. Without the ozone layer there would be an increase in damage to eyes and skin cancers.

The visible light spectrum as seen by human eyes ranges from purple to red in a spectrum of increasing wavelengths. Just beyond the visible red spectrum is infrared radiation. About 60 percent of the sun radiation is infrared, invisible to humans and to most animals. The tongues of snakes have infrared sensors to detect the heat of animals in the dark. Camera film has been designed to detect infrared radiation. It is this form of radiation that heats the earth.

Visible light and infrared radiation penetrate the earth’s atmosphere as if they were light shining through a glass pane. Much of the radiation is absorbed by plants or by cultivated areas of the earth’s surface or by the oceans. However, some of the radiation is blocked by clouds, and some it returns to space from bright surfaces on the earth like deserts or ice-snow fields.

As radiation warms the earth’s surface, some infrared radiation is radiated back into space, but not all. The earth’s radiation is heat energy in the form of long-wave infrared radiation. The heat radiation waves have wavelengths ranging from 4-100 micrometers. The earth’s heat radiation is much longer in wavelength than that striking the earth’s surface directly as sunshine. The electromagnetic energy from the sun penetrates the atmosphere as if through an open window. However, the longer wavelengths of the earth’s radiation act differently. The result is that the atmosphere is transparent to the sun’s radiation, but not to the long-wave infrared radiation coming from the earth’s surface. The earth’s radiation is absorbed in the Troposphere by greenhouse gases. The gases, in effect, act like a blanket warming the earth.

Greenhouse Effect Process

The greenhouse effect is caused naturally by the small quantities of carbon dioxide (CO2), carbon monoxide (CO), ozone (O3), nitrous oxide (N2O); Chlorofluorocarbons (CFCs); water vapor (H2O), and particulates of various kinds. In addition, in the atmosphere are some trace gases such as argon that also have a role in the greenhouse effect. Neither oxygen nor nitrogen hold the energy of the sun very well; however, these other gases do hold in the energy of the sun. These two gases constitute nearly 99 percent of Earth’s atmosphere. The greenhouse gases compose less than one percent.

Carbon dioxide, water vapor, and trace gases all absorb some to the heat energy of the earth. Carbon dioxide absorbs infrared waves that are 13-100 micrometers. Water vapor absorbs infrared waves that are between 4-7 micrometers. Infrared waves that are between 7-13 micrometers, on the other hand-the “infrared window”-are not usually absorbed. Instead, they pass easily through the atmosphere and into space.

The infrared energy absorbed by the greenhouse gases is given off as radiation that returns to earth. In effect, these gases “trap” heat energy coming from the earth and return it to the earth. Without the atmospheric greenhouse effect, the earth would be a block of ice. Eventually, some of the radiation is radiated out into outer space. Historically, the natural system of the greenhouse effect has been in equilibrium. Without the effect, the surface of the earth might look like the moon, which at about the same distance from the sun as the earth, receives roughly the same amount of radiation. The temperature on the surface of the moon is 212 degrees F (100 C) in the sunshine, but -238 degrees F (-150 C) in the dark, on average.

Early Observations

The greenhouse effect was first observed by French scientist Jean-Bapiste-Joseph Fourier. He described the earth atmosphere in 1827 as being like a glass vessel that retained heat. In the 1850s James Tyndall, a British physicist, analyzed the earth’s atmosphere in order to identify the greenhouse gas. He was surprise to discover that neither oxygen nor nitrogen hold the sun’s energy. Most of the earth’s atmosphere is composed of nitrogen and oxygen. This meant that 99 percent of the earth atmosphere was not involved in the greenhouse effect.

In 1938 George Callendar, a British coal engineer, publishrd a sudy of global weather readings in cluding temperatures. He concluded that the earth’s atmosphere was gradually getting warmer. He attributed the atmospheric warming to the burning of fossil fuels since the Industrial Revolution. Distracted by World War II and by a downspike in global temperatures from the 1940s until the 1970s, scientists ignored the issue of global warming, or better put, “global climate change.” Those who did consider the subject thought that the oceans would absorb the additional carbon dioxide because the oceans act as a carbon sink as great quantities of vegetation and animals sink to its depths.

During the Geophysical Year (1957-58) measurement of carbon dioxide were made Charles David Keeling of California, who developed a device for measuring in parts per million the amount of carbon dioxide in the atmosphere. He took reading from the top of the Hawaiian volcano far from an industry. His readings have been accumulated into the Keeling Curve, which since then have shown that the amount of carbon dioxide has increased significantly since the Industrial Revolution and that the amount in the earth’s atmosphere is rapidly rising.

Carbon dioxide is part of the carbon cycle that is used by plants in photosynthesis. From tests done on ice core samples taken from Antarctica and Greenland that go back to 160,000 years ago it has been determined that carbon dioxide was present in the atmosphere at an average of 270 parts per million (ppm) until the advent of the Industrial Revolution. However, since then, carbon dioxide in the atmosphere has risen to around 380 ppm. The same increase is also happening with methane and other greenhouse gases. Their increases are predicted to cause global warming, which is better described as global climate change.

Scientists studying the greenhouse gases have noted that the infrared window is being “dirtied” by the increase in greenhouse gases. Some of these gases are much more absorbent of infrared radiation than is carbon dioxide-in the case of methane, 30 times as absorbent. Added to the increase in gases is global deforestation, and the increased use of nitrous oxide as a fertilizer.

Climate models are forecasting major global climate changes if the increases in greenhouse gases are not stopped. Some of the increases will be from human industrial or agricultural sources. Others such as the melting of the permafrost in the Arctic region will release huge quantities of carbon dioxide and methane from bacterial action on thawed plants.

Bibliography:

Ronald F. Abler, Global Change and Local Places: Estimating, Understanding and Reducing Greenhouse Gases (Cambridge University Press, 2003);
F. Follett. R. Lal, and J.M. Kimble, Potential of U. S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect (CRC Press, 2000);
Martin H. Halmann and Meyer Steinberg, Greenhouse Gas Carbon Dioxide Mitigation: Science and Technology (CRC Press, 1998);
Ann Henderson-Sellers and Russell J. Blong, The Greenhouse Effect: Living in a Warmer Australia (UNSW Press, 1989);
Chang-Jun Liu, M. Aresta, and Richard G. Mallinson. , Utilization of Greenhouse Gases (American Chemical Society, 2003);
Patrick J. Michaels, e, Shattered Consensus: The True State of Global Warming (Rowman & Littlefield Publishers, 2006);
Roland Paepe and R. W. Fairbridge, , Greenhouse Effect, Sea Level and Drought (Springer-Verlag, 2002);
Darlene R. Stille, Robert Davis, and Terrence E. Young, Greenhouse Effect: Warming the Planet (Capstone Press, 2006).