What is the Greenhouse Effect?
The Greenhouse Effect is the rise in the Earth’s temperature that occurs when gases in our atmosphere trap energy from the sun.
A visualization of this phenomenon: Imagine that Earth has been encircled by a giant glass sphere. The heat of the sun penetrates through the glass. Some of the heat is absorbed by the Earth, and some of it is radiated back towards space. The radiated heat reaches the glass sphere and is prevented from dispersing any further.
The actual process is very similar: The earth is surrounded by a blanket of gases including water vapor, carbon dioxide (CO2), methane, nitrous oxides, and chlorofluorocarbons (CFCs).
This blanket traps energy in the atmosphere, much the same way as glass traps heat inside a greenhouse. Energy accumulates, and the atmosphere increases in overall temperature.
An excellent six-minute video on the Greenhouse Effect can be viewed at:
Causes of the greenhouse effect:
1. Natural phenomenon. For example, when a volcano erupts, huge amounts of CO2 (carbon dioxide, a greenhouse gas) are emitted into the atmosphere.
2. Human activities such as burning fossil fuels and cutting down trees also generate carbon dioxide. Over the last century the burning of fossil fuels like coal and oil has increased the concentration of atmospheric CO2. This happens because the coal or oil burning process combines carbon (C) with oxygen (O2) in the air to make CO2. To a lesser extent, the clearing of land for agriculture, industry, and other human activities have increased the concentrations of other greenhouse gases like methane (CH4), and further increased (CO2).
Consequences of the greenhouse effect:
As more heat gets trapped in the Earth, the planet will become extremely warm, leading to severe changes throughout the world.
Weather: Storms, floods, and droughts are some expected consequences which may affect different areas of the world.
Sea Levels: Increase in temperature may cause melting glaciers and rising sea levels, which will cause flooding coastlines, affecting food supplies.
Farming: A severe disruption of the world’s food supplies through floods, droughts, crop failures and diseases brought about by climate change would trigger famines, wars and civil disorder in many countries.
Plants and Animals: Many natural ecosystems will not be able to adjust fast enough to a rapidly warming world. This could lead to species extinction for many plants and animals. Interestingly, some crops and other plants may respond favorably to increased atmospheric CO2, growing more vigorously and using water more efficiently.
How do scientists predict the consequences of the Greenhouse Effect?
Scientists use computer models to simulate the Earth’s environment in response to increases in greenhouse gases. For example, the relationship that clouds play in the heating and cooling process of the Earth’s atmosphere are not completely understood. However, scientists continue to use the models while these complex processes are being studied.
For more detailed information on the Greenhouse Effect
epa.gov/climatechange/kids/greenhouse.html
http://www.gsfc.nasa.gov/gsfc/service/gallery/fact_sheets/earthsci/green.htm
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