Greenhouse effect
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What is the greenhouse effect?
The greenhouse effect is the process where certain gases in the atmosphere trap heat, warming the Earth. These greenhouse gases, including water vapor, carbon dioxide, and methane, absorb infrared radiation emitted from the Earth's surface, raising the atmosphere's temperature. The heated atmosphere then radiates infrared radiation back to the surface, contributing to further warming.
Human activities, such as burning fossil fuels and deforestation, have increased the concentration of greenhouse gases, potentially intensifying the greenhouse effect and leading to global warming.
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How does the greenhouse effect warm the Earth?
The greenhouse effect warms the Earth through a process where greenhouse gasses in the atmosphere absorb heat energy emitted from the Earth's surface and reradiate it back.
Visible light from the sun passes through the atmosphere and warms the Earth's surface. The surface then emits infrared radiation, which greenhouse gasses like water vapor, carbon dioxide, and methane absorb, raising the atmosphere's temperature. The heated atmosphere then radiates infrared radiation back to the surface, further warming the planet. Without the greenhouse effect, Earth’s average surface temperature would be approximately -18 °C (0 °F).
6 Britannica Sources- Definition of greenhouse effect
- 5 Notorious Greenhouse Gases: Surface-level ozone
- Climate Change: Pro 2: Rising levels of human-produced gases released into the atmosphere create a greenhouse effect that traps heat and causes global warming.
- greenhouse effect
- electromagnetic radiation: The greenhouse effect of the atmosphere
- climate: Effects of the atmosphere
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What are greenhouse gases, and which ones are most important?
Greenhouse gases trap heat energy, contributing to the greenhouse effect. The most significant ones are water vapor, carbon dioxide, and methane.
Carbon dioxide's sources include volcanoes, decaying organic matter, and human activities like burning fossil fuels. Methane, though less concentrated, is more potent than carbon dioxide. Additional trace gases with greenhouse properties include nitrous oxide and fluorinated gases. Human activities, especially since the Industrial Revolution, have increased the concentrations of these gases.
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How does human activity affect the greenhouse effect?
Human activities, especially since the Industrial Revolution, have increased greenhouse gas concentrations in the atmosphere, which has amplified the greenhouse effect. This occurs mainly through the combustion of fossil fuels for electricity, heating, and transportation, in addition to deforestation and cement production.
The most significant greenhouse gas is carbon dioxide, but other gases like methane and nitrous oxide also contribute. These gases trap heat and cause the planet to warm.
5 Britannica Sources- greenhouse gas
- Definition of greenhouse effect
- global warming: Land-use change
- 5 Notorious Greenhouse Gases: Nitrous oxides and fluorinated gases
- Climate Change: Pro 2: Rising levels of human-produced gases released into the atmosphere create a greenhouse effect that traps heat and causes global warming.
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What are the consequences of too much greenhouse effect on Earth's climate?
The greenhouse effect is the warming of Earth's surface and troposphere caused by greenhouse gases like water vapor and carbon dioxide. Too much of these gases can intensify the effect, leading to several environmental consequences.
A rise in global average temperature may occur, which, by the end of the 21st century, could reach 3 to 4 °C (5.4 to 7.2 °F) relative to the 1986–2005 average. Such global warming could alter Earth’s climates, causing new patterns and extremes of drought and rainfall, and disrupt food production. It can also cause melting of ice and snow in the Greenland and Antarctic ice caps and in mountain glaciers, resulting in rising sea levels. Additionally, it can challenge the natural adaptive capacity of many species, with a large fraction of plant and animal species likely to be at an increased risk of extinction.
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How can we reduce human impact on the greenhouse effect?
To reduce human impact on the greenhouse effect, mitigation policies can be adopted to lower greenhouse gas emissions. This can be achieved by transitioning to less carbon-intensive energy sources like wind, solar, and hydropower, improving energy efficiency in vehicles, and supporting the development of new technologies such as carbon capture and storage (CCS). Individuals can contribute by using energy more efficiently, reducing the combustion of fossil fuels, and supporting carbon sequestration through forest growth and underground storage. Sustainable agriculture practices, such as managing manure and implementing animal feed additives, can also reduce emissions from livestock production.
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Greenhouse effect, a warming of Earth’s surface and troposphere (the lowest layer of the atmosphere) caused by the presence of water vapour, carbon dioxide, methane, and certain other gases in the air. Of those gases, known as greenhouse gases, water vapour has the largest effect.
The origins of the term greenhouse effect are unclear. French mathematician Joseph Fourier is sometimes given credit as the first person to coin the term greenhouse effect based on his conclusion in 1824 that Earth’s atmosphere functioned similarly to a “hotbox”—that is, a heliothermometer (an insulated wooden box whose lid was made of transparent glass) developed by Swiss physicist Horace Bénédict de Saussure, which prevented cool air from mixing with warm air. Fourier, however, neither used the term greenhouse effect nor credited atmospheric gases with keeping Earth warm. Swedish physicist and physical chemist Svante Arrhenius is credited with the origins of the term in 1896, with the publication of the first plausible climate model that explained how gases in Earth’s atmosphere trap heat. Arrhenius first refers to this “hot-house theory” of the atmosphere—which would be known later as the greenhouse effect—in his work Worlds in the Making (1903).
The atmosphere allows most of the visible light from the Sun to pass through and reach Earth’s surface. As Earth’s surface is heated by sunlight, it radiates part of this energy back toward space as infrared radiation. This radiation, unlike visible light, tends to be absorbed by the greenhouse gases in the atmosphere, raising its temperature. The heated atmosphere in turn radiates infrared radiation back toward Earth’s surface. (Despite its name, the greenhouse effect is different from the warming in a greenhouse, where panes of glass transmit visible sunlight but hold heat inside the building by trapping warmed air.)
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Without the heating caused by the greenhouse effect, Earth’s average surface temperature would be only about −18 °C (0 °F). On Venus the very high concentration of carbon dioxide in the atmosphere causes an extreme greenhouse effect resulting in surface temperatures as high as 450 °C (840 °F).
Although the greenhouse effect is a naturally occurring phenomenon, it is possible that the effect could be intensified by the emission of greenhouse gases into the atmosphere as the result of human activity. From the beginning of the Industrial Revolution through the end of the 20th century, the amount of carbon dioxide in the atmosphere increased by roughly 30 percent and the amount of methane more than doubled. A number of scientists have predicted that human-related increases in atmospheric carbon dioxide and other greenhouse gases could lead by the end of the 21st century to an increase in the global average temperature of 3–4 °C (5.4–7.2 °F) relative to the 1986–2005 average. This global warming could alter Earth’s climates and thereby produce new patterns and extremes of drought and rainfall and possibly disrupt food production in certain regions.