Greenhouse Effect, the capacity of certain gases in the atmosphere to trap heat emitted from Earth’s surface, thereby insulating and warming the planet. Without the thermal blanketing of the natural greenhouse effect, Earth’s climate would be about 33°C (about 59°F) cooler—too cold for most living organisms to survive.The greenhouse effect has warmed Earth for over 4 billion years. Now scientists are growing increasingly concerned that human activities may be modifying this natural process, with potentially dangerous consequences. Since the advent of the Industrial Revolution in the 1700s, humans have devised many inventions that burn fossil fuels such as coal, oil, and natural gas. Burning these fossil fuels, as well as other activities such as clearing land for agriculture or urban settlements, releases some of the same gases that trap heat in the atmosphere, including carbon dioxide, methane, and nitrous oxide. These atmospheric gases have risen to levels higher than at any time in at least the last 650,000 years. As these gases build up in the atmosphere, they trap more heat near Earth’s surface, causing Earth’s climate to become warmer than it would naturally.
Scientists call this unnatural heating effect global warming and blame it for an increase in Earth’s surface temperature of about 0.6°C (about 1°F) over the last 100 years. Scientists project global temperatures to continue rising during the 21st century. Warmer temperatures could melt parts of polar ice caps and most mountain glaciers, causing a rise in sea level that would flood coastal regions. Global warming could also affect weather patterns causing, among other problems,
prolonged drought or increased flooding in some of the world’s leading agricultural regions.
Earth’s atmosphere and the way it interacts with the oceans and radiation from the Sun are responsible for the planet’s climate and weather. The atmosphere plays a key role in supporting life. Almost all life on Earth uses atmospheric oxygen for energy in a process known as cellular respiration, which is essential to life. The atmosphere also helps moderate Earth’s climate by trapping radiation from the Sun that is reflected from Earth’s surface. Water vapor, carbon dioxide, methane, and nitrous oxide in the atmosphere act as “greenhouse gases.” Like the glass in a greenhouse, they trap infrared, or heat, radiation from the Sun in the lower atmosphere and thereby help warm Earth’s surface. Without this greenhouse effect, heat radiation would escape into space, and Earth would be too cold to support most forms of life.
Scientists call this unnatural heating effect global warming and blame it for an increase in Earth’s surface temperature of about 0.6°C (about 1°F) over the last 100 years. Scientists project global temperatures to continue rising during the 21st century. Warmer temperatures could melt parts of polar ice caps and most mountain glaciers, causing a rise in sea level that would flood coastal regions. Global warming could also affect weather patterns causing, among other problems,
prolonged drought or increased flooding in some of the world’s leading agricultural regions.
Earth’s atmosphere and the way it interacts with the oceans and radiation from the Sun are responsible for the planet’s climate and weather. The atmosphere plays a key role in supporting life. Almost all life on Earth uses atmospheric oxygen for energy in a process known as cellular respiration, which is essential to life. The atmosphere also helps moderate Earth’s climate by trapping radiation from the Sun that is reflected from Earth’s surface. Water vapor, carbon dioxide, methane, and nitrous oxide in the atmosphere act as “greenhouse gases.” Like the glass in a greenhouse, they trap infrared, or heat, radiation from the Sun in the lower atmosphere and thereby help warm Earth’s surface. Without this greenhouse effect, heat radiation would escape into space, and Earth would be too cold to support most forms of life.
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