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Main Causes of Global Warming Summary: Greenhouse Gases

A greenhouse, of the type used for plants, is designed to take in sunlight and heat from other sources, such as artificial lights and growing plants, and trap the heat inside. The buildup of certain gases in the earth's atmosphere is causing the same effect to take place worldwide, which is putting many of the earth's ecosystems, especially in arctic and coastal regions, at risk.

  1. What are Greenhouse Gases

    • The Earth has always had some level of greenhouse effect. Without it, the world would be unbearably cold. Historically, most of the greenhouse effect has been caused by water vapor, which is self regulating. As temperatures increased, so did the rate of evaporation. Evaporation raised the level of water vapor in the atmosphere; when the level of water vapor reaches a certain level it causes rain, which reduces the level of water vapor. More recently, other gases such as carbon dioxide (CO2), methane, nitrous oxide and chlorofluorocarbons have increased the greenhouse effect, causing temperatures to rise, but these gases aren't as easily removed from the atmosphere.

    Sources of CO2

    • There are a wide variety of sources of CO2. Every time a human or animal breathes, a small amount of CO2 is released. Larger quantities of CO2 are released any time something burns. This includes forest fires and volcanoes, and it also includes the burning of fossil fuels. According to the U.S. Environmental Protection Agency, fossil fuels are, by far, the world's largest source of CO2 emissions. Plants naturally absorb CO2 and convert it into oxygen, but as the level of plant life has declined through deforestation and pollution, the amount of CO2 being absorbed has also declined, causing more CO2 to make its way to the atmosphere.

    Effect on Climate

    • Light from the sun passes through the atmosphere, heating the planet below. Excess heat rises into the atmosphere and is released into space. Some of this heat, though, is trapped by greenhouse gases in the atmosphere and radiates out in all directions. The buildup of greenhouse gases in the atmosphere is causing more and more of the excess solar heat to be trapped in the atmosphere, which is causing a gradual increase in the Earth's temperatures. According to the Natural Resources Defense Council, the 10 hottest years since recordkeeping began have all occurred since 1990, and the overall average temperature on the planet could rise by as much as 9 degrees by the end of the century.

    Global Warming Consequences

    • The consequences of global warming will vary by region. In the Arctic and in high mountain areas, ice caps, glaciers and permafrost have already begun to melt. This means flooding in some areas and higher sea levels. The warmer temperatures and higher sea levels will lead to more frequent and severe storms. While rainfall may actually increase, many areas are expected to see droughts. This is partially due to the higher temperatures and partially due to the loss of glaciers and permafrost that would otherwise trap and slowly release precipitation. Many low-lying coastal areas are expected to flood, and many current agricultural areas may no longer be able to support farms. Plants and animals that cannot adapt to the sudden change are expected to become extinct.

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