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The Greenhouse Effect differs from actual greenhouses that we have in our gardens. In colder climates, tropical and exotic plants are grown in a greenhouse to prevent the air from cooling down too much, particularly at night. A greenhouse for plants allows the sun to warm the ground inside it, which then warms the air. By trapping the warm air inside, a greenhouse prevents cool air from entering and warm air from escaping. The Greenhouse Effect on Earth, however, has been mistakenly described as gases creating a similar barrier to the passage of heat out of earth's atmosphere. During the day, sunlight warms the Earth, and at night that heat is radiated into space in the form of infra-red radiation. Greenhouse gases absorb this radiation, and release the heat into space to cool Earth down. However, unlike with a garden greenhouse, these gases also radiate some of the heat back to earth. They do not create an impermeable barrier keeping the heat inside, but, more greenhouse gases means more heat radiated back to Earth. The greenhouse gases, in ideal quantities, keep Earth warm enough to sustain life. Too little of them, and we would freeze. Too many - as is happening now, and things start warming up. The predicted consequences of global warming (the result of the Greenhouse Effect), are dire indeed, and include climate change, rising sea levels and the possible extinction of both animals and humankind! As with any scientific theory, there are those who dispute it and believe that current evidence of climate change and predictions of worse to come are nothing more than a hiccup in the natural climatic cycle. Growing evidence of melting polar caps and weather changes would seem to indicate that there is some truth to the theory, and although predictions cannot be verified until they actually take place, they do indicate the need for some decisive action now, before it is too late. What has caused the Greenhouse Effect?A combination of factors, mostly man-made, has caused our atmosphere to change. Carbon dioxide is produced by fossil fuel burning - which is how we produce electricity and what most of our transportation is based on. Deforestation removes carbon dioxide-absorbing trees, and modern farming practices and land-use changes increase the levels of methane and nitrous oxide in the atmosphere. Methane is produced in the decomposition of garbage in landfills as well. Population growth contributes to all of these by increasing the amount of fossil fuels burned for energy, transportation and manufacturing, as well as more farming that is needed to feed more and more people. To lessen the long-term effects of global warming, greenhouse gas emissions need to be reduced. This requires a reduction of our dependance on fossil fuels, protecting and expanding forests, and changing our lifestyles to help sustain the environment. How do we do that?By using less stuff that creates greenhouse gases. The first step is to use less energy. Not only in terms of transportation and electricity usage, but also in terms of the amount of manufactured product that we use. Recycling is one way. Using alternative sources of energy is another. Growing your own herbs and vegetables is a great way to get healthy produce right outside your kitchen door. What is certain is that we can all make a small difference that will add up to a bigger difference. While we wait for big businesses and even bigger countries to take action, we can start making a change today for a better tomorrow.
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