Have you ever been in a greenhouse? (paper flower, umbrella tree) Greenhouses , sometimes called hothouses, because they work by trapping the sun’s heat. Gardeners also use greenhouses to protect plants from freezing in the winter. When sun rays enter ….
We know how the earth’s atmosphere surrounds our planet like a blanket. It protects us from harmful cosmic radiation, regulates temperature and humidity, and controls the weather. …..As we see in th figure that 20% of the rays r scatr nd reflected by clouds 51% absorbed by th erth , 4% reflectd by surface 19% absorb by atmspre nd clouds nd 6% scater frm atmspre
In our atmspere th Gases like CO2,NO,CH4,O3 r also present these r called greenhouse gases. Whn sun rays pases through these gases they trap the sun rays nd prevent th heat from escaping bak into space therefore these gases preserve the earth’s surface temperature at a medium level which is needed to support life……though…….The greenhouse effect describes how atmospheric gases prevent heat from being released back into space. If therse r more gases , more the Earth heats up. But The greenhouse effect is important. Without it, the Earth would not be warm enough for most living things to survive. However, if the greenhouse effect gets too strong, it can make the Earth warmer than normal. The problem is that even a little more heat creates very big problems for people, plants, and animals……….
Green house effect
BY:- Rishabh sood
<ul><li>Greenhouses are special buildings usually made from glass and steel. They are used to grow plants that need humidity, tropical temperatures, and constant growing conditions. </li></ul><ul><li>In a glass greenhouse, heat builds up and gets trapped due to presence of carbon dioxide and other heat trapping gases in the upper atmosphere. It offers plants a warm and humid environment, even if the outside weather is dry, windy, or cold. </li></ul>
<ul><li>When the sunrays enters the earth’s atmosphere which is made up of several layers of gases and reach the planet Earth, the Earth's surface land, water and biosphere - absorb the solar energy. Once absorbed, this energy gets recycled into the </li></ul><ul><li>atmosphere. </li></ul>
The gases like water vapour, carbon dioxide, nitrous oxide, methane and ozone, which are present in the atmosphere , trap energy from the sun and prevent the heat from escaping back into space. Though some of the energy passes back into space, most of it remains trapped in the atmosphere, which causes the Earth to heat up. These gases are known as greenhouse gases and this natural process of maintaining the earth's average temperature and keeping the Earth warm is known as the Greenhouse EFFECT (cond..) Greenhouse effect
<ul><li>Natural Greenhouse gases </li></ul><ul><li>Man made Greenhouse gases </li></ul>
<ul><li>The primary components of Earth’s atmosphere, N 2 and O 2 do not have absorption in the IR wavelength range, therefore, do not have a significant role in setting the surface temperature of the planet… </li></ul><ul><li>Greenhouse gas are efficient in absorbing IR light … </li></ul><ul><ul><li>The most important greenhouse gases are: </li></ul></ul><ul><ul><li>H 2 O – Water vapor. </li></ul></ul><ul><ul><li>CO 2 – Carbon Dioxide </li></ul></ul><ul><ul><li>CH 4 – Methane </li></ul></ul><ul><ul><li>NH 4 – Nitrous oxide The most abundant greenhouse gas in Earth’s atmosphere is water vapor . Most of the greenhouse heating of Earth’s atmosphere is due to Water vapor absorption of IR radiation emitted by Earth. </li></ul></ul>
<ul><li>Along with natural greenhouse gases, there are some man-made greenhouse gases that keep on increasing in the atmosphere. Human activities like burning of fossil fuels , coal, oil, natural gas, cutting down and burning trees, etc. generate lot of carbon dioxide due to which the balance of greenhouse gases in the atmosphere gets disturbed. Use of aerosols, hairspray cans, fridges, plastics, etc. produce a group of highly dangerous greenhouse gases called chlorofluorocarbons. These are so harmful that even small amounts can trap large quantities of heat, making the Earth extremely hot. This phenomenon is known as global warming , which has a highly dangerous effect on the Earth </li></ul>
<ul><li>Sun’s energy gets trapped in the troposphere </li></ul><ul><ul><li>Some radiation that reaches Earth’s surface is absorbed. </li></ul></ul><ul><ul><li>Some energy is reflected </li></ul></ul><ul><li>Reflected heat get trapped by (Greenhouse Gases) carbon dioxide(56%), methane(18%), CFCs(13%) and nitrous oxide(6%) </li></ul><ul><li>Trapped heat makes atmosphere warmer. </li></ul><ul><li>Warm atmosphere reflects heat to Earth’s surface again! </li></ul>Reflection Of Heat by Greenhouse Gases
<ul><li>Weather </li></ul><ul><li>Sea Levels </li></ul><ul><li>Farming </li></ul><ul><li>Plants And Animals </li></ul><ul><li>People </li></ul>
<ul><li>In some parts of the world, due to rise in the winter and summer temperatures, the weather will become very hot. It may rain more in winters, while summers will become extremely hot. In other parts of the world, the effects may be completely opposite, as some areas may get very warm while other may become very cold. Storms, floods, and droughts are some expected consequences which may affect different areas of the world. </li></ul>Weather
<ul><li>Increase in the temperature may cause melting glaciers , which will increase the water in the seas and oceans, rising the sea levels up to 20 to 40 cm all over the world. People living near the lower coastal areas of the world, like Netherlands and Bangladesh, will be at a higher risk from flooding. As a result, millions of people may have to leave their homes and large areas of farmland may also get destroyed. </li></ul>
<ul><li>The changes in the weather may also cause changes in the amount of rainfall in different parts of the world. Some places may get heavy rains while in other places it may not rain at all. Hence, this will affect the crop growth throughout the world, as crops like wheat and rice grow well in higher temperatures, whereas crops like maize and sugarcane may not grow. Therefore, there will be scarcity of food in some parts of the world and people will suffer from hunger. </li></ul>
<ul><li>Due to these weather and temperature changes, many plants and animals will not be able to cope up and will die eventually. For example, polar bears and seals will have to search for new homes for hunting and living, if the ice in the Arctic melts. Since natural habitats of plants and animals will get affected, most species may become extinct. </li></ul>
<ul><li>Last but not the least, these weather changes will also bring unwanted changes in our lifestyle. The consequences of these climatic variations on human beings depend on how well we adapt ourselves to the changes, and how much we can do to minimize them. </li></ul>
1979 2003 Melting Glaciers + National Geographic Magazine September 2004
Importance Of Greenhouse Effect ! <ul><li>No greenhouse effect would mean colder than average temps. </li></ul><ul><li>Too much, however, can cause a rise in average temps. </li></ul>
Other planets also have Greenhouse Effects, but these are unsuitable for life Sun Mars Atmosphere: mass <1% earth’s GH Gases: >80% CO 2 Sfc. Temp.: -47 C GH Effect: 10 C FAR TOO COLD! Earth <ul><li>GH Gases: ~0.04% CO 2 </li></ul><ul><ul><li> ~ 1% H2O </li></ul></ul><ul><li>Sfc. Temp.: 15 C </li></ul><ul><li>GH Effect: 33 C </li></ul><ul><li>NOT BAD! </li></ul>Venus Atmosphere: mass 90x earth’s GH Gases: >90% CO 2 Sfc. Temp.: 477 C GH Effect: 523 C FAR TOO HOT!
<ul><li>Reduce World’s Population ?? </li></ul><ul><li>Reduce or maintain current levels of CO2 in the atmosphere </li></ul>