Greenhouse is a building with a glass roof and sides enclosing a space in which temperature and humidity cane controlled for cultivating tender or out-of-season plans. Greenhouse became popular in Europe. The favorite crops were pineapples, peaches and grapes; they were grown in green-houses.
Greenhouse effect is defined as the trapping by the earth’s atmosphere of heat energy radiated from the sun. the effect is named after the solar warming observed in greenhouses, although the later effect is in fact more directly the result of trapping warmed air below the ceiling of glass.
All substances absorb energy in the forms of radiation convert fit to heat, and then reradiate the energy. Dark and matt colors absorb higher proportions than lighter shiny colors, such as the ice herein gases, do not absorb very my such radiations (except in the far ultraviolet), unlike the know gases, ozone, nitrous oxide, wear vapors and carbon dioxide, which have a significant effect on atmospheric absorption.
The amount of radiation absorbed and reradiated varies with the nature of the substance and the wavelength of addition. As for the atmosphere, it is nearly transparent for the short, visible wavelengths of the electromagnetic spectrum carbon dioxide, ozone, methane, water vapors and nitrous oxide in the air, however, absorb the solar radiation.
An average of about half of the solar radiation intercepted by the earth passes through the atmosphere and is absorbed by the alone and water surface. These surfaces warm up and emit infrared red radiation. The atmosphere absorbs much of this radiation and in turn warms up and re-emits infrared radiation. The part of the atmosphere’s re-emitted radiation that is directed downward toward the earth, called ‘counter radiation’, is responsible for the greenhouse effect.
There is a continuous exchange of infrared radiation between the earth and the atmosphere,. This exchange keeps the air temperature higher than it would be. The brining of coal, oil and gas increases the carbon dioxide content of the air temperature. On a worldwide scale, the carbon dioxide content of the air has increased by about 25% in the last 100 years.
RISING GROWTH OF GREENHOUSE GASES
Human induced radioactive forcing of the earth’s climate is largely due to increases in the concentrations of the long-lived greenhouse gases CO2, method (CH4) and nitrous oxide (N2O), PFCs, HFCs and SF6 and ozone depleting substances (cfcs, HCFCs, Halos). The predominant sources of the increase in greenhouse gases are from the combustion of fossil fuels.
The largest growth in CO2 emissions has come from power generation and road transport, with industry, households and service sectors. The land use change and forestry sector plays a significant role in the overall carbon balance of the atmosphere. Data indicate that the share of CO2 emissions from deforestation and loss of carbon from the soil delay after logging was 7-16%of 2004 GHG(greenhouse gases) emissions and 11-28% of 2004 fossil CO2 emissions. In the tropic there are large emissions from deforestation and other land use change activities.