While the temperature of the earth surface is almost stable, the other planets in solar system of the earth are either experiencing a very hot or most cold temperature. Thin gases layer which protect the planet accounts for the stable temperature that the earth enjoys. In the past two centuries, it is believed that human activities has changed Earth's atmosphere in so many ways which results into global warming. To understand what global warming is, you must first understand greenhouse effect very well.
Radiations that hit the earth are very many, and these radiations are primarily from the sun. There is always imbalance act between the radiations in which the planet receives from space and the one that is reflected back to the space. These radiations from the sun are in form of Infrared (IR), visible light, ultraviolet and other human eye visible radiations.
The difference between these radiations is; IR has weaker energy level and longer wavelength while UV radiation possesses a high energy level and shorter wavelength than the visible light. Sand, ice, snow, cloud and other reflecting surface are responsible for instant reflection of 30 percent of radiation striking earth’s atmosphere back to space.
The ocean, land and atmosphere absorb the remaining incoming radiation which is about 70 percent. The radiations from the atmosphere heat up the land, oceans and atmosphere. The absorbents of the radiation which include land, ocean and atmosphere release the absorbed heat back to the space inform of IR thermal radiation.
The equilibrium between the absorbed (incoming) and reflected (outgoing) radiation is the main reason the earth is habitable to humans and other organisms. The earth would have been so hot or rather too cold for humans and other organism to survive without atmospheric equilibrium.
Green House Effect
Greenhouse effect is the exchange of radiations that heat up the earth, that is, exchange of incoming (absorbed) and outgoing (reflected) radiation. Strong radiation like UV radiation penetrates greenhouse glass wall easily and it is absorbed by plants and hard surfaces inside. Weaker radiation like IR finds it difficult to penetrate the glass wall and it is confined in the inside, thereby resulting in to greenhouse. This effect allows the survival of plant in the green house and even in the cold weather.
This similar effect also takes place in a car that is parked outside on a sunny day. The car interior is been warmed up by the absorbed radiation, the thermal radiation of IR that is supposed be reflected is trapped inside the car with closed window.
Greenhouse Gases and Global Warming
Significantly enough quantity of gas molecules which absorbs thermal infrared radiation are called greenhouse gases. These greenhouse gases function by absorbing IR radiation from the space and stopping the radiation from escaping back to the atmosphere. The effect of this procedure results into heating up of the surface and earth’s atmosphere. This is referred to as global warming.
The greenhouse gases are made up of the following gases, carbon dioxide, water vapor, methane, nitrous oxide and ozone. These gases work as one to make sure that the temperature of the atmosphere is maintained by confining the infrared radiation within the earth’s atmosphere.
The percentage composition of greenhouse gas is as follow. Carbon dioxide is responsible for 9-26% of greenhouse gas, 36-70% of water vapor is found in greenhouse gas, 4-9% of methane is present while the percentage of nitrous oxide is not mentioned.
Many of human activities are responsible for change in greenhouse effect . The activities include; deforestation of land, production of methane through agriculture and burning of fossil fuels. These activities result to increase in temperature of the earth. It is very important to be careful about the activities that will increase the greenhouse effect because increase in greenhouse effect poses a great threat to the life of all living organisms on the earth.
Chemistry role of greenhouse gas
Human activities increase the level of greenhouse gas. The larger percentage of greenhouse gas is made up of water vapor and as far as human activities continue to contribute methane and carbon dioxide to the atmosphere, there will always be increase in temperature of the atmosphere and increase in evaporation of more water. Also, consumption of fossil fuel and volcanic eruption increase the amount of carbon dioxide on Earth’s atmosphere.
Another activity that increases the amount of atmospheric carbon dioxide as a result of decrease in photosynthesis is deforestation. Besides, methane is a hydrocarbon and its contribution to greenhouse effect is very high. Through manure and waste decomposition, methane is found in the atmosphere. Above all, organic fertilizer, soil cultivation, fossil fuel utilization and nitric acid production are means through which nitrous oxide can be synthesized naturally and artificially.