GREENHOUSE EFFECT

While all the other planets in the earth’s solar system is either scorching hot or bitterly cold,  planet Earth’s surface on the other hand is relatively mild and stable in temperature, this is because carbon dioxide (CO2) helps to maintain the Earth’s temperature by the way of the “Greenhouse Effect”.

Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities causing global warming and ultimately changing the climate which adversely affects the health and wellbeing of all living thing on the planet Earth, now although it is naturally present in the atmosphere as part of the Earth’s carbon cycle during the natural circulation of carbon among the atmosphere, oceans, soil, plants and animals.

Human activities have adversely altered the carbon cycle both by adding more CO2 to the atmosphere and by influencing the ability of natural sinks such as the forest to remove CO2 from the atmosphere. While CO2 emissions come from a variety of natural sources, human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution.

Global warming is essentially a problem of too much carbon dioxide (CO2) in the atmosphere, caused by carbon overload when fossil fuels such as coal, oil and gas and even deforestation. It is worth continuously noting that there are many other heat trapping gases such as methane and water vapours but CO2 poses the greatest risk of irreversible changes if it continues to accumulate unabatedly in the atmosphere for two (2) main reasons:

Carbon dioxide (CO2) more than any other climate driver, has contributed the most to climate change since the 1750’s.
CO2 remains in the atmosphere through the radiative forcing longer than any other major heat trapping gas emitted as a result of human activities.

ANTHROPOGENIC GENERATION AND SINKS OF CARBON DIOXIDE

Industrialization has brought about a greater demand for energy hence the rapid increase in the burning of fossil fuel, resulting in greater amount of carbon dioxide emitted to the atmosphere.

Now, although carbon dioxide is essentially important for the survival of all life on earth, it is also the primary greenhouse gas emitted through human activities. Human activities are altering the carbon cycle both by adding more CO2 to the atmosphere and by influencing the ability of natural sinks, like forests, to remove CO2 from the atmosphere.

While CO2 emissions come from a variety of natural sources, human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution.

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anthropogenic sources of greenhouse effect

The main human activity that emits CO2 as the combustion of fossil fuel (coal, natural gas and oil) for energy and transportation, although certain industrial processes and land-use changes also emit significant amounts of CO2.

To understand and gain an appreciation for the greenhouse effect and its link to global warming it is extremely critical I explain the lingering role of greenhouse gases and undertake an in-depth appreciation of the primary greenhouse gas sources caused by human activities CARBON DIOXIDE.

The main reason CO2 is considered the most important primary greenhouse gas as opposed to all the others is simply because methane (CH4) emissions converts into CO2 to exit the atmosphere, nitrous oxide (N2O) takes about a century to exit while CO2 emissions 80% will be gone within a century but 20% will linger around in the atmosphere for approximately 800 years, consequently CO2 stays in our atmosphere for a long period and any addition has a much more long-term effect.

This literally means that this heat trapping emission will set the climate for our children and grandchildren.

Now methane and water vapour can be considered as an important heat trapping gas, when considering human induced climate change, but not having the same effect as CO2.

The Greenhouse effect  warms the earth temperature; and without this process the ocean would freeze and life on earth as we know would be impossible.

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greenhouse effect

Greenhouse effect involves radiation emitted from the sun and absorption by the earth, through this the planet Earth undergoes a delicate daily balancing act involving the radiation the planet receives from outer space and the radiation that is reflected back out,  the Earth is continuously bombarded with an enormous amount of radiation, mainly from the sun, this solar radiation strikes the Earth’s atmosphere in the form of visible light along with ultraviolet (UV), infrared (IR) and other types of radiation that are not visible by the human eye.

Few thing to note is that UV radiation has a shorter wavelength and a higher energy level than visible light, while IR radiation has a longer wavelength and a weaker energy level, radiation from the Sun is absorbed by the surface, with the amount absorbed depending highly on the type of surface, with approximately 30% of the radiation striking the Earth’s atmosphere reflected back into space immediately by clouds, ice, snow, sand and other reflective surfaces.

The remaining 70% of this incoming solar radiation is absorbed by the ocean, the land and the atmosphere, heating up and releasing heat in the form of IR thermal radiation, which passes out of the atmosphere and into space, noting that much of it is absorbed by greenhouse gases which makes the atmosphere warmer, that re-emits the radiation in all direction and warms the atmosphere further. This essentially traps the heat in the Earth’s atmosphere, and as more greenhouse gas is added, the temperature will increased.

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direct vs indirect radiative forcing

Now we must understand that at the mention of global warming and greenhouse effect, the true underlying scientific concept surrounding this process is radiative forcing. This concept of radiative forcing is fairly simple and straightforward.  Energy is constantly flowing into the atmosphere in the form of sunlight that always shines on half of the Earth’s surface.

This means that everything on the Earth is at equilibrium and nothing will change except for some small unsystematic variant, a number of factors must be considered in the effect on the Earth’s balancing act; with each having it own level uncertainty and difficulties in being precisely measured, because many of the factors overlap for instance different greenhouse gases absorb and emit at the same infrared wavelengths of radiation so their combined warming effect is less than the sum of their individual effects.

BY NAZINA BELLE

REFERENCE: Pidwirny, M. (2006). “The Carbon Cycle”. Fundamentals of Physical Geography, 2nd Edition

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