Global Warming

Global Warming 1

Global warming is the increase of Earth's average surface temperature due to effect of greenhouse gases. These gases affect the Earth's atmosphere. The climate of Earth is influenced by the first six miles of the atmosphere. It is a thin layer which is being damaged from greenhouse gases. Is this damage being caused by the actions of humans?

Greenhouse gases can consist of carbon dioxide emissions from burning fossil fuels or from deforestation. This would trap heat that would otherwise escape from Earth. This is a type of greenhouse effect. A greenhouse gas that is most significant is water vapor. This is something that is not produced directly by humans. The slightest increase in atmospheric levels of carbon dioxide (CO2) can cause a substantial increase in temperature.

This is because the concentrations of these gases are not nearly as large as that of oxygen and nitrogen, which are the main constituents of the atmosphere. Neither, nitrogen or oxygen are greenhouse gases. Carbon dioxide remains in the atmosphere for a very long time. Water vapor can easily condense or evaporate depending on local conditions.

According to the article for National Geographic News, "Global warming is here. It's human caused and it will continue for centuries even if greenhouse gas emissions are stabilized." (Roach, 2007). The Intergovernmental Panel on Climate Change, believe Earth's warming temperatures, rising seas and more intense storms are due to human activity.

"A bold new hypothesis suggests that our ancestors farming practices kicked off global warming thousands of years before we started burning coal and driving cars." (Ruddiman, 2005). The most plausible new factor in this is farming. Over 11,000 years ago, agriculture originated in the Fertile Crescent region of the eastern Mediterranean. Shortly after, northern China began agriculture and years later in the Americas.

There are several farming activities that generate methane. Flooding rice paddies by irrigation generates methane. Natural wetlands do for the same reason. The vegetation decomposes in the stagnant standing water. Methane is also released when farmers burn grassland in an attempt to attract game and promote growth of some crops. Methane is released in feces and belches from domesticated animals as well. "All these factors probably contributed to a gradual rise in methane as human populations grew slowly, but only one process seems likely to have accounted for the abruptness of the reversal from a natural methane decline to an unexpected rise around 5,000 years ago, the onset of rice irrigation in southern Asia." (Ruddiman, 2005). Farmers flooded lowlands near rivers to grow strains of wet adapted rice in China. This explains the quick shift in the methane trend.

Deforestation is another common practice tied to farming. This provides a plausible explanation for the start of carbon dioxide trend. Growing crops in forested areas require cutting trees down. Of natural forest, about 15% to 30% has been converted to pasture or cropland. "When forests are razed or decompose, much of their biomass is converted into greenhouse gases, especially carbon dioxide." (Laurance, 2010).

Rain forests help generate rainfall in drought prone countries elsewhere. The destruction of rain forests in some West African countries may have been the cause of two decades of droughts in the interior of Africa. Deforestation can have catastrophic global effects. Trees are natural consumers of carbon dioxide. This is a greenhouse gas whose buildup in the atmosphere contributes to global warming. Destruction of these trees not only removes this but tree burning and decomposition, pump more carbon dioxide into the