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A Overview of Global Warming

An Overview and the Causes of Global Warming


Getty Images /VisionsofAmerica/Joe Sohm
Updated June 26, 2008
Global Warming, the general increase in the earth's near-surface air and ocean temperatures, remains a pressing issue in a society that has expanded its industrial use since the mid-twentieth century.

Greenhouse gases, atmospheric gases that exist to keep our planet warm and prevent warmer air from leaving our planet, are enhanced by industrial processes. As human activity such as the burning of fossil fuels and deforestation increases, greenhouse gases such as Carbon Dioxide are released into the air. Normally, when heat enters the atmosphere, it is through short-wave radiation; a type of radiation that passes smoothly through our atmosphere. As this radiation heats the earth's surface, it escapes the earth in the form of long-wave radiation; a type of radiation that is much more difficult to pass through the atmosphere. Greenhouse gases released into the atmosphere cause this long-wave radiation to increase. Thus, heat is trapped inside of our planet and creates a general warming effect.

Scientific organizations around the world, including The Intergovernmental Panel on Climate Change, the InterAcademy Council, and over thirty others, have projected a significant change and future increase in these atmospheric temperatures. But what are the real causes and effects of global warming? What does this scientific evidence conclude in regards to our future?

Causes of Global Warming

The crucial component that causes greenhouse gases such as CO2, Methane, Chlorofluorocarbons (CFC's), and Nitrous Oxide to be released into the atmosphere is human activity. The burning of fossil fuels (i.e., non-renewable resources such as oil, coal, and natural gas) has a significant effect on the warming of the atmosphere. The heavy use of power plants, cars, airplanes, buildings, and other man-made structures release CO2 into the atmosphere and contribute to global warming.

Nylon and nitric acid production, the use of fertilizers in agriculture, and the burning of organic matter also release the greenhouse gas Nitrous Oxide. These are processes that have been expanded since the mid-twentieth century.


Another cause of global warming is land-use changes such as deforestation. When forest land is destroyed, carbon dioxide is released into the air thus increasing the long-wave radiation and trapped heat. As we lose millions of acres of rainforest a year, we are also losing wildlife habitats, our natural environment, and most significantly, a non-regulated air and ocean temperature.

Effects of Global Warming

The increase in the warming of the atmosphere has significant effects on both natural environment and human life. Obvious effects include glacial retreat, Arctic shrinkage, and worldwide sea level rise. There are also less obvious effects such as economic trouble, ocean acidification, and population risks. As climate changes, everything changes from the natural habitats of wildlife to the culture and sustainability of a region.

Melting of the Polar Ice Caps

One of the most obvious effects of global warming involves the melting of the polar ice caps. According to the National Snow and Ice Data Center, there are 5,773,000 cubic miles of water, ice caps, glaciers, and permanent snow on our planet. As these continue to melt, sea levels rise. Rising sea levels are also caused by expanding ocean water, melting mountain glaciers, and the ice sheets of Greenland and Antarctica melting or sliding into the oceans. Rising sea levels result in coastal erosion, coastal flooding, increased salinity of rivers, bays, and aquifers, and shoreline retreat.

Melting ice caps will desalinize the ocean and disrupt natural ocean currents. Since ocean currents regulate temperatures by bringing warmer currents into cooler regions and cooler currents into warmer regions, a halt in this activity may cause extreme climate changes, such as Western Europe experiencing a mini-ice age.

Another important effect of melting ice caps lies in a changing albedo. Albedo is the ratio of the light reflected by any part of the earth's surface or atmosphere. Since snow has one of the highest albedo level, it reflects sunlight back into space, helping to keep the earth cooler. As it melts, more sunlight is absorbed by the earth's atmosphere and the temperature tends to increase. This further contributes to global warming.

Wildlife Habits/Adaptations

Another effect of global warming is changes in wildlife adaptations and cycles, an alteration of the natural balance of the earth. In Alaska alone, forests are continually destroyed due to a bug known as the spruce bark beetle. These beetles usually appear in the warmer months but since the temperatures have increased, they have been appearing year-round. These beetles chew on spruce trees at an alarming rate, and with their season being stretched for a longer period of time, they have left vast boreal forests dead and gray.

Another example of changing wildlife adaptations involves the polar bear. The polar bear is now listed as a threatened species under the Endangered Species Act. Global warming has significantly reduced its sea ice habitat; as the ice melts, polar bears are stranded and often drown. With the continuous melting of ice, there will be less habitat opportunities and a risk in extinction of the species.

Ocean Acidification/Coral Bleaching

As Carbon Dioxide emissions increase, the ocean becomes more acidic. This acidification affects everything from an organism's ability to absorb nutrients to changes in chemical equilibrium and therefore natural marine habitats.

Since coral is very sensitive to increased water temperature over a long period of time, they lose their symbiotic algae, a type of algae that gives them coral color and nutrients. Losing these algae results in a white or bleached appearance, and is eventually fatal to the coral reef. Since hundreds of thousands of species thrive on coral as a natural habitat and means of food, coral bleaching is also fatal to the living organisms of the sea.

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