Basic Causes of Global Warming
Global warming is the theory that the Earth's global average temperature is increasing. Although this could be a natural part of the Earth's aging process, global warming focuses more on the man-made changes that are affecting the climate. The "greenhouse effect" is the idea that gases in the atmosphere trap sunlight and heat and cause the overall temperature to rise. Other causes of global warming include carbon dioxide emissions from vehicles and buildings, methane, the clearing of rainforests, and permafrost.
Greenhouse Effect
When sunlight hits the Earth some is absorbed but most is reflected. The greenhouse effect is when sunlight escaping back into space is absorbed by gases in the atmosphere and then reflected back onto the Earth's surface. Most greenhouse gas is water vapor, but other gases that contribute to it include carbon dioxide, methane, ozone, and other gases that have a less significant impact.
Carbon Dioxide
According to the U.S. Emissions Inventory 2004 Executive Summary, in 2002 around 40 percent of carbon dioxide emissions were the result of burning coal for electricity. Around 93 percent of the electric utility industry burns coal. Carbon dioxide emissions also come from cars and other vehicles, airplanes and buildings. New technologies, like the hydrogen fuel cell vehicle and hybrid electric vehicles, are some solutions for minimizing vehicle carbon dioxide emissions.
Methane
Methane is the second largest contributor to the greenhouse effect. Methane is a natural byproduct of living organisms and is produced by plants and bovine flatulence. Bacteria decomposing organic material also produce methane. According to the U.S. Emissions Inventory 2004 Executive Summary, methane levels have increased by 145 percent in the last 100 years. In the United States, all rice fields are grown in flooded areas which produce methane gases.
Deforestation
Deforestation is the process of clearing forests, either rainforest or temperate forests. The burning of forests is responsible for up to 25 percent of carbon dioxide emissions. This is the result of clearing and cutting nearly 34 million acres a year. Forests are also important because they convert carbon dioxide into oxygen. So while carbon dioxide emissions increase, the lack of forests is making the number increase faster.
Permafrost
Permafrost is a layer of land and soil that has been frozen and kept at freezing temperatures or below. In many northern climates like Alaska, Canada and Siberia, the permafrost layer of soil holds vast amounts of carbon. What researchers and scientists fear is that the permafrost will warm up and microbes will decompose the soil and release carbon dioxide. Permafrost has absorbed carbon dioxide for thousands of years, but may release it back if thawed.
