What gases and chemicals are considered to have the greatest effect on global warming?

Anything that increases carbon dioxide (CO2) levels is a risk factor in heating up the planet. In addition to CO2, methane gas (CH4) and chlorofluorocarbons (CFCs) are culprits in global warming. Methane (from livestock, coal mining, and also natural sources like peat bogs and termites decomposing wood) is actually 25 times more effective in holding heat within our atmosphere, and CFCs are 20 thousand times more efficient than CO2.

Methane gases during the 1990s were rising at an annual rate of about 0.8 percent; from 1997 to 2007, however, methane levels stabilized, and scientists believed that a balance had been reached between production of methane gas and its rate of dissipation in the atmosphere. In 2007, however, a sudden spike in methane levels was noted, especially in the Northern Hemisphere, for reasons not well understood. Theories include the idea that global warming increased methane production from wetlands bacteria (i.e., the result of melting permafrost, especially in Siberia), or that the amount of OH (hydroxyl free radical), which breaks down methane, is decreasing in the atmosphere. Today, the amount of methane in the air is more than twice what it was before the Industrial Revolution (about 1,775 parts per billion versus about 700 parts per billion). The current rate of increase for methane is about 10 parts per billion annually, which is considered a significant spike. Meanwhile, because of government regulations, CFC levels have been steadily decreasing in the atmosphere, which is particularly good news for the ozone layer.

Is carbon dioxide the most harmful global warming gas?

No. Actually, water vapor contributes much more to global warming than CO2 or methane do. The problem is that human activities often increase particulates in the air, which provides nuclei for precipitation to form in clouds.

Who first hypothesized that the amount of carbon dioxide in the atmosphere had something to do with climate change?

Swedish chemist Svante Arrhenius (1859-1927) was the first to propose that the atmosphere would hold more heat as concentrations of carbon dioxide increased.

Does all carbon dioxide released as pollution remain in the atmosphere?

No, not at all. A lot of it is reabsorbed by plants, as well as the oceans, where it turns into carbonic acid. Forests and oceans can only do so much, however, especially when people are cutting down forests all over the planet. It only takes one acre of forest to absorb about 13 tons of gas and particle pollutants annually. What is not

Water vapor concentrations and distribution in the atmosphere is a factor in global warming that has twice the impact of carbon dioxide levels. This satellite image depicts water vapor distribution during the fall of 2005, with the brighter shades of blue indicating water vapor at higher elevations. (NASA/JPL)

Water vapor concentrations and distribution in the atmosphere is a factor in global warming that has twice the impact of carbon dioxide levels. This satellite image depicts water vapor distribution during the fall of 2005, with the brighter shades of blue indicating water vapor at higher elevations. (NASA/JPL)

absorbed remains in the atmosphere, and people are producing so much CO2 and other pollutants that there is a net gain in global warming gases.

How much carbon dioxide is being produced by cars and industrial emissions in the United States?

A 2004 study from the Environmental Protection Agency noted that total emissions from 1990 to 2004 have increased by 15.8 percent. While this is not great, when compared to an increase in the U.S. gross domestic product of 51 percent over the same period, it is a somewhat controlled increase.

How much carbon dioxide am I producing when I drive my car or truck?

According to the Environmental Protection Agency, burning a gallon of gasoline creates 19.4 pounds (8.8 kilograms) of carbon dioxide. Burning a gallon of diesel fuel creates 22.2 pounds (10 kilograms) of carbon dioxide. So, for example, if you have a 15-mile, one-way commute to work, work 250 days a year, and drive a gas-powered sedan that gets 18 miles per gallon, you would produce over 8,000 pounds (3,600 kilograms) of carbon dioxide pollution annually. Multiply that by the number of people driving every year worldwide, and you can see the problem!

 
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