Burning Fossil Fuels
When humans burn fossil fuels such as natural gases, coal and oil to create energy for manufacturing, transportation and heating, carbon dioxide is produced. The burning of fossil fuels is responsible for between 80 and 85 percent of the carbon dioxide that is being added to the atmosphere as of 2011. Carbon is an elemental product of the burning process. You cannot easily separate carbon dioxide from fossil fuel emissions. Pollution control programs therefore fail to reduce carbon dioxide.
Deforestation
In addition to ongoing industrial practices, deforestation is also contributing to carbon dioxide emissions. Humans burn vegetation during land clearing programs, releasing carbon dioxide. Trees absorb carbon as they mature. During burning, carbon enters the atmosphere. Deforestation adds huge amounts of carbon to the atmosphere. Land use changes to accommodate agriculture, ranching and logging are responsible for 15 to 20 percent of the present carbon dioxide emissions. The present levels of carbon in the Earth's atmosphere are similar to periods in our planet's history when the Earth was considerably warmer and ocean levels were far higher.
Vehicle Emissions
Ozone occurs in the atmosphere naturally, but motor vehicles contribute toward elevated levels in the lower atmosphere or troposphere. The U.S. Environmental Protection Agency (EPA) indicates that driving a vehicle constitutes an individual's single largest contribution to pollution. Vehicles emit millions of tons of pollutants daily. Vehicles add more to ground level ozone than any other factor. This represents the most serious air pollution problem in the both the Mid Atlantic and Northeast states.
Farming and Fertilizers
The United Nations Food and Agriculture Organization indicates that modern farming is adding more to current global warming than the entire transportation sector. Nitrogen oxides are released through the process of fertilizing and they trap up to 300 times more heat in the atmosphere than does carbon dioxide. The fuel burned during modern farming procedures contributes to an extent, but the release of both nitrogen oxides and methane from the fertilizer is the main cause.