Nitrous oxide global increase

What has changed in the last few hundred years is the additional release of carbon dioxide by human activities. Fossil fuels burned to run cars and trucks, heat homes and businesses, and power factories are responsible for about 98% of carbon dioxide emissions, 24% of methane emissions, and 18% of nitrous oxide emissions. Increased agriculture, deforestation, landfills, industrial production, and mining also contribute a significant share of emissions (5). For example, in 1997, the United States emitted about one-fifth of total global greenhouse gases. 

The global atmospheric nitrous oxide concentration increased from a preindustrial value of about 270 ppb to 319 ppb in 2005. The growth rate has been approximately constant since 1980 and more than 30% of all nitrous oxide emissions are primarily due to agriculture. 

Recent estimates indicate that the level of carbon dioxide in the atmosphere has increased by a third since the beginning of the industrial age, and that it contributes significantly to global warming. Other major contributors include methane, tropospheric ozone, and nitrous oxide. Methane is the principal component of natural gas, but it is also produced by other sources such as rice paddies and farm animals. Tropospheric ozone is generated naturally and by the sunlight-... 

Besides NOx oxides, there is nitrous oxide (N2O), which is of special interest in isotope geochemistry. N2O is present in air at around 300 ppb and increases by about 0.2% per year. Nitrous oxide is an important greenhouse gas that is, on a molecular basis, a much more effective contributor to global warming than CO2 and that is also a major chemical control on stratospheric ozone budgets. 

The global system that regulates the earths temperature is very complex, but many scientists believe the increase in temperature is caused by an increase of certain gases in the atmosphere that trap energy that would otherwise escape into space. These gases, called greenhouse gases, include carbon dioxide, methane, nitrous oxide, chlorofluorocarbons (CFCs), and the ozone in the lower atmosphere. 

---