Select personalised ads. Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email. Anne Marie Helmenstine, Ph. Chemistry Expert. Helmenstine holds a Ph. She has taught science courses at the high school, college, and graduate levels. Facebook Facebook Twitter Twitter. Cite this Article Format.
Helmenstine, Anne Marie, Ph. Solar Radiation and the Earth's Albedo. Journey through the Solar System: Planet Venus. What are the top 5 gases in the atmosphere? Nitrogen — 78 percent. Oxygen — 21 percent. Argon — 0. Carbon dioxide — 0. Trace amounts of neon, helium, methane, krypton and hydrogen, as well as water vapor.
What are the 4 most common gases on Earth? What gases are unique to planet Earth? What is the coldest layer of the atmosphere? Which gas is least in atmosphere? What are the 7 layers of atmosphere? The Troposphere. This is the lowest part of the atmosphere — the part we live in.
This extends upwards from the tropopause to about 50 km. The region above the stratosphere is called the mesosphere. Smaller sources include termites, oceans, sediments, volcanoes, and wildfires.
To find out more about the role of CH 4 in warming the atmosphere and its sources, visit the Climate Change Indicators page. Methane emissions in the United States decreased by 15 percent between and During this time period, emissions increased from sources associated with agricultural activities, while emissions decreased from sources associated with landfills, coal mining, and from natural gas and petroleum systems.
There are a number of ways to reduce CH 4 emissions. Some examples are discussed below. EPA has a series of voluntary programs for reducing CH 4 emissions, in addition to regulatory initiatives. EPA also supports the Global Methane Initiative , an international partnership encouraging global methane reduction strategies.
Upgrading the equipment used to produce, store, and transport oil and natural gas can reduce many of the leaks that contribute to CH 4 emissions. Methane from coal mines can also be captured and used for energy. Methane from manure management practices can be reduced and captured by altering manure management strategies. Additionally, modifications to animal feeding practices may reduce emissions from enteric fermentation. Because CH 4 emissions from landfill gas are a major source of CH 4 emissions in the United States, emission controls that capture landfill CH 4 are an effective reduction strategy.
Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K. Averyt, M. Tignor and H. Miller eds. Cambridge University Press. Cambridge, United Kingdom pp. In , nitrous oxide N 2 O accounted for about 7 percent of all U. Human activities such as agriculture, fuel combustion, wastewater management, and industrial processes are increasing the amount of N 2 O in the atmosphere. Nitrous oxide is also naturally present in the atmosphere as part of the Earth's nitrogen cycle, and has a variety of natural sources.
Nitrous oxide molecules stay in the atmosphere for an average of years before being removed by a sink or destroyed through chemical reactions. The impact of 1 pound of N 2 O on warming the atmosphere is almost times that of 1 pound of carbon dioxide. Nitrous oxide emissions occur naturally through many sources associated with the nitrogen cycle, which is the natural circulation of nitrogen among the atmosphere, plants, animals, and microorganisms that live in soil and water.
Nitrogen takes on a variety of chemical forms throughout the nitrogen cycle, including N 2 O. Natural emissions of N 2 O are mainly from bacteria breaking down nitrogen in soils and the oceans. Nitrous oxide is removed from the atmosphere when it is absorbed by certain types of bacteria or destroyed by ultraviolet radiation or chemical reactions.
To find out more about the sources of N 2 O and its role in warming the atmosphere, visit the Climate Change Indicators page. Nitrous oxide emissions in the United States have remained relatively flat between and Nitrous oxide emissions from mobile combustion decreased by 60 percent from to as a result of emission control standards for on-road vehicles. Nitrous oxide emissions from agricultural soils have varied during this period and were about 9 percent higher in than in , primarily driven by increasing use of nitrogen fertilizers.
The application of nitrogen fertilizers accounts for the majority of N 2 O emissions in the United States. Emissions can be reduced by reducing nitrogen-based fertilizer applications and applying these fertilizers more efficiently, 3 as well as modifying a farm's manure management practices.
Additionally, the introduction of pollution control technologies e. Production of adipic acid results in N 2 O emissions that can be reduced through technological upgrades. Greenhouse Gas Mitigation Potential in U. Forestry and Agriculture. Unlike many other greenhouse gases, fluorinated gases have no natural sources and only come from human-related activities.
They are emitted through their use as substitutes for ozone-depleting substances e. Many fluorinated gases have very high global warming potentials GWPs relative to other greenhouse gases, so small atmospheric concentrations can have disproportionately large effects on global temperatures.
They can also have long atmospheric lifetimes—in some cases, lasting thousands of years.
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