Science News. Story Source: Materials provided by Princeton University. Methane fluxes show consistent temperature dependence across microbial to ecosystem scales.
Nature , ; : DOI: ScienceDaily, 27 March Princeton University. A more potent greenhouse gas than carbon dioxide, methane emissions will leap as Earth warms. Retrieved November 12, from www. Methane is emitted from active underground and surface mines as well as from abandoned mines and undeveloped coal seams. The geological formation of oil can also create large methane deposits that get released during drilling and extraction. The production, refinement, transportation and storage of oil are all sources of methane emissions, as is incomplete combustion of fossil fuels.
No combustion process is perfectly efficient, so when fossil fuels are used to generate electricity, heat, or power vehicles these all contribute as sources of methane emissions. Here are an important four:. We should certainly strive to reduce methane from all sources.
Methane has a relatively short life of 12 years compared to the hundreds or even thousands of years that CO 2 hangs around. After about 12 years, 80 to 89 percent of methane is removed by oxidation with tropical hydroxyl radicals OH , a process referred to as hydroxyl oxidation. As a result of its short lifespan, methane is only significantly warming our atmosphere for those 12 years, which is why it is considered a short-lived climate pollutant SLCP.
Its short lifespan is further relevant in regard to warming, because it means that as methane is being emitted it is also being destroyed in the atmosphere, making it a flow gas. This is a change in the rate of emission. For example, if a herd of cattle emits the same amount of methane over 12 years, they are contributing to warming for those 12 years. JavaScript appears to be disabled on this computer.
Please click here to see any active alerts. A million metric tons is equal to about 2. For comparison, a small car is likely to weigh a little more than 1 metric ton. Thus, a million metric tons is roughly the same mass as 1 million small cars! The U. Inventory uses metric units for consistency and comparability with other countries. GHG emissions are often measured in carbon dioxide CO 2 equivalent. Concentration, or abundance , is the amount of a particular gas in the air.
Larger emissions of greenhouse gases lead to higher concentrations in the atmosphere. Greenhouse gas concentrations are measured in parts per million, parts per billion, and even parts per trillion.
One part per million is equivalent to one drop of water diluted into about 13 gallons of liquid roughly the fuel tank of a compact car. To learn more about the increasing concentrations of greenhouse gases in the atmosphere, visit the Climate Change Indicators: Atmospheric Concentrations of Greenhouse Gases page.
Each of these gases can remain in the atmosphere for different amounts of time, ranging from a few years to thousands of years. All of these gases remain in the atmosphere long enough to become well mixed, meaning that the amount that is measured in the atmosphere is roughly the same all over the world, regardless of the source of the emissions.
Some gases are more effective than others at making the planet warmer and "thickening the Earth's blanket. For each greenhouse gas, a Global Warming Potential GWP has been calculated to reflect how long it remains in the atmosphere, on average, and how strongly it absorbs energy. Note: All emission estimates are from the Inventory of U.
Greenhouse Gas Emissions and Sinks: — Carbon dioxide CO 2 is the primary greenhouse gas emitted through human activities. In , CO 2 accounted for about 80 percent of all U. Carbon dioxide is naturally present in the atmosphere as part of the Earth's carbon cycle the natural circulation of carbon among the atmosphere, oceans, soil, plants, and animals.
Human activities are altering the carbon cycle—both by adding more CO 2 to the atmosphere, and by influencing the ability of natural sinks, like forests and soils, to remove and store CO 2 from the atmosphere. While CO 2 emissions come from a variety of natural sources, human-related emissions are responsible for the increase that has occurred in the atmosphere since the industrial revolution. Carbon dioxide is constantly being exchanged among the atmosphere, ocean, and land surface as it is both produced and absorbed by many microorganisms, plants, and animals.
However, emissions and removal of CO 2 by these natural processes tend to balance, absent anthropogenic impacts. Since the Industrial Revolution began around , human activities have contributed substantially to climate change by adding CO 2 and other heat-trapping gases to the atmosphere.
In the United States, since , the management of forests and other land e. This carbon sink offset is about 12 percent of total emissions in and is discussed in more detail in the Land Use, Land-Use Change, and Forestry section. To find out more about the role of CO 2 in warming the atmosphere and its sources, visit the Climate Change Indicators page.
Carbon dioxide emissions in the United States increased by about 3 percent between and Since the combustion of fossil fuel is the largest source of greenhouse gas emissions in the United States, changes in emissions from fossil fuel combustion have historically been the dominant factor affecting total U.
Changes in CO 2 emissions from fossil fuel combustion are influenced by many long-term and short-term factors, including population growth, economic growth, changing energy prices, new technologies, changing behavior, and seasonal temperatures. Between and , the increase in CO 2 emissions corresponded with increased energy use by an expanding economy and population, including overall growth in emissions from increased demand for travel.
The most effective way to reduce CO 2 emissions is to reduce fossil fuel consumption.
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