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After a decade of near-zero growth in methane levels, "globally averaged atmospheric methane increased by [approximately] 7 nmol/mol per year during 2007 and 2008. During the first half of 2009, globally averaged atmospheric CH 4 was [approximately] 7 nmol/mol greater than it was in 2008, suggesting that the increase will continue in 2009."
Global monitoring of atmospheric methane concentrations began in the 1980s. [11] The Earth's atmospheric methane concentration has increased 160% since preindustrial levels in the mid-18th century. [11] In 2013, atmospheric methane accounted for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases. [63]
Methane's GWP 20 of 85 means that a ton of CH 4 emitted into the atmosphere creates approximately 85 times the atmospheric warming as a ton of CO 2 over a period of 20 years. [23] On a 100-year timescale, methane's GWP 100 is in the range of 28–34. Methane emissions are important as reducing them can buy time to tackle carbon emissions. [24] [25]
The variation in temperature that occurs from the highs of the day to the cool of nights is called diurnal temperature variation. Temperature ranges can also be based on periods of a month or a year. The size of ground-level atmospheric temperature ranges depends on several factors, such as: Average air temperature; Average humidity
This is an accepted version of this page This is the latest accepted revision, reviewed on 28 February 2025. Gas in an atmosphere with certain absorption characteristics This article is about the physical properties of greenhouse gases. For how human activities are adding to greenhouse gases, see Greenhouse gas emissions. Greenhouse gases trap some of the heat that results when sunlight heats ...
Because of its temperature, the atmosphere emits infrared radiation. For example, on clear nights Earth's surface cools down faster than on cloudy nights. This is because clouds (H 2 O) are strong absorbers and emitters of infrared radiation. This is also why it becomes colder at night at higher elevations.
In the absence of such extreme air-mass changes, diurnal temperature variations typically range from 10 °F (5.6 °C) or smaller in humid, tropical areas, up to 40 to 50 °F (22.2 to 27.8 °C) in higher-elevation, arid to semi-arid areas, such as parts of the U.S. Western states' Intermountain Plateau areas, for example Elko, Nevada, Ashton ...
More than 70% of atmospheric methane comes from biogenic sources. Methane levels have risen gradually since the onset of the industrial era, [13] from ~700 ppb in 1750 to ~1775 ppb in 2005. [10] Methane can be removed from the atmosphere through a reaction of the photochemically produced hydroxyl free radical (OH).