mas evidencia del calentamiento global

peyistez mecayo dijo:

Buenol, el principal gas de efecto invernadero es el vapor de agua: 95%

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In order, Earth's most abundant greenhouse gases are:

• water vapor
• carbon dioxide
• atmospheric methane
• nitrous oxide
• ozone
• chlorofluorocarbons

The contribution to the greenhouse effect by a gas is affected by both the characteristics of the gas and its abundance. For example, on a molecule-for-molecule basis methane is about eighty times stronger greenhouse gas than carbon dioxide [7], but it is present in much smaller concentrations so that its total contribution is smaller. When these gases are ranked by their contribution to the greenhouse effect, the most important are:[8]

• water vapor, which contributes 36–72%
• carbon dioxide, which contributes 9–26%
• methane, which contributes 4–9%
• ozone, which contributes 3–7%

It is not possible to state that a certain gas causes an exact percentage of the greenhouse effect. This is because some of the gases absorb and emit radiation at the same frequencies as others, so that the total greenhouse effect is not simply the sum of the influence of each gas. The higher ends of the ranges quoted are for each gas alone; the lower ends account for overlaps with the other gases.[8][9] The major non-gas contributor to the Earth's greenhouse effect, clouds, also absorb and emit infrared radiation and thus have an effect on radiative properties of the greenhouse gases.[8][9]
In addition to the main greenhouse gases listed above, other greenhouse gases include sulfur hexafluoride, hydrofluorocarbons and perfluorocarbons (see IPCC list of greenhouse gases). Some greenhouse gases are not often listed. For example, nitrogen trifluoride has a high global warming potential (GWP) but is ************SPAM/BANNEAR************ present in very small quantities.[10]


Greenhouse gas - Wikipedia, the free encyclopedia

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The 2007 Fourth Assessment Report compiled by the IPCC (AR4) noted that "changes in atmospheric concentrations of greenhouse gases and aerosols, land cover and solar radiation alter the energy balance of the climate system", and concluded that "increases in anthropogenic greenhouse gas concentrations is very likely to have caused most of the increases in global average temperatures since the mid-20th century".[14] In AR4, "most of" is defined as more than 50%.
Gas Preindustrial level Current level Increase since 1750 Radiative forcing (W/m2) Carbon dioxide 280 ppm 387ppm 107 ppm 1.46 Methane 700 ppb 1745 ppb 1045 ppb 0.48 Nitrous oxide 270 ppb 314 ppb 44 ppb 0.15 CFC-12 0 533 ppt 533 ppt 0.17

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Role of water vapor


Water vapor accounts for the largest percentage of the greenhouse effect, between 36% and 66% for water vapor alone, and between 66% and 85% when factoring in clouds.[9] However, the warming due to the greenhouse effect of cloud cover is, at least in part, mitigated by the change in the Earth's albedo. According to NASA, "The overall effect of all clouds together is that the Earth's surface is cooler than it would be if the atmosphere had no clouds." (cf. NASA Clouds and Radiation) Water vapor concentrations fluctuate regionally, but human activity does not significantly affect water vapor concentrations except at local scales, such as near irrigated fields. According to the Environmental Health Center of the National Safety Council, water vapor constitutes as much as 2% of the atmosphere.[32]

http://en.wikipedia.org/wiki/Greenhouse_gas#cite_note-31

http://en.wikipedia.org/wiki/Greenhouse_gas#cite_note-31
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http://en.wikipedia.org/wiki/Greenhouse_gas#cite_note-31

http://en.wikipedia.org/wiki/Greenhouse_gas#cite_note-31
Other important considerations involve water vapor being the ************SPAM/BANNEAR************ greenhouse gas whose concentration is highly variable in space and time in the atmosphere and the ************SPAM/BANNEAR************ one that also exists in both liquid and solid phases, frequently changing to and from each of the three phases or existing in mixes. Such considerations include clouds themselves, air and water vapor density interactions when they are the same or different temperatures, the absorption and release of kinetic energy as water evaporates and condenses to and from vapor, and behaviors related to vapor partial pressure. For example, the release of latent heat by rain in the ITCZ drives atmospheric circulation, clouds vary atmospheric albedo levels, and the oceans provide evaporative cooling that modulates the greenhouse effect down from estimated 67 °C surface temperature.[5][34]

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Removal from the atmosphere and global warming potential

Natural processes

Greenhouse gases can be removed from the atmosphere by various processes:

• as a consequence of a physical change (condensation and precipitation remove water vapor from the atmosphere).

• as a consequence of chemical reactions within the atmosphere. For example, methane is oxidized by reaction with naturally occurring hydroxyl radical, OH· and degraded to CO2 and water vapor (CO2 from the oxidation of methane is not included in the methane Global warming potential). Other chemical reactions include solution and solid phase chemistry occurring in atmospheric aerosols.
• as a consequence of a physical exchange between the atmosphere and the other compartments of the planet. An example is the mixing of atmospheric gases into the oceans.
• as a consequence of a chemical change at the interface between the atmosphere and the other compartments of the planet. This is the case for CO2, which is reduced by photosynthesis of plants, and which, after dissolving in the oceans, reacts to form carbonic acid and bicarbonate and carbonate ions (see ocean acidification).
• as a consequence of a photochemical change. Halocarbons are dissociated by UV light releasing Cl· and F· as free radicals in the stratosphere with harmful effects on ozone (halocarbons are generally too stable to disappear by chemical reaction in the atmosphere)

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amigable dijo:

Si mae pero no estaria mal si dejaramos de ayudar a acelerar el proceso.
Por supuesto que la tierra ocupa del co2 para las plantas y para mantener la atmosfera como debe ser pero muy poco o mucho de el rompe el equilibrio ambiental.
Los oceanos que son los que tragan mas co2 y se estan volviendo acidos por la cantidad.

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aherreracr dijo:

+1

Has indicado un excelente, hay que llegar a un equilibrio, ni podemos seguir como estamos ni podemos pretender parar toda actividad humana, el punto principal es encontrar un punto de equilibrio, donde la tecnología juega un papel determinante por dicha.

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2010 podría ser el año más caluroso de la historia - ALDEA GLOBAL:: - nacioncom

Imágenes satelitales reveladas este mes por científicos del National Snow and Ice Data Center (NSIDC) de EE. UU. y de la Agencia Espacial NASA muestran que, mientras las temperaturas globales ascienden paulatinamente, la capa de hielo del Ártico llegó el pasado mes de marzo a un récord mínimo de superficie helada, un récord que supera las alertas reportadas en el 2005.
Los expertos aseguran que desde el año 1979 – en que se tienen registros de la zona– no ha habido tan poco hielo flotando en el Ártico durante un mes de marzo. “Actualmente, la plataforma de hielo mide 20.300 kilómetros cúbicos, un 38% menos del nivel de 1979”, enfatizó el reporte publicado en Nasa.gov.

En marzo de cada año, precisamente, es cuando el Ártico alcanza su mayor extensión de hielo del año. De ahí, la preocupación de los expertos.

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peyistez mecayo dijo:

La noticia no es sobre tendencias, sino sobre minimos o maximos hisotoricos.

En abril la extension de hielo fue similar al promedio de 30 años.

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peyistez mecayo dijo:

El grafico es muy claro, abril de 2010 registra mas hielo que los años precedentes, la noticia habla de marzo, pero marzo del 2010 tambien tiene mas hielo que 2007.

O sea los datos del grafico del SSM contradicen la noticia.

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peyistez mecayo dijo:

Otra vez: no me interesan sus "retos" para desviar el tema, me interesa cuestionar la noticia que puso herrera y eso es lo que hace el grafico.

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peyistez mecayo dijo:

El grafico es muy claro y muy facil de entender, ver la linea roja: extensión de hielo del 2010

Habla por si solo.

Abril de 2010 está arriba del promedio de 30 años, tal como dije arriba....

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