Water Vapor and Global Warming

Discussion in 'Environment' started by antagon, Sep 29, 2010.

  1. antagon
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    antagon The Man

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    Water vapor of course is the most abundant greenhouse gas in the atmosphere and is responsible for the majority of greenhouse effect. It is often left out of the debate (and its accompanying charts) altogether, which I find puzzling. The explanation for brushing aside this top contributor is the fact that water vapor is seen as a 'feedback' greenhouse gas rather than a 'forcing' green house gas. That is to say that it increases in reaction to warming as well as functioning to perpetuate and exacerbate it. Indeed, CO2 can't be excluded from this characterization, either. How is it purported that the characterization of feedback and forcing negates the fact that atmospheric H2O levels have risen, and that it is the most effective contributor to greenhouse effect? Granted a warming trend, why isn't water vapor the preeminent target for climate change study?

    It is also contended that water vapor remains in the atmosphere for just over a week at most, while CO2 could stay afloat for decades. Nevertheless, with water vapor levels rising on aggregate, how does this fact negate the effectiveness of atmospheric H2O as a greenhouse gas?

    Where the ins and outs of CO2 and CH4 are being poured over diligently, apparently for their capacity to implicate human contribution, why is there so little earnest exploration of the role good 'ol water plays? The big role.
     
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  2. IanC
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    IanC Gold Member

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    Because water vapour and clouds are so complex. This is one of the main problems with the computer climate models. Warmers believe water vapour and clouds are a positive feedback but many other scientists believe they are a negative feedback, and some say it depends...
     
  3. Old Rocks
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    Old Rocks Diamond Member

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    First, the people that study climate hardly leave out the influence of water vapor. It is definately a positive feedback. Clouds are quite another thing. Still arguements concerning whether clouds are a positive or negative feedback.

    Second, as you state, the warming created by the CO2 has caused there to be more water vapor in the atmosphere, and therefore, accelerated the warming. There is no negation of the warming effect of water vapor by CO2. The two work in tandem.

    Do this thought experiment. Add water vapor to the atmosphere to the capacity of the air to hold the water, 99% humidity world wide. In a little over a week, the amount of the water vapor in the air is back to where it was, and it is just a little warmer. Now double the CO2 in the air, and it will be hundreds of years before the CO2 is back to the prior level. And during that time, the warming created by the CO2 will draw more water vapor into the atmosphere, ampllfying the warming. And continue to do so.

    Now let us do the opposite. Remove all the water vapor from the atmosphere. In a little over a week, the normal amount will be restored, for 2/3rds of the atmosphere is over water where it will immediatly evaporate more, according to how warm the atmosphere is.
    Now remove all the CO2. In the space of a few years, there will be glaciers at the equator. We know this because mama nature has already performed this experiment for us. CO2 is the big control knob on the temperature of the atmosphere and oceans.
    A23A
     
  4. antagon
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    antagon The Man

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    rocks, you've left out water vapor yourself. if water is removed from the atmosphere per your hypothetical, it would also freeze. the dependence you allude to with respect to the temp of the atmosphere in facilitating WV equilibrium presents a fallacy. how would the atmosphere be any warmer than the CO2 model you conclude with? it stands to reason that it will be much, much cooler. the role of water vapor is significantly greater in greenhouse effect than CO2, but you are swift to disproportionately attribute warming capacity to that compound.
     
  5. westwall
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    westwall USMB Mod Staff Member Gold Supporting Member Supporting Member

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    Wow, that's quite the load of horse manure you're peddling there olfraud!

    1. INTRODUCTION

    Global warming scenarios from CO2 increases are envisioned to bring about rainfall enhancement and resulting upper tropospheric water vapor rise. This initial water vapor enhancement has been hypothesized and programmed in climate models to develop yet additional rainfall and water vapor increase. This causes an extra blockage of IR energy to space (a positive feedback warming mechanism). This additional rainfall and IR blockage is modeled to be approximately twice as large as the additional rainfall needed to balance the increased CO2 by itself. The reality of this additional warming and extra IR blockage has been questioned by many of us. This study analyzes a wide variety of infrared (IR) radiation differences which are associated with rainfall differences on different space and time scales. Our goal is to determine the extent to which the positive rainfall feedbacks as are included in the climate model simulations are realistic.

    We have analyzed 21 years (1984-2004) of ISCCP (International Satellite Cloud Climatology Project) outgoing solar (albedo) and outgoing longwave infrared (IR) radiation (often referred to as OLR) on various distance (local to global) and time scales (1 day to decadal). We have investigated how radiation measurements change with variations in precipitation as determined from NCEP-NCAR Reanalysis data on a wide variety of space and time scales (Figure 1). We have stratified our radiation and rainfall data into three latitudinal sections and six distinctive longitudinal areas (Figure 2). Infrared and albedo changes associated with rainfall variations by month (January to December) and by yearly periods for the globe (70oN-70oS; 0-360o) as a whole and separately for the tropics (30oN-30oS; 0-360o) have been studied. This analysis shows they are not realistic.

    http://climaterealists.com/attachments/ftp/AMS-Final5-10.pdf

    Eco Factory - NOAA, NASA: Water Vapor Largely Responsible for Global Warming


    Etc. etc. etc. Alarmists have no clue how it works so they throw up their hands and ignore it
     
  6. Matthew
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    Matthew Blue dog all the way!

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    Would a warmer world have more Atmospheric water vapor. If so it would also help to warm the planet with co2, but water vapor is not equal over all surfaces of the earth being within colder area's would have less then the warm area's...But yes more Atmospheric water vapor, I'd think would cause a warmer tropical earth.:cool: I believe that global warming will cause our planet to become a tropical earth.
     
    Last edited: Sep 29, 2010
  7. Old Rocks
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    Old Rocks Diamond Member

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    No, I did not. Note, 2/3 of the area of this planet is water. Deplete the atmosphere of water, and immediatly water will evaporate from the oceans and restore the normal amount of water vapor in the air for the temperature of the air. There might be a bit of cooling, but very little.
     
  8. Old Rocks
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    Old Rocks Diamond Member

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    Global Warming and Extreme Weather: The Science, the Forecast, and the Impacts on America - Environment America

    The consequences of global warming are already beginning to be experienced in the United States, and are likely to grow in the years to come, particularly if emissions of global warming pollutants continue unabated.

    Average temperature in the United States has increased by more than 2° Fahrenheit over the last 50 years. Temperatures are projected to rise by as much as an additional 7° F to 11° F on average by the end of the century, should emissions of global warming pollutants continue to increase.
    The United States has experienced an increase in heavy precipitation events, with the amount of precipitation falling in the top 1 percent of rainfall events increasing by 20 percent over the course of the 20th century. The trend toward extreme precipitation is projected to continue, even as higher temperatures and drier summers increase the risk of drought in much of the country.
    Snow cover has decreased over the past three decades in the Northern Hemisphere, and the volume of spring snowpack in the Mountain West and Pacific Northwest has declined significantly since the mid-20th century.
    Sea level has risen by nearly 8 inches globally since 1870. Global sea level is currently projected to rise by as much as 2.5 to 6.25 feet by the end of the century if global warming pollution continues unabated. Parts of the northeastern United States could experience an additional 8 inches of sea-level rise due to changes in ocean circulation patterns.
     
  9. Old Rocks
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    Old Rocks Diamond Member

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    Early Warning Signs of Global Warming: Downpours, Heavy Snowfalls, and Flooding | Union of Concerned Scientists

    Early Warning Signs of Global Warming: Downpours, Heavy Snowfalls, and Flooding
    An increase in global temperatures will lead to an intensification of the hydrological cycle. This is because an increase in surface air temperature causes an increase in evaporation and generally higher levels of water vapor in the atmosphere. In addition, a warmer atmosphere is capable of holding more water vapor. The excess water vapor will in turn lead to more frequent heavy precipitation when atmospheric instability is sufficient to trigger precipitation events. Intense precipitation can result in flooding, soil erosion, landslides, and damage to structures and crops.

    Parallel to the likely increase in heavy precipitation events in winter, increased temperatures will also amplify the drying out of soils and vegetation due to increased evaporation in the summer. This is likely to result in more severe and widespread droughts where and when atmospheric conditions do not favor precipitation (see Droughts and Wildfires).

    The largest changes in precipitation are expected at mid- to- high latitudes (Kattenberg et al., 1996). Climate models predict an increase in average precipitation in winter at high latitudes due to poleward transport of evaporated moisture from lower latitudes. There is also an increase in the expected frequency and areal extent of intense precipitation over the continents. Predictions for soil moisture changes are less certain; however, models show an increase in soil moisture in high northern latitudes in winter.
     
  10. Old Rocks
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    Old Rocks Diamond Member

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    Extreme Weather Events Signal Global Warming to World's Meteorologists

    GENEVA, Switzerland, August 17, 2010 (ENS) - Fires across Russia, record floods in Pakistan, a huge Greenland iceberg - this current unprecedented sequence of extreme weather events "matches" scientific projections of more frequent and intense extreme weather events due to global warming, says an organization of meteorologists from 189 countries.

    "Several diverse extreme weather events are occurring concurrently around the world, giving rise to an unprecedented loss of human life and property. They include the record heatwave and wildfires in the Russian Federation, monsoonal flooding in Pakistan, rain-induced landslides in China, and calving of a large iceberg from the Greenland ice sheet," said the World Meteorological Organization in a statement August 11.


    A chunk of ice, roughly 251 square kilometers (97 square miles) in size, broke off the Petermann Glacier along the northwestern coast of Greenland, August 5, 2010. (Photo courtesy NASA JPL)
    "These should be added to the extensive list of extreme weather-related events, such as droughts and fires in Australia and a record number of high-temperature days in the eastern United States of America, as well as other events that occurred earlier in the year," said the WMO, a specialized agency of the United Nations.
     

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