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Global Warming & Dimming Page Contents

This page contains information, explanations and facts on Global Warming and the lesser publicised phenomenon of Global Dimming.

What is Global Warming and How is it Caused?

  • Global Warming is characterised by an increase in average temperatures on a year-on-year basis.
    • This may be greater in some areas of the earth than others.
    • Global Warming and indeed Cooling phases do occure naturally, but the increase in average temperatures since about 1865 is unprecedented in the earth’s long history.
    • The Industrial Revolution began around 1865.
  • This gradual increase in global temperatures is due to more of the sun’s radiation (Heat Energy) being reflected back towards the earth by the atmosphere, than would normally be the case.
    • Under normal circumstances the sun’s radiation enters the earth’s atmosphere, hits the surface of the earth and is then reflected back out through the atmosphere, only a very small percentage of the sun’s radiation is reflected back by the atmosphere, for a second go.
    • With Global Warming a much higher percentage of the sun’s radiation is reflected back from the atmosphere toward the earth, the atmosphere acts as a barrier, that allows radiation in but not out, the sun’s radiation just bounces between the earth’s surface and the atmosphere. This increases the amount of energy that is released from the sun’s radiation and this in turn raises the temperature, leading to Global Warming.
  • So why does more of the sun’s radiation (Heat Energy) get reflected back toward the earth?
    • Carbon Dioxide (Co2), mostly from the burning of Fossil Fules (Coal, Oil and Gas) traps Heat Energy that would otherwise be radiated back into space from the earth.
    • The greater the percentage of Co2 present in the atmosphere the more the sun’s radiation is trapped, leading to an acceleration in Global Warming.
    • To make matters worse the earth has undergone massive deforrestation over the past 75 years.
      • Green plant life thrives on Co2 and converts this back into Oyrgen, this in turn reduces the amount of Co2 in the atmosphere.
      • A significant part of the earths green plant life is made up of huge Rain Forrests. These hardwood forrests take hundreads of years to grow and mature.
      • Felling massive swathes of Rain Forrest has severly reduced the earths capacity for converting Co2 back into Oxygen to neutralise the threat that Co2 causes.
      • The rate of felling far outstrips any new plantations and even if we planted on a new for old basis, the process would still be unsustainable due to the amount of time it takes to grow new hardwood trees.
  • Fortunately we have not yet been subjected to the full effects of Global Warming, until recently we had been protected by the opposing effects of Global Dimming, but things are on the change, read on...

What is Global Dimming and How is it Caused?

  • Global Dimming is characterised by an decrease in average temperatures on a year-on-year basis.
    • This may be greater in some areas of the earth than others.
    • Global Dimming, as opposed to a Cooling phase, does not occure naturally, it is a totally man made phenomena.
  • This gradual decrease in global temperatures is due to less of the sun’s radiation (Heat Energy) being able to enter the earths atmosphere, than would normally be the case.
    • Under normal circumstances the sun’s radiation passes through the earth’s atmosphere, hits the surface of the earth and is then reflected back out through the atmosphere.
    • With Global Dimming a much higher percentage of the sun’s radiation is reflected back out into space, the atmosphere acts as a barrier that prevents the sun’s radiation from reaching the earth. This is the exact opposite of the way the atmosphere acts in Global Warming.
  • So why does more of the sun’s radiation (Heat Energy) get reflected back out into space?
    • Particulates (airborn particles, as opposed to Carbon Dioxide gas) mostly from the burning of Fossil Fules (Coal, Oil and Gas) are released into the atmosphere, these change the light transmiting properties of clouds.
      • A cloud is formed when moisture accumilates around each of the above Particles. The Particulates act as nuclei for moisture dropletts, when the droplets get too heavy we get rain.
    • Much higher levels of Particulates are present in the atmosphere due to the burning of Fossil Fules, this vastly increases the number of water dropletts that are able to form in an average cloud.
    • The water droplets in clouds reflect the sun’s radiation back out into space, each cloud now has many more water droplets, as explained above and this causes more of the sun’s radiation to be reflected back out into space, this leads to the phenonena known as Global Dimming.

Global Warming V’s Global Dimming - “The Ultimate Clash”

  • So in the Red corner we have Global Warming trying to heat everything up and in the Blue corner we have Global Dimming trying to cool everything down.
  • Global Warming has always been the stronger partner in this environmental tug-of-war, thats why we have seen average Global Temperatures rise rather than fall over the past 140 years or so.
  • But up until very recently (Q2 2004) all data relating to the prediction of average Global Temperature rise, due to Global Warming, was based soley on the Global Warming theories. The effect that Global Dimming was having on Global Warming, as an opposing force, was never taken into consideration, it was believed that Global Warming was acting alone.
  • Existing theories and data, based on Global Warming acting alone, estimated that there would be a temperature rise of between 1.4C and 3C in the 100 year period from 2000 to 2100.
  • But we have already seen a rise of 0.6C in the 25 year period from 1980 to 2005, that means we would hit the upper estimate of 3C by 2100 and 5 of the last 8 years have been the warmest on record. The signs are that the rate of increase in average temperatures (Global Warming) is accelerating.
  • The reason that Global Warming is accelerating is because we are reducing the amount of Particlate polution in the atmosphere, this is reducing the Global Dimming phenomena, the opposing force that has kept Global Warming in check.
  • If we go on reducing Particulate polution (Global Dimming) and do nothing about Co2 emmisions (Global Warming) then the rate of increase of Global Warming will go on accelerating.
  • If the current data, relating to global average temperature rise, is recalculated to include the restraining effect that Global Dimming has on Global Warming, then the estimate for the increase in average temperatures up to 2100 soars to somewhere between 8C and 12C.

 Facts Related To Global Warming And Global Dimming

  • Average gobal temperature rise of 0.6C in the last 25 years.
  • Rate of increase in temperature rise (Global Warming) accelerating.
  • Global Dimming now known to be restraining the effects of Global Warming.
  • Out of date theories on Global Warming acting alone only predict an average global temperature rise of between 1.4C and 3C by 2100.
  • Average global temperatues predicted to rise by between 8C and 12C by 2100 when Global Dimming taken into acount as an opposing (restraining) force to Global Warming, that is gradually reducing.
  • Good work has been crried out to reduce Particulate polution, but we continue increase the global output of Co2, particularly in the U.S.A and the developing countries, such as India and China. The net effect of this is an acceleration in Global Warming.
  • One of the most compelling proofs that Particulate Polution (Global Dimming) has a restraining effect on Global Warming was carried out during two consequtive days after the 9/11 terrorist attacks on the U.S. Not a single aircraft was permitted to fly over U.S. arispace for two weeks after the 9/11 attacks. During just two days of this period the drop in Particulate Polution (Global Dimming) over the U.S. allowed average temperatures to rise by 2C above where they would have been if the no-fly ban had not been in place.
  • Even with the small Temperature rises that we have seen over the past 25 years the polar ice caps have become extreemly vulenerable and we have already seen two major ice shelves collapse and fragment into the sea in 2002.
    • The Larsen B Antartic ice shelf, which took just 31 days to shatter 3,250 square kilometers of 200 meter thick ice into the Pacific Ocean.
    • And the Thwaites Glacier Tounge, also part of the Antartic ice cap, an iceburg the size of the county of Norfolk in the UK broke away and melted into the Pacific.
    • There is also evidence of a build-up of melt water under the Greenland ice sheet, if this ice cap were to melt sea levels in the Atlantic would rise by seven meters, yes thats seven meters.

Environmental Effects Of Temperature Increase

  • The Environmental Effects of Temperature Change will vary greatly depending on where you live, where we are on the Temperature Change curve and how resilient, or sensative something is to Temperature Change.
  • Some entities, like Coral and Plankton are very sensative to Temperature Change. A change as small as +/- 2C in average seasonal Temperatures is enough to kill off both these species and subsequently huge amounts of other marine life that relly totally on these for life support. This in turn affects the whole of the food chain.
  • A small rise in sea levels will have huge effects on many countries all over the world, a rise of some seven meters (see above) would be nothing short of a global catastrophy. This would submerge many of the major costal towns and cities and change the world map as we know it at present.
  • When polar ice melts it deposits ffresh water into the sea. Ocean currents are driven by the differences in Temperature and Salinity (how salty the water is) of seawater, changing the composition of seawater in this way will have a major effect on many Ocean currents.
    • More to come soon...

 

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