Global Dimming vs. Global Warming - An atmospheric tug of war - Journal #9 (10)

After 9/11 the entire U.S. air fleet was grounded for three days. During those three days the weather across the U.S. was unusually clear and sunny. This was caused by a lack of vapor trails usually left by airplanes. These vapor trails affect the temperature around the globe significantly. Usually the temperature range (the change from the highest recorded temperature to the lowest recorded temperature in a 24 hour period) is somewhat consistent. During the three days following 9/11 the change in temperature range was just over one degree Celsius, a dramatic change from a climate perspective. This is the first example of Global Dimming.

The second example given is based in Israel. In the 1980’s a British scientists used light meters to collect sunlight to determine the amount of water needed to successfully grow crops,  twenty years later the tests were updated and showed a staggering 22% drop in solar energy over the 20 year period. Unfortunately these findings were ignored by the scientific community. After looking more in depth at the numbers, it was determined from the 1950s to the early 1990s there was a 9% decrease in sunlight in the Antarctic, a 10% decline in areas of the U.S., a  30% decline in regions of Russia, and a 16% decrease in parts of the British isles. Evidence once again pointed to Global Dimming and was once again ignored.

Further evidence, dating back more than 100 years, was evident in the declining Pan Evaporation Rate.  

One of the keys to Global Dimming is the amount of pollution in the air. If there is a layer of pollution three km thick, it will cut down sunlight more than 10! This pollution will turn the clouds into giant mirrors and reflect more sunlight than normal back into space. These reflective clouds could alter the pattern of the world’s rainfall

As we continue to strive to clean the earth’s atmosphere, we are creating a tug of war between the cooling gases and the warming gases. If we remove too many cooling gases, while continuing to pump ridiculous amounts of greenhouse gases in the atmosphere, we will create the most devastating situation for our World.