The Dark Apocalyspe

Global Dimming and how it will take us back into the Ice Age

A Dark Discovery

In the mid-1980s, when meteorologist Gerry Stanhill reported that a dramatic 22 percent reduction of sunlight had occurred in Israel between the 1950s and the 1980s, the news hardly made a splash in the scientific community or popular press. But Stanhill was not alone in measuring such a drop. When he combed the scientific literature, he found that other scientists had measured declines of 9 percent in Antarctica, 10 percent in areas of the U.S., 16 percent in parts of Great Britain, and almost 30 percent in one region of Russia. Alarmed by the trend, Stanhill coined the term "global dimming." By the turn of the 21st century, with mounting evidence of just how human pollution had caused it, global dimming finally gained the attention it warranted.

Causes of Global Dimming

Earlier it was thought that changes in the sun’s luminosity cause global dimming but later it was realized that this was very small to explain the enormity of global dimming.

Aerosols have been found to be the major cause of global dimming. The burning of fossil fuels by industry and internal combustion engines emits by-products such as sulfur dioxide, soot and ash. These together form particulate pollution—primarily called aerosols. Aerosols acts as precursor to global dimming in the following two ways:

  • These particle matters enter the atmosphere and directly absorb solar energy and reflect radiation back into the space, before it reaches the planet’s surface.

  • Water droplets containing these air-borne particles form polluted clouds. These polluted clouds have heavier and larger number of droplets. These changed properties of the cloud – such clouds are called ‘brown clouds’ – makes them more reflective.

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“Global dimming is cooling our planet by more than a degree Celsius (1.8°F)”- James Hanson

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Effects of Global Dimming

Global dimming has devastating effects on the earth’s environment and living beings. The pollutants causing global dimming also leads to acid rain, smog and respiratory diseases in humans.

Due to reflection of solar energy and global dimming, the water in the northern hemisphere has become colder. This leads to slower evaporation and generation of lesser water droplets. This further causes reduction in the amount of rain reaching certain parts of the globe, resulting in drought and famine situations. This has tragic consequences like miserable lives and deaths due starvation. It has now been determined that the drought and famine of The Sahel which has killed thousands of innocent people in sub-Saharan Africa during 1970s, was largely due to global dimming. A growing concern is the impact of global dimming on Asian monsoons which cause 50% of the world’s annual rainfall. If this happens, then half of the world’s population will be starving.

Global dimming is also believed to cause heat waves and runaway fires. Also, decrease in sunlight or solar radiation will negatively impact process of photosynthesis in plants.

Global dimming is thought to be counteracting the actual effect of carbon emissions on global warming. So, if efforts are made to reduce particulate emission causing global dimming, it will enhance global warming and increase the global temperatures to more than double. This will make planet Earth, almost uninhabitable. To prevent this situation, it is important that emission of both greenhouse gases and particulate matter should be reduced simultaneously. This will balance out both phenomena.