Global Dimming

Global dimming.

Ask most people about their opinion on global warming and they would be able to tell you that pollution is causing the planet to warm up and some of the consequences of this. However, most people haven’t heard about the effect of global dimming. This is a decrease in the amount of the sunlight that reaches the surface of the planet. Measurements and data taken since the 1960s show significant declines in the suns energy reaching Earth but these vary widely geographically. The main causes of this are the same as for global warming; the burning of fossil fuels and aerosol use, however natural events such as volcanic activity can also contribute. During incomplete combustion fuels can produce carbon particulates (soot) which are transported into the atmosphere. Aerosol particles also get taken up into the atmosphere. These both can act as tiny mirrors, reflecting the sun’s light back into space. These tiny particles also create a nucleus around which water droplets can coalesce creating smaller water particles in clouds which are more reflective and also less likely to fall as rain, reducing rainfall. It is thought that in the more polluted regions of the world such as India and China this phenomenon could be causing a massive 10% decrease in sunlight and also masking the true extent of global warming. Since a lot of countries have now signed up to various treaties tackling the amount of pollution released there have been noticeable periods of ‘brightening’, particularly in Europe. Although these measures can only help the planet the amount of pollution already in circulation will be a cause for concern for generations to come and the conflicting effects of Global dimming and warming will not be truly seen for some time.