You’ve heard about global warming, but did you know about the (possibly more serious) issue of global dimming?
The sun keeps us (i.e. the earth) warm. And gives us all energy and life. And over the last 50 years, the amount of sunlight reaching the earth’s surface has reduced by about 1 to 3% per decade.
And the culprit is air pollution. Some of the pollutants absorb the sunlight before it reaches us, while others reflect it back into space.
Golden Gate Bridge with California‘s characteristic brown cloud in the background — the most likely cause of global dimming. Photo CC 2004 by Aaron Logan
There are a number of interesting issues related to this:
- Global dimming might be masking the effects of global warming.
- For the few days after the 9/11 terrorist attacks, temperatures were 1 to 2 degrees higher than average in the US. Due to fewer jet flights, resulting in fewer aircraft contrails (aka vapor trails).
- There exists something called the Asian Brown Cloud which sits over India and much of South and South-East Asia which is being blamed for a lot of things.
I found out about this from this Straight Dope article.