BCB311

Wednesday, March 08, 2006

GLOBAL DIMMING SHOULD WE BE CONCERNED?

Global dimming is the result of an increase in the amount of light being
reflected out of the earth's atmosphere and thus causing a drop in solar
energy or solar radiation. The main contributors to Global dimming are
thought to be the by-products of fossil fuel use such as sulphur
dioxide, soot, and ash (www.globalissues.org). These pollutants change
the properties of clouds as the excess air-borne particals result in
clouds with larger number of droplets and thereby making them more
reflective (turning the clouds into gaint 'mirrors).
Between 1950 and 1990 there have been recordings of a drop in solar
radiation over various places. The following readings were obtained:
60 % over parts of the British Isles
30 % over Russia
22 % over Israel
10 % over the U.S.A, and
9 % over Antarctica
Although there has been a drop in solar radiation the earth is getting
hotter instead of cooler. This can be attributed to the effects of
Global warming as the trapped CO2 in the atmosphere is making the earth
hotter. The full extent of the warming caused by Global warming is
masked by the cooling effects of Global dimming and thus Global warming
is greatly underestimated.If, however, the problems of global dimming
are only addressed, then the effects of global warming will increase
even more.

Nashreen Williams
University of the Western Cape
E-mail 2318364@uwc.ac.za

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