BCB311

Wednesday, March 08, 2006

BRIEFLY DESCRIBE THE CONCEPT OF GLOBAL DIMMING, IS IT AN ISSUE WE SHOULD TAKE SERIOUSLY?

Global dimming is a term describing the gradual reduction in the amount of global hemispherical irradiance (or total solar irradiance) at the Earth's surface Global dimming creates a cooling effect that may have led scientists to underestimate the effect of greenhouse gases on global warming.

It is now thought that the effect is probably due to the increased presence of aerosols and other particulates in the atmosphere. It is thought that the water droplets in clouds collect around the particles, resulting in the clouds consisting of a greater number of smaller droplets, which in turn makes them more reflective: bouncing more sunlight back into space.

Clouds intercept both heat from the sun and heat radiated from the Earth. . Usually, during the day the interception of sunlight predominates, giving a cooling effect; however, at night the re-radiation of heat to the Earth slows the earth's heat loss.

Global dimming should be taken seriously as it has negative consequences on our environment. if the amount of energy from the sun decreases, it will affect the rate of photosynthesis of plants and other autotrophic organisms, it will also result in a decrease in global temperature. however global dimming, reduces the amount of sunlight entering the atmosphere, it also keeps out harmful uv rays. After September 11, air travel stopped in America climatologists, found that the air temperature raised by a significant amount, this was because there was a decrease in pollutants in the air, and more sunlight was able to penetrate. it was a clear indicator the pollutants are the major contibutor to global dimming.

Peer reviewer: Celeste Thomas.






 

1 Comments:

  • You missed the point of the implications, but at least you explain the concept well. The reduction in primary productivity is not that important, and clouds do not significantly stop UV light.

    By Anonymous James, at Wednesday, March 15, 2006 5:12:00 pm  

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