Fewer of the Sun's Rays Reaching the Earth's Surface

English scientist, Gerry Stanhill, noticed an unusual drop in the amount of solar radiation reaching the surface of the earth when he compared current sunlight levels to ones recorded in the 1950s. Recently researchers have confirmed his observations. The level of sunlight fell one to two percent each decade from the 1950s to the 1990s. Dr. Stanhill called this phenomenon “global dimming”.

It seems that particulate pollution in the atmosphere is causing the decrease in sunlight. The particles both reflect light directly and seed the formation of water droplets causing clouds to be more reflective.

The same industrial revolution that put pollutants into the air, possibly causing the greenhouse effect to warm the earth may have been putting pollutants into the air that cooled the earth. Recent anti-pollution measures have been more successful at reducing the amount of particulates added to the atmosphere than the amount of greenhouse gasses. Climate modellers are concerned that they may have been underestimating the current rate of global warming due to the dimming effect.

Link: Why the Sun seems to be “dimming” from the BBC News

Posted by Eric La Fountaine at 3:34 PM on March 1, 2005

Want to talk about this weblog entry? As of August 22, 2006, all new entries and most older entries are cross-posted to the UBC Botanical Garden Discussion Forums for discussion (you might need to use the search function to find the thread you are looking for).

This is an effort to reduce the amount of time spent dealing with spam (the forums are very good at stopping spam, the weblog commenting system is not so good).

Older entries already containing comments remain open for discussion.