Global Dimming

Clouds intercept both heat from the sun and heat radiated from the Earth. Their effects are complex and vary in time and location and height. 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 is a term describing the gradual reduction in the amount of sunlight observed reaching the Earth's surface since the 1950s. The effect varies by location but globally is of the order of a 5% reduction over the three decades 1960-1990; the trend has reversed during the past decade. Global dimming creates a cooling effect that may have led scientists to underestimate the effect of greenhouse gases on global warming.
© 2004 onwards by Dr Himanshu Tyagi. All the photographs in this blog are copyright protected and can not be reproduced or stored in any medium without the written permission from Dr Himanshu Tyagi.