Wednesday, March 17, 2010

UV radiation levels haven't increased much in the last few decades

UV radiation that is able to reach Earth's surface has slightly to moderately increased over the last 30 years - this is the conclusion of NASA scientists that have been analyzing the amounts of ultraviolet radiation (UV) that reached the Earth in the last 30 years. Scientists believe that the main factor responsible for this increase in UV radiation are decreasing levels of stratospheric ozone that acts as Earth's natural sunscreen by shielding the surface from harmful UV radiation.

Scientists have also found out that the biggest increase in UV radiation has occurred in the mid-and-high latitudes, while there's been little or no increase in tropical regions.

The results of this study have also confirmed the fact that UV levels are stabilizing after countries began signing an international treaty that limited the emissions of ozone-depleting gases in 1987, and it also confirms that increased cloudiness in the southern hemisphere over the 30-year period has impacted UV.

The scientists have stated that although there is still an increase in UV on a 30-year timescale, this increase has been moderate, and it could have been lot worse, meaning that the world is on the right track regarding ozone.

Despite overall positive results there have been some negative examples too as for instance the UV radiation has increased by more than 20 percent in Patagonia and the southern portions of South America.

Despite this it is good to know that study confirmed how ultraviolet radiation levels are falling since the mid 1990s.