A new report suggests that Earth has become brighter since 1990. This opposes against global dimming theories which suggested that the amount of light reaching Earth was decreasing because of air pollution. The last few years the opposite is happening:
"We see the dimming is no longer there," said Martin Wild, a climatologist at the Swiss Federal Institute of Technology in Zurich and the lead author of one of three papers analyzing sunlight that appear in today's issue of the journal Science. "If anything, there is a brightening."
But scientists aren't sure what caused the dimming and the brightening, and the effects on our climate. More details at CNET