Earth Has Become Brighter, but No One Is Sure Why - New York Times

Earth Has Become Brighter, but No One Is Sure Why - New York Times: "Reversing a decades-long trend toward 'global dimming,' Earth's surface has become brighter since 1990, scientists are reporting today.

The brightening means that more sunlight - and thus more heat - is reaching the ground. That could partly explain the record-high global temperatures reported in the late 1990's, and it could accelerate the planet's warming trend."