Earth's reflectivity a great unknown in gauging climate change impacts

Earth's climate is being changed substantially by a buildup of atmospheric greenhouse gases, but a group of leading climate scientists contends the overall impact is not understood as well as it should be because data are too scarce on how much energy the planet reflects into space.
Reflectivity, or albedo, is largely governed by clouds and atmospheric particles called aerosols, but it is one of Earth's least-understood properties, said Robert Charlson, a University of Washington atmospheric scientist. Yet research aimed at quantifying the effects of albedo and helping scientists understand how it could affect future climate change has been delayed or shelved altogether.