Traditionally the Earth's reflectance has been assumed to be roughly constant, but large decadal variability, not reproduced by current climate models, has been reported lately from a variety of sources. We compare here the available data sets related to Earth's reflectance, in order to assess the observational constraints on the models. We find a consistent picture among all data sets of an albedo decreased during 1985--2000 between 2--3 and 6--7 W/m2, which is highly climatically significant. The largest discrepancy among the data sets occurs during 2000--2004, when some present an increasing reflectance trend, while CERES observations show a steady decrease of about 2 W/m2.