Although Temperatures Have Fluctuated Throughout the Earth's History,scientists Are Greatly

Although temperatures have fluctuated throughout the earth's history,scientists are greatly concerned about the current warming because ____.

A) it is occurring at a more rapid rate than in the past
B) the Sun is getting warmer which amplifies warming on the earth
C) clouds are not reflecting as much radiation now as in the past
D) the ozone hole is allowing more radiation to enter the atmosphere
E) wildfires are more sever and occur with greater frequency