[单项选择]It’s impossible to write about how human activities are altering the climate without bringing protests that such a thing is impossible, that puny humanity cannot possibly alter such a gargantuan system through loading the atmosphere with additional carbon dioxide. Unfortunately for the denialists, examples of how human activities can alter climate keep accumulating. The latest has nothing to do with the greenhouse effect but underlines the fact that ordinary activities can have unexpected meteorological (气象的) consequences. To wit: large dams seem to be altering rainfall patterns.
Geophysicists have suspected as much for years, notes a team of scientists in a paper in the Dec. 1 issue of Eos, a publication of the American Geophysical Union. But it is becoming clearer that in addition to providing lots of water to evaporate and then return to the ground as rainfall, as scientists at MIT described in a 1996 study, dams also make local meteorological conditions more conducive to preci
A. the possible higher frequency of flood raises concerns about dam safety
B. conventional dam design hasn’t realized the possible feedback mechanisms
C. dam design protocol shouldn’t assume unchanging extreme precipitation events
D. the dams’ function has been weakened mainly because it is getting older