[单项选择]　　Scientists studying the effect of large volcanic eruptions on global climate have long focused on the major quantities of carbon dioxide (C02), a gas known to contribute to the greenhouse effect, produced by these eruptions. It is well observed that such greenhouse gases trap heat radiated from the surface of the earth, thereby forming a type of insulation around the planet. The greenhouse effect is essential for ecological equipoise because it maintains the temperature of the planet within habitable parameters, but there is growing concern that man-made production of gases such as CO[,2] from the burning of fossil fuels may be threatening the system’’s tolerance, and have resulted in excessive warming on a global scale. While volcanic eruptions indubitably metabolize and accumulate C0[,2] in the atmosphere, it has been recently discovered that their impact is virtually trivial compared to the quantity produced by human activities, especially heavy industry. In reality, the more subs
A. The influence of volcanic eruptions on global weather patterns is almost completely understood at present.
B. Scientists have only begun to understand, however, the effects of these wavelengths of light on the global environment.
C. The majority of global cooling effects have thus been attributed to volcanic explosions.
D. The human warming activities ameliorate by volcanic eruptions include those produced both by heavy industry and agriculture.
E. The reason that sulfate aerosols take an unusually large time to disperse owes primarily to meteorological factors, including the jet stream.