▶ Your Answer :
In the reading passage, there is ample support for the author's claim that there are a few trustworthy theories in terms of cause of the Little Ice Age. However, the professor in the lecture gives several reasons as a rebuttal to the author's point. The lecturer maintains that the reading passage's theories are problematic. To begin with, the lecturer contends that it is not proved that the amount of sunspots accounts for the reduction of radiation. According to the recent research, amount of solar energy did not decline while the number of sunspots in the sun decreased. This casts doubt on the reading passage's assertion that weakened solar radiation caused by a decrease in the number of sunspots gave rise to the Little Ice Age. In addition, the lecturer points out that the cooling effect of earth was not affected by volcanic activities. Generally speaking, The cooling phenomenon can not keep for a long time. However, the Little Ice Age was persisted for about 500years. Some people who supporting this theory did not take this point into consideration. This counters the reading passage's claim that massive volcanic eruption made an impediment of solar radiation such as ash and dust and this was the result of the Little Ice Age. Lastly, the lecturer claims that the increase of the earth's reflectivity was not the cause of the global cooling. To be specific, Ice and snow were not only cause of this occurrence. Less amount of cloud also had an influence on the reflectivity. There was less cloud because of low temperature and the reduction of water evaporation at that time. Therefore, comprehensive reflectivity of earth could not affect decreasing global temperature. This refutes the reading passage's claim that ice and snow reflected about 90% of sunlight and this led to drop of earth's temperature. |