▶ Your Answer :
In the reading passage, there is ample support for the author's claim that there are a few explainable causes of the Little Ice Age. However, in the lecture, the professor gives several reasons as a rebuttal to the author's point. First, the professor contends that decreasing of the number of sunspots did not reduce radiation from the Sun. One recent research has shown that when the number of sunspots are very small, intensity of sunlight is not weak. Therefore, the total amount of radiation are not dependent on the number of sunspots. This casts doubt on the reading passage's argument that considering that sunspots can affect radiation of the Sun, the Little Ice Age was caused by small intensity of the Sun radiation since the number of sunspots in that period was low. Next, the professor insists that it is highly implausible that volcanic phenomenons brought about the Little Ice Age. Because the Little Ice Age persisted for a long time, ongoing the Little Ice Age after all ash and dust disappeared cannot be explained. This counters the reading passage's assertion that ash and dust from huge volcanic eruption covered the Earth's atmosphere and this lowered the amount of sunlight which entered the Earth. Finally, the professor maintains that the global cooling occurrence was not provoked by increasing of the Earth's reflectivity. Clouds play the most important role in the Earth's reflectivity. However, low temperature in the period generated less moisture. So, few clouds were created in the sky. Therefore, There was only slight change of the magnitude of the Earth's reflectivity caused by ice and snow. This refutes the reading passage's claim that a lot of glaciers and snow which were made by cold temperature in the period caused the Little ice Age due to their high reflective character. |