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TOPIC: ARGUMENT47 - Scientists studying historical weather patterns have discovered that in the mid-sixth century, Earth suddenly became significantly cooler. Although few historical records survive from that time, some accounts found both in Asia and Europe mention a dimming of the sun and extremely cold temperatures. Either a huge volcanic eruption or a large meteorite colliding with Earth could have created a large dust cloud throughout Earth's atmosphere that would have been capable of blocking enough sunlight to lower global temperatures significantly. A large meteorite collision, however, would probably create a sudden bright flash of light, and no extant historical records of the time mention such a flash. Some surviving Asian historical records of the time, however, mention a loud boom that would be consistent with a volcanic eruption. Therefore, the cooling was probably caused by a volcanic eruption.
WORDS: 216(410) TIME: 0:29:33(+30’) DATE: 2006-7-6
The arguer asserts that according to some survived historical records, scientists have discovered that Earth became significantly cooler in the mid-sixth century by weather patterns study. The cooling was probably caused by a volcanic eruption. Another possible cause, a large meteorite collision has been ruled out by the arguer for no relevant phenomena like a flash mention in extant historical record of the time. The assertion seems logical at the first sight. Actually, it is not well reasoned to reach the conclusion.
First of all, some accounts found in Asia and Europe could not convince us a dimming of sun and extremely cold temperatures did happen all around Earth in mid-sixth century. It is still doubted that whether or not there was a global cooling, or just a regional one. Since Asia and Europe are on the same continental plate, grand climate phenomena probably were shared by these two continents at that time. But we cannot be sure that same climate change happened in other area on Earth. And, skimpy historical records survived from that time even cannot assure the affirmative of the cooling did happen in all over Eurasia. The records could be found in the high latitude area, like Siberia and Hokkaido, where were cold in normal circumstance.
Moreover, no evidence or scientific support has been presented in the argument that the cooling on Earth was caused by either a huge volcanic eruption or a large meteorite collision. Maybe the two things happened at the same time. Other factors, like earthquake, tsunami or blizzard, might also cause the dimming of sun and extremely cold, then influence the climate in a significant way.
Nevertheless, though there were only two possible reasons, the arguer failed to convince us that the volcanic eruption would be the right answer to the cooling. Even if the laud boom recorded in Asian materials and the volcanic eruption happened at the same moment, we still have no 100% confidence to judge there is no-doubt causal relationship between the two phenomena. In terms of the meteorite collision, the sudden bright flash of light might not be seen by any people anywhere in the world. So no record of the flash cannot rule out the possibility of meteorite collision.
In sum, the argument remains problematic with above fallacies. To make the conclusion more credible, the arguer should justify if there was a volcanic eruption and its scale, and how we can eliminate other reasons of the cooling. |
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