Argument47 【0710G Victors互助小组】

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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: 428          TIME: 00:40:00         
  The auguer claims that it 's the volcanic eruption that caused the significantly low temperatures in the mid-six century.To support the assertion,the auguer cites a varity of evidences.Close srutiny of these evidences,however,I find this argument unconvincing for several reasons.

  First of all,the credibility of dimming of the sun and extremely cold temperatures in this era is open to doubt.In the one hand,the occurence of these phenomenoe in Asia and Europe is not representative of the global weather pattern,perhaps that it was the case in these two regions mentioned above but might not happen in other regions ,for example ,the relative high temperature and strong sun light in other continents would balance or even strenthen the overal temperature and sunlight condition.In the other hand ,the author even acknowdges that there are few records suivive from that time ,the truth actually weakers the author's assertion.

  Secondly,even if the extremly low global temperatures and dimming of sun light did happen in mid-six century, the author fails to rull out the possibility other than a volcanic eruption and a meteorite collision which caused the dimming of sun and significantly change of temperatures.Perhaps some other factors were instead of the causes ,but the author provides no evidence to justify that it is the case .Without rulling all other explanations,the author can not convince me that volcanic eruption or large meteorite collision are the only two causes .

Thirdly, even if only a large meterite collision or volcanic eruption would cause the change of sunlight and temperature ,the author provides not enough evidence to prove that it is the volcanic eruption that is the real cause . The author assumes mereorite collision would create a suden bright flash of light,but the assumption might not meet the reality,the mereorite collision would have happened  without any flash of light ,or  the bright flash of light occured but was not recorded. Moreover,a loud boom would be created by volcanic eruption and also other phenomenoe such as earthquake.Without additional evidences for rulling out these possibilities,I can not accept the arguer’s broad assertion about the cause of the dimming of sun and extremly low temperatures.

  In sum,the scant evidence of evidence the arguer cites proves nothing about the reason for the change of sunlight and temperature.To strenghen the argument the author should provide more about the global weather pattern records in details of the mid-six centrury ,the author must also provide scientific evidence and not only assumptions that a large meteorite collision would create bright flash of light and a volcanic eruption would be consistent with a loud boom.