3.16 Argument47 [peresistence小组] 第十五次作业~

cicicamusUID: 2347182

47. 研究历史上气候变化的学者发现在六世纪中叶，地球突然变冷了很多。尽管那个时期很少有历史记录被保存下来，一些在亚洲和欧洲所发现的记录提到了太阳变暗和极度的寒冷。要么是巨大的火山喷发，要么是撞击地球的大型小行星导致地球大气形成一大片尘埃云层，这阻止了一定的阳光导致全球温度显著下降。然而，大型小行星的撞击可能产生突然的强闪光，而现存的那时的历史记录中没有提到过这样的闪光。然而那时遗留下来的一些亚洲历史纪录提到过与一次火山喷发相一致的巨大隆隆声。因此，那时的温度下降多半是火山喷发导致的。
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.

提纲：1。一定是火山爆发吗？
      2．即使是，一定是亚欧变冷的原因吗？
      3．即使是，亚欧变冷就会影响全世界吗？

Before accepting the arguer’s claim that the cooling of earth in the mid-sixth century was likely to be caused by a volcanic eruption, the evidence given in the argument should be examined more carefully. The researchers who conjecture the result seem to rule out many other factors which may also affect and even determine the result.

To begin with, the arguer points out there are two possibilities—a huge volcanic eruption and a large meteorite colliding-- of leading to the dimming and cooling in Asia and Europe and because of the historical records of that time the latter was excluded. However, the evidence in the argument, in fact, fails to support that the volcanic eruption actually happened and the meteorite colliding did not. On the one hand, no extant historical records mentioning such a flash which can prove the existence of the meteorite collision does not mean this event(?) did not ever happen. Since so many years have passed, there is a good reason that the record was lost or destroyed or have not been found yet. Even if this record never existed, there is a chance that no one saw that event at that time, but does not mean it did not happen. On the other hand, a loud boom may be consistent with a volcanic eruption, yet it may also be associated with other phenomenon, say, a large earthquake. Since the research has ignored so many possible alternatives, it cannot prove the existence of the volcanic eruption.

Secondly, even if the volcanic eruption did happened in the mid-sixth century, the arguer still fails to prove that this is the reason rendering the dimming and cooling in Asia and Europe. Common sense tells us that several other factors could also result in this big climate change. Perhaps because of some unknown reasons, the distance between sun and earth at that time became abnormally far, which made the world extremely cold. Or perhaps the ocean currents near Asia and Europe changed, which also might affect the temperature in this two places. And when either of the possible events happened, a big meteorite collided the earth and brought about dimming of the sun. That is to say, even the volcanic eruption happened at that time, it is also lacking information to rule out other possibilities that this event is the very reason of the dimming and cooling in Asia and Europe.

Finally, even if the arguer can substantiate all the foregoing assumptions, it is questionable that whether it could affect the whole world in mid-six century. Firstly, the arguer does not provide any information to prove that this two places’ climates would change the whole world’s. I am very suspicious to this conjecture. Moreover, again, the reasons of the worldwide cold at that time could have many other explanations. Could the volcanic eruption be the only one? Scientific research should consider all the possibilities before coming to the conclusion, and this research apparently failed to do so.

To sum up, the research that the arguer cites does not provide enough information to rule out several other factors that could affect and even determine the cooling of world in mid-six century which indicates an incompletely thought. Therefore the conclusion is unreliable.  

10:00-11:07
2008-3-20