How a comet 12,900 years ago change climate?

Climate has a lot to do with the meteor that destroyed mammoths" Did A Comet really kill the Mammoths 12,900 years ago?" By: Robert Kunzig http://news.nationalgeographic.com/news/2013/09/130910-comet-impact-mammoths-climate-younger-dryas-quebec-science/

One of the most potential theories for why mammoths went extinct is a comet. In 2007 the idea of a comet hitting the earth at the beginning of the Younger-Dryas about 12,900 years ago was proposed. The Younger Dryas was the period were the climate cooled. Evidence of this idea includes: 1) Researchers in Dartmouth College have discovered tiny glassy specks of rock in Pennsylvania. This rocks date exactly 12,900 years and are possible residue of a comet. 2) In the northern countries like Greenland and Canada platinum residue has been found. Though the platinum was not from a comet it was from an iron rich meteor. Though this facts are not useful to scientists, some agree there is more truth in the comet than lies. The mammoth-killing impact made the earth's climate change.12,900 years ago the ice sheets were in full retreat from the past ice age. The climate was almost as warm as it was today. During the next decades the cold returned and it was more severe than ever. Even though the Younger Dryas happened many years ago scientist are worry about the severe climate the Earth faces. If it happened once why can't it happen again. The comet in present day Quebec is said to be what caused mammoth population to become extinct. Though it is a strong fact it also proves that the climate can be altered by such a powerful thing like a comet.

This author made a terrific job in catching the readers attention. This article is well written and it provides evidence and facts for the reader to draw conclusions from it. I can relate to this article because I have always been interested in comets. Though it happened many years ago it can still affect today. For example the climate shifts described in this article can happen again and its up to the next generations to be informed and prepared.