GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - R0NQ77WX58RNPW75K

Samples taken from the ice of glaciers show that during the last ice age there was far more dust in the atmosphere than there is now. Since greater amounts of dust in the atmosphere would result in less sunlight's reaching the Earth's surface, it is likely that the large amount of dust then present helped maintain low global temperatures and thus prolonged the ice age.