The Ice Ages episode of In Our Time with Melvyn Bragg discusses many fascinating concepts surrounding Earth’s glacial history and Climate Change. The most striking things to learn may be… -There have been at least five major Ice Ages (or glaciations) in Earth’s history. -Earth has been ice-free, even in the high latitudes, for about 85% of its history. -The first Icehouse Earth occurred at about noon on the 24-hour geologic time scale (about 2.5Ba). -The last Snowball Earth, where polar ice sheets grow and meet at the equator, occurred about 800Ma and ended with increasing CO2 caused by volcanism. -The change into an ice age occurs gradually, when more snow falls than melts, rather than a sudden cold snap. Our current Ice Age: -Our current geologic period, the Cenozoic era or the “Age of Mammals”, began 65Ma with the Cretaceous-Paleogene (K-Pg) extinction event. -The current ice age, the Quaternary glaciation, beginning about 2.6Ma has featured 40K/100K year cycles of glacials/interglacials. -The conditions needed to setup the current ice age took about 40M years, beginning with the thermal isolation of the Antarctic. -The end of the current ice age will occur when the Greenland and Antarctic ice sheets melt. This will happen whether or not humans accelerate it.
Posted on: Sun, 16 Jun 2013 03:25:38 +0000
Trending Topics
Recently Viewed Topics
© 2015