Ice age
Article
An ice age is a long interval of Earth's history during which permanent ice sheets or extensive glaciers exist on the continents. Within an ice age, colder glacial periods alternate with warmer interglacial periods.
Earth has experienced several major ice ages. Their initiation and termination are influenced by greenhouse gases, continental positions, ocean circulation, mountain building, weathering, and changes in Earth's orbit.
During the current Quaternary ice age, ice sheets have repeatedly expanded and retreated over the Northern Hemisphere. Orbital variations help pace these cycles, while feedbacks involving ice albedo, carbon dioxide, oceans, and vegetation amplify the climate response.
Ice ages reshape landscapes, sea level, ecosystems, and species distributions. Evidence comes from glacial landforms, sediments, ice cores, ocean cores, fossils, isotope ratios, and geological dating.
Source details and credits
- Source / publisher: Wikipedia
- URL type: WWW
- Credits: Wikipedia
- URL: https://en.wikipedia.org/wiki/Ice_age