Greenhouse and icehouse Earth

"Climate state" redirects here. For the different levels of climate due to climate change, see Equilibrium climate sensitivity.

Throughout Earth's climate history (Paleoclimate) its climate has fluctuated between two primary states: greenhouse and icehouse Earth.[1] Both climate states last for millions of years and should not be confused with the much smaller glacial and interglacial periods, which occur as alternating phases within an icehouse period (known as an ice age) and tend to last less than one million years.[2] There are five known icehouse periods in Earth's climate history, namely the Huronian, Cryogenian, Andean-Saharan (also known as Early Paleozoic), Late Paleozoic and Late Cenozoic glaciations.[1]

The main factors involved in changes of the paleoclimate are believed to be the concentration of atmospheric greenhouse gases such as carbon dioxide (CO2) and less importantly methane (CH4), changes in Earth's orbit, long-term changes in the solar constant, and oceanic and orogenic changes from tectonic plate dynamics.[3] Greenhouse and icehouse periods have played key roles in the evolution of life on Earth by directly and indirectly forcing biotic adaptation and turnover at various spatial scales across time.[4][5]

Timeline of the five known great icehouse periods, shown in blue. The periods in between depict greenhouse conditions.
  1. ^ a b Summerhayes, Colin P.. (8 September 2020). Palaeoclimatology : from snowball earth to the anthropocene. John Wiley & Sons. ISBN 978-1-119-59138-2. OCLC 1236201953. Archived from the original on 18 April 2021. Retrieved 17 April 2021.
  2. ^ Paillard, D. (2006-07-28). "ATMOSPHERE: What Drives the Ice Age Cycle?". Science. 313 (5786): 455–456. doi:10.1126/science.1131297. ISSN 0036-8075. PMID 16873636. S2CID 128379788. Archived from the original on 2021-11-21. Retrieved 2021-04-17.
  3. ^ P., Summerhayes, C. (13 July 2015). Earths evolving climate : a geological perspective. John Wiley & Sons. ISBN 978-1-118-89737-9. OCLC 907811494. Archived from the original on 21 November 2021. Retrieved 17 April 2021.{{cite book}}: CS1 maint: multiple names: authors list (link)
  4. ^ Cite error: The named reference :3 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference :14 was invoked but never defined (see the help page).