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Climate state describes a state of climate on Earth and similar terrestrial planets based on a thermal energy budget, such as the greenhouse or icehouse climate state. The orbital forcing from Milankovitch cycles is a periodical factor to determine Earth's energy budget and responsible for the glacial cycles on Earth, depending on the radiative equilibrium. Other factors include processes and change in geospheric systems. These include oceanic processes (such as oceanic circulation), biotic processes, variations in solar radiation received by Earth, plate tectonics, volcanism, albedo vegetation changes and human-induced alterations of the natural world. The main climate state change is between periodical glacial and interglacial cycles in Earth history, studied from climate proxies. The climate system is responding to the current climate forcing and adjusts following climate sensitivity to reach a climate equilibrium, Earth's energy balance. == General == The greenhouse has been the dominant state in Earth's past. Recovered ocean sediments of the past 120 million years contain evidence of the long-term transition from a greenhouse to icehouse climate state. A time when there are no glaciers on Earth is considered a greenhouse climate state.〔 An ice age implies the presence of extensive ice sheets at Earth polar regions. The time during an Ice Age glacial period, when glaciers reach their maximum extent is referred to as icehouse climate state. There have been five known ice ages in the Earth's past, with the Earth experiencing currently an interglacial period (warming) during the present Quaternary Ice Age, identified as the "marine isotope stage 1" (MIS1) in the Holocene epoch (or recently the Anthropocene epoch). The current climate state and evidence from the past of the climate system are important in determining the future evolution of climatic anomalies. Dansgaard–Oeschger events are considered switches between states of the climate system. Tipping points in the climate system describe thresholds, such as ice-albedo feedback〔(Albedo definition by the National Snow and Ice Data Center )〕〔Croll, James (1885). Climate and Time in Their Geological Relations. A Theory of Secular Changes of the Earth's Climate. New York: Appleton.(Online )〕 which can cause abrupt climate change, and possibly leading to a new state. The climate state affects the formation processes of large volcanic provinces. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「climate state」の詳細全文を読む スポンサード リンク
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