Ice age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and greenhouse periods during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation.[1] Individual pulses of cold climate within an ice age are termed glacial periods (glacials, glaciations, glacial stages, stadials, stades, or colloquially, ice ages), and intermittent warm periods within an ice age are called interglacials or interstadials.[2]
This article is about glacial periods in general. For specific recent glacial periods often referred to as the "Ice Age", see Last Glacial Period, Pleistocene, and Quaternary glaciation. For other uses, see Ice age (disambiguation).In glaciology, the term ice age is defined by the presence of extensive ice sheets in the northern and southern hemispheres.[3] By this definition, the current Holocene period is an interglacial period of an ice age. The accumulation of anthropogenic greenhouse gases is projected to delay the next glacial period.[4][5][6]