The recent, or Gaiacene, episode of glaciation on Old Earth (also known as the New Ice Age)
Any period of prolonged and widespread glaciation on a terrestrial world. Often used to refer specifically to the five major ice ages of Old Earth, traditionally known as the Gunz, Mindel, Riss, Wurm and New Ice ages.
However the most detailed surviving data indicates that the pattern of glaciation during this period was in fact quite complex, and many interglacial and interstadial periods occurred to divide the traditional ice ages still further.
The causes of ice ages on Earth and other terrestrial planets are complex. Quite often small, temporary or permanent variations in CO2 content of the atmosphere or minor variations in the eccentricity of the orbit are sufficient to cause an ice age event. Sometimes the star is variable on a long term basis, and a lower level of insolation is the cause, but most stars gradually increase in luminosity over time due to the buildup of helium in their cores so this cause of glacial events is comparatively rare.
The New Ice age on Earth started in approximately 8600 AT, after the effects of Anthropogenic Global Warming finally disappeared.
Milankovitch Cycles - Text by M. Alan Kazlev Fluctuations in temperature on Garden Worlds, especially ice ages, caused by slight variations in the amount of sunlight reaching the planet caused by the eccentricity of its orbit around its primary. The orbital eccentricity changes the planet's average distance from the sun and therefore slightly changes the amount of sunlight reaching the Earth. Eccentricity cycles last over 100,000 years. The theory was first proposed by the Old Earth human Milutin Milankovitch in 31 AT (1938 c.e.).
TundralPelagic Subtype - Text by John M. Dollan in his Planet Classification List Largely arctic Gaian Type worlds. However, small and scattered continents will inspire great amounts of precipitation, leading to large polar caps and land glaciation. Only the equator of most worlds have a warm year around climate.
TundralXeric Subtype - Text by John M. Dollan in his Planet Classification List Gaian Type world with a cold climate, with an average temperature of around -50 °C. Oceanic ice, even near the equator, can be up to 1 kilometer thick or greater. With almost no precipitation the continents are barren dry wastelands. On land life is restricted to microbial forms, while in the oceans it is typically found only around hot springs and thermal vents.