A glacier is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.
The Younger Dryas, which occurred circa 12,900 to 11,700 years BP, was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM), which lasted from circa 27,000 to 20,000 years BP. The Younger Dryas was the last stage of the Pleistocene epoch that spanned from 2,580,000 to 11,700 years BP and it preceded the current, warmer Holocene epoch. The Younger Dryas was the most severe and longest lasting of several interruptions to the warming of the Earth's climate, and it was preceded by the Late Glacial Interstadial, an interval of relative warmth that lasted from 14,670 to 12,900 BP.
Mount Kilimanjaro is a dormant volcano located in Kilimanjaro Region of Tanzania. It has three volcanic cones: Kibo, Mawenzi, and Shira. It is the highest mountain in Africa and the highest single free-standing mountain above sea level in the world: 5,895 metres (19,341 ft) above sea level and about 4,900 metres (16,100 ft) above its plateau base. It is the highest volcano in Africa and the Eastern Hemisphere.
The Last Glacial Period (LGP), also known colloquially as the last ice age or simply ice age, occurred from the end of the Eemian to the end of the Younger Dryas, encompassing the period c. 115,000 – c. 11,700 years ago. The LGP is part of a larger sequence of glacial and interglacial periods known as the Quaternary glaciation which started around 2,588,000 years ago and is ongoing. The definition of the Quaternary as beginning 2.58 million years ago (Mya) is based on the formation of the Arctic ice cap. The Antarctic ice sheet began to form earlier, at about 34 Mya, in the mid-Cenozoic. The term Late Cenozoic Ice Age is used to include this early phase. The previous ice age, the Saale glaciation, which ended about 128,000 years ago, was more severe than the Last Glacial Period in some areas such as Britain, but less severe in others.
The Byrd Polar and Climate Research Center (BPCRC) is a polar, alpine, and climate research center at The Ohio State University founded in 1960.
The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent 26 ka - 20 ka. Ice sheets covered much of Northern North America, Northern Europe, and Asia and profoundly affected Earth's climate by causing drought, desertification, and a large drop in sea levels. Based on changes in position of ice sheet margins dated via terrestrial cosmogenic nuclides and radiocarbon dating, growth of ice sheets commenced 33,000 years ago and maximum coverage was between 26,500 years and 19–20,000 years ago, when deglaciation commenced in the Northern Hemisphere, causing an abrupt rise in sea level. Decline of the West Antarctica ice sheet occurred between 14,000 and 15,000 years ago, consistent with evidence for another abrupt rise in the sea level about 14,500 years ago. Glacier fluctuations around the Strait of Magellan suggest the peak in glacial surface area was constrained to between 25,200 and 23,100 years ago. Continental ice sheets never reached their isostatic equilibrium during the LGM, as evidenced by high variability in ice volume over short spans of time.
The Holocene Climate Optimum (HCO) was a warm period that occurred in the interval roughly 9,500 to 5,500 years ago BP, with a thermal maximum around 8000 years BP. It has also been known by many other names, such as Altithermal, Climatic Optimum, Holocene Megathermal, Holocene Optimum, Holocene Thermal Maximum, Hypsithermal, and Mid-Holocene Warm Period.
The Older Dryas was a stadial (cold) period between the Bølling and Allerød interstadials, about 14,000 years Before Present, towards the end of the Pleistocene. Its date is not well defined, with estimates varying by 400 years, but its duration is agreed to have been around 200 years.
The Oldest Dryas is a biostratigraphic subdivision layer corresponding to a relatively abrupt climatic cooling event, or stadial, which occurred during the last glacial retreat. The time period to which the layer corresponds is poorly defined and varies between regions, but it is generally dated as starting at 18.5–17 thousand years (ka) before present (BP) and ending 15–14 ka BP. As with the Younger and Older Dryas events, the stratigraphic layer is marked by abundance of the pollen and other remains of Dryas octopetala, an indicator species that colonizes arctic-alpine regions.
The Bølling–Allerød interstadial, also called the Late Glacial Interstadial, was an abrupt warm and moist interstadial period that occurred during the final stages of the Last Glacial Period. This warm period ran from 14,690 to 12,890 years before the present (BP). It began with the end of the cold period known as the Oldest Dryas, and ended abruptly with the onset of the Younger Dryas, a cold period that reduced temperatures back to near-glacial levels within a decade.
Lonnie Thompson, is an American paleoclimatologist and university professor in the School of Earth Sciences at Ohio State University. He has achieved global recognition for his drilling and analysis of ice cores from ice caps and mountain glaciers in the tropical and sub-tropical regions of the world. He and his wife, Ellen Mosley-Thompson, run the ice core paleoclimatology research group at the Byrd Polar Research Center.
The retreat of glaciers since 1850 affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glacier-melt, and, in the longer term, the level of the oceans. Deglaciation occurs naturally at the end of ice ages, but glaciologists find the current glacier retreat is accelerated by the measured increase of atmospheric greenhouse gases and is an effect of climate change. Mid-latitude mountain ranges such as the Himalayas, Rockies, Alps, Cascades, Southern Alps, and the southern Andes, as well as isolated tropical summits such as Mount Kilimanjaro in Africa, are showing some of the largest proportionate glacial losses. Excluding peripheral glaciers of ice sheets, the total cumulated global glacial losses over the 26 year period from 1993–2018 were likely 5500 gigatons, or 210 gigatons per yr.
Furtwangler Glacier is located near the summit of Mount Kilimanjaro in Tanzania. The glacier is named after Walter Furtwängler who, with Siegfried König, formed the fourth party to ascend to the summit of Kilimanjaro in 1912.
The climate of Mount Kenya has played a critical role in the development of the mountain, influencing the topography and ecology amongst other factors. The area around Mount Kenya is covered by a comparably large number of weather station data with long measurements series and thus the climate is well recorded. It has a typical equatorial mountain climate which Hedberg described as winter every night and summer every day.
Deglaciation is the transition from full glacial conditions during ice ages, to warm interglacials, characterized by global warming and sea level rise due to change in continental ice volume. Thus, it refers to the retreat of a glacier, an ice sheet or frozen surface layer, and the resulting exposure of the Earth's surface. The decline of the cryosphere due to ablation can occur on any scale from global to localized to a particular glacier. After the Last Glacial Maximum, the last deglaciation begun, which lasted until the early Holocene. Around much of Earth, deglaciation during the last 100 years has been accelerating as a result of climate change, partly brought on by anthropogenic changes to greenhouse gases.
Drygalski Glacier was on Mount Kilimanjaro in Tanzania, on the northwest slope of the peak. The glacier terminus once extended to an elevation of 4,800 metres (15,700 ft) with an origination point near the summit of Mount Kilimanjaro and was fed by the Northern Ice Field. The Great Penck Glacier once flanked Drygalski Glacier to the south and until recently, the Credner Glacier did as well to the north. Drygalski Glacier is named for German geographer Erich von Drygalski.
Great Penck Glacier was on Mount Kilimanjaro in Tanzania, on the west slope of the peak. Extending from the Northern Ice Field, the glacier once flowed 2.4 kilometres (1.5 mi), to an elevation of 4,750 metres (15,580 ft). Between the years 1962 and 1975, Great Penck Glacier separated from the Northern Icefield and disappeared. Drygalski Glacier once also existed to the north of Great Penck, while the same is true of the Little Penck Glacier, which was to the south.
Little Penck Glacier is on Mount Kilimanjaro in Tanzania, on the west slope of the peak. Once extending from the Northern Ice Field, the glacier detached from the icefield by 1992. A sizeable but stagnant ice body remains near the 1912 historical terminal end of the glacier. The now vanished Great Penck and Uhlig Glaciers once flanked Little Penck Glacier to the north and south, respectively.
The Quelccaya Ice Cap is the second largest glaciated area in the tropics, after Coropuna. Located in the Cordillera Oriental section of the Andes mountains in Peru, the cap covers an area of 42.8 square kilometres (16.5 sq mi) with ice up to 200 metres (660 ft) thick. It is surrounded by tall ice cliffs and a number of outlet glaciers, the largest of which is known as Qori Kalis Glacier; lakes, moraines, peat bogs and wetlands are also present. There is a rich flora and fauna, including birds that nest on the ice cap. Quelccaya is an important source of water, eventually melting and flowing into the Inambari and Vilcanota Rivers.
