Deglaciation in the context of "Jökulhlaup"

The Holocene glacial retreat is a geographical phenomenon that involved the global retreat of glaciers (deglaciation) that previously had advanced during the Last Glacial Maximum. Ice sheet retreat initiated ca. 19,000 years ago and accelerated after ca. 15,000 years ago. The Holocene, starting with abrupt warming 11,700 years ago, resulted in rapid melting of the remaining ice sheets of North America and Europe.

The early Holocene sea level rise (EHSLR) was a significant jump in sea levelby about 60 m (197 ft) during the early Holocene, between about 12,000 and 7,000 years ago, spanning the Eurasian Mesolithic. The rapid rise in sea level and associated climate change, notably the 8.2 ka cooling event (8,200 years ago),and the loss of coastal land favoured by early farmers, may have contributed to the spread of the Neolithic Revolution to Europe in its Neolithic period.

During deglaciation since the Last Glacial Maximum, between about 20,000 to 7,000 years ago (20–7 ka), the sea level rose by a total of about 100 m (328 ft), at times at extremely high rates, due to the rapid melting of the British-Irish Sea, Fennoscandian, Laurentide, Barents-Kara, Patagonian, Innuitian and parts of the Antarctic ice sheets. At the onset of deglaciation about 19,000 years ago, a brief, at most 500-year long, glacio-eustatic event may have contributed as much as 10 m (33 ft) to sea level with an average rate of about 20 mm (0.8 in)/yr. During the rest of the early Holocene, the rate of sea level rise varied from a low of about 6.0–9.9 mm (0.2–0.4 in)/yr to as high as 30–60 mm (1.2–2.4 in)/yr during brief periods of accelerated sea level rise.

In geomorphology, an outburst flood—a type of megaflood—is a high-magnitude, low-frequency catastrophic flood involving the sudden release of a large quantity of water. During the last deglaciation, numerous glacial lake outburst floods were caused by the collapse of either ice sheets or glaciers that formed the dams of proglacial lakes. Examples of older outburst floods are known from the geological past of the Earth and inferred from geomorphological evidence on Mars. Landslides, lahars, and volcanic dams can also block rivers and create lakes, which trigger such floods when the rock or earthen barrier collapses or is eroded. Lakes also form behind glacial moraines or ice dams, which can collapse and create outburst floods.