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The natural world. Looking pretty for 3.5b years.

Ice Age Deglaciation

Ice Age Deglaciation

Author: Hugh Bollinger/Tuesday, June 27, 2017/Categories: natural history, sustainability, environment, climate change

            

                            Ice Age Rivers from Melting Eurasian Ice Sheet (credit: CAGE)

Deglaciation in Ice Age Europe unfolded at the end of the Pleistocene and provided massive amounts of water as the ice sheet began to collapse. The process began ~22,000 year ago and had largely concluded in most of Europe by ~12,000 years later. Vast river systems flowed from ice-cap catchment areas that affected the European landscapes emerging from under all the ice. By the end of the deglacation, Northern Europe, the British Isles, Siberia, and most of the continental outlines were ice-free and the resulting landforms would be largely recognizeable today.

Now research from Norway's Center for Arctic Gas Hydrate, Environment, and Climate (CAGE) has reconstructed those past deglaciation events and their impact on sea level rise and landscape boundaries. The Norwegian agency investigates the role and history of frozen methane gas hydrates in the Arctic, and future effects they may have on oceans and climate. CAGE glaciologist Henry Patton, and the author of a new article in Quaternary Science Reviews, said:

"Our model experiments show that from 15000 to 13000 years ago, the Eurasian ice sheet lost 750 cubic kilometres of ice a year. For short periods, it peaked at ice loss rates of over 3000 cubic kilometres per year."

(for perspective, 1 cubic km of ice = 1,000,000,000 tons of water, so this volume of ice needs to be multiplied by 3000)

The influence of the melting ice sheet extended beyond what was covered by the ice itself. According to the glaciologists, one of the most dramatic impacts resulted from a mega-river system that drained the present-day Vistula, Elbe, Rhine and Thames rivers. The meltwater also drained directly into the North Atlantic rising the sea level. The colossal volume meant areas previously land became seabed. As noted earlier this year, a chalk-dam burst from this water in a massive hydrologic event separating the UK from Europe. “Britain and Ireland, which had been joined to Europe throughout the last ice age, finally separated with the flooding of the English Channel around 10,000 years ago." 

              Sequence of Pleistocene Ice Sheet Collapse in Europe, 22,000 YrsBP to Present Day (credit: CAGE

CAGE author Alum Hubbard added a note on present-day consequences of melting glacial ice sheets:

“The Ice Age melting is almost 10 times the current rates of ice being lost from Greenland and Antarctica today. What is fascinating is that not all Eurasian ice retreat was from surface melting alone. The ice sectors across the Barents Sea, Norway, and Britain terminated directly into the sea. They underwent rapid collapse through calving of vast armadas of icebergs and undercutting of the ice margin by warm ocean currents. This is a harbinger of what is starting to happen to the Greenland ice sheets."

Greenland and Antarctica play major roles in global climate, weather systems, and sea levels. As the climate continues to change, 'stay tuned' is the advice from Norway's glacial experts!

WHB

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