The relation between the Arctic and global warming has attracted public awareness over the past years. To really understand the future challenge of climate change we need to understand the climate of the past.
CAGE researchers Jochen Knies, Karin Andreassen, Soma Baranwal and Karl Fabian have contributed to a recent publication in Earth and Planetary Science Letters which presents new knowledge of the Arctic climate in the Pliocene.
Crucial event four million years ago
The researchers conclude that a tectonic uplift event four million years ago intensified the ice build-up during the Northern Hemisphere Glaciation.
Previously it has been very challenging to study environmental changes in the Arctic Ocean because available data is difficult to date. However, the researchers have now studied a sequence from the Yermak Plateau off northwestern Spitsbergen which they have dated back to the Pliocene (5.33 to 2.58 million years ago).
They have collected sedimentary and geochemical data which indicate that the terrigenous sediment supply and sources changed abruptly in response to a regional tectonic uplift event. Hence the landmasses were preconditioned for glacial ice build-up during the intensification of the Northern Hemisphere Glaciation. The result was the first large build-up of glaciers in Scandinavia, Svalbard and the Barents Sea – 2.75 million years ago.
Important knowledge to understand global warming
Knowledge about what happened in the Arctic during the Pliocene is important for a better understanding of future climate changes. The sea ice was possibly gone during the summer and the treeline may have been shifted further north compared to today, according to Jochen Knies.
“I think our findings will be a ‘master stratigraphy’ for the Arctic Ocean in many years to come, until new drilling initiatives are implemented. That means that the interpretations of climate change based upon this sequence will be used a lot by climate modellers to get a better understanding of Pliocene and future climate changes”, says Knies.