[Global] It is impossible to think of the Arctic today without thinking of ice sheets that stretch for miles.
The word is so deeply associated with freezing temperatures that it has even become a colloquial term for feeling extremely cold.
But the North Pole has not always been such a frozen landscape, according to new research.
But new research has revealed there was no ice at the North Pole during summer.
‘The Arctic sea ice is a very critical and sensitive component in the global climate system,’ said Proferssor Ruediger Stein, expedition leader and lead author of the study.
‘It is therefore important to better understand the processes controlling present and past changes in sea ice.’
Professor Stein and his colleagues at the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research looked at sediment samples from the Lomonosov Ridge, a large underwater mountain range in the Arctic Ocean.
‘One of our expedition’s aims was to recover long sediment cores from the central Arctic, that can be used to reconstruct the history of the ocean’s sea ice cover throughout the past 50 million years,’ Professor Stein added.
The researchers found that six to 10 million years ago the central Arctic was completely ice-free during summer and sea-surface temperature reached values of 4°C to 9°C.
The ocean was covered by changing amounts of ice during spring, autumn and winter.
Our understanding of the Arctic climate millions of years ago has been limited in the past because the sediment cores needed could not be found.
But the team discovered an ideal place to recover the sediment cores.
‘This slope must have experienced gigantic recurring landslides in the past, which resulted in the exhumation of more than 500-metre thick ancient sediment and rock formations,’ Professor Stein said.
‘We were also surprised about the wide-spread occurrence of these slide scars, which extend over a length of more than 186 miles (300km), almost from the North Pole to the southern end of the ridge on the Siberian side.’
Understanding the climate millions of years ago, including the amount of carbon dioxide in the atmosphere, will help scientists to improve climate models. This will also help predict future climates.
‘Once our climate models are capable of reliably reproducing surface-water temperature and sea ice cover of earlier periods, we will also be able to further improve the climate models for a better prediction of future climate change and sea ice conditions in the central Arctic Ocean, a major challenge for all of us for the coming years,’ Professor Stein said.
The team will keep drilling in the hopes of finding older sediments, to build up a picture of the Arctic climate over the past 20 to 60 million years.
Photo: Previously scientists believed the Arctic Ocean was covered with dense sea ice all year round between six and 10 million years ago. But new research has revealed there was no ice at the North Pole during summer. The research icebreaker, called Polarstern, used in the study is pictured
View original article at: Algae fossils reveal the North Pole was ice-free during the summer months 10 million years ago