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Travel in time 56 million years, and you will arrive during a period of heightened volcanic activity on Earth. The activity triggered significant changes in the planet’s climate, effectively turning parts of the Far North into a tropical paradise.
One of the causes of this warming is the effusion of carbon dioxide, but it seems there is more to the story. According to a new study, volcanism has blocked the seaway between the Arctic and the Atlantic, changing the way the waters of the oceans have mixed.
While the Paleocene-Eocene Thermal Maximum (PETM) is a well-known event in Earth’s geological history, the remote northeastern region of Greenland studied here has not been the subject of much geological research – although it is at a crucial point for volcanic activity and the flow of water between the Arctic and the Atlantic.
Through a combination of sedimentary analyzes over hundreds of kilometers, studying microfossils and mapping geological boundaries using seismic imagery, a team of researchers led by the Geological Survey of Denmark and Greenland (GEUS) discovered that a rise in geology in the area at this time caused a level of fragmentation that more or less cut two large oceans from each other.
“We discovered that volcanic activity and the resulting uplift from the edge of the Greenlandic continent 56 million years ago led to the formation of a new tropical landscape and the narrowing of the seaway connecting the Atlantic and Arctic Oceans. “says paleontologist Milo Barham of Curtin University. in Australia.
“So not only did the peak of volcanic activity produce an increase in greenhouse gases, but the restriction of the seaway also reduced the flow of water between the oceans, disrupting the distribution of heat and the acidity of the deeper ocean. “
The uplift, created by a combination of movements of tectonic plates and rocks made from cooling lava, is said to have narrowed the seaway between Greenland and Norway (which is much larger than it was before). The deep waters would have been transformed into estuaries, rivers and shallow swamps.
Then as now, these ocean connections play a major role in shaping the circulation of winds and weather around the globe. In this case, Arctic waters would have been almost entirely isolated from Atlantic waters, exacerbating the warming that was already taking place.
There was another consequence, however: more land meant more migration options for the flora and fauna of the region. Researchers believe many animals may have taken advantage of the extra space to move to cooler places.
“The volcanic surge has also altered the shape of the Earth’s continents, creating land bridges or narrowed straits, and allowing crucial migratory responses for mammal species such as early primates, to survive climate change,” says geologist Jussi Hovikoski from GEUS.
Fast forward to today: While we don’t have molten lava extending the size of the continents, the oceans and air currents that move over them are just as important in terms of management of the planet’s climate.
The current climate crisis means that some of the critical weather regimes we rely on are now starting to crumble. As they do, it will have serious consequences for how the planet will continue to cool or warm in the future.
Our current condition has made many comparisons to PETM – a time when there were palm trees in the Arctic – and by understanding how the climate has changed in the past, we should be able to better prepare for the future.
“Recent studies have reported alarming signs of weakening ocean circulation, such as the Gulf Stream, which is an important ocean current for the global climate and this slowdown can lead to climate tipping points or irreversible changes in weather systems.” , said Barham.
“As fires and floods increasingly ravage our ever-warmer planet, the frozen north of eastern Greenland would seem an unlikely place to provide a glimpse of a greenhouse world. However, the geological records provide a crucial understanding of the environmental and ecological responses to complex climatic disturbances. . “
The research was published in Earth & Environment Communications.
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