You travel back 56 million years and arrive during a period of intense volcanic activity on Earth. The activity brought about significant changes in the planet’s climate, effectively turning some parts of the far north into a tropical paradise.
Carbon dioxide spillage is one of the causes of this warming, but there seem to be more things in history. According to a new study, volcanism covered the seaway between the Arctic and the Atlantic, changing the way ocean waters mixed.
Although the Paleocene-Eocene Thermal Maximum (PETM) is a well-known event in the geological history of the Earth, the remote area of northeastern Greenland studied here has not been the subject of much geological research, although it is 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 analysis across hundreds of kilometers, the study of microfossils and the representation of geological boundaries using seismic images, a team of researchers led by the Geological Survey of Denmark and Greenland (GEUS) found that an increase in geology in the area at this time caused a level of fragmentation that cut more or less two important oceans apart.
“We discovered that volcanic activity and the consequent uplift of the shores of the Greenland continent 56 million years ago led to the formation of a new tropical landscape and the narrowness of the seaway connecting the Atlantic and Arctic oceans. “says paleontologist Milo Barham of Curtin University in Australia.
“Thus, the increase in volcanic activity not only produced an increase in greenhouse gases, but the restriction of the seaway also reduced the flow of water between the oceans, disrupting the distribution of the heat and acidity of the deeper ocean. “
The elevation, created through a combination of tectonic plate movements and rock made from cooling lava, would have narrowed the seaway separating Greenland and Norway (which is much larger than it was before). Deep waters would have been transformed into shallow estuaries, rivers and swamps.
Then, as now, these ocean connections play an important role in shaping the circulation of winds and climate around the world. In this case, the waters of the Arctic would have been almost completely isolated from the waters of the Atlantic, which would have aggravated the warming that was already taking place.
However, there was another consequence: more area meant more migration options for the flora and fauna of the area. Researchers think many animals could have taken advantage of the extra space to move to cooler places.
“The volcanic wave also changed the shape of the Earth’s continents, creating reduced terrestrial or narrow bridges and allowing crucial migration responses for mammalian species such as early primates, to survive climate change,” says geologist Jussi Hovikoski of GEUS.
Fast-forward to the present day: although we do not have molten lava that extends the size of the continents, the oceans and air currents that move above them are just as important in terms of climate management. planet.
The current climate crisis means that some of the crucial weather patterns we have relied on are now beginning to collapse. As and when they do, this would mean serious consequences for how the planet continues to cool or warm in the future.
Our current condition has allowed us to make many comparisons with PETM – a time when there were palm trees in the Arctic – and, 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 trigger points or irreversible changes in weather systems,” he said. says Barham.
“As fires and floods increasingly hit our planet in constant warming, the icy north of eastern Greenland seems an unlikely place to give information about a greenhouse world. However, the record there provides a crucial understanding of environmental and ecological responses to complex climatic disturbances. “
The research has been published in Earth and Environment Communications.