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Scientists have discovered a "climate link" between the North Atlantic Ocean and Antarctica.
An international team of scientists says that there are two forms of communication used to warn of major events related to climate change – and that an "SOS" message has already been sent due to current conditions.
They say that there is a fast atmospheric channel and a much slower ocean channel.
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An international team of scientists discovered that there were two forms of communication used to warn of major events of climate change, using atmospheric conditions and ocean currents. To rebuild the climate, researchers examined ice cores (shown) at five different locations in Antarctica and synchronized dates by examining layers of volcanic ash.
"The North Atlantic sends messages to Antarctica on two different time scales," said Christo Buizert, climate change specialist at Oregon State University and senior author of the study. .
"The atmospheric connection is like a text message that arrives right away, while the ocean connection is rather a postcard that takes its time to get there – in this case, 200 years, which gives the postal service a beautiful appearance in comparison. "
The study, published in Nature, revealed extremely abrupt climatic changes 60,000 to 12,000 years ago, due to the repeated strengthening and weakening of an ocean current that warms Greenland and Canada. Europe by bringing hot tropical water via the Gulf Stream to the North Atlantic. .
This current is known as the Southern Turnover Atlantic (AMOC) circulation.
The new research documents how the North Atlantic communicates these extreme events to Antarctica on the other side of the world.
HOW TO COMMUNICATE THE POLAR REGIONS OF EARTH
The researchers found that polar regions communicate in two ways.
The first, an atmospheric connection, is like a text message that arrives right away, say the researchers.
The second, an oceanic map, looks more like a postcard that takes its time to get there.
The researchers found that "extremely brutal" climate change 60,000 to 12,000 years ago was the result of the repeated strengthening and weakening of an ocean current that warms Greenland and Europe. bringing hot tropical water via the Gulf Stream into the North Atlantic Ocean.
This current is known as the Southern Turnover Atlantic (AMOC) circulation.
"When the North Atlantic gets warmer because of the strengthening of AMOC, the whole of the Antarctic will eventually get colder because of oceanic changes," said Buizert.
"It starts with the winds, but the ocean produces a much larger impact two centuries later.
During the last ice age, this AMOC current was generally very weak, plunging the North Atlantic region into freezing conditions.
But on occasion, it would strengthen very quickly, causing a sudden warming of Greenland, according to the researchers.
Whenever Greenland warms, the climate of Antarctica on the other side of the world would change – twice.
Global weather conditions immediately changed and the west winds blowing around Antarctica moved away from the ground, causing warming in parts of the Antarctic and cooling in parts of the Antarctic. # 39; others.
The second half of the impact was much slower, a cooling effect of the oceans of the southern hemisphere that has not occurred in Antarctica for 200 years.
To rebuild the climate, researchers examined ice cores from five different locations in Antarctic and synchronized dates by examining layers of volcanic ash. They measured the temperature changes by analyzing the isotope ratios of water. They then compared the data with well-established dates of the so-called "Dansgaard-Oeschger" events in Greenland ice cores to identify the connection between the hemispheres. According to the researchers, these extremely steep events occurred about 25 times during the last ice age, 100,000 to 20,000 years ago.
The observational data and climate models show that the current AMOC is weakening due to global climate change. What happened during the last ice age could therefore happen again.
Researchers say that if the past is a guide for the future, the weakening of AMOC will likely reduce the power of Asian monsoons and that billions of people depend on this rain for their livelihood.
The changing wind regimes in the southern hemisphere will also reduce the ocean's ability to absorb carbon dioxide, which means that more CO2 emissions will remain in the atmosphere. atmosphere, thereby enhancing the greenhouse effect.
"The results could also have consequences for the future," Buizert said.
"AMOC is weakening due to global warming and Greenland meltwaters.
The & # 39; text message & # 39; is being sent and the weather conditions are changing. The "postcard" is on the way. "
The researchers warned that other factors besides AMOC would also affect climate change – rising temperatures due to greenhouse gases is a major factor globally. , and changes in the ozone layer affect wind patterns and climate in Antarctica.
Buizert, who has participated in numerous scientific expeditions to Antarctica and Greenland, said the research was "really exciting for climate geeks, like us, to understand how the elements of our climate are connected.
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