Ice carrot research climate change
The final segment extracted from an ice carrot that went 3.405 metres deep, buried for 68.000 years. Photo by Krystina Slawny

How do poles communicate?

Scientific magazine “Nature” has recently published a study that explains the climatic interconnections between North Atlantic and Antarctica, after observing a two-speed ‘communication’ system in the changes that happened during the last ice age. This discovery could tell us a lot about possible future scenarios.

Italians Mirko severi, analytical chemistry researcher at the University of Florence and Barbara Stenni, professor of geochemistry and paleoclimatology at Ca’ Foscari University of Venice, took part in the Oregon State University’s research, supervised by Christo Buizert.

In the period of time that goes from one-hundred-thousand and twenty-thousand years ago, our planet’s climate experienced rapid temperature changes for approximately 25 times. To better understand this phenomenon, researchers have analyzed ice carrots, extracted from five different sites in Antarctica, and compared them to those previously collected in Greenland. 

Data has shown how the sudden climate changes that happened at the time, are a consequence of the alternation between strong and weak oceanic current, that same current which warms up Greenland and Europe, bringing warm water from the Tropics to the North Atlantic thanks to the Gulf Stream. During these swift climate variations, when the Gulf Stream reaches its maximum power, Greenland can experience a rapid increase in temperature, which can reach 10 to 15°C (50-59°F) within a decade. 

“While the Gulf Stream transfers the heat towards the North, the rest of the Oceans begin to cool down – explains Mirko Severi from the University of Florence – The cooling phenomenon affects the Antarctic continent only after 200 years. This new research documented how changes happening in the North Atlantic  have repercussions on Antarctica, located on the opposite side of the globe, in two different ways. The first way is through atmosphere, which has a lesser impact and takes just a few years to induce changes in Antarctica, while the second way, conveyed by the ocean, shows its first effects after two centuries, but results in more radical changes.” 

“Observation and models suggest that we might be experiencing a phase of weakened Gulf Stream, due to climate change – said Barbara Stenni from the Department of Environmental Sciences, Informatics and Statistics of Ca’ Foscari University of Venice – This study is proof that whatever happened in the past can help us understand future scenarios” 

According to scientists, if what happened in the past were to happen again, the weakening of the Gulf Stream could reduce the intensity of Asian monsoons, causing trouble for millions of people whose lives depend on those rains. Furthermore, variations in the Southern Hemisphere winds could impare the ocean’s ability to absorb carbon dioxide, which would then remain in the atmosphere and worsen the greenhouse effect.  

To carry out this study, the ice carrots have been syncronized and then placed on the same time scale, by using the numerous vulcanic eruptions registered on ice in the last 60.000 years. 

Moreover, the ice carrots have allowed for the recostruction of the temperature changes, thanks to the stable isotopes analysis in the water that resulted from the ice samples melting.

This study was made possible thanks to Italy’s involvement in two European projects, EPICA (European Project for Ice Coring in Antarctica) and TALDICE (TALos Dome Ice CorE). Additional funding came from the MIUR for the National Program for Research in Antarctica (PNRA)