Climate: discovered how the “Poles” communicate
A study in Nature, in which researchers from the universities of Florence and Ca’ Foscari, Venice took part, explains the ‘two-speed’ effects between the Gulf Stream and the Antarctic climate. A fundamental detail to understand the future scenarios related to climate change.
A study published in the scientific journal Nature explains the climatic interconnections between the North Atlantic and Antarctica, discovering in the changes that occurred during the last glacial period a ‘two-speed communication’ system that could say a lot about possible future scenarios.
The research, coordinated by Christo Buizert of Oregon State University, saw the collaboration of Italians Mirko Severi, a researcher in analytical chemistry at the University of Florence and Barbara Stenni, professor of geochemistry and paleoclimatology at the Ca’ Foscari University of Venice. (“Abrupt ice-age shifts in southern westerly winds and Antarctic climate forced from the north”).
In the period between 100,000 and 20,000 years ago, the climate of our planet had undergone about 25 episodes of rapid changes in temperature. To better understand these phenomena, the researchers analyzed ice cores obtained from five different sites in Antarctica, comparing them with those previously extracted in Greenland.
The data showed how the abrupt climate changes occurred in that period are derived from a change in the strengthening and weakening of the oceanic current that heats Greenland and Europe, bringing warm water from the tropics to the North Atlantic Ocean through the Gulf Stream .
During these rapid changes in the climate regime, when the Gulf Stream reaches its maximum power, Greenland can undergo very fast heating — up to 10–15° C over a decade.”
As the heat is transferred to the North by the Gulf Stream, the rest of the oceans begin to cool — explains Mirko Severi, analytical chemistry researcher. The phenomenon of cooling the oceans has repercussions on the Antarctic continent only after 200 years. This new research documents how the changes occurring in the North Atlantic affect Antarctica, on the opposite side of the Earth, in two different ways. The former, due to atmospheric conditions, has a minor impact and takes only a few years to cause the first changes in Antarctica, while the second, operated by the ocean, manifests itself about two centuries later, but causes more drastic changes.”
“Observations and models suggest that we could now find ourselves in a phase of a weakening of the Gulf Stream due to climate changes — says Barbara Stenni of the Ca’ Foscari University of Venice. This study provides a testimony of what has happened in the past that can help us understand future scenarios.
“According to the scientists, if what happened in the past were to be repeated, the weakening of the Gulf Stream could reduce the power of the Asian monsoons, putting millions of people, whose life depends on the rains, in difficulty. Moreover, variations in the winds of the southern hemisphere would reduce the ocean’s ability to capture carbon dioxide, which would remain in the atmosphere and worsen the greenhouse effect.
To accomplish this study, ice cores were synchronized and then placed on the same timescale, using the numerous volcanic eruptions recorded in the ice over the last 60,000 years. In addition, ice cores have allowed the reconstruction of temperature variations thanks to the analysis of stable isotopes of water from melting ice samples.
The realization of this study was possible thanks to the Italian participation in the two European projects EPICA (European Project for Ice Coring in Antarctica) and TALDICE (TALOS Dome Ice CorE, www.taldice.org), as well as the Ministry of Education, University and Research (MIUR) funding towards the National Research Program in Antarctica (PNRA)