climate change is slowing the ocean current dramatically. A slowdown that in the 20th century is unprecedented because the Gulf Stream, which carries hot water to Europe, is traveling at the slowest speed of the last millennium. This is the result of the new study, published in Nature Geoscience conducted by a team of scientists from Ireland, Great Britain and Germany which are able to reconstruct the history of the flow of the ocean current in the Atlantic Ocean (the so-called AMOC, and Atlantic Meridional Overturning Circulation, a term used to indicate the Current of the Gulf) in the last 1600 years, by using, among other things, that the data from tree rings, ice cores, sediments, ocean and coral. At the same time, a separate study published in the Proceedings of the National Academy of Sciences found that if the pace of global warming accelerates, you risk even the total closure of the circulation of the Gulf stream. With consequences, of course, disastrous. Such as rapid sea level rise towards the east coast of the United States and extremely harsh winters in Europe. < / p>
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WHAT's HAPPENING? And how can the slowdown in the Gulf Stream impact our lives ? < br/> Mattia Gussoni, technical meteorologist of Ilmeteo.it and expert in monitoring the glaciers of Lombardy.
first we need to understand what the Gulf Stream is.
"This is a huge ocean current that carries warm water from the Caribbean Sea and pushes as far as the North Atlantic. Once arrived at these latitudes it cools and being very salty it sinks, descends back to the North American continent and from there completes the tour. It's a circle. It is also called a “conveyor belt " because it forms a worldwide circulation traveling from the Atlantic Ocean through the Indian Ocean and the Pacific and then back again and represents, therefore, a simplified model of the entire ocean circulation. A very important current that is abbreviated with the term AMOC, from the corresponding name in English Atlantic meridional overturning circulation. That is, the southern reversal of the Atlantic circulation". < / p>
Why is it so important?
" because it regulates the climate system of many areas of the planet. The current is characterized by a northward flow of warm saline water in the surface layers of the Atlantic and a southward flow of cold water in depth. That is, it carries a significant amount of thermal energy from the tropics and southern hemisphere to the North Atlantic, while heat is transferred to the atmosphere. Water has a greater thermal inertia than the atmosphere because it releases heat more slowly and in this way it goes to modify the climate of those sectors that would otherwise be in the most total Frost". < / p>
the study speaks of a slowdown in the Gulf Stream...
"since the Fifties of the last century it has slowed by 15% and this change is beginning to affect weather patterns, such as the most frequent heat waves in southern Europe. Changes in this ocean circulation could have a profound impact on the global climate system. It is an important mechanism for heat redistribution and crucial for the world's climate, a sharp slowdown in AMOC could trigger disruptions around the world, including a sudden rise in sea level , changes in the location of Major rainfall and arid climate zones." < / p>
What about Europe? Could you be affected by this change? "of course, the warm waters of the Gulf Stream moderate the climate of Western Europe, contributing to our milder winters. The slowdown of the Gulf Stream could lead to a change in the climate especially in Central and Northern Europe because the warm supply of this current would be lacking". < / p> < p class="chapter-paragraph" style=""> and Italy?
"Italy being halfway between the North Pole and the equator would surely be involved, perhaps in a more marginal way".
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Why is the AMOC system slowing down?
"one of the reasons is due to the melting of ice in Greenland, where large volumes of cold fresh water enter the ocean and alter the natural sinking mechanism of the current. Increased rainfall in North America, which brings more fresh water into rivers, streams and the ocean, and warmer ocean temperatures that reduce the temperature gradient between the tropics and the pole, are also contributing to the slowdown. Global warming could knock out this current earlier than expected, with severe climate consequences."
analysis of The data collected from the study published indicates that while the AMOC was relatively stable until the 19th century, the system of ocean currents began to decline at the end of the little ice age, i.e., after 1850.
" yes in fact, in the cold period that goes from 1450 to 1850, with a second more drastic decline following from the mid-20th century. In the past there have been reports that this circulation has even been almost interrupted by natural causes such as solar activity. A mini ice age that occurred mostly in North America. The correlation between the state of health of the Gulf Stream and the influence on the European climate is important and should never be underestimated".