During the last decades, Research into the behavior of major ocean and air currents has gained increasing importance. to understand climate changes both in Europe and on a global scale. One of the most enigmatic areas is the marine area south of Greenland, where For more than a century, a region of unusually cold waters has been detected Despite the general warming recorded elsewhere in the North Atlantic, this so-called "cold hole" has sparked interest and debate in the scientific community, as its presence seems paradoxical in the context of climate change.
A new study points out how The main cause of this anomaly is the progressive weakening of the Atlantic Current, also known as AMOC.This complex system of ocean currents acts like a giant conveyor belt, moving warm, salty water from tropical regions northward, thereby regulating the climate and thermal balance throughout the Atlantic basin and directly affecting weather conditions in Europe.
Slowing of the Atlantic Current: causes and consequences
The persistent cooling in southern Greenland is due, according to experts, to the arrival of a smaller volume of warm, saline water. over the past few decades. By analyzing historical records of temperature and salinity, scientists have found that AMOC has been weakening for more than a century, although direct observations of its current state only go back the last twenty years. When researchers compared this extensive data record with nearly a hundred climate models, Only those who contemplated a slowdown of the Atlantic Current were able to replicate the cooling observed in reality.
The impact of this phenomenon goes far beyond the water temperature itself. The decrease in salinity and the change in the trajectory of the ocean current impact atmospheric circulation, modifying the jet stream., the high-altitude air flow that drives weather systems and determines the weather in North America and Europe. As a result, precipitation patterns, extreme temperatures, and, therefore, the frequency of adverse events are altered.
Polar jet stream: what influences it more, nature or climate change?
Parallel, For years, climatologists have been focusing their attention on the polar jet stream., a high-altitude wind belt that regulates the climate in mid-latitudes and whose undulations can cause both sudden cold snaps and intense winter storms.
Several recent studies, led by US teams, have used machine learning to analyze climate records since the beginning of the 20th century, managing to reconstruct the natural variability of the polar jet stream for more than 120 years. Surprisingly, the results show that despite the increase in greenhouse gases and the reduction of Arctic ice in recent decades, The jet stream had previously experienced periods of great instability and undulation.In fact, during certain phases of the last century, it was even more volatile than it is today.
This casts doubt on the theory that the recent atmospheric chaos is caused solely by climate change. Researchers believe that many extreme events may be due to the natural variability of the jet stream., while global warming intensifies storms and extreme precipitation through alternative mechanisms, such as increased moisture retention in a warmer atmosphere.
Impacts on Europe, America and the future of the climate
Variations in oceanic and atmospheric circulation They affect the distribution of marine species, the intensity of storms and the stability of coastal ecosystems.Experts warn that if this trend continues, we could see a further differentiation of climates in northern and southern Europe: while the north could experience a sharp cooling, the southern regions would experience temperature increases, intensifying the current contrasts and creating challenges for both agriculture and water resource management.
Likewise, Variations in oceanic and atmospheric circulation impact the distribution of marine species, the intensity of storms, and the stability of coastal ecosystems.Scientists emphasize the importance of continuing to monitor these phenomena to anticipate potential consequences and better prepare societies for future scenarios of change.
The integrated study of major ocean currents and atmospheric dynamics reveals that climate is the result of complex natural interactions, on which global warming adds new pressures. The importance of the Atlantic Current and the polar jet stream as climate modulators is indisputable. Understanding their evolution and effects allows progress toward greater resilience to extreme events and contributes to the adoption of policies that are more closely aligned with the reality of the climate system.