Gulf Stream currents at their weakest level in 1600 years: Study

The warm Atlantic current play an important role in our climate and new study suggests that the current is at its weakest level in 1,600 years. Researchers added that the current is nearly 15 percent weaker compared to its strength around 400 AD. This could mean extreme winters in Western Europe. Earlier, researchers had estimated that the Gulf Stream could suffer a catastrophic collapse after many decades. But, considering the current trend, researchers believe that it has the potential to disrupt tropical rains.

The Atlantic Meridional Overturning Circulation (Amoc) carries warm water northwards towards the North Pole. In the cold region, the warm current cools and becomes dense. It then moves southwards. As the Amoc current weakens, it will have a strong impact on weather in many nearby regions, leading to climate change.

Sophisticated instruments were installed in 2004 to measure Amoc. Scientists were aware that the current was weakening over time, but they weren’t sure about the impact. With two new studies offering comprehensive ocean based evidence, it could be a warning sign of major change in weather.

Dr David Thornalley, from University College London led one study to check the changes in Atlantic current. Dr. Thornalley informed, “Amoc is a really important part of the Earth’s climate system and it has played an important part in abrupt climate change in the past. The current climate models do not replicate the observed slowdown.” The study led by Dr. Thornalley has been published in the journal Nature.

The research paper further informed, “The current climate models don’t predict an Amoc shutdown is going to happen in the future – the problem is how certain are we it is not going to happen? It is one of these tipping points that is relatively low probability, but high impact.”

The study team found significant Amoc weakening after the end of the little ice age in about 1850, the result of natural climate variability, with further weakening caused later by global warming.

Nature published another study discussing the changes in Amoc. The second study suggests most of the weakening came later, and can be squarely blamed on the burning of fossil fuels. Further research is now being undertaken to understand the reasons for the differences. Both the studies concluded that there is nearly 15 percent decline in Amoc strength over the last 1,600 years.

“If we do not rapidly stop global warming, we must expect a further long-term slowdown of the Atlantic overturning,” said Alexander Robinson, at the University of Madrid. Professor Robinson was associated with the second study. More research will be needed and climate models should factor in the changes in Amoc to accurately predict the changes we can expect in future.