Gulf Stream weakening now 99% certain, and ramifications will be global

It's difficult to determine if the Gulf Stream's slowdown is caused by climate change, notwithstanding the conclusion of a recent investigation.

A recent research has revealed the most likely weakening of the Gulf Stream.

Over the past 40 years, the flow of warm water across the Florida Straits has decreased by 4%, which has serious consequences for the global climate.

Originating close to Florida, the ocean current follows a warm water belt through the East Coast of the United States and Canada before making its way across the Atlantic to Europe. Its ability to carry heat is crucial for preserving temperate weather and controlling sea levels.

However, according to a study that was published on September 25 in the journal Geophysical Research Letters, this stream is slowing down.

Lead author Christopher Piecuch, a physical oceanographer at the Woods Hole Oceanographic Institution in Massachusetts, said in a statement, "This is the strongest, most definitive evidence we have of the weakening of this climatically-relevant ocean current."

The thermohaline circulation, a worldwide network of ocean currents that transports heat, carbon, nutrients, oxygen, and other elements throughout the world while also assisting in the regulation of sea levels and hurricane activity, includes the Gulf Stream as a minor part.

The Gulf Stream transports warmer, denser, and saltier southerly waters northward to cool and sink in the North Atlantic. It originates in the Caribbean and flows through the Florida Straits into the Atlantic. The water slowly moves southward after submerging deeply under the ocean and releasing its heat into the atmosphere, where it warms up once again and the cycle continues.

The sweeping action of the current keeps the seas around the U.S. East Coast up to five feet (1.5 meters) lower than the waters farther offshore, therefore this mechanism is essential to sustaining sea levels and temperatures there.

Scientists believe that as Earth's temperature rises, a massive amount of cold, fresh water from ice sheets that are melting is seeping into the seas. This may potentially slow down or perhaps cause the Gulf Stream to completely collapse. However, this is difficult to establish because of the system's complexity and size.

Scientists examined data from three different sources spanning 40 years to investigate the current's movements throughout the Florida Straits: underwater cables, satellite altimetry, and on-site observations. The goal was to discover conclusive proof that the stream is slowing down.

According to their statistical analysis, there was only a 1% possibility that their measurement was an anomaly due to random oscillations, meaning that the current had slowed by 4%.

Although a 4% shift might not seem like much at first, oceanographer Helen Czerski of University College London (UCL), who was not involved in the study, told Live Science that "the worry is that's just the slow start."

It's similar to the early COVID years. "Oh, there's only 60 cases," someone said. We're not interested in this," she continued. "Yes, there are just 60 instances, but there were 30 yesterday and 15 the day before that. We have an issue if you simply plan one week ahead of time."

Scientists will have to distinguish between the effects of global warming and the inherent variability of ocean systems in order to find conclusive evidence that climate change is the cause. This will be a challenging task considering how recently humans have been able to measure ocean flows precisely.