AccuWeather
The Gulf Stream is the weakest in over 1,000 years, says study
This Tuesday, November 10, 2020, the satellite image made available by NOAA shows the Tropical Storm Eta at 10:40 EST in the Gulf of Mexico, Theta, on the right, and a tropical wave to the south that became the Tropical Storm Iota. An overheated world destroyed meteorological records in 2020 – an extreme year for hurricanes, forest fires, heat waves, floods, droughts and melting ice – the United Nations weather agency reported Wednesday, December 2, 2020. (NOAA via AP) A group of scientists from Europe presented new research this week, claiming that the Gulf Stream is weaker now than at any time in the past 1,000 years. The Gulf Stream is a stream in the Atlantic Ocean that plays a very hidden role in the formation of weather patterns in the United States. Much has been researched and learned about the influential current in the last 500 years, mainly due to the experience of one of the founders of America, Benjamin Franklin. But in the past few decades, a change in the circulation of the Gulf Stream has become weaker than at any time in the past millennium, according to a study recently published by scientists from Ireland, Britain and Germany. The weakening of the Gulf Stream, formally known as Atlantic Meridional Overturning Circulation (AMOC), can be mainly attributed to a catalyst, the researchers said: man-made climate change. The Gulf Stream moves a large amount of water across the Atlantic Ocean. According to Stefan Rahmstorf, one of the study’s authors, it moves almost 20 million cubic meters of water per second, acting like a giant conveyor belt. How strong is this current? “Almost a hundred times the flow of the Amazon,” he told the Potsdam Institute. The location of the Gulf Stream in the 2016 Global Real-Time Ocean Forecasting System (RTOFS) model. (Image via NOAA) The main function of the Gulf Stream is to redistribute heat on Earth through the ocean current. The ocean’s circulatory system plays a crucial role in many weather patterns around the world, particularly along the east coast of the United States. Rahmstorf said his team’s research was groundbreaking in that it was able to combine fragments of previous research to bring together a 1,600-year-old picture of the evolution of AMOC. “The results of the study suggest that it has been relatively stable until the end of the 19th century,” he said. “With the end of the small ice age around 1850, ocean currents began to decline, with a second, more drastic decline following since the mid-20th century.” An original mapping of the Gulf Stream by Timothy Folger and Benjamin Franklin from 1768. (Image via Library of Congress) So what are the implications of this decline in ocean currents? AccuWeather senior meteorologist Bob Smerbeck said this could lead to sea levels rising if the water level is heated this year. However, Smerbeck added that it is difficult to know how hot the waters can get. Previously, studies have shown that rising water temperatures and rising sea levels can lead to more extreme weather events, such as stronger tropical storms, an increased likelihood of extreme heat waves or decreased rainfall in the summer. However, other researchers have also presented contrasting data, suggesting that the Gulf Stream has not actually decreased in the past 30 years. Using a different data modeling system, researchers from the United Kingdom and Ireland gathered data from climate models that, according to them, in a study published earlier this month, “there was no general decline in AMOC”. “Our results reinforce that adequate capture of changes in deep circulation is the key to detecting any anthropogenic decline of AMOC related to climate change,” write the authors in their study, which was written just days before Rahmstorf’s team published its research on the subject. Smerbeck, who has been a AccuWeather meteorologist for almost 25 years, urged caution in interpreting the survey’s new claims. “A possible repercussion discussed in article 1 [the first study mentioned above] on warming water along the east coast from an AMOC slowdown could lead to sea level rise due to the thermal expansion of sea water. That seems plausible, “said Smerbeck. However, he added that the amount of seawater rise would depend on how hot the water could get and he was not ready to speculate about it. This undated print shows the scene on 4 July 1776, when the Declaration of Independence was approved by the Continental Congress in Philadelphia, Pennsylvania.The document, written by Thomas Jefferson, Benjamin Franklin, John Adams, Philip Livingston and Roger Sherman, announces the separation of 13 British North American colonies from Great Britain, the formal signature by 56 members of Congress began on August 2. (AP Photo) How was the Gulf Stream discovered as we know it today? Well, the discovery was fueled by a need to increase the efficiency of the and was inspired by whalers’ empiricism. In 1768, Benjamin Franklin worked in London as deputy director of mail, according to The Smithsonian Magazine, responsible for superv to prevent the arrival of correspondence to and from the American colonies. His cousin, older Timothy F, worked as a captain on a merchant ship at the same time. One day, Franklin asked Folger why his merchant ships arrived in the colonies much faster than Franklin’s mail ships returned to England. Folger explained to his cousin that merchant captains followed the advice of whalers, who followed a “hot, strong current” to track and kill whales. While Franklin said the captains of the post were too proud to follow the advice of “simple American fishermen”, sailing against the current was costing precious time, according to author Laura Bliss. Thus, Folger outlined a general location of the chain for Franklin, calling it “Gulph Creek”. However, Franklin’s postmen refused to follow instructions. A Gulf Stream chart, published in 1786 in the Transactions of the American Philosophical Society. (Image via Library of Congress, Geography Division and Map) But when Franklin moved to the United States during the Revolutionary War, he traced a more precise route to AMOC and gave it to French allies, giving them an important advantage in the battle of European maritimers, according to The Smithsonian. The combination of Folger’s knowledge of whaling and Franklin mapping would become crucial to further understanding the importance of the current, even if they were originally just trying to figure out how to deliver mail more quickly. Although AMOC’s knowledge can go back only a few hundred years, Smerbeck said that the dating of the currents can be done in several different ways. Direct measurements of instruments from the ocean floor date back to 2004, he said, but other methods may help to put the puzzle together, such as coral analysis and historical data from ship records. “Tree rings can tell you how wet or dry the nearby terrestrial climate was in the past, which could be related to sea surface temperatures,” explained Smerbeck. “Ice cores can say pretty much the same thing, as well as how hot or cold it was in the past,” he said. “Ocean sediments can show whether there have been periods of high or low runoff due to close precipitation on land, which may be related to hot or cold sea surface temperatures in the past.” The researchers used all of these clues to inform the understanding, which goes back more than a millennium, that they developed from the Gulf Stream. Continue to access AccuWeather.com and stay connected to the AccuWeather Network on DirecTV, Frontier, Spectrum, Fubo and Verizon Fios.