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What is the Gulf Stream? -

The Gulf Stream is a strong, swift current that accelerates warm water from the Gulf of Mexico into the Atlantic Ocean.

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Juan Ponce de León (1474–1521) -

European discovery of the Gulf Stream dates back to the 1512-13 expedition of Juan Ponce de León. The Spanish explorer and conquistador noted that there was a strong current off land he called La Florida, after which it became widely used by Spanish ships sailing from the Caribbean to Spain.

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Benjamin Franklin (1705–1790) -

It was Benjamin Franklin, one of the founding fathers of the United States, who was the first to chart the Gulf Stream after his interest in the North Atlantic Ocean circulation patterns led him to investigate why it took British merchant ships several weeks longer to reach New York from England than American vessels sailing in the opposite direction.

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Franklin's chart -

Benjamin Franklin's original chart of the Gulf Stream, printed in London in 1769, was largely ignored by British sea captains. A copy of the chart was printed in Paris circa 1770–1773, and a third version was published by Franklin in Philadelphia in 1786. The original map was sketched by Timothy Folger, a Nantucket fisherman and a cousin of Franklin, and is now held in the Library of Congress.

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Florida coast -

The swift Gulf Stream warm waters influence the climate of the east coast of Florida. It keeps temperatures there warmer in the winter and cooler in the summer.

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Western Europe -

The current follows the eastern coastline of the US and Canada and also extends towards the European continent, thus ensuring that the climate of Western Europe is much warmer than it would otherwise be.

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What causes the Gulf Stream? -

The Gulf Stream is caused by a large system of circular currents and powerful winds.

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How does the Gulf Stream work? -

The ocean is constantly in motion, moving water from place to place via currents. As warm water flows from the equator to the poles it cools and some evaporation occurs, which increases salt content.

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Low temperatures -

Low temperatures and a high amount of salt means greater density, and as such the water sinks deep in the oceans.

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Flowing to the Antarctic -

This cold, denser water begins moving slowly south—eventually flowing along the bottom of the ocean all the way to Antarctica.

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North-South divide -

In other words, the Gulf Stream sends warm water to the North Atlantic Ocean, forcing colder water to sink and travel southward.

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A global process -

This global process of circular currents aided by powerful winds makes sure that the world's oceans are continually mixed, and that heat and energy are distributed to all parts of the Earth.

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Climate control -

It's a process that contributes to the generally settled climate we experience today.

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Tracking the Gulf Stream -

Tracking the Gulf Stream, together with its northern extension the North Atlantic Current, is made by imaging sea surface temperature, as seen in this NASA photograph. The North American landmass is black (cold), while the Gulf Stream is red (warm).

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Sea temperature - Knowing sea temperature is of great benefit to scientists, as it gives them more information about what is happening in and around the ocean. This is vital knowledge because changes in this temperature can influence the behavior of fish, cause the bleaching of corals (pictured), and affect weather along the coast.

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Decline in Atlantic Ocean circulation -

Any decline in the Atlantic Ocean circulation, which underpins the Gulf Stream, is cause for alarm. And that's exactly what scientists believe is happening now. New data suggests climate breakdown is the probable cause. Pictured: heavy snowfall in Athens in February 2021, a phenomenon not seen in the city center for several decades.

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Atlantic Meridional Overturning Circulation -

According to a study involving researchers from University College London (UCL), the Gulf Stream System, also known as the Atlantic Meridional Overturning Circulation (AMOC), is at its weakest in over 1,000 years. But what does this mean?

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Unprecedented slowdown -

The team found that the Gulf Stream’s slowdown in the 20th century is unprecedented and is likely linked to human-induced climate change. Further weakening of the AMOC could result in more storms battering the United Kingdom, for example, more intense winters, and an increase in damaging heatwaves and droughts across Europe.

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Colder, harsher winters -

Similarly, and quite ironically, a weakening AMOC and the subsequent effect of global warming could bring with it colder and harsher winters to Western Europe.

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Rise in sea and rainfall levels -

Furthermore, an abrupt slowdown of the AMOC could trigger disruptions around the globe, including a sudden rise in regional sea levels, changes in the position of major rainfall, and arid climate zones, UCL scientists warn.

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Severe flooding -

The consequences for people living on both sides of the Atlantic would be severe. A weakened Gulf Stream would raise sea levels on the United States' eastern seaboard, with potentially disastrous results.

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Impact already seen -

The study, published in Nature Geoscience, paints a bleak picture. Professor Stefan Rahmstorf, who co-authored the paper, told the UK's Guardian newspaper that circulation of the AMOC had already slowed by nearly 15%, and the impacts were already being seen.

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More storms, more heatwaves -

"In 20 to 30 years it is likely to weaken further, and that will inevitably influence our weather, so we would see an increase in storms and heatwaves in Europe, and sea level rises on the east coast of the US," he predicted.

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Earth's rotation -

Lead author Dr. Levke Caesar, speaking to Nature Geoscience, elaborated: "The northward surface flow of the AMOC leads to a deflection of water masses to the right, away from the US east coast. This is due to Earth's rotation that diverts moving objects such as currents to the right in the northern hemisphere and to the left in the southern hemisphere."

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Coastal erosion -

"As the current slows down, this effect weakens and more water can pile up at the US east coast, leading to an enhanced sea level rise," added Dr. Caesar. 

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Impact on marine ecosystems -

Another co-author, Dr. David Thornalley, said: "This study shows the increasing evidence in support of the modern Atlantic Ocean undergoing unprecedented changes in comparison to the last millennium. Alongside other human pressures on the marine environment, the changes we are observing in ocean circulation are impacting marine ecosystems in both the surface and deep ocean. We will need to take account of these ongoing changes in our efforts to conserve and manage marine resources."

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Tipping point -

"If we continue to drive global warming, the Gulf Stream System will weaken further—by 34 to 45% by 2100 according to the latest generation of climate models," warned Professor Rahmstorf. "This could bring us dangerously close to the tipping point at which the flow becomes unstable."

Sources: (National Ocean Service) (Study of Place) (Library of Congress) (Met Office) (Earth Observatory) (Guardian) (UCL) (Nature Geoscience) (Encyclopedia)

See also: How whales help to combat climate change

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