On The Ocean Front Part 1: Are the Ocean Currents in the Atlantic Going to Change in the Near Future

The world’s oceans are often called the Last Frontier, even less accessible to humans than outer space. They are also the key to climate change mitigation and a vast food resource for our growing world population. Knowing all that one would think that we humans would be better stewards of the largesse the oceans of the world provide. But, unfortunately, we are not.

Today, I’m going to talk about findings that have significant ramifications for the countries and continents that border the North Atlantic Ocean.

In a paper published on July 25, 2023, in Nature Communications, two researchers from Denmark’s University of Copenhagen describe findings that indicate the circulation of North Atlantic Ocean currents, known as the Atlantic Meridional Overturning Circulation (AMOC) is showing increasing signs of slowing down. This isn’t the first research by climatologists and oceanographers that indicates a change in the resilience of the Gulf Stream and North Atlantic Drift. But what makes this paper different is the precision mathematical modelling that indicates an undesirable future beginning as much closer than previously described, and certainly as early as the mid-21st century. The cause of the change is linked directly to increasing greenhouse gasses in the atmosphere and how they affect the ocean.

The Gulf Stream is best described as a giant heat pump. It can be seen in the image that accompanies this posting. The warm water it transports affects the climate of North America and Europe. It is one of several currents of consequence in the Atlantic.

The warm water of the Gulf Stream sweeps west to east. A feeder current north of the Equator that starts off the coast of West Africa and arrives in the Caribbean Sea provides some of the heat along with the path for hurricanes. In the Gulf of Mexico the ocean water heats even further and then passes through the Florida Straits to become the conveyor belt current off the eastern coast of North America, and then spreading across in what is called the North Atlantic Drift to Europe.

Africa and South America are the bottom half of AMOC which influences temperatures, rainfall, drought, and other weather phenomena on four Atlantic Ocean neighbouring continents.

The Danish research which includes some pretty significant mathematical modelling is seeing a pattern which it describes as “tipping elements.” These elements include the warm water in the North Atlantic contributing to a warming ocean that melts sea ice and accelerates the melting of land ice. The water produced by the melting is fresh and overrides the heavier warmer salt water causing the changes to AMOC.

The normal pattern we have observed for as long as historic records and observations have been kept is the reason that the United Kingdom and Western Europe are far more temperate than they should be considering latitude. Two examples illustrate this:

• New York City sits at 40 degrees north latitude. Comparable European cities are Madrid, in Spain, and Naples, in Italy. The climate conditions of the latter two are far different than New York.
• St. John’s, Newfoundland sits at 47.5 degrees north latitude. Paris is further north with Salzburg, Austria at the same latitude. Comparing the latter two’s climate with St. John’s illustrates just how influential the Gulf Stream and North Atlantic Drift are related to a relatively benign Europe.

One more observation to add to the evidence is the temperature of surface water off the Southern Florida coast. In the last two weeks, reports have indicated the surface water of the ocean is warmer than human body temperature (37 Celsius or 98.6 Fahrenheit). This heat is transported by the Gulf Stream and North Atlantic Drift as far north as Iceland and Greenland with the impact already noticeable for the latter which is losing 270 billion tons of ice annually.

There is also a change in temperatures that go beyond surface water. The warming atmosphere is impacting the entire water column from the surface to the seafloor with rising temperatures showing up in deeper water. This is affecting deep ocean counter-currents that lie under the Gulf Stream. The result is the transportation mechanism from southwest to northeast appears to be slowing down. The Director of the Woods Hole Oceanographic Institution recently told a New York Times reporter when commenting about these observations, that he wished none of this were true calling the changes happening “monstrous.” I don’t know about you but anytime a scientist from a prestigious institute like Woods Hole uses the word monstrous it makes me sit up and take notice.

So what is anticipated for AMOC? It is described as an irreversible and abrupt shift leading to dramatic weather changes on both sides of the North Atlantic. We are not talking about the dire conditions that occurred in the 2004 science fiction movie, “The Day After Tomorrow,” but we will see Europe losing the warming advantages of The Gulf Stream and North Atlantic Drift. And temperatures in the Atlantic closer to the equator will be hotter while stronger storms will pound the Eastern Seaboard of North America.

In an interview in The Washington Post, Stefan Rahmstorf, an oceanographer at the Potsdam Institute in Germany, who did not participate in the Danish study, states, “The scientific evidence now is that we can’t even rule out crossing a tipping point already in the next decade or two.”

Is there a natural explanation for all of this? Some would consider the emerging El Niño as being the principal cause for the observed changes. But El Niños in the past have never caused these types of changes in the North Atlantic. Without any other observable natural change, it is impossible to rule out human causes.

In Part 2 we look at the insatiable appetite of humans for destruction even in pursuit of a low-carbon future (a seemingly good cause) and the impact it may have on our oceans and the life within them.