Scientists warn of Gulf Stream collapse: The dire consequences for humanity explained

In the 2004 film The Day After Tomorrow, a shutdown of the Atlantic Meridional Overturning Circulation (AMOC) which includes the Gulf Stream spells disaster for humanity. The science fiction film was at the time criticised for its scientific inaccuracies. But now, less than two decades later, scientists are saying it could actually happen. Researchers in a study in the peer-reviewed British journal Nature Communications are warning of a possible halt of the Gulf Stream by the middle of this century or even after 2025 because of man-made climate change. But what is the Gulf Stream? How does it work? And what could be the consequences for humanity? Let’s take a closer look: What is it? How does it work? As per the UK Met Office website, the Gulf Stream is a warm and swift Atlantic Ocean current. The Gulf Stream begins in Florida, before moving along the eastern coastlines of the US and Canada and then crossing the Atlantic Ocean to Europe. The Gulf Stream makes the climate of Western Europe warmer far warmer than it otherwise would be.

The Gulf Stream is a tiny part of the large, worldwide AMOC.

Scientists describe the AMOC as a giant ocean conveyor belt that moves water from Greenland south to beyond the tip of Africa and into the Indian Ocean. Warm, salty water near the surface moves north and mixes with cold, fresher water near Greenland. As that water cools and sinks it drives a slow circulation of the oceans that is critical to global climate, affecting the location of droughts and frequency of hurricanes. It also stores heat-trapping carbon dioxide deep in the ocean. The faster it moves, the more warm water gets sent into the depths to cool. The AMOC itself helps control among other things sea level rise and the temperatures in Europe. “The Atlantic Meridional Overturning Circulation really is one of our planet’s key circulation systems,” Niklas Boers from the Potsdam Institute for Climate Impact Research in Germany, told USA Today. What does the study say? According to USA Today, the study, which relies on ocean data from the past 150 years, predicts that the Gulf Stream will stop between 2025 and 2095.

The study pegs the odds of this happening at a 95 per cent certainty.

“Using new and improved statistical tools, we’ve made calculations that provide a more robust estimate of when a collapse is most likely to occur, something we had not been able to do before,” study co-author Susanne Ditlevsen, a professor at the University of Copenhagen, told the outlet. The blame, as ever, lies with climate change. Study co-authors Peter and Susanne Ditlevsen explained to USA Today, “Greenhouse gas emissions cause global warming, which speeds up the melting of Greenland ice. The melted freshwater entering the North Atlantic can then disrupt the AMOC, potentially causing major climate disruptions. “When the increased meltwater from Greenland enters the North Atlantic, it’s freshwater, which is lighter than the salty seawater around it,” the Ditlevsens said. “This excess freshwater can disrupt the normal sinking of the salty water, weakening or even shutting down the AMOC. If the AMOC collapses, it can have far-reaching effects on weather patterns and ocean currents, leading to significant climate changes.” According to Vox, scientists say such a scenario would potentially be irreversible – and as such would be a major ‘tipping point’ for Earth’s climate. “I think we should be very worried,” Peter told The Guardian. “This would be a very, very large change. The AMOC has not been shut off for 12,000 years.” What could be the consequences for humanity? Experts say the possible shutting off of the Gulf Stream would have a dire impact on humanity. Penny Holliday, head of marine physics and ocean circulation at the UK’s National Oceanography Centre, told Politico this would be the end of global climate as we currently know it. The Northern Hemisphere would witness freezing temperatures. Sea ice would begin heading towards Europe from the North Pole. Rainfall patterns would change across the planet – leaving some continents parched and others drenched. “This would lead to dramatic change in every nation’s ability to provide enough food and water for its population,” Holliday added. As per The Guardian, the situation would worsen for the already endangered Amazon rainforest and Antarctic ice sheets.

As per USA Today, Europe could experience an ice age.

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Cities such as Boston and New York would face a sea-level rise and America’s East Coast would be facing stronger storms and hurricanes. Peter de Menocal, the president of the Woods Hole Oceanographic Institution, told CNN such an outcome  “would affect every person on the planet – it’s that big and important.” Menocal was not involved in the study. But not everyone agrees with the study’s findings. Michael Mann, of the University of Pennsylvania, told USA Today,, “I’m not sure the authors bring much to the table other than a fancy statistical method. History is littered with flawed predictions based on fancy statistical methods; sometimes they’re too fancy for their own good.” Politico quoted Niklas Boers of the Technical University of Munich as calling the study modelling “heavily oversimplified.”

On Tuesday, the study’s authors themselves said some of their assumptions were “uncertain”.

Vox also noted that the study contradicts the latest UN IPCC report on climate change which states that an AMOC shut down this century is “very unlikely”. Michael Mann, a climate scientist at the University of Pennsylvania who has published research on AMOC told Vox while the methods were questionable, the results are “plausible.” “I think the authors in this case are on to something real,” Mann told Axios. “We could be talking decades rather than a century.” With inputs from agencies