Slow-Motion Ocean: Atlantic’s Circulation Is Weakest in 1600 Years

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Slow-Motion Ocean: Atlantic’s Circulation Is Weakest in 1600 Years‘Scientific AmericanClimate change dials down Atlantic Ocean heating system‘BBC NewsThe oceans’ circulation hasn’t been this sluggish in 1000 years. That’s bad news.‘Washington Post

Slow-Motion Ocean: Atlantic’s Circulation Is Weakest in 1600 Years

In recent years sensors stationed across the North Atlantic have picked up a potentially concerning signal: The grand northward progression of water along North America that moves heat from the tropics toward the Arctic has been sluggish. If that languidness continues and deepens, it could usher in drastic changes in sea level and weather around the ocean basin.

That northward flow is a key part of the larger circulation of water, heat and nutrients around the world’s oceans. Climate scientists have been concerned since the 1980s that rising global temperatures could throw a wrench in the conveyor belt–like system, with possibly stark climatic consequences. Sea levels could ratchet upward along the U.S. east coast, key fisheries could be devastated by spiking water temperatures and weather patterns over Europe could be altered.

Such concerns had been quelled over the last decade as climate models suggested this branch of the ocean’s circulatory system was not likely to see a rapid slowdown, which would slow any consequences. But two new studies, published Wednesday in the journal Nature, suggest the recent weakening spotted by ocean sensors is not just a short-term blip, as some had thought. Rather, it is part of a longer-term decline that has put the circulation at its weakest state in centuries. The results imply climate models are missing key pieces of the puzzle, and that ill effects could be on their way.

Which pieces might be missing, though, could determine how worrying this trend is. If models are not sensitive enough to the changes going on in the North Atlantic, “that sort of puts the warning flag a little higher,” says Thomas Delworth, an ocean and climate modeler at the National Oceanic and Atmospheric Administration who was not involved in the research.

The warm, salty waters of the tropical Atlantic cruise northward along the eastern U.S. before darting toward northwestern Europe (giving the British Isles a climate far balmier than Newfoundland at a similar latitude). As that segment of ocean flow, known as the Gulf Stream, pushes north, it cools and becomes denser and eventually sinks, forming the so-called deepwater that flows back southward along the ocean floor toward Antarctica.

  • Publisher: Scientific American
  • Date: April 11, 2018
  • Author: Andrea Thompson
  • Twitter: @sciam
  • Citation: Web link

Were you following this:

Climate change dials down Atlantic Ocean heating system

They say the Atlantic Ocean circulation system is weaker now than it has been for more than 1,000 years – and has changed significantly in the past 150.

The study, in the journal Nature, says it may be a response to increased melting ice and is likely to continue.

Scientists involved in the Atlas project – the largest study of deep Atlantic ecosystems ever undertaken – say the impact will not be of the order played out in the 2004 Hollywood blockbuster The Day After Tomorrow.

But they say changes to the conveyor-belt-like system – also known as the Atlantic Meridional Overturning Circulation (Amoc) – could cool the North Atlantic and north-west Europe and transform some deep-ocean ecosystems.

Scientists believe the pattern is a response to fresh water from melting ice sheets being added to surface ocean water, meaning those surface waters “can’t get very dense and sink”.

The oceans’ circulation hasn’t been this sluggish in 1000 years. That’s bad news.

The Atlantic Ocean circulation that carries warmth into the Northern Hemisphere’s high latitudes is slowing down because of climate change, a team of scientists asserted Wednesday, suggesting one of the most feared consequences is already coming to pass.

The Atlantic meridional overturning circulation has declined in strength by 15 percent since the mid-20th century to a ‘new record low,’ the scientists conclude in a peer-reviewed study published in the journal Nature. That’s a decrease of 3 million cubic meters of water per second, the equivalent of nearly 15 Amazon rivers.

The circulation is also’critical for fisheries off the U.S. Atlantic coast, a key part of New England’s economy’that have seen changes in recent years, with’the cod fishery collapsing‘as lobster populations’have boomed‘off the Maine coast.

Some of the AMOC’s disruption may be driven by the melting ice sheet’of Greenland, another consequence of climate change that is altering’the region’s water composition and interrupts the natural processes.

This is ‘something that climate models have predicted for a long time, but we weren’t sure it was really happening. I think it is happening,’ said one of the study’s authors, Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany. ‘And I think it’s bad news.’

Watching: Atlantic Circulation Is Weakest, Scientific American Climate, Atlantic Ocean

What people are talking about:

Slow-Motion Ocean: Atlantic’s Circulation Is Weakest in 1,600 Years (If hemisphere-spanning currents are slowing, greater flooding and extreme weather could be at hand)
World’s weather ‘facing CHAOS because Atlantic Ocean’s circulation is at weakest point for 1,500 years’
Global warming is likely slowing the main Atlantic Ocean circulation, which has plunged to its weakest level on record; this could make for more extreme weather across the Northern Hemisphere, especially Europe, and could increase sea level rise along the U.S. East Coast
[Banned] /r/WayOfTheBern/: Stronger evidence for a weaker Atlantic overturning circulation
Climate Change Is Weakening a Crucial Ocean Current
The oceans’ circulation hasn’t been this sluggish in 1,000 years. That’s bad news.
Gulf Stream system at weakest point in 1,600 years | Environment| All topics from climate change to conservation | DW

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Slow-Motion Ocean: Atlantic’s Circulation Is Weakest in 1,600 Years
on 11th of Apr 2018 In recent years sensors stationed across the North Atlantic have picked up a potentially concerning signal: The grand northward progression of water along North America that moves heat from the tropics toward the Arctic has been sluggish. If that

Gulf Stream system at its weakest in 1,600 years, study shows
on 11th of Apr 2018 (CNN)A key component of the global oceanic circulatory system, which includes the Atlantic’s Gulf Stream, is at its weakest in more than 1,600 years, a new study has . has found that the circulation of water in the Atlantic has been declining since

Here’s some extra reading:

Studies say Atlantic Ocean’s circulation slowing dramatically, increasing climate change fears
on 11th of Apr 2018 The Atlantic Ocean circulation that carries warmth . As for the future, Rahmstorf predicts the circulation will only weaken further as climate change advances. It may not be slow and steady: There is great fear that there may be a “tipping point” where

World faces climate CHAOS because the circulation of the Atlantic Ocean is the weakest it has been in more than 1,500 years, warn scientists
on 11th of Apr 2018 There could be weather chaos across Europe, US and Africa as scientists warn circulation of the Atlantic Ocean is at its weakest point in . eventually circulates back up to the Gulf Stream. This motion is fuelled by thermohaline currents – a combination

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