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Atlantic Circulation Weakening: No, We’re Not All Gonna Die (I Mean, Not Because Of This)

There are many more climate-based doomsday scenarios with real data that you can worry about.

Claudia GeibApril 12th 2018

Remember the mid-aughts disaster-porn summer blockbuster “The Day After Tomorrow”? A maligned climate scientist, a circulation-less North Atlantic Ocean, a sudden new ice age?

Well, if recent headlines are to believed, two new studies published in Nature predict that some version of this movie disaster might actually happen — and sooner than you might think.

Headlines have shuddered:

  • The oceans’ circulation hasn’t been this sluggish in 1,000 years. That’s bad news.

  • Global warming is slowing Atlantic Ocean circulation, study finds

  • Global Ocean Circulation Appears To Be Collapsing Due To A Warming Planet

  • But scientists told Futurism that interpreting these results as a sign of a coming catastrophe, as some media reports have, is a pretty big leap. (We’ll say straight off that there’s zero risk that the Statue of Liberty is going to be frozen up to her nostrils in ice any time soon.)

    The two Nature papers highlight that the Atlantic meridional overturning circulation (AMOC), a cycle that moves heat throughout the world’s oceans and has a major impact on climate, slowed down abruptly 150 years ago, moving much more slowly than the 1,500 years prior. They also suggest that it’s continued slowing down since then, potentially due to climate change.

    The overturning circulation of the global ocean. Atlantic circulation, on the left side of the image, is a significant driver of this entire cycle.
    The overturning circulation of the global ocean. Atlantic circulation, on the left side of the image, is a significant driver of this entire cycle. Image Credit: NASA/JPL

    Climate models have suggested that human-caused climate change could cause this cycle to slow, as warmer ocean temperatures and fresh water from melting ice stop water from sinking as it normally would, which would drive the cycle. If that slowdown really does happen, the climates of North America and Western Europe could be radically different, and as would hurricane and monsoon cycles around the world.

    However, research has suggested that the likelihood of Atlantic circulation stopping altogether — a situation that would, indeed, have “Day After Tomorrow” effects on the planet — is very low, and that any of those drastic effects would take centuries to manifest.

    “In regard to the AMOC, don’t believe the hype,” Richard Seager, research professor at Columbia University’s Lamont Doherty Earth Observatory who focuses on climate change and climate variability, told Futurism. “While state-of-the-art climate models have many problems simulating the AMOC they do not project a collapse of the AMOC for the future, but do project a weakening.”

    So far, models have not definitively linked alleged changes in the AMOC to human-caused climate change. Indeed, the two recent Nature papers take different stances on this as an explanation for the cycle’s change over the past 150 years; one spells out associations between the slowdown and human-cased climate change, while the other suggests natural processes slowed the Atlantic’s roll.

    Another important thing to remember: the idea that the AMOC is slowing down is not based on direct observation. Scientists have made some direct measurements over the past ten years or so that show a slowdown, but given how variable the current is decade to decade, we can’t say for sure that they establish a long-term trend.

    “Both Nature papers come to the conclusion that we have been able to measure [a significant change in the AMOC],” said Martha Buckley, assistant research professor in atmospheric, oceanic and earth sciences at George Mason University. “However, I believe that the majority of scientists in the field would suggest that we have not. Furthermore, I believe that the public has been mislead to believe that the papers are based on observations, whereas the results are highly dependent on climate models.”

    (Buckley also added that many reports had mistakenly conflated the AMOC with the Gulf Stream, which is incorrect; though the Gulf Stream plays a role in the AMOC, and would be weaker without it, the Gulf Stream is driven by wind and would continue to exist even if this cycle stopped.)

    Annalisa Bracco, a professor in oceanography and climate dynamics at Georgia Tech, also pointed out in an email to Futurism that other researchers’ reconstructions disagree with the conclusions of these papers, and don’t show any significant decline over the last 150 years at all.

    Does the research supported the idea that a collapse of the Gulf Stream could happen faster than previously expected? we asked Bracco. She simply responded: “No.”

    “At this point in climate research, concern over AMOC collapse and circum-North Atlantic cooling is minimal,” added Seager. “There is more concern about, say, floods, droughts, extreme weather, heat waves, Greenland Ice Sheet instability and sea level rise … as the really big issues.”

    In other words, there are plenty of other climate-related existential threats to keep you up at night that have, you know, actual data supporting them. Sudden disaster scenarios might make for a good headline, but we’d be better off leaving the climate drama to Hollywood.

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