AMOC Continually Slowing (Importance RE Total Shutdown + Major Climate Impacts)

[Kirkcaldy Weather]

I've had plans of creating this thread for ages and my Intuition tells me it will be a very noteworthy focus within the next decade and thereafter, It is a similar situation with the Antarctic ocean current which I'll make a secondary focus within here. 

Please DONT use this thread for climate change debating / arguing I'd like to keep it focused on the importance of the thread title. Thanks

What is AMOC? 

"AMOC stands for Atlantic Meridional Overturning Circulation. The AMOC circulates water from north to south and back in a long cycle within the Atlantic Ocean. This circulation brings warmth to various parts of the globe and also carries nutrients necessary to sustain ocean life.

The circulation process begins as warm water near the surface moves toward the poles (such as the Gulf Stream in the North Atlantic), where it cools and forms sea ice. As this ice forms, salt is left behind in the ocean water. Due to the large amount of salt in the water, it becomes denser, sinks down, and is carried southwards in the depths below. Eventually, the water gets pulled back up towards the surface and warms up in a process called upwelling, completing the cycle.

The entire circulation cycle of the AMOC, and the global conveyor belt, is quite slow. It takes an estimated 1,000 years for a parcel (any given cubic meter) of water to complete its journey along the belt."

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What is the Atlantic Meridional Overturning Circulation (AMOC)?

OCEANSERVICE.NOAA.GOV

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The Atlantic Meridional Overturning Circulation (AMOC) is a system of ocean currents that circulates water within the Atlantic Ocean, bringing warm water north and cold water south.

In recent years evidence has been shown of AMOC being at its weakest for upwards of the past 1000 years also a connection with rising CO2 being a contributing factor in said weakening 

"An increasing CO2→→AMOC weakening causal connection inferred here based on observed and reanalysis data, is consistent with the anticorrelated millennial record levels of high atmospheric CO2 concentrations and the reconstructed record low level of the AMOC strength over the last decades."

Early-onset of Atlantic Meridional Overturning Circulation weakening in response to atmospheric CO2 concentration

WWW.NATURE.COM

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npj Climate and Atmospheric Science - Early-onset of Atlantic Meridional Overturning Circulation weakening in response to atmospheric CO2 concentration

Very recent we had news that CO2 is at record levels 

There has been a little research into AMOC having a 'tipping point' with some collective thinking a mean temperature of +2.5C would be sufficient though no exact temperature is certain so a shutdown could realistically occur at any time. I'll discuss below likely major effects that would entail however also we've just had the +1.5C barrier reached 

If you follow my model thread posts you might know I expected similar trends with 2023 and 2015 which was the other year to reach (debates if it crossed the threshold) of 1.5C 

What would the impacts of further slowing +/or full shutdown of AMOC be 

I've studied lots and lots of the AMOC research constructed so far with a reoccurring outcome 

The scenario is Eerily close to the eventual outcome in The Day After Tomorrow, some might think that is absurd but I'll give further proof in a sec and if you haven't watched I massively recommend it's one of if not my all time #1 Film. 

'But a new paper led by the Met Office’s Dr Richard Wood stresses the need for more research into those climate events which are considered less likely to happen, but if they did could unleash even greater impacts. Climate scientists refer to these as ‘High-Impact Low-Likelihood’ events; or HILL events for short.

Examples of these events include levels of warming or rainfall changes that are at the top end of what’s considered plausible. Those events which cross ‘tipping points’ – such as the collapse of the West Antarctic Ice Sheet or the breakdown of the Atlantic Meridional Overturning Circulation (AMOC), are also included. AMOC disruption would strongly influence Europe’s climate.

The consequences of such changes for the world, Europe and the UK could be profound.'

'Professor Rowan Sutton is the Director of Climate Research at the National Centre for Atmospheric Science (NCAS). He said: “As the Covid pandemic has reminded us, the greatest risks sometimes come from hazards that are not the most likely. We mustn’t be complacent about the low-likelihood aspect of higher-than-expected levels of climate change, ice sheet collapse, or disruption of ocean circulation.  Such changes could create impacts well beyond the scope of current plans for adaptation to climate change.”

May 2023 - Met Office 

Researchers point the way to managing climate change risks | Official blog of the Met Office news team

BLOG.METOFFICE.GOV.UK

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The consequences of climate change are many and varied. However, most of them bring considerable risk to communities and ecosystems. Up until now climate scientists across the globe have largely...

 

We can see the impacts with the UK being impacted massively and the charts almost having a look of SSW impacts perhaps that across a much larger period of time? 

A comparison with SSW effects 

 

I believe the impacts are likely already occurring from the current AMOC slowdowns with increasingly abnormal and extreme weather across the Northern Hemisphere and the similar scenario is developing in the Southern Hemisphere as the Antarctic current is trending slower 

"The deep-water flows which drive ocean currents could decline by 40% by 2050, a team of Australian scientists says.

The currents carry vital heat, oxygen, carbon and nutrients around the globe.

Previous research suggests a slowdown in the North Atlantic current could cause Europe to become colder.'

Antarctic ocean currents heading for collapse - report

WWW.BBC.CO.UK

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Melting ice could trigger a disastrous chain reaction, a new Australian study warns

The 2018 Atlas Study found the Atlantic Ocean circulation system was weaker than it had been for more than 1,000 years, and had changed significantly in the past 150.

There were a couple websites with AMOC data but they haven't had new data since around lockdown times, if anyone has a link with live data that'd be hugely appreciated

 

 

 

[LetItSnow!]

Fascinating read. The coldie in me might have to bite more than I can chew if that’s the case!

Edited June 30, 2023 by LetItSnow!

[LetItSnow!]

Coming back to this, I found it interesting the part where it says climate models aren’t taking into account the possible effects of this. I wonder if, if they do, we could be seeing different projections for the future. I’m not sure. All I know is we’ve got to do better for this planet.  

[Kirkcaldy Weather]

I'd been waiting to get all the info possible but some significant situations have developed over the past 2 or so weeks, whilst the direct reason attached to this incredible SST increase is persistent high pressure Sat over this region, we've seen similar oceanic heatwaves occuring most noteably in correlation to the persistent high pressure within the Atlantic which extended across the UK - North Sea during June plus an ongoing marine Heatwave situation through the Mediterranean again linked with a slow moving high pressure. 

My big concern is the situation around Newfoundland extending through the Gulf Stream zone, we should have the movements of both cold and warm currents getting transported within the Gulf Stream however recently at least at surface level this area has taken a rather concerning appearance with the typical wavy boundary of warm and cold surface temperatures has become solely heat based 

It's important to distinguish that the Gulf Stream and AMOC are different entities as the Gulf Stream is a part within the AMOC 

Clearly I'm not the only one becoming increasingly concerned seeing these developments with some good discussions via Twitter

Lots of helpful explaining of the AMOC within this thread

 

[Bristawl Si]

Met Office official response:

As far as we’re concerned in the Met Office, the paper is far too simplistic,” said Richard Betts, the Head of the Climate Impacts at the Met Office Hadley Centre.

He added: “There’s still no evidence that we’re kind of past the point of no return in terms of devastating impacts.

“On the basis of one paper, don’t despair.”

[raz.org.rain]

I'm not convinced a hypothetical collapse would result in the catastrophic temperature drop their models suggest. It'd be interesting to hear their rationale for suggesting such a catastrophic drop contending with anthropomorphic warming and associated changes in land use being more conductive to trapping heat that rejecting it. It would appear that their theory is based on analysis of ice core samples and ocean sediments, which have allowed them to reconstruct how the climate cooled in response to events leading to the Younger-Dryas, but the conditions are just not comparable to the Anthropocene. 
 

Not only that, but they've demonstrated that the immediate response to the slowdown is a proportional increase in temperature averages across Europe.

Why Are Heat Waves Becoming So Common in Europe?

WWW.VOANEWS.COM

 

[LetItSnow!]

8 hours ago, razorgrain said:

I'm not convinced a hypothetical collapse would result in the catastrophic temperature drop their models suggest. It'd be interesting to hear their rationale for suggesting such a catastrophic drop contending with anthropomorphic warming and associated changes in land use being more conductive to trapping heat that rejecting it. It would appear that their theory is based on analysis of ice core samples and ocean sediments, which have allowed them to reconstruct how the climate cooled in response to events leading to the Younger-Dryas, but the conditions are just not comparable to the Anthropocene. 
 

Not only that, but they've demonstrated that the immediate response to the slowdown is a proportional increase in temperature averages across Europe.

Why Are Heat Waves Becoming So Common in Europe?

WWW.VOANEWS.COM

 

It could be possible that the scenario could see a temperature drop, but perhaps not quite pronounced as it could be without the extra CO2. Not that it would probably soften the blow that much. I'm no scientist, but I really do think this is something we should take seriously. And seeing as a collapse hasn't happened yet I'm not surprised Europe has warmed so much. Perhaps its proximity with the Atlantic and Africa that gives it extra warming? I'm not sure.

[matty40s]

..an in depth update on Prof Rahmstorfs views...

Thread by @rahmstorf on Thread Reader App

THREADREADERAPP.COM

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@rahmstorf: Here's a thread in pictures about the Atlantic overturning circulation #AMOC which is making headlines this week. I've studied this topic since 1991 and will show key data and models &...