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A forthcoming collapse of the Atlantic meridional overturning circulation

nature.com

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Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#121

Post by godelski »

Biologist123 wrote: post #90
braaannigan wrote: post #50

I've got a background in this field and I am very surprised to see this published in Nature. The model presented is purely statistical with no representation of the underlying physics. When we are dealing with a phenomenon that is driven by well-understood physical laws (e.g. geophysical fluid dynamics, radiation physics etc) then these physical models are the most reliable basis for prediction. When I say physical m…

As a lay-bystander to the climate debate, I get a little spooked when I see comments like this. Like 99.9% of people, the science of complex climate systems is beyond me as are the de facto black box models that project climate change. Instead I use “appears in a credible journal” as a basis for trusting the apparent direction of travel and I’m disconcerted when I see that proxy challenged. I also, I am somewhat sorr…

> Question for the community: how does one navigate such uncertainty?

Not climate scientist, but researcher in ML (another highly hyped and arguably more noisy field).

After Bourbon, the hard truth is expertise + don't.

Unfortunately journals/conferences/venues are an extremely noisy mechanism which in general aren't realistically much better than arxiv (at least over here). Peer review isn't journals/conferences, it is peers reading and evaluating the works. Reviewers are doing a service and often not giving a work significant time as they got other stuff to do. The only real way to know if a paper is valid or not is to be an expert in the subject matter (more focused than the field) and to read it __and the code__. All too often it is a nuanced point that is the crux of a paper, and would be entirely missed if you're not deep in that subcommunity. I know this answer sucks, but that's what it is.

Fwiw, I wouldn't realistically change your strategy as a layman. It's probably the best you got. Maybe only thing is don't think "journal publication == 100% true" but rather "journal publication == probably right." The process is noisy and there's no way around this.

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#122

Post by chriskanan »

braaannigan wrote: post #50

I've got a background in this field and I am very surprised to see this published in Nature. The model presented is purely statistical with no representation of the underlying physics. When we are dealing with a phenomenon that is driven by well-understood physical laws (e.g. geophysical fluid dynamics, radiation physics etc) then these physical models are the most reliable basis for prediction. When I say physical m…

The journal is Nature Communications, which has a much lower impact factor than Nature. Many of the papers rejected from Nature are encouraged to be automatically transferred to Nature Communications. One nice thing about Nature Communications is that one can read the reviews: https://static-content.springer.com/esm/art%3A10.1038%2Fs414...

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#123

Post by oceanthrowaway »

barbazoo wrote: post #112
oceanthrowaway wrote: post #100

Earlier quoted context omitted.

To me this is the great utility of the IPCC reports. If you look at the full report you can find subsections on many aspects of climate change and a discussion of the state of the field complete with citations compiled by an expert.

How would a layperson like myself judge what's in the IPCC report? The predictions are so dramatic that we have to act now and can't wait and see how it turns out. How is it different from this submission here?

I think if you read the full IPCC report you will see they are far from dramatic. Often news articles on the reports include calls to action (which I am all for given the path we are on). I believe the IPCC may also issue a statement about the report as a whole on release. However, if you read subsections of the full report you will see each domain specialist assign low medium or high confidence to each potential climate outcome. They also include useful descriptions of the physical mechanisms behind many climate phenomenon

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#124

Post by refulgentis »

barbazoo wrote: post #112
oceanthrowaway wrote: post #100

Earlier quoted context omitted.

To me this is the great utility of the IPCC reports. If you look at the full report you can find subsections on many aspects of climate change and a discussion of the state of the field complete with citations compiled by an expert.

How would a layperson like myself judge what's in the IPCC report? The predictions are so dramatic that we have to act now and can't wait and see how it turns out. How is it different from this submission here?

When you frame it that way, your question is "how can $NONEXPERTS confirm $EXPERTS"

First and foremost: read.

Second: don't demand certitude and table the idea that there's a universal judgement. Think: am I asking for an up/down vote on a conversation, or on an assertion?

Uncertainty can't always be driven down to 0. People usually expect this from other fields and yet understand when it is silly in their own field. (imagine: climate scientist forum noting cosmic rays, asking how any system can possibly be secure given memory safety causes security issues, and cosmic rays can flip memory bits, then hand-wringing about how they can even figure out what software research to trust)

This thread is itself a good example: OP has no issue with the research, or type of research, or anything, just is concerned how laypeople might believe it is certain and confirmed because it is in Nature. The paper itself makes no such claim, as the OP goes to great lengths to explain (c.f. it is statistical model)

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#125

Post by marcfalk »

Don't wanna downplay the seriousness of an ocean current collapse, however, articles covering this Danish study seems to grab the "we're gonna die soon"-angle by default. Danish media has found other scientists that do not quite accept the conclusion based on methods used. E.g. this abstract summarized by ChatGPT:

> Climate scientist Steffen Malskær Olsen (specializing in ocean currents at the National Center for Climate Research under DMI) questions the predictions made by Peter Ditlevsen and Susanne Ditlevsen (authors of the study) about a potential collapse of thermohaline circulation. He cites limited data and uncertainty about the correlation between surface temperatures in the Northwest Atlantic and the thermohaline circulation as main concerns. Despite this, he acknowledges the study's importance for demonstrating the potential of advanced mathematical models in predicting climate phenomena. He believes that the IPCC's prediction, which deems a collapse highly unlikely, remains the most reliable. Peter Ditlevsen accepts this uncertainty, arguing they are working with the best data currently available. (https://nyheder.tv2.dk/klima/2023-07-25-danske-forskere-med-...)

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#126

Post by pvaldes »

hathchip wrote: post #108
pvaldes wrote: post #52

Earlier quoted context omitted.

There is a good way to see the problem in a second Think about New York, is at 40 degrees N latitude. This means that if NY would be in the Atlantic coast of Europe would fall in Portugal! a little North to Lisbon! (38ºN). Sometimes Is easy to forget that NY is "Southern Europe" league. Southern than the North Coast of Spain. Now lets see Quebec (53ºN). Well, London is 51ºN. Without the sea current bringing hot tropi…

But the West Coast of North America is has milder winters than the East Coast, which has milder winters than the center. Shouldn't we expect London to end up with a similar climate as somewhere on the West Coast of Canada at the same latitude?

Probably Yes, because NY is also warmer that it should be. It receives still part of this warm water before the current turns toward east, plus it has also a heath-island effect created by cars and houses.

So if you remove this effect for both Europe and US, NY should be much colder than it is currently (And most of Europe also).

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#127

Post by vkou »

Biologist123 wrote: post #90
braaannigan wrote: post #50

I've got a background in this field and I am very surprised to see this published in Nature. The model presented is purely statistical with no representation of the underlying physics. When we are dealing with a phenomenon that is driven by well-understood physical laws (e.g. geophysical fluid dynamics, radiation physics etc) then these physical models are the most reliable basis for prediction. When I say physical m…

As a lay-bystander to the climate debate, I get a little spooked when I see comments like this. Like 99.9% of people, the science of complex climate systems is beyond me as are the de facto black box models that project climate change. Instead I use “appears in a credible journal” as a basis for trusting the apparent direction of travel and I’m disconcerted when I see that proxy challenged. I also, I am somewhat sorr…

> Instead I use “appears in a credible journal” as a basis for trusting the apparent direction of travel

Using that is like using 'Someone raised a concern in a meeting' as a basis for believing something.

Anyone can raise a concern, or publish a paper. What matters is whether or not other people are convinced by the paper. Consensus.

Use 'scientific consensus' as your weather-vane. (PS. The scientific consensus on climate change is 'things aren't looking great, we need to turn the bus around, we aren't turning the bus around'.)

... Or go learn and become an expert in the field for yourself. It should only take ~20,000 hours of making a lot of mistakes along the way.

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#128

Post by jeffbee »

lamontcg wrote: post #114
SirMaster wrote: post #81

Earlier quoted context omitted.

You are saying there are no scientists that predicted we would have more sea level rise than we actually do by now?

If you're asking if you can disprove the previous statement by finding a single example of a scientist who predicted wild rises in sea level that haven't happened, the answer is 'no'. Most scientists can still have historically been overly conservative even if you can find a few that made over the top predictions. It should be perfectly obvious that the presence of a few outliers doesn't invalidate the median of the…

The IPCC 1990 report predicted that sea level rise would abruptly accelerate from recent historic averages of 1-2mm/yr to 2-7mm/yr, and that is what happened. Satellite altimetry has tracked the central estimate of the 1990 IPCC predictions quite closely.

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#129

Post by [deleted] »

lamontcg wrote: post #114
SirMaster wrote: post #81

Earlier quoted context omitted.

You are saying there are no scientists that predicted we would have more sea level rise than we actually do by now?

If you're asking if you can disprove the previous statement by finding a single example of a scientist who predicted wild rises in sea level that haven't happened, the answer is 'no'. Most scientists can still have historically been overly conservative even if you can find a few that made over the top predictions. It should be perfectly obvious that the presence of a few outliers doesn't invalidate the median of the…

[deleted]

Re: A forthcoming collapse of the Atlantic meridional overturning circulation

#130

Post by boondoggle16 »

barbazoo wrote: post #109
whalesalad wrote: post #102

Earlier quoted context omitted.

critical thinking skills, don't believe everything that you see, perform your own independent investigation of truth.

> critical thinking skills, don't believe everything that you see, perform your own independent investigation of truth. How would one possibly do that here?

Personally, I just use my instincts. If my instincts are wrong, well, there's always another lifeform that will evolve someday, even if that's billions of years from now.

Hopefully they will be smarter than myself. If not, a few billion more years and we may get another shot...

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