The tipping point of the Atlantic overturning circulation

[raz.org.rain]

11 minutes ago, WYorksWeather said:

A lot will also depend on how much warming we get. Probably the coldest scenario would be warming just enough to shut down the AMOC. Obviously if we keep warming beyond that point it'll balance out any cooling. E.g. I can't imagine if we got a worst case of 4-5C warming (very unlikely scenario) that we'd be cooler than today, even if the AMOC did shut down. Of course, at global warming of 4-5C in this century, that'd be the least of our worries...

I would think it's highly dependent on how anthropogenic warming impacts the polar regions. Even with a total ocean current shutdown, those heat trapping GHGs wouldn't disappear. It's more than likely that anthropogenic heat will still cause enough warming in the polar regions to greatly diminish their capacity to cool enough to impact lower latitudes. 

[alexisj9]

1 hour ago, WYorksWeather said:

A lot will also depend on how much warming we get. Probably the coldest scenario would be warming just enough to shut down the AMOC. Obviously if we keep warming beyond that point it'll balance out any cooling. E.g. I can't imagine if we got a worst case of 4-5C warming (very unlikely scenario) that we'd be cooler than today, even if the AMOC did shut down. Of course, at global warming of 4-5C in this century, that'd be the least of our worries...

Your right, basically you can't call that far ahead from observations done now, you get a general idea of what may happen on the path, but the eventual outcome has to many factors, you can perhaps come up with scenarios for different end points, perhaps that actually where the disagreements arrise.

[LetItSnow!]

On 18/11/2023 at 23:31, alexisj9 said:

summers will be dependent as usual on where  the weather is coming from, but heat domes are not going to disappear,  may even get stuck over one area for longer perhaps.

I theorised this some months ago. If the weather became more blocky by default, then that offers one of two extremes: Summers like 2012 and also summers like 1976. Perhaps extremes would be more balanced and some years would have atrocious summers and others baking hot. Maybe the trend of poor summers with heat spikes we've seen since 2015 speaks of this being a possibility. We've yet to have a full on terrible summer since 2012 but I think it will happen at some point.

[raz.org.rain]

On 21/11/2023 at 17:24, LetItSnow! said:

I theorised this some months ago. If the weather became more blocky by default, then that offers one of two extremes: Summers like 2012 and also summers like 1976. Perhaps extremes would be more balanced and some years would have atrocious summers and others baking hot. Maybe the trend of poor summers with heat spikes we've seen since 2015 speaks of this being a possibility. We've yet to have a full on terrible summer since 2012 but I think it will happen at some point.

It pretty much happened this year. Summer '23 was a demonstration of how "bad" a bad summer can get these days. I was expecting something like that to happen for a few years and figured that a decade's worth of warming would still throw in enough heat to give out some hot weather events. I'm not too convinced that a true 2012 repeat can happen now, this summer is as bad as it can get for the most part. 

[LetItSnow!]

13 hours ago, razorgrain said:

I'm not too convinced that a true 2012 repeat can happen now, this summer is as bad as it can get for the most part. 

I do disagree with this only because extremes on the other end are still able to occur. December 2022, while a different season, showed that notable cold is possible. It’s a lot harder in another season where warmth fills the atmosphere, but some recent summers have had short periods of notably below average temperatures and even some local records. It’s a tall order, but I think it is possible that the pieces could fall together to create a 2012/2007 style summer, but it is harder. 

[Hairy Celt]

https://www.science.org/doi/10.1126/sciadv.adk1189

[raz.org.rain]

 Hairy Celt the latest publication has already raised some doubts;

 

[Hairy Celt]

Of course. That's what research is about. Why would you publish just already known facts?