Jens Terhaar

Does that help?

So I would also put an uncertainty around the month when SSTs should return, but I cannot say how large that is due to the very small sample size. It might well be 2-4 months. That might sound disappointing but I'd say the primary conclusion above (higher ECS) is relatively robust.

An important point: We have "only" 11 simulations with record-shattering SST jumps out of which 8 have not a very high ECS. Thus, certain statistical uncertainty exists in the maximum duration until SSTs are expected to come back to pre-jump levels (similar to the uncertainties in the return period)

It looks as if SSTs might return in the coming months. If that happens, it would indeed indicate that ECS and warming is not at the very high end but slightly on the higher than expected side.

Increased future ocean heat uptake constrained by Antarctic sea ice extent Abstract. The ocean takes up over 90 % of the excess heat stored in the Earth system as a result of anthropogenic climate change, which has led to sea level rise and an intensification of marine extre...

Hi Peter,

Thanks for asking. Indeed they have not come back yet. Last winter, daily values have briefly been back but not monthly values.
This is in line with an ECS on the slightly higher side. Something that is supported by a study we published yesterday (esd.copernicus.org/articles/16/...).

By linking Antarctic sea ice, cloud cover, deep ocean temperatures, and global warming, our new study led by @linusvogt.bsky.social finds that ocean heat uptake and thermal sea level rise by 2100 could be 3–14% higher, and global surface warming 3–7% greater than previously thought👇

And the associated press release for the highlight paper by Earth System Dynamics:

www.egu.eu/news/1505/an...

Increased future ocean heat uptake constrained by Antarctic sea ice extent Abstract. The ocean takes up over 90 % of the excess heat stored in the Earth system as a result of anthropogenic climate change, which has led to sea level rise and an intensification of marine extre...

🚨🌊 New highlight paper out today in Earth System Dynamics!

We find an observational constraint implying more future global ocean heat uptake, cloud feedback, and warming than the CMIP6 mean.

This contrasts with previous estimates based on past warming trends.

🔗 esd.copernicus.org/articles/16/...

And of course, I forgot the wave 🌊 to add it to the oceanography feed.
So here is the post about this paper, which was published today, and highlights how the deep ocean impacts future atmospheric and ocean warming.
We also show that future warming might be underestimated by past studies!

I also want to thank all the other co-authors that have contributed to this: Casimir de Lavergne, @jbsallee.bsky.social, Lester Kwiatkoswki and @froeltho.bsky.social! It was a fun and sometimes difficult ride.

Also a big thanks to @whoi.edu, @snsf.ch, and the University of Bern!

A 2 or 3 months research visit might be ideal to look into one of these ideas. So do not hesitate & get in contact if you are interested. We have different funding options here in Bern and I would be really happy to organize such a project and try to help to successfully apply for funding.

If anyone would be interested in an extended research visit in my group, I would be more than happy! I have a few more ideas for such projects but I am lacking time at the moment to work on this.

I really want to thank Linus for having accepted the invitation to @whoi.edu and for having taken this initial idea and having turned it into a magnificent paper. This was extraordinary work & I am proud & happy that I could accompany you and work with you on it, @linusvogt.bsky.social!

For future projections, it is thus not only important to understand cloud physics and dynamics but also to well simulate the ocean circulation including the deep waters, a part of the earth system that often receives less attention than it should receive.

Interestingly, the present day sea ice extent is strongly linked to deep-ocean temperatures that upwell in the Southern Ocean. This suggests that the deep ocean in climate models may determine the Southern Ocean climate state now, & hence a large part of the global cloud feedback and future warming.

As sea ice extent has only very lately been declining, this mechanism has not yet been captured by past atmospheric and ocean warming trend.

Thus, past studies that constrained future atmospheric and ocean warming with past trends likely underestimate future warming.

Overall, an underestimation of the sea ice extent in models leads to an underestimation of the cloud feedback, and hence an underestimation of future atmospheric and ocean warming.

The larger shift in the Southern Ocean affects global atmospheric and ocean warming through cloud feedbacks. The warming in the Southern Ocean starts a cloud feedback that leads to warming further north, which again initiates a cloud feedback further north, and so on.

When sea ice disappears with global warming, all models end up at a similar final state. Hence, a warmer Southern Ocean at present can warm less than a colder Southern Ocean at present. A larger Antarctic sea ice extent hence is a sign of a larger change coming over the 21st century,

We find that biases in too little sea ice extent at present are linked to biases towards too little future atmospheric and ocean warming.

The mechanism is that Antarctic sea ice indicates the present-day Southern Ocean state. Less sea ice extent is linked to a warmer Southern Ocean and vice versa.

Increased future ocean heat uptake constrained by Antarctic sea ice extent Abstract. The ocean takes up over 90 % of the excess heat stored in the Earth system as a result of anthropogenic climate change, which has led to sea level rise and an intensification of marine extre...

Future atmospheric and ocean warming over the 21st century might be larger than previously expected based on a new study by @linusvogt.bsky.social

Linus & I developed the idea during Linus research visit with me at @whoi.edu and turned it then into this paper:

esd.copernicus.org/articles/16/...

Hi Jens, we are really happy to soon have you with us at the @unibe.ch. It will be a true hub for ocean biogeochemical research. Looking forward to a lot of great research and a lot of fun together!

Welcome in Bern, @jens-d-mueller.bsky.social. I am excited to have you around. I am sure it will be a time of great science and great fun :)

It's scary how fast the earth is warming.

For a long time, the 🌊 ocean surface was warming at a slower 🐌 rate but the warming rate appears to have caught up 🐇.

➡️ In our study about the jump in SSTs, we also estimated a 0.27°C per decade warming of global SSTs (www.nature.com/articles/s41...)

Is a monster web of ocean currents headed for collapse? The race is on to find out Research ships rarely brave the Greenland Sea in winter. Early this year, scientists ventured into the ice-covered waters to capture crucial data about the planet’s future.

Informative and interesting news feature in @nature.com about the AMOC & large existing uncertainties about its past & future by @timkalvelage.bsky.social who accompanied oceanographer Kjetil Våge from @bjerknes.uib.no on the Norwegian ice-breaker RV Kronprins Haakon.

www.nature.com/articles/d41...

However, this does not mean that it is unexpected fast on the long term. It is an expected acceleration with added variability in my opinion. And every gram of reduced emissions s will reduce the warming rate

... for a long time. Once the sea ice disappears, warming will even more accelerate. In brief, I believe we come out of one or two decades with slower warming due to decadal variability and turn to a phase of faster warming now, we basically catch up to the long term trend as sea ice melts

... so much variability in the system. In the end, it is not surprising that warming is accelerating because emissions have continously risen. It was more surprising that warming was linear for such a long time. My take on that is that relatively robust sea ice has halted the acceleration...

I'd not take it out, the years 2023/24 were also exceptional because they years before were unusual cold compared to the long-term trend. So, it does not make much sense to remove it, I believe. However, statistical analyses 9f significance are important to be able to determine trends with...

It can also not be excluded at the moment that there is no unexpected accelerated warming in addition to the expected and observed acceleration of warming. But at the moment SSTs are consistent with climate models and can well be within expected accelerated warming based on emission increases