Lightnews — Scholar-powered news

Jens Terhaar @polarocean.bsky.social · 5d

Does that help?

Jens Terhaar @polarocean.bsky.social · 5d

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.

1 1

Jens Terhaar @polarocean.bsky.social · 5d

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)

1 1

Jens Terhaar @polarocean.bsky.social · 5d

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.

1 1

Jens Terhaar @polarocean.bsky.social · 5d

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/...).

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...

esd.copernicus.org

1 1

Reposted by Jens Terhaar

Thomas Frölicher @froeltho.bsky.social · 6d

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👇

Linus Vogt @linusvogt.bsky.social · 6d

🚨🌊 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/...

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...

esd.copernicus.org

6 14

Jens Terhaar @polarocean.bsky.social · 6d

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

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

3

Reposted by Jens Terhaar

Linus Vogt @linusvogt.bsky.social · 6d

🚨🌊 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/...

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...

esd.copernicus.org

3 9 30

Jens Terhaar @polarocean.bsky.social · 6d

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!

Jens Terhaar @polarocean.bsky.social · 6d

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/...

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...

esd.copernicus.org

4

Jens Terhaar @polarocean.bsky.social · 6d

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!

1

Jens Terhaar @polarocean.bsky.social · 6d

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.

1

Jens Terhaar @polarocean.bsky.social · 6d

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.

1

Jens Terhaar @polarocean.bsky.social · 6d

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!

1

Jens Terhaar @polarocean.bsky.social · 6d

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.

1 1

Jens Terhaar @polarocean.bsky.social · 6d

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.

1

Jens Terhaar @polarocean.bsky.social · 6d

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.

1

Jens Terhaar @polarocean.bsky.social · 6d

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.

1 1 2

Jens Terhaar @polarocean.bsky.social · 6d

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.

1

Jens Terhaar @polarocean.bsky.social · 6d

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,

1

Jens Terhaar @polarocean.bsky.social · 6d

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.

1 1

Jens Terhaar @polarocean.bsky.social · 6d

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/...

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...

esd.copernicus.org

1 12 25

Jens Terhaar @polarocean.bsky.social · 23d

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!

1

Jens Terhaar @polarocean.bsky.social · 23d

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 :)

Jens Terhaar @polarocean.bsky.social · Jun 19

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...)

5 66 130

Jens Terhaar @polarocean.bsky.social · Jun 19

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...

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.

www.nature.com

2 6