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Posts by Jonathan Rosser

Please do get in touch if you would like to hear more, collaborate, or if you have any comments or suggestions.

Photo Credit to Gaia Scianca

4 weeks ago 0 0 1 0

We have ongoing work in ensemble design, socio-economic impacts of AMOC change, and potential future work on uncertainties around the North Atlantic Subpolar Gyre.

4 weeks ago 0 0 1 0

I also flagged our intention to organise further discussions and workshops around climate ensemble design, climate economics, and how to better align climate science with information provision for decision-makers.

4 weeks ago 1 0 1 0

They have covered a range of current work from workshops on how to use climate information for policy makers and the financial institutions, the design of climate model ensembles, and our assessments of uncertainties around the impacts of the Atlantic Meridional Overturning Circulation.

4 weeks ago 0 0 1 0
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***Seminars on Climate Uncertainty, Decision-making, and AMOC changes***

I have really enjoyed giving seminars at Uppsala University, Stockholm University, SMHI, and Lund University over the past few weeks.

4 weeks ago 1 0 1 0

I will, feel free to grab me at my poster session or drop me a dm/ email and we can find an alternative time.

2 months ago 0 1 0 0
Global map showing sea surface temperature anomalies in January 2026 relative to 1982 to 2010. Most areas are warmer than average. Red is shown for warmer sea surface temperatures, and blue is shown for colder sea surface temperatures. Data is from NOAA OISSTv2.1.

Global map showing sea surface temperature anomalies in January 2026 relative to 1982 to 2010. Most areas are warmer than average. Red is shown for warmer sea surface temperatures, and blue is shown for colder sea surface temperatures. Data is from NOAA OISSTv2.1.

While the La Niña signature (cooling in the eastern Tropical Pacific) remained prevalent in January, there are signs it is beginning to fade in recent weeks. Elsewhere, anomalous warmth continues in the extratropics of both hemispheres.

Data from NOAA OISSTv2.1 (www.ncei.noaa.gov/products/opt...) 🌊

2 months ago 45 23 0 0

The RMT is the regional mean temperature of Northern Europe, using IPCC AR6 boundaries. We have conducted equivalent analysis for all of the IPCC AR6 boundaries and national boundaries, but focused on Northern Europe here as a relevant case study.

2 months ago 0 0 1 0

Thank you for your message, I'd be happy to discuss our work further if you would like to call sometime. The colours in Figure 3 represent the density of trajectories or how many runs enter a given part of the distribution, due to the methodology they don't correspond to probabilities.

2 months ago 0 0 1 0

I am also very interested in the economic impacts of these climate changes, and how we think about model information in this space more generally. I will be at my poster 4-6pm on Tue Feb 24th in the PS24A Session. Message to find out more or to meet up. I have attached a preview of the poster here!

2 months ago 0 0 0 0
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If you would like to learn more about the uncertainty surrounding the impacts of changes to the Atlantic Meridional Overturning Circulation and approaches to projecting these impacts combined with global warming scenarios, please do come and chat.

2 months ago 0 0 1 0
AGU - iPosterSessions - an aMuze! Interactive system

*** Ocean Sciences Poster on "Uncertainty Quantification of the Regional Temperature Consequences of a Large AMOC Reduction"***
I will be presenting a poster at the Ocean Sciences Meeting #OSM next week. See this link for a sneak preview:
osm26.ipostersessions.com?s=77-E2-6D-B...

2 months ago 2 0 2 0

This means that we may be able to say more about the future of the Southern Ocean than we might expect from "initial condition anomalies".

7 months ago 0 0 0 0

Therefore, when we look at the change from "present day" (the initial value anomaly), the high initial condition uncertainty is spuriously moved to our projections, when we actually know our current conditions well, and the projections agree on our future trajectories.

7 months ago 0 0 1 0

This means that variance in the raw data is much higher at the start than the end of the run, due to initial condition impacts.

7 months ago 0 0 1 0

This is key for all modellers projecting the Southern Ocean (and potentially more widely). As shown in the attached figure, the Antarctic Circumpolar Current shows great variability in the present day but much lower in the future as long-timescale variability shuts down.

7 months ago 0 0 1 0
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I am very excited about this point: it makes a huge difference whether we analyse raw data, changes from the "present day", or from "pre-industrial" in our models. Changes from the "present day" can mean projecting forward current variability and add potentially spurious uncertainty to projections.

7 months ago 0 0 1 0
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▪️ Consequences for Climate Projections: Long timescale variability can contribute the majority of uncertainty in climate projections.

7 months ago 0 0 1 0

▪️ Shutdown of the lower circulation cell: Under even weak future forcing the oscillations are damped out and the strength of the lower circulation cell decreases

7 months ago 0 0 1 0

The key points were:
▪️ Centennial Oscillations: Southern Ocean oscillations on hundred-year timescales exist in the CMIP6 ensemble of global climate models

7 months ago 0 0 1 0
Shutdown of Southern Ocean Convective Centennial Variability under Global Warming and Implications for Climate Projections Centennial oscillations occur in the Southern Ocean in the majority of an ensemble of pre-industrial control runs of 16 CMIP6 models. These oscillations involve features such as the Antarctic Circumpo...

*** Presentation on Uncertainties in Climate Models and the Southern Ocean ***
Really enjoyed presenting at the Challenger Society Ocean Modelling Special Interest Group this week. For more info see our recent preprint: essopenarchive.org/users/946271...

7 months ago 1 0 1 0
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🌊 The Atlantic “conveyor belt” (AMOC) is weakening under climate change. A new @nature.com study suggests collapse is unlikely this century, but the risks remain very serious.

Hear from lead author @jonbakerocean.bsky.social in our next webinar.

📅 2 Sep 2025, 2–3PM CEST
🔗 bit.ly/climtip-webi...

8 months ago 12 7 1 1
Preview
The shutdown of ocean currents could freeze Europe When climate change poses a strategic threat, it needs a strategic response

Great article in The Economist on the Atlantic Meridional Overturning Circulation (AMOC) and the impact of potential changes in it (a key focus of my current work). www.economist.com/leaders/2025...

8 months ago 4 3 0 0
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Earth’s climate is approaching irreversible tipping points Scientists are racing to work out just how close they might be

It is good to see @economist.com highlighting the importance of climate tipping points, and the work being done to understand and prepare for them. It discusses the work being done by UK groups (including the @aria-research.bsky.social project which I am part of) www.economist.com/interactive/...

8 months ago 57 27 3 0
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Finally, the thesis also shows that under global cooling (perhaps due to a future overshoot in temperatures), the Southern Ocean becomes destabilised, triggering new and faster oscillations (such as in the Antarctic Circumpolar Current), and even a counterintuitive loss of sea ice in some sectors.

8 months ago 3 0 0 0
Shutdown of Southern Ocean Convective Centennial Variability under Global Warming and Implications for Climate Projections Centennial oscillations occur in the Southern Ocean in the majority of an ensemble of pre-industrial control runs of 16 CMIP6 models. These oscillations involve features such as the Antarctic Circumpo...

^^For more on this point, see our recent preprint: essopenarchive.org/users/946271...

8 months ago 1 0 1 0

As centennial variability dominates the uncertainty in some of the Southern Ocean, this shutdown in variability dominates the behaviour of uncertainty in features (e.g. the Antarctic Circumpolar Current), so the initial oscillation state accounts for a large amount of uncertainty in trajectories.

8 months ago 1 0 1 0

Applying global warming forcing to the system leads to the shutdown of convection and the loss of the oscillatory behaviour (shown in figure). Under plausible future scenarios (SSP scenarios for CMIP), this shutdown occurs even with strong mitigation, suggesting a tipping point may have been passed.

8 months ago 1 0 1 0

These oscillations involve multiple mechanisms, both the more traditional heat release behaviour and a novel advective mechanism involving the gyres. While both mechanisms involve deep convection, the advective mechanism involves motion of heat around the gyre.

8 months ago 1 0 1 0

Centennial (roughly hundred year period) oscillations exist in the Southern Ocean across the CMIP6 ensemble of climate models. These oscillations can be seen in many features such as the ocean heat, currents (such as the Antarctic Circumpolar Current, shown in the figure), and dense water formation.

8 months ago 1 0 1 0