Markus Grimmer
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mgrimmer.bsky.social
Markus Grimmer
@mgrimmer.bsky.social
Postdoctoral researcher at University of Bern; lover of ice cores, paleo climate, and well-behaved mass specs
Reposted by Markus Grimmer
Fresh of the press, a new study where we investigated the response of the Greenland ice-sheet and AMOC to warming scenarios, in a coupled Earth system model:
iopscience.iop.org/article/10.1...
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iopscience.iop.org
August 8, 2025 at 12:02 PM
Reposted by Markus Grimmer
New paper alert! 🌊

What processes control the efficiency of ocean heat uptake under CO₂ forcing?

We show that Southern Ocean stratification and overturning are key, check out our publication in Ocean Science here:
doi.org/10.5194/os-2...

More details below 🧵👇
Stratification and overturning circulation are intertwined controls on ocean heat uptake efficiency in climate models
Abstract. The global ocean takes up over 90 % of the excess heat added to the climate system due to anthropogenic emissions, thereby buffering climate change at Earth's surface. A key metric for quant...
doi.org
June 23, 2025 at 1:35 PM
Reposted by Markus Grimmer
🚨 WORK WITH US at @utas.edu.au IN HOBART!

🧊 Research Associate – Ice Core Atmospheric Sciences

🫧 Play a lead role in interpreting gas records from the Million Year Ice Core (MYIC) @millionyearice.bsky.social project

✍️ Applications close 13 July 2025

▶️ aappartnership.org.au/vacancies/#i...
June 11, 2025 at 5:40 AM
Reposted by Markus Grimmer
🚨--- New Paper ---🚨

Watch Florian Krauss @iceflow42.bsky.social wield the ¹³C of CO₂ sword across the highest, NATURAL spike in CO₂ and CH₄ of the last 800,000 years.

www.pnas.org/doi/10.1073/...
Multiple sources of atmospheric CO2 activated by AMOC recovery at the onset of interglacial MIS 9 | PNAS
Using high-precision ice core measurements of CO2, δ13C–CO2, CH4, and N2O, this study provides carbon isotope constraints on a sizeable, centennial...
www.pnas.org
June 3, 2025 at 10:50 AM
Reposted by Markus Grimmer
🌊🔥 Marine heatwaves often do not occur in isolation—they frequently coincide with extreme conditions in ocean acidity and oxygen levels.

In our new paper, we assess the distribution and projected changes of these compound ocean extremes within the top 2000 meters of the ocean.
Surface and Subsurface Compound Marine Heatwave and Biogeochemical Extremes Under Climate Change
Extreme conditions in temperature, acidity and oxygen frequently coincide at the sea surface and in large parts of the subsurface ocean Subsurface compound events are often linked to vertical wat...
agupubs.onlinelibrary.wiley.com
May 1, 2025 at 3:30 PM
Reposted by Markus Grimmer
Ocean Heat Content is increasing faster in two bands around the globe according to a new detailed study. In both hemispheres the warming areas are near 40º latitude and the tropics where it is modulated by El Niño cycles.

#climatechange #oceans #oceancurrents #TOA #oceanheatcontent #OHC #aerosols
May 2, 2025 at 12:53 PM
Reposted by Markus Grimmer
2. A poster on the ocean heat redistribution response to long temperature stabilization simulations at different global warming levels —> Thursday 14:00-15:45 X4.37 in OS1.13 (ocean carbon/heat session) meetingorganizer.copernicus.org/EGU25/EGU25-...
April 27, 2025 at 5:37 PM
Reposted by Markus Grimmer
About 20 years ago, researchers drilled a 3,260-meter ice core in East Antarctica. Now, scientists are using it to uncover new insights. 🧪🌊
When Ice Ages End, Ocean Circulation Fine-Tunes Ocean Heat - Eos
New Antarctic ice core data bolster model predictions of ocean heat content during glacials and interglacials.
eos.org
April 19, 2025 at 1:55 PM
Reposted by Markus Grimmer
Together with Beni Stocker @stineb.bsky.social we have an open postdoc position (2yr with possibility of extension) in coupled Earth system modelling with a focus on dynamic global vegetation modelling.
ohws.prospective.ch/public/v1/jo...
Get in touch if you are interested.
Uni Bern: Postdoc position: “Coupled Earth System Modeling”
(2 years)
ohws.prospective.ch
April 18, 2025 at 8:15 AM
Reposted by Markus Grimmer
Researchers present the first record of ocean heat content during the ends of the last four ice ages and the subsequent warm periods. 🧪🌊
When Ice Ages End, Ocean Circulation Fine-Tunes Ocean Heat - Eos
New Antarctic ice core data bolster model predictions of ocean heat content during glacials and interglacials.
eos.org
April 15, 2025 at 7:02 PM
Reposted by Markus Grimmer
By analyzing dozens of ice cores, @mgrimmer.bsky.social @unibe.ch & colleagues learned more about the role AMOC plays in controlling heat uptake by Earth’s oceans. 🌊https://eos.org/research-spotlights/when-ice-ages-end-ocean-circulation-fine-tunes-ocean-heat
April 14, 2025 at 3:56 PM
Does the ocean warm when the AMOC weakens? 🌊 Our new ice-core noble-gas data say it does, at least during the last four deglaciations. A warmer ocean stores a lot of energy but also expands and has lower solubility, which has implications for CO2, sea level, and climate.
doi.org/10.1029/2024...
AMOC Modulates Ocean Heat Content During Deglaciations
First ocean heat content (OHC) record covering the last four deglaciations All studied deglaciations show millennial OHC variability anti-correlated with Atlantic meridional overturning circulati...
doi.org
March 30, 2025 at 8:04 PM
Reposted by Markus Grimmer
📢 Postdoc Opportunity: Ocean Tipping Points & Impacts!

We're hiring a postdoc in my group at the University of Bern, Switzerland, to study ocean tipping points and their impacts. The position is part of HEurope project TipESM (@tipesm.bsky.social). Feel free to reach out with any questions. 🌊
March 9, 2025 at 10:53 AM
Reposted by Markus Grimmer
Es geht uns alle an. SRF gehört zu den wenigen Medienhäusern, die in der Wissenschaft noch fundierte Berichterstattung leisten. Danke!👏
Helfen wir Ihnen, dass das so bleibt.

✏️✏️✏️ Unterschreiben, teilen, kommentieren!
www.openpetition.eu/ch/petition/...
Fakten statt Falschinformationen: Für einen starken Wissenschaftsjournalismus! - Online-Petition
Offener Brief aus der Wissenschaft an SRF Sehr geehrte Direktion der SRG, sehr geehrte Geschäftsleitung von SRF, sehr geehrte Medien- und Wissenschaftspolitiker:innen Mit grosser Besorgnis haben wir z...
www.openpetition.eu
February 14, 2025 at 9:01 AM
Reposted by Markus Grimmer
Has the Atlantic Meridional Overturning Circulation (AMOC) weakened over the last decades? In our new study, we combine state-of-the-art CMIP6 models and observation-based estimates of the air-sea heat flux in the North Atlantic to show that the AMOC has not declined since the 1960s! 🌊
Atlantic overturning inferred from air-sea heat fluxes indicates no decline since the 1960s - Nature Communications
The AMOC is crucial for the global ocean overturning circulation and controls the climate around the North Atlantic. Here, the authors use 24 Earth System Models from the CMIP6 to demonstrate tha...
www.nature.com
January 15, 2025 at 10:11 AM
Reposted by Markus Grimmer
I'm thrilled to share our new @nature.com paper! We present ice core methane isotope data revealing that past abrupt climate changes likely triggered surges in wildfires, simultaneously driving rapid methane—and possibly CO2—rises 🌎🔥

Read it here 👉 www.nature.com/articles/s41...
Abrupt changes in biomass burning during the last glacial period - Nature
An increase in wildfire extent and related greenhouse gas emissions can be linked to abrupt climatic changes during the last glacial period.
www.nature.com
January 2, 2025 at 6:26 PM
Reposted by Markus Grimmer
We are hiring! Full details at the link below. We are looking for 2 postdocs to work on reconstructing past sea surface temperatures and sea ice distributions as part of the "Past 2 Future" consortium seeking to improve climate models with palaeoclimate data durham.taleo.net/careersectio...
December 18, 2024 at 6:53 PM