ClimTip | Climate Tipping Points in the Earth System

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🥵 2024 El Niño pushed us over 1.5°C, making it the hottest year on record:

heatwaves
floods
hunger for +110 mln people
$3.4 trn in costs

Could such extremes trigger tipping points too?

@aromanou.bsky.social #NASA explains in next #ClimTipWebinar

Join 👉 3 Feb 2–3pm CET
bit.ly/climtip-webi...

Today, ESM2025 officially comes to an end!

Since 2021, our European consortium has been building a new generation of Earth System Models to support mitigation & adaptation strategies aligned with the Paris Agreement. Watch these clips of our final video to see how far we've come!
🧵👇

#ESM2025isOver

#IPCC Chair Jim Skea said of the IPCC’s first joint Lead Author Meeting in Paris today that the meeting marks the beginning of our assessment of the latest science related to climate change.

🔗 bit.ly/4ir09cC

Goodbye to my incredible lead author team for Chapter 8 in IPCC's 7th assessment report. I will miss you all. IPCC, TSU, amazing LAM1 colleagues from all 3 working groups. I will miss Paris... All this till LAM2, thankfully. #IPCC_AR7 #LAM1

Strange Atlantic cold spot traced to ocean slowdown For more than a century, a patch of cold water south of Greenland has resisted the Atlantic Ocean’s overall warming, fueling debate amongst scientists. A new study identifies the cause as the long-ter...

“This work shows the #AMOC has been weakening for more than a century, and that trend is likely to continue if greenhouse gases keep rising.”

#ClimateEmergency

Indicators of Global Climate Change 2024: annual update of key indicators of the state of the climate system and human influence Abstract. In a rapidly changing climate, evidence-based decision-making benefits from up-to-date and timely information. Here we compile monitoring datasets (published at https://doi.org/10.5281/zenodo.15639576; Smith et al., 2025a) to produce updated estimates for key indicators of the state of the climate system: net emissions of greenhouse gases and short-lived climate forcers, greenhouse gas concentrations, radiative forcing, the Earth's energy imbalance, surface temperature changes, warming attributed to human activities, the remaining carbon budget, and estimates of global temperature extremes. This year, we additionally include indicators for sea-level rise and land precipitation change. We follow methods as closely as possible to those used in the IPCC Sixth Assessment Report (AR6) Working Group One report. The indicators show that human activities are increasing the Earth's energy imbalance and driving faster sea-level rise compared to the AR6 assessment. For the 2015–2024 decade average, observed warming relative to 1850–1900 was 1.24 [1.11 to 1.35] °C, of which 1.22 [1.0 to 1.5] °C was human-induced. The 2024-observed best estimate of global surface temperature (1.52 °C) is well above the best estimate of human-caused warming (1.36 °C). However, the 2024 observed warming can still be regarded as a typical year, considering the human-induced warming level and the state of internal variability associated with the phase of El Niño and Atlantic variability. Human-induced warming has been increasing at a rate that is unprecedented in the instrumental record, reaching 0.27 [0.2–0.4] °C per decade over 2015–2024. This high rate of warming is caused by a combination of greenhouse gas emissions being at an all-time high of 53.6±5.2 Gt CO2e yr−1 over the last decade (2014–2023), as well as reductions in the strength of aerosol cooling. Despite this, there is evidence that the rate of increase in CO2 emissions over the last decade has slowed compared to the 2000s, and depending on societal choices, a continued series of these annual updates over the critical 2020s decade could track decreases or increases in the rate of the climatic changes presented here.

Our new paper updating key metrics in the IPCC is now out, and the news is grim:

⬆️ Human induced warming now at 1.36C
⬆️ Rate of warming now 0.27C / decade
⬆️ Sharp increase in Earth's energy imbalance
⬇️ Remaining 1.5C carbon budget only 130 GtCO2

essd.copernicus.org/...

Warming is accelerating. Tipping risks increasing. Net zero may not stop temperature rise.

‼️ Our joint policy brief outlines what new Earth System modelling means for EU climate policy.

👏 with @esm2025.bsky.social @optimesm-eu.bsky.social @tipesm.bsky.social #nextgems @rescueclimate.bsky.social

🌍 Earth System Insights: from our Horizon Projects Briefing 6 European Horizon projects gathered their insights together for an in-depth forum with the European Commission (DG RTD & DG CLIMA). Here’s what they had to say 👇 🔗 bit.ly/4pgvktX #ClimateAction #EarthSystem #HorizonEU

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🪾Large parts of the #Amazon face savanna-like dry seasons if deforestations levels reach 25%.

In the next #ClimTip webinar #JuliaPongratz @lmumuenchen.bsky.social talks about the state and future of the rainforest from the latest findings.

👉 Join on 2 Dec 2025 at 2–3pm CET
bit.ly/climtip-webi...

Shell ready to invest more in Italy if drilling permits unlocked Shell is ready to invest more in Italy to boost hydrocarbon production, the head of the energy group's Italian unit said on Wednesday, urging the government to allow new drilling.

This is corporate manslaughter!

Every new well that Shell sinks kills more people.

Recent cutting-edge work by #climate scientists demonstrates how we can now attribute the deaths that will be caused from individual oil & gas projects...

www.nature.com/articles/s44...

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Overshoot: Exploring the implications of meeting 1.5C climate goal ‘from above’ - Carbon Brief The first-ever international conference on the contentious topic of “overshoot” was held last week in...

"Opening the conference, @iiasa.ac.at director general Prof Hans Joachim Schellnhuber shared his personal view that '1.5C is dead, 2C is in agony and 3C is looming'."

www.carbonbrief.org/overshoot-ex...

⚖️ Most scientists agree #Greenland melt will likely tip the Atlantic currents, but can the #WestAntarcticIceSheet melt stabilize it?

Sacha Sinet @utrechtuniversity.bsky.social shares his findings soon to appear in @science.org #AMOC

Join #ClimTipWebinar 4 Nov 2-3pm CET
🔗 bit.ly/climtip-webi...

Climate Research at the Heart of EU Policy: Six Projects Unite to Inform Decision-Making Climate research provides the scientific foundation of the European Union’s climate policies, including the ambitious European Green Deal, which aims to make Europe climate-neutral by 2050. Scienti…

6 EU-funded climate & Earth system modelling projects—@esm2025.bsky.social, @optimesm-eu.bsky.social, @tipesm.bsky.social, @climtip.bsky.social, @rescueclimate.bsky.social & NextGEMS—came together for a clustered science-to-policy meeting to present insights.💬🌐 ukesm.ac.uk/climate-rese...

Has anyone else been dealing with some serious headline whiplash recently?

Even for those of us who follow #climate and #energy matters closely, it can be hard to know what the hell is going on!

So here's a thread to help climate communicators get a grip on how to deal with this 🧵

📈 It matters not just much our planet heats up, but how fast that happens.

Join today's #ClimTip webinar with Jan Swierczek-Jereczek from @ucm.es on this process called rate-induced tipping and the stability of Antarctic Ice Sheet.

7 October, 2025
2:00–3:00 pm CEST
👉 bit.ly/climtip-webi...

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Image of the Earth precariously balancing on a jenga tower with text that reads: "Out of Balance". Image credit: "Out of Balance" (Digital collage from Ai generated art with typography) by Kuat Abeshev.

⚠️ New study in @nature.com shows convincing observational evidence that the Greenland Ice Sheet, Atlantic Ocean currents (AMOC), Amazon rainforest & South American monsoons – are all losing resilience.

Read more tinyurl.com/26heycew

#ClimTip @tum.de @pik-potsdam.bsky.social @exeter.ac.uk

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Continued Atlantic overturning circulation even under climate extremes - Nature Climate models suggest that the Atlantic Meridional Overturning Circulation is unlikely to collapse this century, owing to stabilization from wind-driven upwelling in the Southern Ocean.

10/ To refine these projections, we need better observations of the Southern Ocean and Indo-Pacific to check these stabilising processes.

🔀 If models are biased here, the picture could change.
www.nature.com/articles/s41...

9/ Collapse this century looks unlikely, but weakening is almost certain and carries serious risks⚠️

“This is no excuse for complacency. A “big freeze” in Europe may not be imminent, but the urgency to act has never been greater. The AMOC’s future depends on our actions today," says the author

Climate impacts of a weakened Atlantic Meridional Overturning Circulation in a warming climate The global and regional impacts of the AMOC slowdown on climate change in the 21st century are isolated and quantified.

8/ 🪾A weaker AMOC could shift rainfall belts, bringing drought to parts of the tropics.
❄️ Europe may face stormier winters and drier summers, ⬆️ the US east coast faster sea-level rise,
🌾 while ecosystems and food security worldwide could be disrupted.

www.science.org/doi/10.1126/...

Overturning Pathways Control AMOC Weakening in CMIP6 Models The magnitude of 21st century Atlantic Meridional Overturning Circulation (AMOC) weakening in CMIP6 models is highly correlated with an AMOC pathway into the Indo-Pacific Ocean The real-world “In...

7/ Together, these processes explain why models show slowdown rather than collapse.

⚠️ Climate projections suggest the AMOC will weaken by ~25–40% by 2100, depending on emissions.

And that weakening matters.
agupubs.onlinelibrary.wiley.com/doi/full/10....

6/ 2️⃣ Pacific circulation is too weak. In extreme cases, a Pacific Meridional Overturning Circulation (PMOC) forms – a reversed version of Pacific circulation today.

🌊 If strong enough, it could replace Atlantic sinking and trigger collapse.

But under realistic warming, it stays weak or absent.

5/ 1️⃣ 🌬️ Southern Ocean winds act like a pump, hauling deep water to the surface.

⚖️ That upwelling must be balanced by sinking elsewhere. Unless the Pacific fully takes over, some sinking will always remain in the Atlantic.

Continued Atlantic overturning circulation even under climate extremes - Nature Climate models suggest that the Atlantic Meridional Overturning Circulation is unlikely to collapse this century, owing to stabilization from wind-driven upwelling in the Southern Ocean.

4/ To see AMOC’s response, authors used 34 climate models under two extreme scenarios:
1) quadrupling CO₂; 2) adding huge freshwater from Greenland.

In both cases the AMOC weakened, but didn’t completely shut down.

‼️ The explanation comes down to two stabilising factors:
tinyurl.com/264rmmrt

Assessing the stability of the Atlantic meridional overturning circulation of the past, present, and future - Journal of Meteorological Research This paper is a review of the recent development of researches on the stability of the Atlantic meridional overturning circulation (AMOC). In particular, we will review recent studies that attempt to ...

3/ Global warming and Greenland’s meltwater entering the North Atlantic weaken this circulation, raising fears it could fail.

Yet most climate models don’t show collapse (i.e., weakening below 6 Sv) this century.

Until now, the reason for that stability wasn’t clear.

tinyurl.com/mrx5fza4