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Carl Schleussner

@carlschleussner.bsky.social
2K followers 153 following 206 posts

Climate Scientist at @iiasa.ac.at and Humboldt Universität zu Berlin Views are my own.

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Reposted by Carl Schleussner
Setu @setupelz.bsky.social · 28/09/2026
Two years plus in the making... our paper building fair effort sharing directly into how integrated assessment model (IAM) scenarios are generated is out in Environmental Research Letters🧵 @iopp-environment.bsky.social @iiasa.ac.at doi.org/10.1088/1748-9326/aea34d
First page of the article 'Equitable cooperation deepens the solution space for high ambition pathways' by Setu Pelz and eleven co-authors, published open access in Environmental Research Letters 21 (2026) 184019 on 18 September 2026. The page shows the author list, affiliations and the abstract.
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Carl Schleussner @carlschleussner.bsky.social · 24/09/2026
Fantastic work!
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Sadie J. Ryan (she/her) @sjryan3.bsky.social · 23/09/2026
Fingerprint is here! Great long thread about our new Nature paper that dropped today (but has been multiple years of enormous team effort).
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IIASA @iiasa.ac.at · 22/09/2026
⚖️ New IIASA-led research shows that integrating fairness into climate models can change how the global mitigation effort is shared across regions while still achieving the same climate goal. The findings offer new insights for translating global ambition into action. 👉 iiasa.ac.at/news/sep-202...
iiasa.ac.at
Fairness informs how the world cuts emissions
Who cuts emissions fastest, and who supports others do so, are central questions in global climate action. New IIASA-led research shows that building fairness into climate models from the start can in...
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Joeri Rogelj @joerirogelj.bsky.social · 02/09/2026
New UN Report @unep.org World set to cross 1.5°C global warming, but options to limit, adapt to and return from higher temperatures exist. The report covers implications of temperature overshoot of 1.5°C, for our responses, adapt and manage this new normal. Some key messages /1
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IngerAndersen.bsky.social @ingerandersen.bsky.social · 02/09/2026
The world is set to cross 1.5°C global warming. But it is still possible to bring temperatures down and achieve #ParisAgreement goals. We must double down on #ClimateAction New @unep.org report shows how we can still limit, adapt to & return from higher temperatures: www.unep.org/resources/li...
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IIASA @iiasa.ac.at · 02/09/2026
🎧 Listen to the nine-part Overshoot Podcast series, featuring experts on mitigation, carbon removal, tipping points, adaptation, loss and damage, & more: overshootconference.org/the-overshoo... 🔗 Find out more 👉 iiasa.ac.at/news/sep-202... 📷 LCVA | Dreamstime @carlschleussner.bsky.social
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SPARCCLE @sparccle.bsky.social · 29/08/2026
Summer 2026 is a stark reminder that climate extremes are no longer distant🌡️ SPARCCLE’s Stress Test Scenario 1 looks at what Europe under heat stress means for resilience. Meanwhile, a Nature study links emissions from major fossil fuel and cement producers to intensified heatwaves. #LinksInComments
EGU 2026 - SPARCCLE researchersEGU 2026 - SPARCCLE researchers
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Carl Schleussner @carlschleussner.bsky.social · 24/08/2026
Didn’t realize this existed. But should have known better 🤣. Count me in as well as @andrijevic.bsky.social
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Erich Fischer @erichfischer.bsky.social · 21/08/2026
Projection has become reality 22 years ago, Christoph Schär et al. published a landmark paper in Nature explaining that the 2003 heatwave was a harbinger of things to come. The study featured an iconic figure - shown in countless lectures - illustrating how outlandish the event was at the time
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IIASA @iiasa.ac.at · 19/08/2026
How can we turn complex climate science into information decision makers can actually use? A new IIASA-led Climate Impact Taxonomy connects IPCC climate drivers with key risks and adaptation options, helping translate authoritative science into actionable information. 🔗 iiasa.ac.at/news/aug-202...
iiasa.ac.at
Helping decision makers navigate climate risks
As climate impacts such as heatwaves, floods, and fires are intensifying worldwide, there is an urgent demand for information on how to respond. IIASA researchers and partners have developed a new too...
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Peter Pfleiderer @klimapeter.bsky.social · 17/08/2026
What is changing with extreme European summers? 🥵 We look at many simulated 100-year summers in western Europe to find out how current day extreme summers differ from similarly rare pre-industrial summers. @robinnoyelle.bsky.social and @sebastian-sippel.bsky.social doi.org/10.1029/2026...
doi.org
Heat Extremes Within Hot Summer Seasons Intensify More Than in Average Summers Under Global Warming
Rare heat summers today (with ≈ 100-year return period) show a different evolution of sub-seasonal temperatures than similarly rare summers in pre-industrial climate. Faster drying of soils in cu...
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Alaa Al Khourdajie @dralaaclimate.bsky.social · 17/08/2026
New publication in Environmental Research Letters: overshooting 1.5°C then cooling back down does not undo the damage. We map where, for whom, and through what mechanisms temporary overshoot becomes permanent loss. Paper (OA): iopscience.iop.org/article/10.1... 1/12
"Three stacked panels sharing a time axis. Top: global temperature rises past 1.5°C, peaks, then declines (the overshoot pathway), with a flat permanent-exceedance line at the peak for comparison. Middle: biophysical responses to the same trajectory diverge; some track temperature down, some recover with a lag, one keeps intensifying. Bottom: socioeconomic impacts of the same biophysical change diverge by adaptive capacity; high-capacity systems recover, while one crosses a dashed adaptive-capacity threshold and never recovers: the permanent overshoot legacy.
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Prof Friederike Otto @frediotto.bsky.social · 06/08/2026
Yet another fire season that has been made more severe due to the burning of fossil fuels - displacing communities, killing ecosystems, putting huge strain on health systems & fire fighting capacities. New @wwattribution.bsky.social study on Canada www.worldweatherattribution.org/climate-chan...
Three graphics showing months of the year on the x-axis, burned area on the y-axis for Canada as a whole and Ontario and the Northwest Territories separately. Highlighting the years 2026, 2025, 2024 and 2023 as well as the 2003-2022 mean.
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Carl Schleussner @carlschleussner.bsky.social · 30/07/2026
Incredibly proud of this major milestone in climate impact emulation. We can now provide climate risks for dozens of indicators almost in real time. Made possible by a fantastic team around Niklas Schwind, Mia Werning, Mahé Perrette, Ed Byers and many others! 👏👏👏
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Daniel Huppmann @danielhuppmann.bsky.social · 23/07/2026
Friendly reminder: a consortium led by Piers Forster @cjsmith.eu @wflamb.bsky.social @robinlamboll.bsky.social et al. and funded by @copernicusecmwf.bsky.social compiled the data on the global climate system... And the #ScenarioServices team at @iiasa.ac.at put together an interactive dashboard!
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Carl Schleussner @carlschleussner.bsky.social · 24/06/2026
Absolutely thrilled that the Overshoot Conference is going into its second round. This year at @tsinghuauniversity.bsky.social. Call for abstract out now - hope to welcome many familiar and new faces.
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Emily Theokritoff @etheokritoff.bsky.social · 04/06/2026
How are impacts from extreme weather events linked to climate change? How much responsibility do large emitters such as companies or countries carry? How do scientists go about calculating these things & how is it then interpreted by lawyers in climate litigation cases? 🌪️ ⚖️
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Neil Grant @neilgrant.bsky.social · 03/06/2026
Chart of the day. The energy transition is happening in real time! 😍
Two area charts showing that in Australia's National Electricity Market, battery discharge replaced peaking gas at the evening demand peak between April 2025 and April 2026.
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Paul Behrens @profpaulbehrens.bsky.social · 21/05/2026
40+ scientists (incl. me) warn that new methane accounting metrics such as "no additional warming", "temperature neutrality” are being used to grandfather high emitters, penalise developing countries, and undermine the Global Methane Pledge. Full statement: methanescience.org
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Carl Schleussner @carlschleussner.bsky.social · 21/05/2026
This is an important one! If you wonder what's wrong here, see for example a paper from @joerirogelj.bsky.social and myself a while back: iopscience.iop.org/article/10.1... or also from @meinshausen.bsky.social and Zeb Nicholls: iopscience.iop.org/article/10.1...
iopscience.iop.org
Unintentional unfairness when applying new greenhouse gas emissions metrics at country level
Unintentional unfairness when applying new greenhouse gas emissions metrics at country level, Rogelj, Joeri, Schleussner, Carl-Friedrich
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Carl Schleussner @carlschleussner.bsky.social · 21/05/2026
In another world, you could have imagined a criticism of the scenario set of dropping a massive fossil fuel expansion future coming from the same quarters (see IEA debate). But you can't have it both ways... (and yes, there are nuances to this debate re coal etc, ofc).
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Carl Schleussner @carlschleussner.bsky.social · 21/05/2026
Enough has been said on the SSP5-85 debate. But what I find somewhat ironic: What the new ScenarioMIP say: a global fossil-fuel driven high-growth path is not plausible anymore. To be attacked by proponents of precisely such a narrative of economic development.
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Giacomo Falchetta @giacfalk.bsky.social · 13/05/2026
🌳🥵 🌇 In our new study (dx.doi.org/10.1088/1748-9326/ae5c20), we find that street green space (trees, bushes, green space visible to the pedestrian, etc.) can reduce urban heat stress, but even ambitious greening efforts are unlikely to offset much of the additional heat expected from climate change.
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Netzwerk Klimajournalismus Österreich @netzwerkklimajourn.bsky.social · 13/04/2026
"Es gibt keinen Spielraum für Ziel-Abweichungen. Netto-Null-Ziele reichen nicht aus", sagt @carlschleussner.bsky.social im Gespräch mit @lukasbayer.bsky.social bei unserem 5vor12 Live-Briefing. #overshoot
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Carl Schleussner @carlschleussner.bsky.social · 13/04/2026
Heute Abend im Volkstheater Wien. Veranstaltung des Netzwerk Klimajournalismus mit @lukasbayer.bsky.social. Ich freu mich drauf. @iiasa.ac.at www.volkstheater.at/event/332609...
volkstheater.at
CLIMATE OVERSHOOT –WIE KRIEGEN WIR NOCH DIE KURVE? - Volkstheater Wien
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IIASA @iiasa.ac.at · 09/04/2026
🌳A new IIASA-led study shows that expanding street green space can reduce urban heat stress, but it won’t be enough to offset climate change on its own. While having greener streets help, broader, context-specific adaptation will be essential. 👉 iiasa.ac.at/news/apr-202... @tuberlin.bsky.social
iiasa.ac.at
Street green space can help cool cities, but it will not be enough on its own
A new IIASA-led study finds that expanding street green space can reduce urban heat stress in cities worldwide, but even ambitious greening efforts are unlikely to offset a significant share of the additional heat expected under climate change. Instead, the research shows that street greenery should be part of a broader portfolio of urban adaptation measures.
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Malte Kreutzfeldt @mkreutzfeldt.bsky.social · 09/04/2026
In ihrem aktuellen FAZ-Gastbeitrag beklagt Katherina Reiche eine "Selbsttäuschunug" in der Energiepolitik. Tatsächlich fällt der Täuschungsvorwurf aber teilweise auf sie selbst zurück, denn der Text enthält diverse falsche oder irreführende Zahlen. Ein Thread. (1/17) www.faz.net/aktuell/wirt...
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Ben Sanderson @benmsanderson.bsky.social · 08/04/2026
So... now we can breathe again. Let's talk about ScenarioMIP. The final version is now up on GMD - and there's some changes since the first draft. /THREAD/ gmd.copernicus.org/articles/19/...
gmd.copernicus.org
The Scenario Model Intercomparison Project for CMIP7 (ScenarioMIP-CMIP7)
Abstract. Scenarios serve as a critical tool in climate change analysis, enabling the exploration of future evolution of the climate system, climate impacts, and the human system (including mitigation...
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Karl Scheifinger @karlscheifinger.bsky.social · 01/04/2026
Emission scenarios inevitably embed assumptions about fairness. Tracking these assumptions is genuinely difficult, but making them transparent matters. We developed a framework to do just that. @ic-cep.bsky.social #IIASA @imperialcollegeldn.bsky.social 1/2
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Emanuele Bevacqua @bevacquae.bsky.social · 25/03/2026
In a new Nature study, we show that extreme global climate outcomes may occur even under moderate 2°C warming for several sectors. The findings reinforce the urgency of limiting warming well below 2°C. Together with @erichfischer.bsky.social @janasillmann.bsky.social @zscheischlerjak.bsky.social
nature.com
Moderate global warming does not rule out extreme global climate outcomes - Nature
Extreme global climate outcomes may occur even under moderate 2 °C warming and may turn out to be more extreme than model-averaged projections at 3 °C or 4 °C warming.
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World Weather Attribution @wwattribution.bsky.social · 26/02/2026
NEW STUDY: Winter downpours are getting heavier in parts of Spain, Portugal and Morocco as the region recovers from a month of relentless storms. Between mid-January and mid-February nine named storms brought torrential rain hurricane force winds causing major damage and disruption. 1/5
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IIASA @iiasa.ac.at · 24/02/2026
🌍 Just published: The hard road back from overshoot by IIASA Journalist in Residence, @lisapalmer.bsky.social. The piece examines some of the realities of climate overshoot and features insights from IIASA's @carlschleussner.bsky.social & @joerirogelj.bsky.social. 👉 www.nature.com/articles/s41...
nature.com
The hard road back from overshoot - Nature Climate Change
As global temperatures move beyond 1.5 °C, overshoot now defines the landscape ahead, sharpening legal claims, exposing economic risks and revealing how far politics still trail the pace of change.
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Prof Friederike Otto @frediotto.bsky.social · 26/02/2026
The Mediterranean is a hotspot of climate change, not only due to more heat, droughts and wildfires, but increasingly severe rainstorms led to catastrophic flooding this winter, highlighting again the urgent need to transition away from fossil fuels. www.worldweatherattribution.org/increasingly...
Maps of the rainfall associated with two of the nine storms hitting the Mediterranean in January and February 2026.
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IIASA @iiasa.ac.at · 12/02/2026
Can climate mitigation scenarios be trusted without equity at their core? A new @plosclimate.org study "highlights a research agenda combining incremental improvements & participatory approaches - practical yet ambitious” says @joerirogelj.bsky.social iiasa.ac.at/news/feb-202...
iiasa.ac.at
Rebuilding trust in global climate mitigation scenarios
A new IIASA-led study examines growing critiques of how global climate mitigation scenarios address equity and justice and identifies key conditions for fair, feasible, and politically credible climat...
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Daniel Huppmann @danielhuppmann.bsky.social · 02/02/2026
For a decade, the Shared Socioeconomics Pathways #SSP are used for scenario research related to climate change mitigation. Now, GDP & population projections were updated by @iiasa.ac.at & the team at the #OECD, and the #ScenarioServices team set up a new interactive app to explore the scenarios!
ssp.apps.ece.iiasa.ac.at
Shared Socioeconomic Pathways | Scenario Explorer hosted by IIASA
The Shared Socioeconomic Pathways (SSPs) are a set of scenarios that describe potential future developments in society, economics, and demographics until the end of the 21st century. This Explorer pre...
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Mar Hicks @histoftech.bsky.social · 06/02/2026
No joke: I got angry hate mail today for writing an obituary of a Black woman scientist—because the person felt she did didn’t deserve the recognition. Which just makes me want to share it again: www.nature.com/articles/d41...
nature.com
Gladys Mae West obituary: mathematician who pioneered GPS technology
She made key contributions to US cold-war science despite facing huge barriers as a Black woman.
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Daniel Ospina @daniel-ospina.bsky.social · 05/02/2026
*DEADLINE EXTENDED* February 8 Submit your suggestions and nominate (yourself or others) as a co-author for the 2026 edition of the 10 New Insights in Climate Science
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Lauri Myllyvirta @laurimyllyvirta.bsky.social · 29/01/2026
New from us: The average EU citizen spent EUR880 on fossil fuel imports in 2025, as gas imports increased and the U.S. became the largest supplier. Slow progress on electrifying transport and buildings as well as building wind power are harming the bloc's economy and energy security.
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Carl Schleussner @carlschleussner.bsky.social · 29/01/2026
Thanks. I agree that getting serious about understanding 'how we got here' in quantitative terms can be very informative.
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
@iiasa.ac.at @granthamicl.bsky.social @pik-potsdam.bsky.social
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
In an overshoot world, we need to 1️⃣ bend the emissions curve towards the race to net zero. Fast. 2️⃣ Hold those responsible to account for delivering carbon removal, and financing adaptation and loss & damage. Failing to stay below 1.5°C does not erase obligations – it strengthens them.
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
Exploring such roads not taken can help us understand how we ‘got here’ and show that exceeding 1.5°C was not inevitable, but a result of political choices. And choices continue to matter, also in difficult times for climate policy. Science should illustrate the consequences. 10/
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
To do so, we argue we need to systematically explore past roads not taken. What if countries had used key political moments – Kyoto, Paris, economic stimulus packages post COVID – to accelerate decarbonisation? 9/ www.science.org/doi/abs/10.1...
science.org
COVID-19 recovery funds dwarf clean energy investment needs
A modest fraction of current global stimulus funds can put the world on track to achieve Paris Agreement goals
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
But to understand accountability for remedies, we also need to understand actors' past actions on climate. Ultimately, exceeding 1.5°C is the result of more than 30 years of insufficient global decarbonisation efforts. 8/
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
We need to put particular emphasis on equity in an overshoot world. One way to do this is the carbon debt concept. See here: www.pnas.org/doi/10.1073/... Carbon debt can allow us to link past inaction to future responsibilities. 7/
pnas.org
PNAS
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
So what changes in an overshoot world? It’s no longer enough for the world to aim at net zero CO2. To return warming back below 1.5°C, high emitters will need to go net negative. And provide additional adaptation and loss & damage funding for the harms caused 6/ www.nature.com/articles/s41...
nature.com
Overconfidence in climate overshoot - Nature
Aiming for declining global temperatures can limit long-term climate risks compared with a mere stabilization of global warming, including sea-level rise and cryosphere changes.
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
Failing to limit warming to 1.5°C requires a reflection of why this had to happen. And who’s responsible and should be held accountable for the remedial measures to address that failure. 5/
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Carl Schleussner @carlschleussner.bsky.social · 28/01/2026
The obligation to limit warming to 1.5°C also remains in case of exceedance. But it will be challenging to bring temperatures back down under an overshoot trajectory. And some consequences of overshoot will be irreversible. 4/ www.science.org/doi/10.1126/...
science.org
The pursuit of 1.5°C endures as a legal and ethical imperative in a changing world
As the world nears 1.5°C of global warming, near-term emissions reductions and adequate adaptation become ever more important to ensure a safe and livable planet for present and future generations
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