Alaa Al Khourdajie

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

Alaa Al Khourdajie reposted

IPCC

@ipcc.bsky.social

📣 PRESS RELEASE 65th Plenary Session of IPCC suspended Read more: 🔗 https://bit.ly/3WdQDm1

16 Sept

The IPCC hosted a workshop on Methods of Assessment earlier this year, looking at systemic reviews, use of artificial intelligence for knowledge synthesis, and ex-post evaluations. I had the pleasure of sharing the floor with Michal to give a talk about AI and the IPCC www.ipcc.ch/site/assets/...

ipcc.chipcc.ch

IPCC@ipcc.bsky.social

📗The report from the #IPCC Workshop on Methods of Assessment is now online. It covers how AI, systematic reviews and ex-post evidence evaluation could help IPCC authors manage the exponential growth of climate literature and widening knowledge base. 🔗 bit.ly/4h2MhVD

Alaa Al Khourdajie reposted

Zeke Hausfather

@zekehausfather.com

14 Sept

Replying to @zekehausfather.com

As always, check out the Climate Dashboard for daily updates. It now includes more nerdy ENSO data including trade winds, southern oscillation index, and warm water volume tracking! dashboard.theclimate...

ScenarioMIP marker scenarios for CMIP7 are now public. Seven IAM pathways from ~1.4°C to ~3.4°C at 2100 [panel a] that will shape IPCC AR7 assessment 1/6

Overshoot map: Peak warming (x-axis) vs 2100 warming (y). Below the diagonal = overshoot magnitude. Grey bands: range covered only by Tier-3 scenarios. Red bands: gap between Low and Medium-to-Low. SSP2-Com sits inside the inner red gap on both axes. 5/6

Implications for AR7: the 2°C coverage sparser than the extremes in early production runs. The impacts community will inherit the final out of the ensemble. 6/6

ScenarioMIP marker scenarios for CMIP7 are now public. Seven IAM pathways from ~1.4°C to ~3.4°C at 2100 [panel a] that will shape IPCC AR7 assessment 1/6

The 2°C gap: marker peaks cluster at 1.68–1.86°C (three scenarios) and 2.27–3.42°C (four). The 1.9–2.2°C peak window has no marker and SSP2-Com from the MINES model fills the design gap, peaking ~2.0°C around 2070, declining to ~1.84°C [panel c] 3/6

Overshoot: only Medium and High grow monotonically. Overshoot and return pattern dominates. That puts hysteresis, drawdown timing and irreversibility at the centre of AR7. 4/6

ScenarioMIP marker scenarios for CMIP7 are now public. Seven IAM pathways from ~1.4°C to ~3.4°C at 2100 [panel a] that will shape IPCC AR7 assessment 1/6

National Academy of Sciences

Priority: CMIP7 asks modelling centres to run High and Very Low first (Tier 1), then Medium and High-to-Low (Tier 2). Low, Medium-to-Low and Low-to-Negative come later. [panel b] 2/6

Alaa Al Khourdajie reposted

@nasonline.org

2 Sept

Small changes in the ocean can trigger global consequences. 🌊 The new summary from the 2026 US-UK Scientific Forum on ocean tipping points explores how researchers are working to understand, predict & respond to shifts in ocean systems. Read here: royalsociety.org/-/media/abou... @royalsociety.org

Alaa Al Khourdajie reposted

Chris Bataille

@chrisbataille.bsky.social

28 Aug

For all the sturm and drang, opinions and POVs, this is numerically how fast CCS injections are growing in the world. Most of the volume is a few big projects @dralaaclimate.bsky.social @jack-cavanaugh.bsky.social imperialcollegelondon.github.io/The-London-R...

11/12 The capacity to respond, to cut emissions, finance adaptation & sustain removals, sits with those most responsible for the overshoot & least exposed to its legacies. The imperatives: rapid near-term cuts & sustaining the reductions & removals that bring temperatures down.

iopscience.iop.orgOvershoot pathways: reversible biophysical change, irreversible socioeconomic impactsOvershoot pathways: reversible biophysical change, irreversible socioeconomic impacts, Al Khourdajie, Alaa, Andrijevic, Marina, Byers, Edward, Pathak, Minal, Pirani, Anna, Schleussner, Carl-Friedrich, Stuart-Smith, Rupert

12/12 Grateful to my co-authors for the great collaboration: @andrijevic.bsky.social , Edward Byers, Minal Pathak, Anna Pirani, @carlschleussner.bsky.social & Rupert Stuart-Smith. Paper (OA): iopscience.iop.org/article/10.1...

9/12 Two issues to reflect on. First, a feasibility feedback loop: the deeper the overshoot, the more it erodes the finance, institutions and land needed for the carbon removal that ends it.

10/12 Second, a governance gap: falling temperatures may be read as the crisis resolving precisely while permanent harm accumulates fastest, weakening political will for removals and Loss and Damage finance exactly when it is needed most.

7/12 Socioeconomic legacy: nature recovers, people do not (livelihoods collapsed by repeated drought). This quadrant is the paper's central thesis. Existential loss: beyond all adaptation (small island states; communities dependent on vanished glaciers).

8/12 Which outcome a community faces is determined primarily by socioeconomic factors, not only biophysical ones.

5/12 Three mechanisms make loss permanent 1 Non-substitutability: some losses have no substitute. Lives, species, cultural heritage 2 Threshold-crossing: repeated shocks exhaust a community's coping resources 3 Lock-in: adapting to peak conditions creates barriers to reversal even when well designed

6/12 Crossing the layers yields four outcomes. Temporary adaptation challenge: stress endured, recovery follows (heat deaths cut by early-warning systems). Permanent adaptation challenge: nature permanently altered, but well-resourced systems reconfigure (managed retreat from rising seas).

3/12 A community displaced by repeated drought does not return home because global temps fall. A farming household that sold its land after successive crop failures has no capital base to re-enter. Lives lost to heat extremes are not restored.

4/12 Our framework traces overshoot pathways' impacts through a three-layer cascade: the temperature path (how high, how long, how fast up & down), the biophysical response it triggers, & the socioeconomic outcome that follows. Reversibility at one layer does not guarantee it at the next.

2/12 The only remaining route back is an overshoot pathway: temperatures rise past the threshold, peak, then decline through sustained emissions cuts and carbon removal. That pathway carries a tempting assumption: when temperatures come back down, impacts reverse. They do not!

Alaa Al Khourdajie reposted

Kate Mackenzie

@katemac.bsky.social

18 June

This might be one of the funniest chart about energy scenarios I’ve seen. You can hardly see “actual” for gas

Alaa Al Khourdajie reposted

David Ho

@davidho.bsky.social

12 June

Replying to @davidho.bsky.social

@dralaaclimate.bsky.social is an expert in climate change economics and integrated assessment modeling at Imperial College London's Department of Chemical Engineering. He specializes in climate mitigation scenarios, AI for climate science, and has contributed significantly to IPCC reports.

@iain-staffell.bsky.social

11 June

🙃🤷🏻‍♂️

Daniel@danielwilliams965.bsky.social

Yes, the IPCC is utterly, totally corrupt and trying to destroy the entire planet I know what the cause is: Alaa Al Khourdaji: @dralaaclimate.bsky.social

Alaa Al Khourdajie reposted

Dr Iain Staffell

3 June

The UK’s AI race is all about electricity. 70% of data centre capacity lies within 20 miles of London. They block new homes being built because the grid can’t cope. We must look beyond - to places with clean power and strong grid access. Read in full: reports.electricinsights.co.uk

Alaa Al Khourdajie reposted

PLOS Climate

@plosclimate.org

29 May

New on the Latitude blog: meet PLOS Climate Academic Editor @dralaaclimate.bsky.social, who recently joined the team on our Machine Learning and AI section 👇 latitude.plos.org/2026/05/meet...

latitude.plos.orgMeet PLOS Climate Academic Editor Alaa Al Khourdajie - LatitudeWe are delighted to introduce Alaa Al Khourdajie (Imperial College London, UK) as an Academic Editor in PLOS Climate‘s new Machine Learning and…

Alaa Al Khourdajie reposted

IPCC

@ipcc.bsky.social

26 May

In response to recent misinformation about the use of scenarios in IPCC reports: the IPCC does not conduct its own research, run models or make measurements. The IPCC’s role is to assess the available scientific, peer-reviewed literature relevant to climate change: www.ipcc.ch/2026/05/20/i...

Alaa Al Khourdajie reposted

Gavin Schmidt

@climateofgavin.bsky.social

22 May

This is a quick summary of the latest CMIP process. It is a complex beast and a consensus project so there are always things that you’ll agree with and those that you might not. 1/

Carbon Brief@carbonbrief.org

Guest post: How CMIP7 will shape the next wave of climate science ✍️ written by Beth Dingley, Helene Hewitt, John Dunne and Eleanor O'Rourke Read here ⬇️

carbonbrief.orgGuest post: How CMIP7 will shape the next wave of climate science - Carbon BriefHundreds of scientists in dozens of institutions are embarking on the next phase of the world’s largest coordinated climate-modelling effort.

Alaa Al Khourdajie reposted

Emily Theokritoff

@etheokritoff.bsky.social

28 Apr

The climate #litigation pico session and splinter meeting are back at #EGU26! ⚖️ We’re looking forward to another round of enriching, highly interdisciplinary talks and discussions. Based on this year’s impressive line-up of abstracts and speakers, it’s set to be a great one.

Alaa Al Khourdajie reposted

Chris Bataille

@chrisbataille.bsky.social

5 Feb

I've been privileged over the years to write a sequence energy modelling methodology papers with (now Professor 🥳) Steve Pye of UCL, along with a rotating cast of amazing people. The latest dropped today in Nature Energy ➡️ rdcu.be/e2tt6

rdcu.beAddressing context-specific energy modelling risks and dynamics in low- and middle-income countriesNature Energy - Low- and middle-income countries face unique challenges when it comes to balancing growing energy needs with broader, long-term development needs. This Perspective argues for...

@beatricecointe.bsky.social

25 Dec 2025

Sadly, “for now”

Neil deGrasse Tyson@neildegrassetyson.com

Not that anybody asked, but the Northern Arctic is just Ocean. So Santa’s North Pole Workshop has only ever existed on a floating sheet of ice. No fur trees. No hills. Occasional seals. And polar bears — for now.

Alaa Al Khourdajie reposted

PLOS Climate

@plosclimate.org

22 Dec 2025

On the 22nd day of our #PLOSClimateCountdown, we're featuring an Essay by @dralaaclimate.bsky.social: "The role of Artificial Intelligence in climate change scientific assessments" 🔗 journals.plos.org/climate/arti...

Alaa Al Khourdajie reposted

Natassa Romanou

@aromanou.bsky.social

18 Dec 2025

#NCAR is a leading institution in climate science. Climate science is not woke. It is the science that explains the evidence we have over the last few decades of an earth system that is stressed by anthropogenic interference.

Alaa Al Khourdajie reposted

Béatrice Cointe

17 Dec 2025

Replying to @beatricecointe.bsky.social

[2/3] One in Futures on "Constructing futures through climate modelling", that I'm co-editing with @dralaaclimate.bsky.social, @natasja.bsky.social, @a-nikas.bsky.social and Chris Groves Submission deadline for *papers* : March 31 www.sciencedirect.com/special-issu...

sciencedirect.comFutures | ScienceDirect.com by Elsevier - Futures | ScienceDirect.com by ElsevierRead the latest articles of Futures at ScienceDirect.com, Elsevier’s leading platform of peer-reviewed scholarly literature

Alaa Al Khourdajie reposted

Grantham Institute - Climate Change and the Environment

@granthamicl.bsky.social

9 Dec 2025

Climate change, biodiversity loss, land degradation, and pollution are together claiming millions of lives and costing trillions of dollars every year, according to the most comprehensive assessment of the global environment ever undertaken 🧵

Grantham Institute - Climate Change and the Environment

1 Dec 2025

Here we go, @ipcc.bsky.social first lead author meeting (and for the first time ever covering all three working groups) A mixed feeling of excitement and responsibility

Alaa Al Khourdajie reposted

@granthamicl.bsky.social

24 Nov 2025

#COP30: Imperial researchers react to ‘deeply disappointing’ climate talks In the aftermath of the agreement, Imperial experts Dr Nathan Johnson, Dr Robin Lamboll, Prof Joeri Rogelj, Dr Alaa Al Khourdajie, Dr Emily Theokritoff and Dr Caterina Brandmayr have weighed in 🧵 ow.ly/9CSZ50XwZzs

Alaa Al Khourdajie reposted

David Ho

@davidho.bsky.social

24 Nov 2025

A lot of people are going to lose money on this. Solar radiation modification only makes sense if followed by large-scale carbon dioxide removal, and we ain't got that.

Politico@politico.com

A 25-person startup is developing technology to block the sun and turn down the planet’s thermostat. The stakes are huge — and the company and its critics say regulations need to catch up. Read more: politi.co/4iaojIc

Alaa Al Khourdajie reposted

Spent Saturday night reviewing the final #COP30 Belém draft text. A friend joked it counts as “light reading.” Unfortunately, it is very much a light read. 1/

Spent Saturday night reviewing the final #COP30 Belém draft text. A friend joked it counts as “light reading.” Unfortunately, it is very much a light read. 1/

The text’s “national pacing” fundamentally misunderstands this: Delay doesn’t provide options; it eliminates them. Every year without output cuts pushes the peak higher, making any return to 1.5°C less feasible. End/

23 Nov 2025

Quick clarification: at roughly today’s global emissions, an extra five years of “holding steady” would add about 0.1°C of warming. So talk of a remaining 1.5°C “gap” is not a reassuring buffer… every year of plateau deepens any future overshoot and makes a return less feasible. End +1

Spent Saturday night reviewing the final #COP30 Belém draft text. A friend joked it counts as “light reading.” Unfortunately, it is very much a light read. 1/

Yet the text acknowledges a 2.3–2.5°C trajectory, risking even this overshoot-and-return scenario. Without binding requirements for immediate fossil fuel cuts, we face two failures: 3/

Either we accept 2.3°C as permanent, OR we attempt course correction so late that overshoot becomes unnecessarily deep and prolonged, if return remains feasible at all. Both mean more irreversible climate impacts. 4/

Spent Saturday night reviewing the final #COP30 Belém draft text. A friend joked it counts as “light reading.” Unfortunately, it is very much a light read. 1/

My main remark: the increased risk of and from overshoot. Our only chance for 1.5°C is now likely through overshoot; temporarily exceeding before returning. Even that comes with huge feasibility challenges. 2/

Alaa Al Khourdajie reposted