Alaa Al Khourdajie

Sadly, “for now”

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...

#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.

[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...

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 🧵

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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

#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

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.

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.

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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

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.

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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.

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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:

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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.

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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/

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As the final text is being hammered out here in Belém for #COP30, the issue of fossil fuel phase-out is on the table again.

Looking at the actual numbers from the IPCC AR6 1.5°C assessed scenarios to decompose reduced fossil fuel output vs. carbon capture and storage - CCS (i.e. abatement)

1/3

If the final text implies that "abatement" is a valid alternative to a "transition away," it isn't just offering flexibility, it is ignoring the physical reality of the transition.

#COP30 #Belem #FossilFuels #EnergyTransition

The hierarchy is clear: 75–85% of emission reductions through 2050 come from using less fossil fuel.

CCS plays a role, but it is strictly secondary, contributing a median of just 15–25%.

Technological neutrality is a political concept, not a scientific one.

2/3

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As the final text is being hammered out here in Belém for #COP30, the issue of fossil fuel phase-out is on the table again.

Looking at the actual numbers from the IPCC AR6 1.5°C assessed scenarios to decompose reduced fossil fuel output vs. carbon capture and storage - CCS (i.e. abatement)

1/3

Overshoot: Returning to 1.5°C Requires Net-negative Emissions Targets Global warming is set to rise above 1.5°C by the early 2030s. Returning to 1.5°C before the end of the 21st century would not prevent all harms...

Overshoot: returning to 1.5°C requires net-negative emissions targets. @swp-berlin.org policy brief with Oliver Geden.

Keeping 1.5 alive will require reframing “net-zero” as transitional stage towards net-negative GHG emissions rather than an endpoint, and policy instruments able to deliver this.

To be Paris Agreement compatible, the label 'abated fossil fuels' needs to apply to Carbon Capture and Storage applications with net-zero greenhouse gas emissions on a lifecycle basis.

This requires four things...🧵

ow.ly/j0lz50XsO8a

#COP30

We will be guided by the audience questions, given the format of the event, but I doubt such a question won’t come up

About the session: This interactive session will cut through misinformation on CCUS by using trusted voices to explain the facts. The event will include live audience polling, a CCUS ‘teach-in’ from @katharinehayhoe.com, and rapid myth-busting shaped by audience Q&A.

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Join our #COP30 event

“CCUS Myth-Busting Live: Ask the Experts”

Date and time Monday 17 November, 10:00–11:30 am local time (1:00-2:30pm UK time)
Location: UK Pavilion, Blue Zone (A23)
YouTube live stream: www.youtube.com/live/SjaW3Ob...

Do climate conferences actually achieve anything? A lot of people have strong opinions, but we wanted measurements, so we look at how the stock market moves during yearly international meetings called COPs – explanation below, or read the paper here:
iopscience.iop.org/article/10.1...

📈COP delivers stock market boost for ‘green’ companies but renewables unaffected, Imperial College London study shows 🧵

Read it here: ow.ly/o6xY50XnEuH

An overview of FRIDA v2.1: a feedback-based, fully coupled, global integrated assessment model of climate and humans Abstract. The current crop of models assessed by the Intergovernmental Panel on Climate Change (IPCC) to produce their assessment reports lack endogenous process-based representations of climate-drive...

The FRIDA overview paper: gmd.copernicus.org/articles/18/...

A coupled human-Earth IAM, with integrated climate impacts.

Multi-century global and regional sea-level rise commitments from cumulative greenhouse gas emissions in the coming decades - Nature Climate Change It is important to understand how much long-term sea-level rise is already committed due to historical and near-term emissions. Here the authors use a modelling framework to show how decisions on glob...

Really important paper led by my @iiasa.ac.at colleague Alex Nauels www.nature.com/articles/s41...
“The difference between decisive climate action today and continued high emissions is not just measured in degrees of warming but also in meters of sea-level rise” 👏👏👏

Every ton of CO2 matters :
@climatenerilie.bsky.social quantifies the climatic impacts of one large fossil fuel project and its implications for further human heat exposure or coral reef loss, and how committed emissions challenge climate pledges

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