Ali Duffey

Ali Duffey

@aliduffey.bsky.social

Climate science | Stratospheric aerosol injection | Arctic climate change Senior Scientist at Reflective and visiting researcher at UCL

306 followers772 following105 posts

Ali Duffey reposted

“Nobody has ever studied this carefully” said the people who spent 10 years threatening to tank the carrier of anybody daring to studying that thing carefully and systematically. I’m going to have a brain aneurysm before 40.

Paper out today on high-latitude low-altitude stratospheric aerosol injection (HiLLA-SAI). It's long, with literally 100s of sub-plots, so TL:DR: HiLLA-SAI is a polar-focused but still global intervention, with ~40-70% the global cooling efficiency of "normal" SAI esd.copernicus.org/articles/17/...

esd.copernicus.orgThe global climate response to High-Latitude Low-Altitude Stratospheric Aerosol Injection (HiLLA-SAI)Abstract. High-latitude low-altitude (HiLLA) Stratospheric Aerosol Injection (SAI) would face fewer logistical barriers than high-altitude low-latitude SAI, because it could use repurposed existing la...

Ali Duffey reposted

On Friday, I'm talking with the head of Reflective, a nonprofit trying to accelerate the responsible research of solar radiation modification (SRM), ie, blocking some sunlight from reaching earth in order to cool the atmosphere. Geoengineering! Got questions?

reflective.orgReflective | Radically Accelerating the Pace of Sunlight Reflection ResearchWe equip the world with the data and tools needed to make informed decisions about sunlight reflection, fast enough to matter.

Reading back through @eaterofsun.bsky.social 's The Planet Remade and thought this snippet about German involvement in geoengineering research was interesting. 10 years later the opposite seems true. On the other hand, the description of GeoMIP conferences fits the recent ones pretty well..

Ali Duffey reposted

Our paper is published! 🎉🎉🎉 If you want to understand changes in total rainfall under warming, give this a read! Happy to chat about it with people :) agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Andrew Williams@andrewilwilliams.bsky.social

When Earth warms, the total rainfall increases. Here we show that this change in rainfall is also sensitive to the *pattern* of warming, build a theory to explain why, and use it to explain why rainfall increases more in uniform warming exps than abrupt-4xCO2 :) essopenarchive.org/doi/full/10....

Ali Duffey reposted

In 2022, archaeologists at @uni-kiel.de's @neolithicbodies.bsky.social found 34 decapitated skeletons piled in a space the size of a parking spot. In the 3 years since, they’ve found 50 more. The mass grave is evidence for the collapse of the 1st pan-European culture 7,000 years ago. @science.org 🏺💀

science.orgHeadless bodies hint at why Europe’s first farmers vanishedWave of mass brutality accompanied the collapse of the first pan-European culture

Ali Duffey reposted

Ali Duffey reposted

"when we deploy it we will see how effective is" I hear this quite a bit but it isn't true. 10 years into a hypothetical SAI deployment, observed rainfall patterns would be pretty much useless for reducing our uncertainty in e.g. indian summer monsoon impacts

umsonst.bsky.social@umsonst.bsky.social

Absolutely! The effect just depends on the model taken. So it's easy to meddle around... When we will deploy it we will see how effective it is and understand the side effects Sadly, we will need it... If we start we have with all we've got to reduce our emissions as otherwise its a death trap

Did Northern Hemisphere air pollution contribute to 70s and 80s Sahel drought? We think so, but we're still arguing about how much. For the most important risks of solar geo, consensus would (hopefully) emerge, but slowly. Informed by observed climate, but still based on theory and modelling

Ali Duffey reposted

The NYT piece quoted here is amazing. Written over 70 years ago and reads exactly like articles about this summer's Texas Rainmaker conspiracy

Longtime climate scientist J. Michael Wallace got his start in meteorology back when pre-internet conspiracy theorists asserted that a nuclear test caused a tornado... Now he reflects on a heap of lessons learned as global warming science has piled up. revkin.substack.com/p/warming-wo... 🧪

love this chart. It's too late for 1.5, but the fight for 2C is very much still alive

Zeke Hausfather@zekehausfather.com

Yep, while there is a growing literature on emissions and climate outcomes under current policy scenarios (and we can more firmly rule out things like 5x more coal by 2100 globally), current policies represent neither a ceiling nor floor on future emissions: journals.sagepub.com/doi/10.1177/...

Ali Duffey reposted

wrote about this last year and sure I wasn't in any way the only one but imo people voting for populist politics in the 21st century *is* a sign that they do just have too much faith in institutions, as opposed to not enough - they want to have their little tantrum but assume things will just hold

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Is this a crisis or not? Are tipping point risks serious or not? Net zero is non-negotiable, but climate impacts are here, and all plausible emissions scenarios see us pass 1.5C. If now is not a reasonable time to explore radical ideas, when would be?

Damian Carrington@dpcarrington.bsky.social

Polar #geoengineering dismissed as “unimaginably expensive” and “dangerous” Giant underwater curtains and artificial ice thickening diverts attention from cutting fossil fuel burning, climate scientists argue - but proponents disagree #climatecrisis Story by me www.theguardian.com/environment/...

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The SAI section bends over backwards to try to fit it into the same mould as the others (logistically difficult, expensive, and ineffective), but in doing so makes some surprising errors as well as being one-sided.

The evidence we have, though, suggests SAI is not like these other ideas, being instead logistically feasible, effective and quite cheap. We could be wrong on all three of these, of course, but honest debate about geoengineering demands that we grapple with that evidence

Is this a crisis or not? Are tipping point risks serious or not? Net zero is non-negotiable, but climate impacts are here, and all plausible emissions scenarios see us pass 1.5C. If now is not a reasonable time to explore radical ideas, when would be?

Damian Carrington@dpcarrington.bsky.social

Polar #geoengineering dismissed as “unimaginably expensive” and “dangerous” Giant underwater curtains and artificial ice thickening diverts attention from cutting fossil fuel burning, climate scientists argue - but proponents disagree #climatecrisis Story by me www.theguardian.com/environment/...

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Similarly for the ice sheet interventions. While those working on these have been the first to ackowledge that they are profoundly ambitious ideas, the Siegert et al study is a valuable and welcome critical perspective to help understand how and why these ideas would face challenges.

But the idea that further research into these is a waste of resources is crazy to me, when i think about what is at stake here. Yes sea-curtains sound difficult, but so does building a sea-wall around Bangladesh.

Is this a crisis or not? Are tipping point risks serious or not? Net zero is non-negotiable, but climate impacts are here, and all plausible emissions scenarios see us pass 1.5C. If now is not a reasonable time to explore radical ideas, when would be?

Damian Carrington@dpcarrington.bsky.social

Polar #geoengineering dismissed as “unimaginably expensive” and “dangerous” Giant underwater curtains and artificial ice thickening diverts attention from cutting fossil fuel burning, climate scientists argue - but proponents disagree #climatecrisis Story by me www.theguardian.com/environment/...

View full thread

My impression is that sea-ice thickening and the ice sheet interventions are somewhere between implausible and just unlikely. The potential for sea-ice thickening to meaningfully impact global climate is often exaggerated, though, and its good to call this out

Is this a crisis or not? Are tipping point risks serious or not? Net zero is non-negotiable, but climate impacts are here, and all plausible emissions scenarios see us pass 1.5C. If now is not a reasonable time to explore radical ideas, when would be?

Damian Carrington@dpcarrington.bsky.social

Polar #geoengineering dismissed as “unimaginably expensive” and “dangerous” Giant underwater curtains and artificial ice thickening diverts attention from cutting fossil fuel burning, climate scientists argue - but proponents disagree #climatecrisis Story by me www.theguardian.com/environment/...

Not all geoengineering proposals are plausible, and we shouldn't waste time and resources on the implausible ones. Siegert et al look at 5 (really, 6): sea-ice thickening, sea-ice albedo modification, sea-bed curtains, basal water removal from ice sheets, CDR via ocean fertilization, and SAI

Ali Duffey reposted

Given this context, I'm delighted to share a new review on the solar geoengineering and earth system tipping points. Its a long read including ice sheets, AMOC, coral reefs, Amazon dieback and various others.. TLDR: solar geo probably helps avoid tipping, but a lot more research is needed

Prof. Stefan Rahmstorf@rahmstorf.bsky.social

New Scientist has a report on a controversial issue discussed last week at the #GlobalTippingPoints conference in Exeter: will we need solar radiation interference as a desperate measure, as politicians are failing to phase out fossil fuels? www.newscientist.com/article/2487...

Given this context, I'm delighted to share a new review on the solar geoengineering and earth system tipping points. Its a long read including ice sheets, AMOC, coral reefs, Amazon dieback and various others.. TLDR: solar geo probably helps avoid tipping, but a lot more research is needed

Prof. Stefan Rahmstorf@rahmstorf.bsky.social

New Scientist has a report on a controversial issue discussed last week at the #GlobalTippingPoints conference in Exeter: will we need solar radiation interference as a desperate measure, as politicians are failing to phase out fossil fuels? www.newscientist.com/article/2487...

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BUT, once things are already tipped, SRM might not be able to get you back - we assessed "reversibiility" as ineffective or only partially effective for many important systems. This shouldn't be surprising - this behaviour is part of what makes these things "tipping points"

Given this context, I'm delighted to share a new review on the solar geoengineering and earth system tipping points. Its a long read including ice sheets, AMOC, coral reefs, Amazon dieback and various others.. TLDR: solar geo probably helps avoid tipping, but a lot more research is needed

Prof. Stefan Rahmstorf@rahmstorf.bsky.social

New Scientist has a report on a controversial issue discussed last week at the #GlobalTippingPoints conference in Exeter: will we need solar radiation interference as a desperate measure, as politicians are failing to phase out fossil fuels? www.newscientist.com/article/2487...

the slight less TLDR version is that SRM likely reduce the strength of driving factors for tipping in a range of systems, generally by reducing temperature but in some cases by restoring other climatic drivers too

Ali Duffey reposted

Replying to @edhawkins.org

And remember that the peak temperatures you experience in SE England in the next couple of days will be 4-5°C warmer than they would have been with similar weather patterns in the climate of a century ago.

Cristi Proistosescu@cristiproist.bsky.social

Why did the UK MetOffice decide it would be easier if climate models had 12 equal months of 30 days each? I don't know. But It doesn't surprise me from the country that decided the most elegant solution to dividing up the Middle East is by drawing straight, uncomplicated, borders.

It was great fun collaborating with Robbie and others on this paper. The stability of the winter Arctic atmosphere is a big part of why it is warming so fast in that season, so its important to understand whether the models are doing a reasonable job, and if not, why.

Robbie Mallett@robbiemallett.bsky.social

Paper out today led by @aliduffey.bsky.social where we compare the atmospheric boundary layer in climate models to 7000 vertical profiles from Soviet ice stations + ~500 from the MOSAiC & SHEBA campaigns. More forays into the world of polar meteorology to come! dx.doi.org/10.1029/2024...

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The scariest plot in the paper is this one. The Arctic is rapidly heading towards a qualitatively different winter atmospheric state, in which strong stability near the surface no longer dominates.

It was great fun collaborating with Robbie and others on this paper. The stability of the winter Arctic atmosphere is a big part of why it is warming so fast in that season, so its important to understand whether the models are doing a reasonable job, and if not, why.

Robbie Mallett@robbiemallett.bsky.social

Paper out today led by @aliduffey.bsky.social where we compare the atmospheric boundary layer in climate models to 7000 vertical profiles from Soviet ice stations + ~500 from the MOSAiC & SHEBA campaigns. More forays into the world of polar meteorology to come! dx.doi.org/10.1029/2024...

This is Vasily Kanaki (left) and Igor Tsigelnitsky preparing a radiosonde at "North Pole 3" station in 1954. One of 1000s of radiosondes that contributed atmospheric profiles to our analysis.

Ali Duffey reposted

Feels like the 1.5C date has been coming towards us faster than we have been going towards it over the last few years

Shannon Osaka@shannonosaka.bsky.social

An underappreciated aspect of the new WMO report -- if the temperature predictions are correct, the world will pass 1.5C in as a long-term average (i.e., the _actual_ Paris goal) in 2027. In just two years. www.washingtonpost.com/climate-envi...