Steve Easterbrook

Director, School of the Environment, University of Toronto. Professor of Computer Science. I study how climate models are built & tested + systems thinking for sustainability. New book, Computing the Climate, order it here: https://www.cambridge.org/9781107589926
He/him

#Climate #Sustainability #Environment #Resilience #STS #Transdisciplinarity #Community #Complexity #SystemsThinking #ClimateJustice #LandBack #Feminism #TransRights #Ecology #Computing #ML #Models #ClimateData
#fedi22

web: http://www.cs.toronto.edu/~sme/
blog: https://www.easterbrook.ca/steve/
prezi: https://prezi.com/user/giav1cdpszww/
Orcid: https://orcid.org/0000-0002-3261-6446

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steve_at_fediscience.org@momostr.pink

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Published at

2026-06-07T08:52:47Z

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Last Notes

2025-12-17 19:53:37 UTC

I'm deeply saddened to learn today that the Trump administration has announced plans to shut down NCAR, one of the world's leading centres for atmospheric research. For those not familiar with NCAR, I've posted an extract about NCAR's work from my book on climate modelling: https://www.easterbrook.ca/steve/2025/12/an-ode-to-ncar/

2025-12-06 22:54:21 UTC

Carney’s pipeline deal contradicts everything he knows about climate change
#ClimateChange #Canada #MarkCarney #Alberta #Oil
https://www.easterbrook.ca/steve/2025/12/carneys-pipeline-deal-contradicts-everything-he-knows-about-climate-change/

2025-04-11 21:26:13 UTC

Trump seeks to end climate research at premier U.S. climate agency
https://www.science.org/content/article/trump-seeks-end-climate-research-premier-u-s-climate-agency

2025-03-28 15:04:23 UTC

Nearly at the end of my course Confronting the Climate Crisis. Looks like most of the students liked my weekly quizzes!
#ClimateChange
https://fediscience.org/system/media_attachments/files/114/240/655/779/692/296/original/f60eab545ede2123.png

2025-02-01 02:43:31 UTC

I'm four weeks into teaching a large introductory course on climate change, and this happens. My work seems more important than ever
https://www.theguardian.com/us-news/2025/jan/31/trump-order-usda-websites-climate-crisis

2025-01-19 20:39:18 UTC

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But this also means net-zero is not an end goal, it's just the first step. When we get to net-zero, we stop further warming. But then we have to start the much harder job of CO2 removal, to cool the planet down again.
#ClimateChange #NetZero

2025-01-19 20:36:04 UTC

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The second question is much harder, but if we take the strict IPCC definition (i.e. natural carbon removal by trees, soils, oceans etc. is all in addition to net-zero), model studies suggest that temperatures would stay roughly where they are, because additional ("owed") warming over the decades it takes to reach a new top-of-the-atmosphere energy balance) would be almost exactly matched by a small cooling effect as natural carbon sequestration starts to remove some of the carbon from the atmosphere.
So nearly everyone got this wrong!
See longer discussion here: http://www.easterbrook.ca/steve/2013/02/how-big-is-the-climate-change-deficit/
#ClimateChange

2025-01-19 20:28:08 UTC

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Okay, poll has ended, and most people got the first question right, despite the fact that nearly every discussion I see about net-zero policy gets it wrong.
The key point is whether you can count natural (i.e. non-anthropogenic) carbon sequestration as an offset in your net-zero goals. The IPCC definition rules this out, so no free ride: all anthropogenic emissions must be offset by anthropogenic removal. Except they define it just in terms of CO2 and ignore other greenhouse gases.

2025-01-18 18:42:21 UTC

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And of course, the obvious follow up #ClimateChange question:
When we reach the global net-zero target, what do the climate models tell us will happen to global average surface temperatures?
Global average surface temperatures will...

2025-01-18 15:55:43 UTC

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Darn, Fedi limits me to four responses, and not many characters per option.
For my students, I'm including some more possible answers:
* All greenhouse gases are banned
* All greenhouse gases have been removed from the atmosphere
* The carbon cycle is in balance: annual carbon emissions match annual carbon removal (same as one of the answers above, but I'll use this phrasing in my course)

2025-01-18 15:51:53 UTC

Another quiz question for my course. Both Google and ChatGPT get this wrong:
What does net-zero mean, according to the UN's Intergovernmental Panel on Climate Change (IPCC)?
#ClimateChange #TestYourKnowledge

2025-01-15 15:26:25 UTC

"I’m a climate scientist and my house in LA burned down. My work has never been more real"
#ClimateChange #Wildfire #LosAngeles
https://www.theguardian.com/commentisfree/2025/jan/15/la-california-fires-climate-science

2025-01-13 02:05:59 UTC

Great news - my student Harshit Gujral had his paper accepted in Environmental Research. Basically, the work is the first to show a there is now a measurable reduction in incidence of childhood asthma in US States that have implemented a Zero-Emissions vehicle mandate.
Here's the pre-print (prior to revision): https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4935175

2025-01-04 20:51:29 UTC

Thoughtful assessment from Gavin Schmidt at NASA on recent progress using AI to help with weather forecasts, and whether this will lead to improvements in climate projection https://www.realclimate.org/index.php/archives/2024/12/ai-caramba/
#WeatherForecasts #ClimateChange

2025-01-02 22:19:48 UTC

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Interesting results! Freon and Water Vapour are greenhouse gases. Neon and Nitrogen are not.
Freon is banned in all 197 UN countries under the Montreal protocol for its damaging effect on the ozone layer. But it's also a GHG! (see, we can ban them when we want to!)
Water vapour is an important GHG because it causes a feedback effect: warmer atmosphere (from other GHGs) can hold more moisture, causing more warming. But it's not a GHG that we can control directly.
#ClimateChange #GreenhouseGases

2025-01-01 22:09:52 UTC

In a week's time, I'll be launching my new first year undergraduate course, ENV101 Confronting the Climate Crisis, so I'm busy making up quiz questions. Try this one...
#ClimateChange #GreenhouseGases
Which of the following are greenhouse gases:

2024-12-31 16:40:56 UTC

Great news for New Years. My daughter, who has lost a year of her life to #LongCovid, has been accepted in this new drug trial, Reclaim. For her, it’s the first piece of good news in a horrible year. If you know someone else suffering with Long Covid, share the study - they’re recruiting participants. https://www.reclaimtrial.ca/

2024-12-29 15:31:54 UTC

New #TieDye just dropped. For this one, I got to use my new wax sinew to create the white lines, and a new dye called Alchemist from Dharma Dyes, designed to give great colour splits.
https://fediscience.org/system/media_attachments/files/113/736/812/630/976/847/original/7342cfffdcb7f03a.jpeg

2024-12-20 13:19:55 UTC

Impact of sea level rise in #Belize. This island resort no longer has a beach, and has had to build a sea wall to prevent further loss of land. From what I understand of coastal erosion, that will probably just accelerate the erosion. The entire island is no more than a few feet above sea level. #ClimateChange #SeaLevelRise
https://fediscience.org/system/media_attachments/files/113/685/315/833/648/967/original/eb3adc085ba6f916.jpeg

2024-12-18 13:27:02 UTC

Today’s bird is a female Magnificent Frigatebird (yes, that’s its official name). There’s a whole flock of them here, who spend their time soaring on the wind, typically holding their position in the sky, waiting for other seabirds to catch fish so they can then harass them and steal the food in midair. They look like pterodactyls when flying. #Belize #Birds #BirdsOfMastodon
https://fediscience.org/system/media_attachments/files/113/674/024/679/433/105/original/7c47d92c30e463df.jpeg

2024-11-28 00:16:10 UTC

Musk and his legions of fanboys are cyberbullying four senior US civil servants working on climate change.
Not stated explicitly in the article, but obvious to anyone paying attention: They're all women.
This is outrageous and disgusting, and there's not a damn thing we can do about it.
https://www.cnn.com/2024/11/27/business/elon-musk-government-employees-targets/index.html
#ClimateChange #USPoli

2024-11-14 22:04:27 UTC

Great paper from a few years ago: "Around the Anthropocene in eighty names"
Catalogues a long list of alternative terms that have been proposed to describe this era, from Agnotocene (the era of ignorance) to Trumpocene (no comment).
https://www.mdpi.com/2071-1050/12/11/4458
#Anthropocene

2024-11-13 19:48:36 UTC

Study finds link between London's low emissions Zone and children's test results at school.
https://www.standard.co.uk/news/london/low-emission-zone-london-school-test-scores-lse-pollution-cognition-b1175236.html
#ClimateChange #AirPollution #Health

2024-11-08 22:11:27 UTC

I’ve never understood the point of academic talks where the presenter just reads a paper. If I just read the paper in my own time, I would likely get a lot from it. When I have to listen to the author read it, I probably hear no more than 20% of it. My mind just drifts. Is that just me, or does this happen to everyone?
[I suspect the people who narrate audiobooks have a very rare skill]

2024-10-24 02:47:48 UTC

For the past 30 years, I've been an immigrant, first in the US and then in Canada. I still have a strong foreign accent.
I've never been told to go home.
Nobody ever describes me as an immigrant.
You guessed it: white skin, British accent.
Fuck this racist shit.

2024-10-21 01:43:21 UTC

Happy to say that we now have some clear guidelines on refusing funding from and partnerships with fossil fuel companies at the School of the Environment. Hope others can adopt the same principles! https://www.theguardian.com/us-news/2024/oct/20/university-toronto-financially-dissociate-fossil-fuels
#ClimateChange #FossilFuels #Divestment #Dissociation

2024-10-07 11:43:33 UTC

I put together a list of the best books on how climate scientists discovered the threat of global warming, and how their work has been attacked over the years by climate deniers.
Please share widely, especially if you have skeptical friends and family members:
https://shepherd.com/best-books/how-scientists-discovered-global-warming-threat
#ClimateChange #ReadingList #Science

2024-10-03 01:49:02 UTC

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I will leave you with this diagram which summarizes a long list of potential therapies that are being explored. I'm not familiar with many of the terms in this diagram, so it's going to take me a while to figure them all out.
TL;DR: It's serious, it's messy, and we still don't really know how to help people suffering from it.
6/n
https://fediscience.org/system/media_attachments/files/113/240/965/733/817/715/original/5a4b1acb56011442.jpeg

2024-10-03 01:43:22 UTC

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...and when we're talking about irreversible tissue damage, that could include almost any tissue:
- lungs
- pancreas (leading to post-COVID diabetes)
- blood vessels (leading to blood clots blocking arteries, stroke, lack of oxygen to other tissues etc)
- brain and nervous system (e.g. brain fog, memory loss, cognitive disfunction, loss of sensory signals)
- gut functioning (and disruption of the gut-brain axis, leading to abnormal stress responses, etc)
5/n

2024-10-03 01:28:08 UTC

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I found this part the most interesting/worrying:
"The most efficient explanation for long COVID is direct virus-mediated damage of tissues that was initiated during the preceding infection and lingers well beyond the acute phase."
and
"If irreversible tissue damage and dysfunction are really the cause of long COVID, then treatment of established disease will rely upon supportive care, symptom management, and non-pharmacologic therapy to improve function."
4/n

2024-10-03 01:26:12 UTC

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Lots of potential therapeutic targets have been identified but clinical trials have been slow to get going.
Study of #LongCovid therapies is hard because there is not yet a reliable bio-marker, so studies are reliant on patient reported outcomes (surveys of how people feel and function).
Many patients presenting with Long Covid have no reliable documentation of the initial infection.
There are currently no treatments for Long Covid approved by the US FDA.
3/n

2024-10-03 01:17:38 UTC

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Causes of #LongCovid are complex and inter-related (see figure).
Current research is exploring potential therapies for each of the causal mechanisms:
- acute initial Covid infection
- persistence of the virus
- post-acute inflammation
- autoimmunity responses
- thrombosis and micro clots
- latent virus reactivation
- changes in gut microbiome
- dysfunction of cell mitochondria
2/n
https://fediscience.org/system/media_attachments/files/113/240/828/473/716/726/original/9268a32aecc747fa.jpeg

2024-10-03 01:10:35 UTC

Here's a new review paper of everything we know about #LongCovid
Some take aways:
- an estimated 65 million people worldwide currently experiencing it
- Prevalence between 5% and 10% in some countries
- Few reliable estimates of the number suffering the most serious, disabling form, but likely over 4 million in the US alone.
- more common in women and older people
- best way to prevent it is to prevent the initial infection
https://www.sciencedirect.com/science/article/pii/S0092867424008869
1/n

2024-09-13 13:27:56 UTC

I now typically get half a dozen emails *every day* from predatory journals and conferences, inviting me to send my paper / give a keynote talk. Many of them greet me using a name of one of my past co-authors.
Anyone know how to make this stop?
I wonder if I could dump them all by filtering on the word "esteemed"?
#AcademicProblems

2024-08-03 15:13:02 UTC

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So I’ve learned a lot about dealing with a hidden disability. Nobody notices your disability unless you tell them, which is usually socially awkward.
Then they’ll make all sorts of wrong assumptions about it.
Some then make a fuss over it, which can be even more embarrassing.
Some get more embarrassed themselves as if it’s their fault I can’t hear them.
I understand these reactions - they’re meant well.
But they don’t help.
It’s best just to ask me if I need any accommodations.
5/n

2024-08-03 14:57:35 UTC

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The first conference I went to after my hearing loss, I signed up for the banquet, and sat with a group of people whose work I really wanted to hear about. There was a live band playing throughout the meal. I couldn’t even hear the person next to me who was talking into my good ear. And I couldn’t explain why I was being so antisocial.
I left halfway through and walked back to my hotel in tears.
Ironically I’d been to a panel session earlier that day about making the field more accessible…
4/n

2024-08-03 14:55:33 UTC

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It’s hard to find quiet restaurants, although I’ve discovered if you eat earlier in the evening it tends to be quieter. But why do they all need background music? Most wont even turn it down when I ask.
Academic conferences are particularly hard. The talks are fine. The rest is not. For me, the value of a conference is in the informal conversations in coffee breaks, and over lunch or dinner. I can’t do that now.
3/n

2024-08-03 14:03:12 UTC

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What’s it like to suddenly lose hearing in one ear, you ask? The other ear works fine, right?
First, it’s a hidden disability. Nobody notices, unless I tell them, which can feel awkward and embarrassing. Took me a long time to get over that.
With only one ear, I’ve lost all ability to detect where sound is coming from.
That means I can’t filter out background noise. I can have a perfectly normal conversation in a quiet environment. But if there’s background noise it gets hard rapidly. 1/n

2024-08-02 02:26:11 UTC

Two years ago, I experienced Sudden Sensorineural Hearing Loss (SSNHL), and am now almost completely deaf in one ear. This year, one of my colleagues had the same thing. Now I see there's a study out showing a strong correlation between COVID and SSNHL.
I guess that explains a lot. But, shit.
BTW If you find you suddenly lose hearing in one ear, get yourself to a specialist *immediately*. You have a 24-36 hour window to save your hearing before it becomes permanent.
https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(24)00338-9/fulltext

2022-11-15 19:34:11 UTC

A fuller #introduction.
My PhD was in software systems analysis: how to handle poorly understood, conflicting system requirements (#RequirementsEngineering)
This led me to explore socio-cognitive processes of large teams (#DistributedCognition, #STS, #Ethnography)
I have worked for NASA studying software safety for spacecraft (#FormalVerification, #OrganizationalBehaviour)
Now I study #ClimateModels + do #ClimateData analytics, using all the above, plus #SystemsThinking, #DataScience, & #ML