David Keith
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davidkeith.bsky.social
David Keith
@davidkeith.bsky.social

Climate science and technology policy since 1989. Building Climate Systems Engineering at UChicago. Founded Carbon Engineering. Work interferes with my climbing.

Read about me and my work at https://davidkeith.earth/

David W. Keith is a professor in the Department of the Geophysical Sciences at the University of Chicago. He joined the University of Chicago in April 2023. Keith previously served as the Gordon McKay Professor of Applied Physics for Harvard University's Paulson School of Engineering and Applied Sciences (SEAS) and professor of public policy for the Harvard Kennedy School at Harvard University. Early contributions include development of the first atom interferometer and a Fourier-transform spectrometer used by NASA to measure atmospheric temperature and radiation transfer from space. .. more

Environmental science 41%
Engineering 15%

Reposted by Katharine Hayhoe

Daniele Visioni and I explain our concerns about Stardust and the commercialization of climate engineering in Technology Review:
Why the for-profit race into solar geoengineering is bad for science and public trust
Two scientists argue that the growing commercial efforts to counter climate change by reflecting away sunlight will thwart responsible research in the field.
www.technologyreview.com

We did approve the first headline, but we did not approve this one...

Notice how much Ray leans on ad hominem arguments. Calling me a charlatan. So what. It's not about me or Ray.

People typically resort to ad hominem attacks when their factual and ethical arguments are weak.

Ray: you should do better.

Zeke's sweet thread on our op-ed:
I have a new @nytimes.com guest essay w/ @davidkeith.bsky.social about sunlight reflection. We note its not a solution for climate change and at best a band aid to treat systems, and suggest if its ever done it should only be to replace the cooling from air pollution today:
Opinion | A Responsible Way to Cool the Planet
A small, carefully scaled geoengineering program could compensate for the loss of cooling as we eliminate sulfur pollution.
www.nytimes.com

One can imagine this rule is simple enough to be useful in international negotiations over sunlight reflection.

My prior NYT op-ed's on this topic: davidkeith.earth/the..., and www.nytimes.com/2008...
4/4
The New York Times: What’s the Least Bad Way to Cool the Planet? - David Keith
By David Keith How to cool the planet? The energy infrastructure that powers our civilization must be rebuilt, replacing fossil fuels with carbon-free sources such as solar or nuclear. But even then, zeroing out emissions will not cool the planet. This is a direct consequence of the single most important fact about climate change:...
davidkeith.earth

First, it ties use of SRM to clean up of pollution, and since this pollution is mostly from burning fossil fuels, this is roughly equivalent to tying use of SRM to cuts in fossil fuels; and second, it provides a non-arbitrary fixed upper limit on how much SRM can be deployed.
3/4

Zeke and I propose a simple rule: limit use of SRM to maintaining Earth’s reflectivity against the decrease in reflectivity that will continue as pollution is cleaned up.

This rule has two useful consequences.
2/4

Zeke Hausfather and I have an NYT op-ed out today, www.nytimes.com/2025...

Here's my short blog post on the topic: davidkeith.earth/pre...

1/4
Opinion | A Responsible Way to Cool the Planet
A small, carefully scaled geoengineering program could compensate for the loss of cooling as we eliminate sulfur pollution.
www.nytimes.com

I have a new @nytimes.com guest essay w/ @davidkeith.bsky.social about sunlight reflection. We note its not a solution for climate change and at best a band aid to treat systems, and suggest if its ever done it should only be to replace the cooling from air pollution today:
Opinion | A Responsible Way to Cool the Planet
A small, carefully scaled geoengineering program could compensate for the loss of cooling as we eliminate sulfur pollution.
www.nytimes.com
📢 SRM360.org launches 26 Nov! 📢

SRM360 is an independent knowledge hub supporting evidence-based discussion on #SunlightReflectionMethods (SRM). As climate challenges grow, we aim to bridge the gap between complex science and public understanding. #SRM #climatescience

Reposted by David W. Keith

𝗦𝗲𝗻𝗱 𝗶𝗻 𝘆𝗼𝘂𝗿 𝗤𝘀 𝘁𝗼𝗱𝗮𝘆! David & Ed welcome listener questions for EvC guest, 𝘕𝘦𝘸 𝘠𝘰𝘳𝘬 𝘛𝘪𝘮𝘦𝘴 columnist David Wallace-Wells. You can email your questions to [email protected] or just put them in the replies here.
www.energyvsclimate.com/new-york-tim...
New York Times Columnist David Wallace-Wells
Send in your questions today! David & Ed chat with best-selling science writer David Wallace-Wells In lieu of a live webinar, David & Ed welcome listener questions for special guest David Wallace-We...
www.energyvsclimate.com

I am particularly excited about research that explores the risks and uncertainties of hemispherically balanced deployment of stratospheric sulfates, which add cooling at no more than 0.1 degrees per decade for half a century.

Research on sunlight reflection is often driven by large or badly managed deployments.

Ken Caldeira, Cael, and I invite submissions for an AGU session assessing potential harms from limited deployment. agu.confex.com/agu/agu25/pr...

And Holly Buck is a powerful writer on geoengineering. See her book "After Geoengineering." Also, her article "The Rise of Green MAGA" is essential reading for the current political environment: www.compactmag.com/a...

Here's Holly on our pod: www.energyvsclimate....
The Rise of Green MAGA
Geoengineering is “probably as dangerous to us as climate change itself,” Robert F. Kennedy Jr. stated on his podcast last year.
www.compactmag.com

Rose Mutiso is a great rising voice in the climate and energy space, and I recently spoke with her about the energy transition in Africa on my Energy vs Climate podcast: youtu.be/DjOcyXPxaoc...

Rose's Ted Talk on the subject is also a must watch: youtu.be/77HUdJ7Tij0...
Energy Transition in Africa & its Climate Dilemma with Dr. Rose Mutiso
*David & Ed chat with Dr. Rose Mutiso (about the tension between energy, climate, and economic development in Africa and the global south.* They touch on many topics to do with sub-Saharan Africa, including energy production and consumption, electricity and power grids, and the vast economic inequ
youtu.be

The conversation focused on SRM in context, alongside carbon removal, adaptation, and emissions cuts. We need to evaluate how they might work together in our messy world, a topic that's on my mind every day as I write a book that tackles this question.

Enjoyed my time in Cape Town last month for the Degrees Forum 2025. I had the pleasure of joining @hollyjeanbuck.bsky.social and Rose Mutiso for a plenary session on how sunlight reflection methods (SRM) fit into the broader climate response toolbox. #DGF2025 youtu.be/jlUQl6YjIjc...
Fitting SRM into the wider landscape
Holly Buck led a session with Rose Mutiso and David Keith focused on how SRM fits into broader discussions of climate change solutions. The session began with a survey, engaging the audience to explore their own thoughts about SRM in the context of CDR, adaptation, and mitigation. Mutiso noted that
youtu.be