David Keith
@davidkeith.bsky.social
3.4K followers 130 following 160 posts
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/
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davidkeith.bsky.social
We did approve the first headline, but we did not approve this one...
davidkeith.bsky.social
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.
davidkeith.bsky.social
Zeke's sweet thread on our op-ed:
hausfath.bsky.social
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
davidkeith.bsky.social
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
davidkeith.bsky.social
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
davidkeith.bsky.social
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.
davidkeith.bsky.social
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...
davidkeith.bsky.social
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
davidkeith.bsky.social
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.
davidkeith.bsky.social
This conversation grew out of meetings that several Canadian SRM leaders, including Ted Parson and Doug MacMartin, had with Canadian government officials and NGOs about a possible SRM research program in Canada.
davidkeith.bsky.social
Superb op-ed from Steven Pinker (@sapinker on X) calling out the right's absurd Harvard Derangement Syndrome.

Harvard has some woke, but its peak has passed, and claims of many on the right are disconnected from the reality I saw as a faculty member.

www.nytimes.com/2025...
davidkeith.bsky.social
See, the concluding section of the article, "If not a negotiated moratorium, then what?” for practical thinking on how governance can move forward without halting research progress.
davidkeith.bsky.social
States can begin research programs while making it clear that deployment is premature. This allows for bottom-up norm setting and transparency without the risks of a negotiated moratorium.
davidkeith.bsky.social
Many people, including (sometimes) me, have argued that a moratorium could provide a safe space under which research can flourish. But a moratorium would not magically create research. And as Sue and Dan point out, there are many ways in which a moratorium might inhibit research.
davidkeith.bsky.social
New high-quality survey on public attitudes toward sunlight reflection in Great Britain:

16% support SAI deployment.
46% are unsure.
Younger people are more supportive overall.

Interesting signals on awareness and openness to geoengineering in general.
yougov.co.uk/health/...
Dimming the sun; brightening clouds; planting forests: would Britons support geoengineering to combat climate change? | YouGov
Most Britons say a drastic change in the steps taken to combat climate change is needed in order to avert its worst effects
yougov.co.uk
davidkeith.bsky.social
What's your basis for confidence that the modelers are wrong?

Economic or energy forecast half a century in the future are near meaningless, but near term forecasts have predictive power.

Of course, it's a long way to zero, but an emissions peak is not insignificant.