David Keith

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:

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:...

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...
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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.
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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.
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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.

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...


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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...

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.

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....

*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 Energy Transition in Africa & its Climate Dilemma with Dr. Rose Mutiso

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...

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.

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 Fitting SRM into the wider landscape

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...

The Globe and Mail: Solar geoengineering – Science fiction – or saviour? - David Keith At the time of this post, David Keith was a professor in Harvard's Schools of Engineering and of Public Policy, and founder at Carbon Engineering. Edward Parson is professor and co-director of the Emmett Institute on Climate Change and the Environment at UCLA, and senior research associate at the Centre for Global Studies,...

Canada can’t just sit on the sidelines regarding SRM research and governance. Ignoring SRM means others will make the decisions. Here’s an old op-ed Ted Parson and I wrote for the Globe & Mail that makes this point:

davidkeith.earth/the... (not our headline)

Why it’s time to explore the potential impacts of Solar Radiation Modification The impacts from climate change will continue to escalate in the years ahead, and a growing number of scientists, philanthropies and companies have become interested in strategies to lower global temperatures more quickly. One of the options is reflecting some sunlight back into space.   Because

Lisa Dilling leads SRM research at the Environmental Defense Fund and has written about the need to explore the potential impacts of SRM before any sort of deployment is considered:

blogs.edf.org/climat...

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.

Can We Afford to Ignore Solar Geoengineering? Should Canada act now to build its SRM research capacity and leadership? How can we foster the local expertise and international partnerships we’ll need to control the technology should solar geoengineering become a reality?

Can Canada afford to ignore sunlight reflection methods (SRM)? I'm joining @ldilling.bsky.social from the @envdefensefund.bsky.social for a discussion hosted by the Transition Accelerator, a major Canadian NGO focused on the climate. June 10, 12pm ET.

Join the Live Q&A: transitionaccelerato...

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...

You're Invited: Has the World Surrendered to Climate Breakdown? Andreas Malm, author of "How to Blow Up a Pipeline," on EvC May 23 at 10AM ET "The climate crisis calls not for moderation, but for militant action." - Andreas Malm Join us for a live recording of Energy vs Climate with special guest Andreas Malm, author of How the World Surrendered to Climate Breakdown and How to Blow Up a Pipeline: Learning to Fight in a

I appreciate the way Andreas has made a careful case for strong actions such as civil disobedience to protect humans and nature. Looking fwd having Andreas join us on Energy vs Climate this morning. (Feel free to join us live)

www.energyvsclimate....

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.

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.

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.

Why Global “Moratorium” on SRM Deployment Should Get a Chilly Reception A bottom-up norm-setting approach would rectify the concerns of agreeing to a global moratorium on solar radiation management deployment.

Smart argument against a moratorium for deployment of sunlight reflection SRM from Sue Biniaz (former top US climate negotiator) and @bodansk.bsky.social (environmental lawyer).

www.justsecurity.org...

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

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/...

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.

Will Trump inadvertently increase the chance of a 2025 peak by slowing the economy?

That is a nice plot, I missed this in the annual report. Helpful.

Analysis: Clean energy just put China’s CO2 emissions into reverse for first time - Carbon Brief For the first time, the growth in China’s clean power generation has caused the nation’s carbon dioxide (CO2) emissions to fall despite rapid power demand growth.

Thanks, Glen -- I give a **lot** of weight to your analysis.

Agreed that we will not know when the peak happens until a few years after it's passed.

What do you make of the new @carbonbrief.org analysis showing a China decline?

www.carbonbrief.org/analysis-cle...

Planetary Aerosol Geoengineering Research Illuminates Earthbound Climate Engineering For decades, insights from planetary aerosol research have pollinated geoscience research with ideas that carry significant societal relevance. Examples include how data from Mars dust storms helped inspire nuclear winter modeling—impacting Cold War arms control discussions—and how understanding the mechanisms linking asteroid impacts to mass extinctions motivated NASA’s successful Double Asteroid Redirection Test. Still, much Read more...

Our UChicago program is supporting Edwin Kite's research on sunlight reflection that explores analogs between geoengineering on Earth and terraforming on Mars.
climateengineering.u...

But I'm not opposed people thinking about it, and I'm impressed by the arguments and authors who just published a case for Mars terraforming research.

Article link: www.nature.com/artic...
Open access version: sseh.uchicago.edu/do...