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Ken Caldeira

@kencaldeira.com
20K followers 4.1K following 2.3K posts

Mostly mentoring a group of postdocs. Conceptual Investigations Unit, housed at Stanford. Senior Scientist at Gates Ventures. climate / energy / etc ciunit.org Posts imperfectly represent the views of my former self and not my employer.

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Ken Caldeira @kencaldeira.com · 01/10/2026
I have allowed the internet to damage my ability to concentrate on prose that does not constantly send dopamine into my brain. I need to rebuild my attachment to long form prose.
Painting by Lubaina Himid shown at the 2026 Venice Biennale.
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Ken Caldeira @kencaldeira.com · 23/09/2026
The underlying paper finds that unfamiliar languages sound equally pleasant to within a couple of percentage points. www.pnas.org/doi/10.1073/...
However, once we have accounted for familiarity and preferences for specific voice types, the scores of all unfamiliar languages varied within just a few percentage points. The 228 world languages that we tested, with all their phonetic and prosodic diversity, thus sounded comparably attractive to the average listener in our sample as long as they were not familiar.
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Ken Caldeira @kencaldeira.com · 17/09/2026
I of course block the sender. Here is typical of my situation. 3 in 3 hours. I have donated to candidates but never in response to an SMS solicitation.
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Ken Caldeira @kencaldeira.com · 14/09/2026
The people who placed people in these cages should be put in prison. The same goes for the people who approved construction of these cages, authorized payments, etc. The detainees were accused of civil violations only. They were not accused of any crime. Only criminals treat people this way.
Images released in a report by the Department of Homeland Security’s inspector general’s office show small metal enclosures that were referred to as “calming areas.”Credit...U.S. Department of Homeland Security, Office of the Inspector General

https://www.nytimes.com/2026/09/14/us/alligator-alcatraz-dhs-inspector-general.html
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Ken Caldeira @kencaldeira.com · 12/09/2026
Kings in ancient Mesopotamia made statements to the effect that a central role of government is to protect the less powerful against abuse by the more powerful. We have lost that understanding of government. Urukagina (Uruinimgina), 2350 BCE. Ur-Nammu, 2100 BCE. Hammarubi, 1750 BCE.
In the prologue, Hammurabi claims to have been granted his rule by the gods "to prevent the strong from oppressing the weak".

https://en.wikipedia.org/wiki/Code_of_Hammurabi
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Ken Caldeira @kencaldeira.com · 09/09/2026
California looks much better in the daytime when the solar is active.
https://app.electricitymaps.com/map/live/fifteen_minutes
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Ken Caldeira @kencaldeira.com · 09/09/2026
Cool map of real time carbon intensity of electricity use. (Unknown why they chose Mercator projection as the default map.) Not sure of the value added by near-real time values, but it is fun and cool. app.electricitymaps.com/map/live/fif...
Map of carbon intensity of electricity use showing high carbon intensity in parts of the western US, Mongolia, etc, and low use in France, the nordic countries, etc.  

https://app.electricitymaps.com/map/live/fifteen_minutes
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Ken Caldeira @kencaldeira.com · 04/09/2026
Satire meets reality. www.theguardian.com/us-news/live...
https://en.wikipedia.org/wiki/Cheeseface
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Ken Caldeira @kencaldeira.com · 31/08/2026
How much of the opposition to new large AI data center derives from insecurity about losing access to well-paying meaningful work? My understanding is that data centers have lower carbon-emissions per unit GDP than the economy as a whole. Of course, they should not use the sky as a CO2 waste dump.
Jenny Kane, Associated Press file
An Amazon Web Services data center is seen on Aug. 22, 2024, in Boardman, Ore.
https://thehill.com/opinion/energy-environment/5420210-data-centers-power-demand-ai/
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Ken Caldeira @kencaldeira.com · 31/08/2026
If Trump really wanted to make America great again, a good place to start would have been restoring marginal income tax rates on top earners to what they were before Reagan started handing our country over to the super wealthy. www.forbes.com/sites/niallm...
Chart showing highest marginal tax rate reached 92% in 1942, was about 90% to 1963 and exceed 69% before Reagan.
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Ken Caldeira @kencaldeira.com · 30/08/2026
When government databases are wrong, enterprises who make a business model of information provision should provide you with correct information. Donald Trump is not Humpty Dumpty.
“When I use a word,’ Humpty Dumpty said in rather a scornful tone, ‘it means just what I choose it to mean — neither more nor less.’

’The question is,’ said Alice, ‘whether you can make words mean so many different things.’

’The question is,’ said Humpty Dumpty, ‘which is to be master — that’s all.”
― Lewis Carroll, Through the Looking Glass

Illustration by John Tenniel

https://boffosocko.com/2011/08/16/meaning-according-to-humpty-dumpty/
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Ken Caldeira @kencaldeira.com · 30/08/2026
Google is disgusting.
Google map showing Lake America.Google map showing Gulf of America.
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Ken Caldeira @kencaldeira.com · 27/08/2026
"Near-term benefits from investment in climate adaptation complement long-term economic returns from emissions reduction" ciunit.org/publications...
A, B show discounted abatement cost and avoided climate damage for cases considering only abatement (Only-Abate) relative to the no-policy case; C, D show abatement plus adaptation cost and avoided climate damage for cases that consider both strategies (Abate-Adapt); E and F show the impact of adaptation represented as the difference between Abate-Adapt and Only-Abate. The Prescribed-emissions scenario (A, C, and E) where annual carbon emissions are prescribed and linearly decrease to zero in 50 years, and the Balancing scenario (B, D, and F) where all decision variables are optimized are compared.

https://www.nature.com/articles/s43247-024-01976-6
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Ken Caldeira @kencaldeira.com · 25/08/2026
"This paper explores how immigration policy affects residential construction and home prices. [W]e show that increased immigration enforcement reduces homebuilding and drives up new construction prices." papers.ssrn.com/sol3/papers....
6. Conclusion
We document that immigration policy has important first-order supply-side impacts on homebuilding and home prices. Increasing immigration enforcement leads to: (i) reductions in residential construction, (ii) increases in the price of new construction, (iii) little overall impact on existing stock house prices, but meaningful underlying variation by a given tract’s share of undocumented residents.
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Ken Caldeira @kencaldeira.com · 24/08/2026
This heating of relatively warm air and cooling of relatively cool air creates density contrasts that create horizontal pressure gradients. These horizontal pressure gradients drive global winds. APE and APE generation decrease ~10% in a high CO2 world. (2/2) journals.ametsoc.org/view/journal...
Globally averaged values for dry APE and dry APE generation G in a 4 × CO2 climate.

Under a 4xCO2 climate APE decreases from 5.42 to 5.04 x 10^6 J/m2, and APE generation (G) decreases from 3.56 to 3.20 W/m2.

https://journals.ametsoc.org/view/journals/clim/30/6/jcli-d-15-0614.1.xml
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Ken Caldeira @kencaldeira.com · 24/08/2026
Where does the atmosphere get the potential energy available to drive winds? Condensation of water vapor above the western tropical Pacific heats relatively warm air, and radiation to space cools relatively cold air near the poles. (1/2) ciunit.org/publications...
Where the energy that drives the winds is generated. Two sources dominate — latent heat release in the tropics, especially over the western tropical Pacific, and radiative cooling in the polar regions.
Figure 3 from Ahbe and Caldeira (2017), Journal of Climate 30, 2089-2101.

https://journals.ametsoc.org/view/journals/clim/30/6/jcli-d-15-0614.1.xml
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Ken Caldeira @kencaldeira.com · 23/08/2026
They apparently don't remember mad cow disease. Or maybe they just don't care, because they will not get their food through the same supply chain as the hoi polloi.
Poster about mad cow disease from https://www.sfchronicle.com/health/article/Mad-Cows-and-Panicked-People-U-S-Anxiety-2957888.php
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Ken Caldeira @kencaldeira.com · 22/08/2026
Some positive climate news. Work that Ian McKay and I did 5 years ago is coming to fruition. We helped create contrails.org and they and others have succeeded in generating some real movement on contrail avoidance -- a major test over the North Atlantic. www.nature.com/articles/d41...
CORRESPONDENCE
18 May 2021

Contrails: tweaking flight altitude could be a climate win

By Ken Caldeira & Ian McKay

By our calculation, preventing most of the damaging impact of aircraft vapour trails (contrails) on climate would cost less than US$1 billion per year and the net value of the benefit could be more than 1,000 times that. We know of no comparable climate investment with a similarly high likelihood of success.

Contrails account for roughly 2% of global warming because they cause cirrus clouds to trap outgoing infrared radiation. The flights responsible are typically within 1,000 metres of trajectories that are much less damaging to the atmosphere, so planes routed to higher or lower altitudes would burn less than 0.1% more fuel (R. Teoh et al. Environ. Sci. Technol. 54, 2941–2950; 2020).

The warming effect of the extra emissions is likely to be more than offset by the reduction in vapour-trail formation (see B. Kärcher Nature Commun. 9, 1824; 2018). Furthermore, any drop in altitude would be insufficient to affect health costs from particulate matter and noise on the ground.

Addressing climate change could cost as much as US$100 trillion (D. P. van Vuuren et al. Nature Clim. Change 10, 329–334; 2020). Abating even 1% of this cheaply could therefore represent a trillion-dollar economic opportunity.

Nature 593, 341 (2021)

doi: https://doi.org/10.1038/d41586-021-01339-7
https://www.nature.com/articles/d41586-021-01339-7
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Ken Caldeira @kencaldeira.com · 20/08/2026
If you told someone you invented a new transportation system but it would kill more than 40,000 Americans each year, they would look at you like you were crazy. A stark example of status quo bias. Cars and guns. Automobile deaths and mass murder. It doesn't have to be this way.
Chart showing that automobile deaths in the US have hovererd around 40,000 to 50,000 deaths per year since 1960.

https://en.wikipedia.org/wiki/Motor_vehicle_fatality_rate_in_U.S._by_year
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Ken Caldeira @kencaldeira.com · 19/08/2026
We have a new web page up with links to our corpus of work. ciunit.org/publications...
Improving human welfare
Conceptual Investigations Unit
The Conceptual Investigations Unit is a research consortium, coordinated by Ken Caldeira, developing information and conceptual frameworks that can broadly contribute to improving human welfare while protecting natural ecosystems.

We perform quantitative calculations to reach qualitative conclusions.

https://ciunit.org/index.html
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Ken Caldeira @kencaldeira.com · 09/08/2026
At first, I thought this was put out by El-Sayed to make the point that even Trump's spouse doesn't want to get close to him but El-Sayed's spouse does want to be with him. www.amazon.com/Systems-Scie... www.amazon.com/Healing-Poli... www.amazon.com/Medicare-All...
Abdulrahman Mohamed El-Sayed (born October 31, 1984) is an American politician and epidemiologist who is the Democratic nominee in the 2026 United States Senate election in Michigan.[1] From 2023 to 2025, he was the director of the Department of Health, Human, and Veterans Services of Wayne County.

El-Sayed is a graduate of the University of Michigan and Oriel College, Oxford, attending them on a full-tuition scholarship and a Rhodes Scholarship, respectively. He received his Doctor of Medicine from Columbia University. El-Sayed was an assistant professor of epidemiology at Columbia University from 2014 to 2015. He was the executive director of the Detroit Health Department and Health Officer for the City of Detroit from 2015 to 2017. His publications in public health include three books and several academic journal articles.

A progressive Democrat, El-Sayed supports regulated capitalism, Medicare for All, enforcing an arms embargo on Israel, and abolishing ICE. He ran for governor in 2018, placing second to Gretchen Whitmer in the Democratic primary.

https://en.wikipedia.org/wiki/Abdul_El-Sayed
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Ken Caldeira @kencaldeira.com · 09/08/2026
The New York Times didn't even mention that Capital One Financial closed hundreds of Trump-related accounts because of evidence of money laundering. Disgusting. www.reuters.com/legal/govern...
Search on Capital One Financial in the New York Times turns up nothing about money laundering .
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Ken Caldeira @kencaldeira.com · 08/08/2026
Row of pomegranate trees/bushes.
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Ken Caldeira @kencaldeira.com · 08/08/2026
When we lived in Livermore, CA, which has a hot sunny climate, we had dozens of pomegranates on each "tree" which we had growing together more like a row of bushes. Doesn't grow well at all on the other side of SF Bay, where it is not as hot and dry in summer.
Pomegranates can be grown in mild-temperate to tropical climates. However, the best quality pomegranate fruit are produced in regions with cool winters and hot, dry summers (Mediterranean climate).

https://ask.ifas.ufl.edu/publication/MG056Pomegranates grow best under the following conditions:

Hot and dry summers
Mild winters
Full sunlight exposure
Low to moderate humidity
Well-drained soil
Temperature range between 25°C and 38°C

https://www.iran-fruit.com/fruits/40-pomegranate/127-suitable-climate-condition-for-pomegranate-growth.html/
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Ken Caldeira @kencaldeira.com · 03/08/2026
When I was a kid, they used to talk about how this is what life was like in the Soviet Union. There used to be something that people called "a right to privacy". Seems quaint and old-fashioned now. www.rwcpulse.com/redwood-city...
Flock Safety, the surveillance technology company behind the street camera system that tracks vehicles, acknowledged in March that some plate reader networks across the state were “inadvertently accessible” to out-of-state agencies, which, in many cases, violated state law regulating data-sharing. 

https://www.rwcpulse.com/redwood-city/2026/08/01/redwood-city-seeks-license-plate-reader-proposals-amid-renewed-public-opposition/
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Ken Caldeira @kencaldeira.com · 03/08/2026
When resources are limited, it is likely that vaccines, etc, have higher ROI in terms of NPV of human welfare. However, it is a little like the trolly problem, where there is an intuition that we may want to limit the deaths we are responsible for more than we want to limit total deaths. 2/2
https://en.wikipedia.org/wiki/Trolley_problem

The trolley problem is a thought experiment in moral philosophy and moral psychology with many variations, involving hypothetical ethical dilemmas about whether to sacrifice one person to save a larger number of people. The series usually begins with a scenario in which a runaway trolley (tram) or train is on course to collide with and kill a number of people (traditionally five) tied to the tracks, but a driver or bystander can intervene and divert the vehicle to kill just one person on a different track.
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Ken Caldeira @kencaldeira.com · 03/08/2026
Much of the motivation for reducing greenhouse gas emissions comes not from cost-benefit optimization, but from the understanding that we are doing something that harms others and that we therefore have a responsibility to stop doing that. 1/2
Photo out of an airplane window on the way to Heathrow, with some land, clouds, and sky.
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Ken Caldeira @kencaldeira.com · 26/07/2026
Does anyone have informed perspectives on this paper? Seems important if true, important to refute if false. "Our results provide the first observational evidence that low clouds have partially offset recent warming, ... " agupubs.onlinelibrary.wiley.com/doi/10.1029/...
In this study, we combined satellite observations, reanalysis data sets, and a cloud-controlling factor (CCF) framework to quantify historical low-cloud cover (LCC) variability and its associated feedbacks. By harmonizing 13 long-term satellite data sets using anomalies and extending the record back to 1979 using CCF-based reconstructions, we constructed a physically grounded and temporally consistent record of LCC variability. The CCF method reproduces observed LCC anomalies well (𝑟 =0.85
 for 1982–2024; 𝑟 =0.93
 for 2001–2020), lending confidence to both the reconstructed record and the associated historical trends.

Across all data sets, tropical ocean LCC increased robustly since 1979 at a rate of 0.18 ±0.07%
 per decade over 1979–2025, concurrent with approximately 1,K
 of global surface warming (0.21 ±0.03%
 per decade). When normalized by the temperature trend, this corresponds to 0.85 ±0.32%,K−1
, with stratocumulus regions accounting for nearly 90%
 of the signal. Using observed 𝑑⁢𝐶⁢𝑅⁢𝐸/𝑑⁢𝐿⁢𝐶⁢𝐶
 relationships, this translates into a strongly negative low-cloud feedback of −0.79 ±0.3,W,m−2,K−1
, in contrast to the positive feedback observationally inferred from idealized abrupt-4×CO2
 experiments (0.50 W m−2 K−1
 in this study and 0.42 −0.56 W m−2 K−1
 in Cesana and Del Genio (2021); Myers et al. (2021)).

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2026GL124158
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Ken Caldeira @kencaldeira.com · 24/07/2026
If the main barrier to implementing good policy is not an information deficit, but rather that individual incentives are not aligned with global well-being, what are appropriate roles for academic researchers? How can information provision help to align individual incentives with global well-being?
Maurizio Cattelan

SKY 2025

Glass, cork, and metal handcuffs
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Ken Caldeira @kencaldeira.com · 23/07/2026
This is a little niche, but here is a chart of the ranking points of the top-ranking WTA tennis player over the past decade.
Line chart of WTA world No. 1 ranking points from August 2016 to July 2026, with shaded background bands indicating which player held the No. 1 ranking. Points ranged from about 6,000 to 12,400. The series was generally lower from 2017 to 2019, rose during Ashleigh Barty’s tenure, and reached its highest level during Aryna Sabalenka’s tenure in July 2025. The latest value, for Aryna Sabalenka on July 20, 2026, is 8,550 points, slightly below the 10-year median of 8,717. No. 1 players shown include Serena Williams, Angelique Kerber, Karolina Pliskova, Garbiñe Muguruza, Simona Halep, Caroline Wozniacki, Naomi Osaka, Ashleigh Barty, Iga Świątek, and Aryna Sabalenka.

Made with the help of ChatGTP. May contain errors.
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Ken Caldeira @kencaldeira.com · 22/07/2026
https://commons.wikimedia.org/wiki/File:African_slave_ship_diagram.jpg

African slave ship diagram.jpg
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Ken Caldeira @kencaldeira.com · 20/07/2026
Sometimes too much is made of Arrow's Impossibility Theorem. If a Condorcet (pairwise ranked choice) voting system results in a unique winner, which in practice it usually does, then all of Arrow's criteria are satisfied. It is only the tie-break procedure that violates Arrow's criteria. 1/2
https://commons.wikimedia.org/wiki/Marquis_de_Condorcet#/media/File:Marquis_de_Condorcet.jpg

Marie Jean Antoine Nicolas Caritat, marquis de Condorcet (1743-1794), French philosopher, mathematician, and political scientist.
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Ken Caldeira @kencaldeira.com · 17/07/2026
Are you studying effects of an AMOC slowdown, what might happen if it slows down, or what we might do about it? If so, please submit an abstract to our session at the 2026 Fall AGU Meeting in San Francisco. agu.confex.com/agu/agu26/pr... #AMOC #climate #AGU @mahendran9990.bsky.social
https://agu.confex.com/agu/agu26/prelim.cgi/Session/280234

GC016

ATLANTIC MERIDIONAL OVERTURNING CIRCULATION (AMOC) SLOWDOWN/SHUTDOWN:
LIKELIHOOD, CONSEQUENCES, RESPONSE OPTIONS
CRITICAL QUESTIONS WE MUST ADDRESS TOGETHER
How much risk is posed by AMOC slowdown or shutdown?
What could we do to reduce that risk?
CONVENERS
Dr. Ken Caldeira
Dr. Nimmakanti Mahendra
Lauren Moody
Social Media
@agu.org
@AGU
@agu_connect
@AmericanGeophysicalUnion
AGU26 FALL MEETING

7–11 Dec 2026

San Francisco, CA, USA

ABSTRACTS DUE

5 Aug 2026

This session will explore the connection between the dynamics of the climate system and the dynamics of social responses to those climate system changes.

POTENTIAL CONSEQUENCES
Regional climate shifts
Sea level rise
Extreme weather changes
Impacts on ecosystems
Socioeconomic disruptions
SUBMIT YOUR ABSTRACT

#AMOC #AGU26
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Ken Caldeira @kencaldeira.com · 12/07/2026
Regressed country-level relationship between departure in detrended GDP growth trend and departure from temperature trend. Hot, low-income, countries suffer from higher temperatures, but cool, high-income countries, seem to benefit. (1/2)
Regression results for

 y_it = beta1_i * T_it + j0_i + j1_i * t + j2_i * t**2, 

using Maddison GDP data and CRU temperature data.
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Ken Caldeira @kencaldeira.com · 08/07/2026
Reducing (especially grazed ruminant) meat intake is a big land-use and climate win, and ultimately the key is for meat alternatives to be cheaper and taste better. But a lot of harm could be reduced by switching away from the worst offenders. interactive.carbonbrief.org/what-is-the-...
Greenhouse gas emissions per kilogram for different food groups. Adapted from Dr Hannah Ritchie/Our World in Data (2020) Data source: Poore & Nemecek (2018). Chart by Carbon Brief using Highcharts.

The chart illustrates how the climate impact of beef and lamb dwarfs that of other foods.

https://interactive.carbonbrief.org/what-is-the-climate-impact-of-eating-meat-and-dairy/index.html
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Ken Caldeira @kencaldeira.com · 07/07/2026
A communication challenge with talking about climate adaptation is that if you talk about adaptation, people suspect you are not serious about reducing greenhouse gas emissions. It is a little like not wearing seat belts because we are afraid people will suspect us of not driving safely.
Photo of me in 2021 wearing a seat belt (and driving safely).
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Ken Caldeira @kencaldeira.com · 06/07/2026
If Platner withdraws by July 13, the Maine Democratic Party can replace him on the ballot with a new candidate for the US Senate. legislature.maine.gov/statutes/21-...
§374-A. General election candidates; vacancy
1.  Vacancy and replacement of nominees.  The Secretary of State shall declare the vacancy as provided in section 362‑A and a political committee may make a replacement nomination for the general election only if a person nominated for an office at a primary election or by a political committee:  
A. Withdraws on or before 5 p.m. of the 2nd Monday in July preceding the general election in accordance with section 367;   [PL 2011, c. 342, §12 (AMD).]

2.  Deadline for replacement of nominee.  A political committee may make a replacement nomination for the general election:  
A. No later than 5 p.m. of the 4th Monday in July preceding the general election for a candidate who has withdrawn in accordance with subsection 1, paragraph A; or   [PL 1993, c. 447, §5 (AMD).]
B. As soon as practicable for a candidate who withdraws or is withdrawn in accordance with subsection 1, paragraph B or C.   [PL 1989, c. 341, §2 (NEW).]
[PL 2019, c. 636, §9 (AMD).]

2-A.  Ballot procedure for replacement candidates.  If a political party makes a replacement nomination for the general election by the deadline established in subsection 2, the Secretary of State shall produce new general election ballots or amend or supplement general election ballots already printed in accordance with section 376 or 604.  
[PL 2019, c. 636, §9 (NEW).]
3.  Deadline for removal of candidate's name from general election ballot.  Removal of a candidate's name from the general election ballot is determined in accordance with this subsection.  
A. The name of a candidate for an office on the general election ballot who withdraws for any reason 70 days or more before the general election must be removed from the ballot.   [PL 2025, c. 363, §4 (NEW).]

https://legislature.maine.gov/statutes/21-a/title21-Asec374-A.html
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Ken Caldeira @kencaldeira.com · 06/07/2026
Fun facts: Mean elevation of Earth's surface, including water as ocean and glacial ice, is about 244 m. (Mean elevation of Earth's surface, not including water, is about -2.4 km.) (I was doing a calculation and got the wrong answer, assuming Earth's surface was at 0 m instead of the mean value.)
Ridgeline map of global elevation

Available here:  https://anvaka.github.io/peak-map/#1.31/0/17.3/0/27
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Ken Caldeira @kencaldeira.com · 03/07/2026
If Americans want a higher standard of living than in other countries, we need to be better educated, more productive, better at equitably distributing fruits of labor, and have a better government with better policies than in other countries. Mean income cannot long exceed mean value generation.
Thomas Hart Benton

Homestead 1938
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Ken Caldeira @kencaldeira.com · 02/07/2026
Apparently, MAGA on social media is mostly a bunch of robots, plus a few over-compensating older males who feel powerless, insecure in their manliness, left behind by economic trends.
Photo of vintage robots from https://www.dreamstime.com/stock-images-robot-group-image16191164.
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Ken Caldeira @kencaldeira.com · 26/06/2026
We wrote about the scale of the challenge and the need for energy R&D, and the Bush II Administration used our work to argue that we need R&D instead of deployment, rather than in addition to deployment. Some things are hard to control. www.science.org/doi/10.1126/... www.nature.com/articles/27638
These results underscore the pitfalls of ‘wait-and-see’. This past
century, accelerated technology development from wartime and
postwar research produced commercial aviation, radar, computer
chips, lasers and the Internet, among other things. Researching,
developing and commercializing carbon-free primary power technologies
capable of 10–30TW by the mid-twenty-first century
could require efforts, perhaps international, pursued with the
urgency of the Manhattan Project or the Apollo space programme.
The roles of governments and market entrepreneurs in the eventual
deployment of such technologies need to be considered more
comprehensively than we can do here. But the potentially adverse
effect of humanity on the Earth’s climate could well stimulate new
industries in the twenty-first century, as did the Second World War
and the ‘cold war’ in this century.

from:

Energy implications of future stabilization of atmospheric CO2 content
Martin I. Hoffert, Ken Caldeira, Atul K. Jain, Erik F. Haites, L. D. Danny Harvey, Seth D. Potter, Michael E. Schlesinger, Stephen H. Schneider, Robert G. Watts, Tom M. L. Wigley & Donald J. Wuebbles 
Nature volume 395, pages881–884 (1998) 

https://www.nature.com/articles/27638
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Ken Caldeira @kencaldeira.com · 24/06/2026
How much of the $300B settlement with Iran will come back to the Trump family as kickbacks? Iran is not stupid and they know what Trump's "Art of the Deal" looks like. Question raised by @therickwilson.bsky.social.
US President Donald Trump speaks during a bilateral meeting with the Taoiseach of Ireland Micheál Martin in the Oval Office of the White House in Washington, DC on March 17, 2026. (Photo by Jim Watson / AFP via Getty Images)

https://www.commondreams.org/opinion/iran-war-belongs-to-trump
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Ken Caldeira @kencaldeira.com · 22/06/2026
The above figure was for RCP8.5, admittedly a high temperature change scenario. Results seem fairly linear with amount of global warming across global warming scenarios. esd.copernicus.org/articles/11/... (Another oldy but goody!)
Figure 3(a) The number of people projected to experience additional climate-related incentive to emigrate under four Representative Concentration Pathways (RCPs) against years, and (b) the number of people projected to experience additional climate-related incentive to emigrate against the change in the 30-year moving mean temperature over global land relative to 2005. The lines show the median value across CMIP5 models with results from 66 % of the models falling within the shaded area. The results hold all factors constant, except for climate and country-level population.

https://esd.copernicus.org/articles/11/875/2020/
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Ken Caldeira @kencaldeira.com · 22/06/2026
If the same methods that Nordhaus used to estimate climate impact on GDP are applied instead to population density, the conclusion is that climate change could give billions motivation to migrate, with India standing out as a hot high-population density country. esd.copernicus.org/articles/11/...
The number of people for whom climate change is projected to provide additional incentive to migrate under RCP8.5 in billions people per country.
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Ken Caldeira @kencaldeira.com · 19/06/2026
If anyone's interested, I wrote a blog post on how the results of the most recent Chopin competition would have differed under different voting systems. kencaldeira.com/2025/11/chop...
Photo of Eric Lu from Deutsche Grammaphon announcing him as the winner of the 19th international Chopin piano competition 2025.
281
Ken Caldeira @kencaldeira.com · 19/06/2026
If our CO2 emissions continue, there will be no place left where corals are surrounded by open ocean waters with the kind of chemistry that supported coral reef growth in the past. However, coral overheating is the primary proximate threat. agupubs.onlinelibrary.wiley.com/doi/full/10....
Aragonite saturation state and coral reefs. (left) Maps of model-predicted aragonite saturation states at different atmospheric CO2 stabilization concentrations (ppm) plotted over existing shallow-water coral reef locations (shown as magenta dots). (right) Percentage distribution of modern day coral reefs at each aragonite saturation bin under different atmospheric CO2 stabilization concentrations. Aragonite saturation value at each reef location is interpolated from nearby open ocean values simulated by the model. Results are obtained by adding model-predicted perturbations in geochemical fields to modern observations, except for the Arctic Ocean where results are directly from model simulations as a result of the lack of observations.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008GL035072
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Ken Caldeira @kencaldeira.com · 18/06/2026
"Combustion of available fossil fuel resources sufficient to eliminate the Antarctic Ice Sheet" by @ricarda-winkelmann.bsky.social et al. Greenhouse gas emissions have the potential to eventually increase sea level by > 50 m (>160 ft). An oldy but goody. www.science.org/doi/10.1126/...
Fig. 2 Sea-level commitment from Antarctic ice loss.
Given is the total sea-level change after 1000 years (yellow), 3000 years (orange), and 10,000 years (red) after year 2000 for each of the scenarios depicted in Fig. 1. The maximum temperature anomaly and the temperature anomaly after 10,000 years are given on the upper x axis. If all of the currently attainable carbon resources [estimated to be between 8500 and 13.600 GtC (4)] were burned, the Antarctic Ice Sheet would lose most of its mass, raising global sea level by more than 50 m. For the 125 GtC as well as the 500, 800, 2500, and 5000 GtC scenarios, the ice-covered area is depicted in white (ice-free bedrock in brown). For more details, see fig. S5.

https://www.science.org/doi/10.1126/sciadv.1500589
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Ken Caldeira @kencaldeira.com · 18/06/2026
Abstract submission guidelines are here: agu.confex.com/agu/agu26/pr...
The official language of the meeting is English. Please submit your abstract in English and, if your abstract is accepted, plan to present in English.

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**Authors cannot request an oral presentation, nor can session conveners guarantee an oral presentation to any author, including an invited author.**
Participation request: When first authors submit their abstract, authors will need to indicate whether they will participate in-person in San Francisco, CA or online.
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Identify presenting author and list all co-authors: First authors must ensure that all co-authors or collaborators associated with the abstract are listed AND each individual listed as a co-author has agreed to serve in that capacity. Ensure correct affiliation and preferred email address for all co-authors. Each co-author will receive a confirmation email in August stating they have been listed as a co-author on the abstract.
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https://agu.confex.com/agu/agu26/prelim.cgi/ModuleMeetingInfo/viewguidelines
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Ken Caldeira @kencaldeira.com · 18/06/2026
This session aims to connect the dynamics of physical systems with the dynamics of human systems. What does the risk of AMOC slowdown/shutdown mean for human beings? How large is the risk? How can we respond to this risk? agu.confex.com/agu/agu26/pr...
Submit an Abstract to this Session

The slowdown or shutdown of the Atlantic Meridional Overturning Circulation (AMOC) is widely considered a potential tipping point in Earth’s climate system, with potentially catastrophic consequences. This interdisciplinary session examines questions spanning climate physics, climate impacts, and response options:
How likely is an AMOC slowdown or shutdown under different climate pathways, and how well can we predict its timing and magnitude?
What physical climate changes would result, and how would these affect humans and natural ecosystems?
What strategies, including adaptation, mitigation, and climate intervention, might reduce risk or ameliorate consequences?
We emphasize priorities for action today:
How can we improve monitoring and prediction of AMOC slowdown?
How can we improve predictions of its impacts?
How can we better understand societal and ecological consequences, and possible adaptive responses?
What research could provide more confidence regarding whether proposed interventions, such as ice-sheet stabilization or solar geoengineering, could reduce AMOC-related risks?

https://agu.confex.com/agu/agu26/prelim.cgi/Session/280234
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Ken Caldeira @kencaldeira.com · 18/06/2026
𝐀𝐭𝐥𝐚𝐧𝐭𝐢𝐜 𝐌𝐞𝐫𝐢𝐝𝐢𝐨𝐧𝐚𝐥 𝐎𝐯𝐞𝐫𝐭𝐮𝐫𝐧𝐢𝐧𝐠 𝐂𝐢𝐫𝐜𝐮𝐥𝐚𝐭𝐢𝐨𝐧 (𝐀𝐌𝐎𝐂) 𝐒𝐥𝐨𝐰𝐝𝐨𝐰𝐧/𝐒𝐡𝐮𝐭𝐝𝐨𝐰𝐧: 𝐋𝐢𝐤𝐞𝐥𝐢𝐡𝐨𝐨𝐝, 𝐂𝐨𝐧𝐬𝐞𝐪𝐮𝐞𝐧𝐜𝐞𝐬, 𝐑𝐞𝐬𝐩𝐨𝐧𝐬𝐞 𝐎𝐩𝐭𝐢𝐨𝐧𝐬 Please submit an abstract to session GC016 at the AGU26 Fall Meeting. Abstracts due 5 Aug 2026. agu.confex.com/agu/agu26/pr...
This graphic shows the AMOC superimposed on a map of average global temperatures from 2014-2018. The development of the 'cold blob' in the North Atlantic has been linked to the slowdown of the AMOC. Credits: AMOC taken from Stephan Rahmstorf (Nature, 1997, CC BY-SA 4.0), Background temperature map from NASA's Scientific Visualization Studio

https://www.theweathernetwork.com/en/news/climate/impacts/gulf-stream-atlantic-meridional-overturning-oscillation-weakest-in-millenium
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