Ken Caldeira
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kencaldeira.com
Ken Caldeira
@kencaldeira.com
19K followers 3.6K following 1.3K posts
Mostly mentoring a group of postdocs at Stanford.
Senior Scientist at Gates Ventures.
climate / energy / etc
https://sustainablesolutions.stanford.edu/people/ken-caldeira

Posts imperfectly represent the views of my former self and not my employer.
Posts Replies Media Videos
kencaldeira.com
The Republican Party is betting on one of two things happening:

1. Republicans in power forever;

2. Pardons, collective amnesia and Democratic party leaders saying:

"Let's move on in the name of unity. We need to look forward, not backwards."
Brassai, c. 1931 Dancers on display in front of their booth, Boulevard Saint-Jacques https://www.moca.org/artist/brassai
December 1, 2025 at 10:18 PM
kencaldeira.com
Nazis were executed for killing survivors of a sunk vessel.

www.executedtoday.com/2009/11/30/1...
1945: Heinz Eck, U-Boat commander Posted on 30 November, 2009 by Headsman On this date in 1945, Heinz-Wilhelm Eck and two of his former subordinates on the Unterseeboot U-852 were shot in Hamburg for killing the survivors of a sunk target. The defendants in the U-852 trial. From left to right: Eck, August Hoffmann, Walter Weisspfennig, Hans Lenz, Wolfgang Schwender. The leftmost three were executed. On March 13, 1944, in the South Atlantic en route to the Indian Ocean, U-852 torpedoed the Greek-flagged Peleus. https://www.executedtoday.com/2009/11/30/1945-heinz-eck-u-boat-commander/
December 1, 2025 at 1:14 AM
kencaldeira.com
Some aircraft contrails persist and spread out to form a hazy layer.

This hazy layer may be responsible for 1-2% of global warming.

Who gave the airline industry permission to alter our sky in this way?

contrails.org
Photo of persistent contrails spreading out to form a hazy layer. Contrast enhanced.
November 26, 2025 at 5:30 PM
kencaldeira.com
"The end of progress against extreme poverty?"

We have to work so that current trends are not good predictors of the future.

Thanks: @maxroser.bsky.social @ourworldindata.org

ourworldindata.org/end-progress...
Total population living in extreme poverty by world region, 1990 to 2040 Extreme poverty is defined as living below the International Poverty Line of $3 per day. This data is adjusted for inflation and differences in living costs between countries. Projections are from the World Bank. From 2026–2030 they are based on growth forecasts from the World Bank and IMF. From 2031, they are based on observed 2015–2024 growth rates. Data source: Lakner et al. (2024) (updated using World Bank PIP in September 2025) – Learn more about this data Note: This data is expressed in international-$ at 2021 prices. It relates to income (measured after taxes and benefits) or to consumption, per capita. OurWorldinData.org/poverty | CC BY https://ourworldindata.org/end-progress-extreme-poverty
November 22, 2025 at 6:55 PM
kencaldeira.com
Our brains are almost incapable of conceiving of technological change.

How many of us can remember how we did things before the invention of the internet or the mobile phone?
My father and uncle working on a car in 1949.
November 22, 2025 at 4:49 PM
kencaldeira.com
Looking at deaths instead of DALYs (Disability Adjusted Life Years) emphasizes diseases of the aging.

Still no homicide or terrorism on the list.

I am using 2018 so as not to consider Covid effects.

www.who.int/data/gho/dat...
Cause Value Category Ischaemic heart disease 144.26 Non-communicable Alzheimer disease and other dementias 80.22 Non-communicable Chronic obstructive pulmonary disease 55.08 Non-communicable Stroke 46.58 Non-communicable Trachea, bronchus, lung cancers 43.29 Non-communicable Kidney diseases 27.45 Non-communicable Hypertensive heart disease 22.14 Non-communicable Drug use disorders 19.45 Non-communicable Colon and rectum cancers 18.29 Non-communicable Lower respiratory infections 18.04 Communicable https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/global-health-estimates-leading-causes-of-dalys
November 16, 2025 at 5:10 PM
kencaldeira.com
Here are the DALY statistics for the US (pre-Covid).

Still no homicide or terrorism in the top 10.

Still mostly disease, much of it preventable. (Interesting how back and neck pain scores so highly.)

www.who.int/data/gho/dat...

(Note: Earlier version of this post was for Afghanistan.)
Cause Value Category Ischaemic heart disease 2659.23 Non-communicable Drug use disorders 1815.40 Non-communicable Back and neck pain 1740.59 Non-communicable Chronic obstructive pulmonary disease 1333.17 Non-communicable Diabetes mellitus 1302.72 Non-communicable Alzheimer disease and other dementias 1121.68 Non-communicable Stroke 1011.22 Non-communicable Trachea, bronchus, lung cancers 971.57 Non-communicable Depressive disorders 827.69 Non-communicable Road injury 804.37 Injuries https://www.who.int/data/gho/data/themes/mortality-and-global-health-estimates/global-health-estimates-leading-causes-of-dalys
November 16, 2025 at 5:07 PM
kencaldeira.com
Actual causes of death in the US and media coverage of same.

And then we wonder why people have such a skewed understanding of the world.

@ourworldindata.org is a treasure. Thanks, @hannahritchie.bsky.social and colleagues.

ourworldindata.org/does-the-new...
Two largest causes of death in the US are heart disease and cancer, but the media focuses on homicide and terrorism.
November 16, 2025 at 5:26 AM
kencaldeira.com
Is this elasticity included in social cost of carbon calculations?

I notice that Rennert et al (2022) assume direct proportionality.

www.nature.com/articles/s41...
We monetize these excess deaths using the value of a statistical life (VSL) as follows: (4) The baseline VSL value for 2020 for the USA (denoted ) is derived using EPA’s 1990 Guidance value of $4.8 million and adjusted for income growth and inflation, resulting in a 2020 US VSL of $10.05 million in 2020 dollars44 (see data explainer notebook in the replication code for this paper for the full derivation). We then base the VSL for country i in year t on the EPA’s baseline VSL for 2020, adjusted for country i’s GDP per capita in year t, as (5) where ε = 1 represents the income elasticity of the VSL. The primary function of ε is to adjust the US VSL to other countries and at uncertain future income levels. We use a unit elasticity, which is in line with the central tendency of values recommended in the literature for such cases92,93,94,95.
November 14, 2025 at 9:22 PM
kencaldeira.com
Maybe the ratio of value of statistical life to income should be much higher for the billionaire, because, if eta>1, the billionaire would need a larger proportional increase to get the same increase in utility.

en.wikipedia.org/wiki/Isoelas...
Isoelastic utility for different values of eta. From https://en.wikipedia.org/wiki/Isoelastic_utility
November 14, 2025 at 8:41 PM
kencaldeira.com
"𝐓𝐡𝐞 𝐞𝐜𝐨𝐧𝐨𝐦𝐢𝐬𝐭'𝐬 𝐭𝐫𝐨𝐥𝐥𝐲 𝐩𝐫𝐨𝐛𝐥𝐞𝐦"

𝘈 𝘵𝘳𝘰𝘭𝘭𝘺 𝘪𝘴 𝘳𝘶𝘯𝘯𝘪𝘯𝘨 𝘥𝘰𝘸𝘯 𝘵𝘩𝘦 𝘵𝘳𝘢𝘤𝘬 𝘢𝘯𝘥 𝘢𝘣𝘰𝘶𝘵 𝘵𝘰 𝘬𝘪𝘭𝘭 𝘢 𝘣𝘪𝘭𝘭𝘪𝘰𝘯𝘢𝘪𝘳𝘦, 𝘣𝘶𝘵 𝘪𝘧 𝘺𝘰𝘶 𝘱𝘶𝘭𝘭 𝘵𝘩𝘦 𝘴𝘸𝘪𝘵𝘤𝘩 𝘺𝘰𝘶 𝘤𝘢𝘯 𝘪𝘯𝘴𝘵𝘦𝘢𝘥 𝘬𝘪𝘭𝘭 𝘧𝘪𝘷𝘦 𝘱𝘦𝘰𝘱𝘭𝘦 𝘭𝘪𝘷𝘪𝘯𝘨 𝘪𝘯 𝘢𝘣𝘫𝘦𝘤𝘵 𝘱𝘰𝘷𝘦𝘳𝘵𝘺. ⁣
⁣
𝘋𝘰 𝘺𝘰𝘶 𝘪𝘯𝘤𝘳𝘦𝘢𝘴𝘦 𝘢𝘨𝘨𝘳𝘦𝘨𝘢𝘵𝘦 𝘶𝘵𝘪𝘭𝘪𝘵𝘺 𝘣𝘺 𝘱𝘶𝘭𝘭𝘪𝘯𝘨 𝘵𝘩𝘦 𝘴𝘸𝘪𝘵𝘤𝘩?
The trolley problem, as usually framed, presents a dilemma: is it preferable to pull the lever to divert the runaway trolley onto the side track with just one person? Illustration from https://en.wikipedia.org/wiki/Trolley_problem
November 14, 2025 at 6:56 PM
kencaldeira.com
In an absurd waste of time, I wrote a blog post about voting and the 19th Chopin Competition.

There has been controversy about who should have won.

Different voting systems would yield different winners. Differences in top rankings are statistically insignificant.

kencaldeira.com/2025/11/chop...
Image of album cover for Eric Lu.
November 13, 2025 at 4:49 AM
kencaldeira.com
I'm preparing slides for a talk I'll be giving at Stanford this Thursday. Here is a draft slide.

events.stanford.edu/event/earth-...
On a background of clouds, the words: "Predicting detailed consequences of human actions in complex coupled socioeconomic-geophysical systems may be as impossible as it is necessary."
November 10, 2025 at 9:26 PM
kencaldeira.com
Please, tell me it isn't so ...

Are Senate Democrats once again snatching defeat from the jaws of victory?

Are they showing they have no spine, no unity, no real ability to govern in the broad interest of Americans?
Unknown photo from my photo archive. Perhaps it is hot springs in Yellowstone?
November 10, 2025 at 1:47 AM
kencaldeira.com
Opinion
Nicholas Kristof

"Trump Aid Cuts Kill More Christians Than Jihadists Do"

www.nytimes.com/2025/11/08/o...
Trump might also reflect that while jihadists have been unable to kill tens of thousands of Nigerian Christians, his own administration appears to be doing just that. The Center for Global Development in Washington calculated earlier this year that before Trump took office, American humanitarian aid was saving about 270,000 lives a year in Nigeria. It’s too soon to predict confidently just how many Nigerian Christian children will die because Trump cut off their access to vaccines, AIDS medications, food assistance and other essentials. But the number killed by jihadists is very likely to pale beside the number dying from Trump aid cuts. So if Trump cares about Christians or anyone else in Nigeria, all he needs to do is restore aid and let babies live.
November 9, 2025 at 2:56 PM
kencaldeira.com
Mafia and fascism in warm embrace.
ChatGTP image generated by the prompt: "Can you make an image of mafia and fascism in warm embrace?"
November 6, 2025 at 7:19 PM
kencaldeira.com
Experience curves indicate that successful technologies reduce in cost by ~20% for each doubling of cumulative production.

However, we find that past learning rates are not very predictive of future learning rates, throwing many energy tech cost projections into doubt.

doi.org/10.1016/j.ad...
Fig. 2. Learning rates for technologies in the Performance Curve Database are seldom constant. (b) Past learning rate (i.e., the learning rate for the first half of points in the data series) versus future learning rate (i.e., the learning rate observed in the second half of the points in the data series) for the same technologies. The past learning rate is not a good predictor of the future learning rate as measured by the Pearson correlation coefficient for the learning exponent of 0.12 and not significantly different from 0 at the 5% confidence level. Outliers (not shown) include nuclear electricity (−109,−32), offshore gas pipeline (−59,13), crude oil (−87,55), and motor gasoline (−29,64).
November 4, 2025 at 4:28 PM
kencaldeira.com
Maybe serfs were proud to see their baron riding in a gilded carriage drawn by stately horses.

There is something deep in human psychology that causes peasants to revel in the grandeur of their dukes and princes.

Trump, in his naive stupidity, may have his finger on the pulse of the masses.
Photo of the King and President Trump having a carriage ride into Windsor Castle. https://www.bbc.com/news/articles/cz9jyzl4532o
October 31, 2025 at 6:12 PM
kencaldeira.com
By the way, here is a photo out the window of a plane at about the position shown in the previous post.
Photo of Greenland glaciers from plane window.
October 28, 2025 at 4:55 PM
kencaldeira.com
If you are interested in a postdoc position on the Stanford campus on the climate effects of a slowdown/shutdown of the Atlantic Meridional Overturning Circulation, please contact me.

Atmosphere or ocean modeling experience is a plus.

sustainablesolutions.stanford.edu/people/ken-c...
October 28, 2025 at 1:50 PM
kencaldeira.com
"Trump, as he often does when he is breaking law or norms, is acting publicly and without shame or unease."
-- @jacklgoldsmith.bsky.social

www.nytimes.com/2025/10/24/u...
“Nixon tried to keep his criminality secret, and the Bush administration tried to keep the torture secret, and that secrecy acknowledged the norm that these things were wrong,” Professor Goldsmith said. “Trump, as he often does when he is breaking law or norms, is acting publicly and without shame or unease. This is a very successful way to destroy the efficacy of law and norms.”
October 24, 2025 at 1:48 PM
kencaldeira.com
I remember when we thought that it couldn't get worse than Bush and Cheney.

en.wikipedia.org/wiki/Abu_Ghr...
Known as The Hooded Man, a prisoner (Abdou Hussain Saad Faleh) being tortured, has become internationally infamous, eventually making it onto the cover of The Economist.
October 23, 2025 at 7:03 PM
kencaldeira.com
More lawlessness and corruption, out in the open.

One of their more minor offenses, but most evidence of lawlessness and corruption doesn't come with good visuals.

(Although ICE abuses have provided an abundance of compelling images.)

www.nytimes.com/interactive/...

vp.nyt.com/video/2025/1...
October 23, 2025 at 5:10 PM
kencaldeira.com
Trump and his co-conspirators provide us with a visual metaphor for what they are doing to our country.
Photo of destruction of the East Wing of the White House, from https://www.washingtonpost.com/politics/2025/10/21/white-house-continues-east-wing-demolition-amid-cries-trump-overreach/
October 22, 2025 at 12:20 AM
kencaldeira.com
Full story.
https://www.newspapers.com/article/honolulu-star-bulletin-german-jews-are-s/12332025/
October 21, 2025 at 10:25 PM