R. Saravanan
@sarava.net
Climate scientist, Professor, and Dept Head at Texas A&M University. Author: ClimateDemon.com Now-and-then-blogger: https://Metamodel.blog Bio: https://r.saravanan.us/about
I sympathize with your argument about research being important, but @climatebook.bsky.social makes a valid point about how entities that ignore the large risks and uncertainties of geoengineering misrepresent the research for profit.
My attempt at a Trolley Problem illustration of the uncertainty:
My attempt at a Trolley Problem illustration of the uncertainty:
October 25, 2025 at 10:09 PM
I sympathize with your argument about research being important, but @climatebook.bsky.social makes a valid point about how entities that ignore the large risks and uncertainties of geoengineering misrepresent the research for profit.
My attempt at a Trolley Problem illustration of the uncertainty:
My attempt at a Trolley Problem illustration of the uncertainty:
Here's another fantasy world that forms the basis for many geoengineering and tipping point discussions.
(I also have a longer comment responding to the original substack post on geongineering: www.theclimatebrink.com/p/revisiting...
)
(I also have a longer comment responding to the original substack post on geongineering: www.theclimatebrink.com/p/revisiting...
)
September 23, 2025 at 4:38 PM
Here's another fantasy world that forms the basis for many geoengineering and tipping point discussions.
(I also have a longer comment responding to the original substack post on geongineering: www.theclimatebrink.com/p/revisiting...
)
(I also have a longer comment responding to the original substack post on geongineering: www.theclimatebrink.com/p/revisiting...
)
Current climate models, with non-eddy resolving oceans, don't simulate AMOC well. The evidence is there in plain sight in the main figure of last week's paper on AMOC collapse. Note the spread in strength of "current" AMOC which is larger than the "collapse" amount for some models! 1/
September 1, 2025 at 12:25 AM
Current climate models, with non-eddy resolving oceans, don't simulate AMOC well. The evidence is there in plain sight in the main figure of last week's paper on AMOC collapse. Note the spread in strength of "current" AMOC which is larger than the "collapse" amount for some models! 1/
Here's what I got just now–still wrong. (it seems to be stochastic; on a different device I got the right answer)
August 8, 2025 at 12:50 AM
Here's what I got just now–still wrong. (it seems to be stochastic; on a different device I got the right answer)
How many times does the letter b appear in blueberry
ChatGPT: The word blueberry has the letter b three times — positions 1, 5, and 6.
How many PhDs does it take to count the letter b in blueberry
ChatGPT: Realistically? Zero — any middle-schooler (or a spell-check) can handle it.
Checked it myself:
ChatGPT: The word blueberry has the letter b three times — positions 1, 5, and 6.
How many PhDs does it take to count the letter b in blueberry
ChatGPT: Realistically? Zero — any middle-schooler (or a spell-check) can handle it.
Checked it myself:
August 8, 2025 at 12:42 AM
How many times does the letter b appear in blueberry
ChatGPT: The word blueberry has the letter b three times — positions 1, 5, and 6.
How many PhDs does it take to count the letter b in blueberry
ChatGPT: Realistically? Zero — any middle-schooler (or a spell-check) can handle it.
Checked it myself:
ChatGPT: The word blueberry has the letter b three times — positions 1, 5, and 6.
How many PhDs does it take to count the letter b in blueberry
ChatGPT: Realistically? Zero — any middle-schooler (or a spell-check) can handle it.
Checked it myself:
Here's a helpful illustration!
July 29, 2025 at 4:09 PM
Here's a helpful illustration!
From the 1908 book by Svante Arrhenius, who built the first (0-dimensional) climate model. As a Scandinavian, he thought that increasing carbonic acid (i.e., CO2) would lead to more "equable" climates and more abundant crops.
P.63 of
www.gutenberg.org/cache/epub/6...
P.63 of
www.gutenberg.org/cache/epub/6...
July 9, 2025 at 6:21 PM
From the 1908 book by Svante Arrhenius, who built the first (0-dimensional) climate model. As a Scandinavian, he thought that increasing carbonic acid (i.e., CO2) would lead to more "equable" climates and more abundant crops.
P.63 of
www.gutenberg.org/cache/epub/6...
P.63 of
www.gutenberg.org/cache/epub/6...
Since 1960s, number of MLB home runs per year has gone up from about 3000 to 4000+ due to many factors (assuming ~2000 games/yr). The global warming effect (58/yr) contributes to this trend, but is a fairly small part of the 1000/yr increase so far.
See Fig 1a of
journals.ametsoc.org/view/journal...
See Fig 1a of
journals.ametsoc.org/view/journal...
July 2, 2025 at 5:48 PM
Since 1960s, number of MLB home runs per year has gone up from about 3000 to 4000+ due to many factors (assuming ~2000 games/yr). The global warming effect (58/yr) contributes to this trend, but is a fairly small part of the 1000/yr increase so far.
See Fig 1a of
journals.ametsoc.org/view/journal...
See Fig 1a of
journals.ametsoc.org/view/journal...
I'll be speaking tomorrow, Thurs., May 29th, at 9:30AM Eastern Time in the Weather & Climate Livestream
www.youtube.com/@wclivestream
Topic: Using climate models to predict solar and wind power droughts, i.e., periods when it is Dark & Still
(agupubs.onlinelibrary.wiley.com/doi/full/10....)
www.youtube.com/@wclivestream
Topic: Using climate models to predict solar and wind power droughts, i.e., periods when it is Dark & Still
(agupubs.onlinelibrary.wiley.com/doi/full/10....)
May 28, 2025 at 8:58 PM
I'll be speaking tomorrow, Thurs., May 29th, at 9:30AM Eastern Time in the Weather & Climate Livestream
www.youtube.com/@wclivestream
Topic: Using climate models to predict solar and wind power droughts, i.e., periods when it is Dark & Still
(agupubs.onlinelibrary.wiley.com/doi/full/10....)
www.youtube.com/@wclivestream
Topic: Using climate models to predict solar and wind power droughts, i.e., periods when it is Dark & Still
(agupubs.onlinelibrary.wiley.com/doi/full/10....)
Some quick comments on your blog post+paper:
Per Betteridge's Law of Headlines, the answer to the question posed in the paper title is NO, observationally constrained multidecadal projections are not predictions. As the plot below from the paper shows, emission scenario matters beyond 2040 or so. 1/
Per Betteridge's Law of Headlines, the answer to the question posed in the paper title is NO, observationally constrained multidecadal projections are not predictions. As the plot below from the paper shows, emission scenario matters beyond 2040 or so. 1/
![Predictive skill in the imperfect model world and prediction of global mean surface temperature evolution conditional on time series of annual global mean temperatures from version 5 of the UK Met Office Hadley Centre/Climatic Research Unit (HadCRUT) data set HadCRUT5. (B) historical ob- servations from 1901 to 2023, unconstrained cMiP6 projections, and future predictions. the left panel shows time series, with the predictions in color and unconstrained projections in gray, with their corresponding 5th to 95th percentile ranges shaded. the right panels display warming of the future periods with 20- and 50-year lead time, with mean changes shown as dots and 5th to 95th percentile ranges represented by error bars. the warming relative to the preindustrial period can be determined by applying an offset between 1994–2023 and 1851–1900, which is estimated to be approximately 0.95 [0.89, 1.02] °c based on the hadcRUt5 dataset.](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:xue5swnq6tayordlqnfretto/bafkreifqqkrmn4567vbgduylgm6qqclp3kpzj4q2e3wyqt4ov75dqs4qfi@jpeg)
May 28, 2025 at 3:04 PM
Some quick comments on your blog post+paper:
Per Betteridge's Law of Headlines, the answer to the question posed in the paper title is NO, observationally constrained multidecadal projections are not predictions. As the plot below from the paper shows, emission scenario matters beyond 2040 or so. 1/
Per Betteridge's Law of Headlines, the answer to the question posed in the paper title is NO, observationally constrained multidecadal projections are not predictions. As the plot below from the paper shows, emission scenario matters beyond 2040 or so. 1/
More one-upmanship today! Microsoft vs. ECMWF
Aurora ML "weather" model (doesn't predict rain, though!)
news.microsoft.com/source/featu...
Aurora ML "weather" model (doesn't predict rain, though!)
news.microsoft.com/source/featu...
May 21, 2025 at 11:37 PM
More one-upmanship today! Microsoft vs. ECMWF
Aurora ML "weather" model (doesn't predict rain, though!)
news.microsoft.com/source/featu...
Aurora ML "weather" model (doesn't predict rain, though!)
news.microsoft.com/source/featu...
I know nothing of this topic, but I asked ChatGPT for you:
May 16, 2025 at 3:33 PM
I know nothing of this topic, but I asked ChatGPT for you:
As I like to say, nobody actually lives in Global-average Land, although it is often featured in the media! Rather like Disney Land...
May 9, 2025 at 6:03 PM
As I like to say, nobody actually lives in Global-average Land, although it is often featured in the media! Rather like Disney Land...
Question motivated by recent trends in the CMIP6 Global SST plot in the post: Do we "know" the TCR range well enough to justify TCR screening?
January 27, 2025 at 11:30 PM
Question motivated by recent trends in the CMIP6 Global SST plot in the post: Do we "know" the TCR range well enough to justify TCR screening?
From the Texas State Climatologist report on extremes:
The coldest temperature of the year has tended to increase since 1900. However, the time series is quite noisy and
looking only at recent decades can be misleading.
climatexas.tamu.edu/files/Climat...
The coldest temperature of the year has tended to increase since 1900. However, the time series is quite noisy and
looking only at recent decades can be misleading.
climatexas.tamu.edu/files/Climat...
January 21, 2025 at 9:01 PM
From the Texas State Climatologist report on extremes:
The coldest temperature of the year has tended to increase since 1900. However, the time series is quite noisy and
looking only at recent decades can be misleading.
climatexas.tamu.edu/files/Climat...
The coldest temperature of the year has tended to increase since 1900. However, the time series is quite noisy and
looking only at recent decades can be misleading.
climatexas.tamu.edu/files/Climat...
We also have a recent paper on PNW 2021-like simulated heatwaves in the near future:
How Do Climate Model Resolution and Atmospheric Moisture Affect the Simulation of Unprecedented Extreme Events Like the 2021 Western North American Heat Wave?
agupubs.onlinelibrary.wiley.com/doi/10.1029/...
How Do Climate Model Resolution and Atmospheric Moisture Affect the Simulation of Unprecedented Extreme Events Like the 2021 Western North American Heat Wave?
agupubs.onlinelibrary.wiley.com/doi/10.1029/...
January 20, 2025 at 11:01 PM
We also have a recent paper on PNW 2021-like simulated heatwaves in the near future:
How Do Climate Model Resolution and Atmospheric Moisture Affect the Simulation of Unprecedented Extreme Events Like the 2021 Western North American Heat Wave?
agupubs.onlinelibrary.wiley.com/doi/10.1029/...
How Do Climate Model Resolution and Atmospheric Moisture Affect the Simulation of Unprecedented Extreme Events Like the 2021 Western North American Heat Wave?
agupubs.onlinelibrary.wiley.com/doi/10.1029/...
If you are attending #AMS2025, I am giving a talk today (Wed 1/15) at 2pm (Room 205) on:
Is Global Mean Surface Temperature the best index of Global Warming?
Here's the Conclusions slide of the talk:
Is Global Mean Surface Temperature the best index of Global Warming?
Here's the Conclusions slide of the talk:
January 15, 2025 at 4:12 PM
If you are attending #AMS2025, I am giving a talk today (Wed 1/15) at 2pm (Room 205) on:
Is Global Mean Surface Temperature the best index of Global Warming?
Here's the Conclusions slide of the talk:
Is Global Mean Surface Temperature the best index of Global Warming?
Here's the Conclusions slide of the talk:
I'm presenting a quirky poster at #AGU2024 on Tuesday, 8:30-12:20 in the Poster Hall (GC210-0052). Drop by if interested.
agu.confex.com/agu/agu24/me...
The main argument is that GMST may not be the best index to describe global warming, esp. on short timescales. It may be a Sisyphean poster...
agu.confex.com/agu/agu24/me...
The main argument is that GMST may not be the best index to describe global warming, esp. on short timescales. It may be a Sisyphean poster...
December 9, 2024 at 8:55 PM
I'm presenting a quirky poster at #AGU2024 on Tuesday, 8:30-12:20 in the Poster Hall (GC210-0052). Drop by if interested.
agu.confex.com/agu/agu24/me...
The main argument is that GMST may not be the best index to describe global warming, esp. on short timescales. It may be a Sisyphean poster...
agu.confex.com/agu/agu24/me...
The main argument is that GMST may not be the best index to describe global warming, esp. on short timescales. It may be a Sisyphean poster...
This figure is a bit misleading for representing asymptotic convergence because the Y axis is stretched. Here's a non-stretch but slightly older version of the figure that captures the convergence better:
December 7, 2024 at 2:58 PM
This figure is a bit misleading for representing asymptotic convergence because the Y axis is stretched. Here's a non-stretch but slightly older version of the figure that captures the convergence better:
Another movie/model image:
December 5, 2024 at 5:41 PM
Another movie/model image:
Human-caused climate change is worsening heat waves and extreme rainfall in Texas, but perhaps not worsening cold extremes.
Here's a figure from the Texas state climatologist's report showing the general warming trend in the coldest temperature of the year
climatexas.tamu.edu/files/Climat...
Here's a figure from the Texas state climatologist's report showing the general warming trend in the coldest temperature of the year
climatexas.tamu.edu/files/Climat...
December 5, 2024 at 3:49 AM
Human-caused climate change is worsening heat waves and extreme rainfall in Texas, but perhaps not worsening cold extremes.
Here's a figure from the Texas state climatologist's report showing the general warming trend in the coldest temperature of the year
climatexas.tamu.edu/files/Climat...
Here's a figure from the Texas state climatologist's report showing the general warming trend in the coldest temperature of the year
climatexas.tamu.edu/files/Climat...
You may be also interested in the next bit of the poster then:
MODERN EQUIVALENT?
“The CEO has no idea if climate risk assessments are any good. However, he needs them to satisfy Fed/Treasury/SEC mandates.”
MODERN EQUIVALENT?
“The CEO has no idea if climate risk assessments are any good. However, he needs them to satisfy Fed/Treasury/SEC mandates.”
December 4, 2024 at 4:42 AM
You may be also interested in the next bit of the poster then:
MODERN EQUIVALENT?
“The CEO has no idea if climate risk assessments are any good. However, he needs them to satisfy Fed/Treasury/SEC mandates.”
MODERN EQUIVALENT?
“The CEO has no idea if climate risk assessments are any good. However, he needs them to satisfy Fed/Treasury/SEC mandates.”