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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · 3d

The deadline for submission to the topical issue has been extended until 31 January 2026.
☀️🔭🧪

Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Feb 26

We are pleased to announce that the Topical Issue (TI) on “Space Climate: Solar Extremes, Long-Term Variability, and Impacts on Earth’s System” is now open for submissions at the Journal of Space Weather and Space Climate (JSWSC) site:
www.swsc-journal.org/topical-issu....
🧪🔭☀️

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Reposted by Dr Theodosios Chatzistergos

Andrew Dessler @andrewdessler.com · 10d

Our comment to the DOE and EPA about the DOE Climate Working Group report is now posted on ESSOAR preprint server. It has a DOI and can now be cited!

essopenarchive.org/users/260056...

Screenshot of an ESS Open Archive preprint page. A green “Download PDF” button sits at top left. The title reads “Climate Experts’ Review of the DOE Climate Working Group Report.” Below are subject tags “Atmospheric Sciences” and “Climate Science,” followed by two listed authors. A “Preprint timeline” box shows “Submitted to ESS Open Archive” on 24 Sep 2025 and “Published in ESS Open Archive” on 29 Sep 2025. A citation block includes the DOI 10.22541/essoar.175745244.41950365/v2 and notes version v2 (processing). A right-side box says “Non-exclusive” and “No reuse.” A yellow banner at the bottom states: “This is a preprint and has not been peer reviewed. Data may be preliminary.”

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Emily Williams @emilywilliams.bsky.social · Sep 2

Grateful to @andrewdessler.com for coordinating this (and keeping us on schedule)! I feel proud for having contributed to this monumental effort alongside some of my role models in this field. It felt necessary to respond to the report that was misleading at best and dangerous at worst.

Andrew Dessler @andrewdessler.com · Sep 2

Our 400+ page comment on the DOE climate working group report is now out.

Our conclusion: The merchants of doubt are back, and they're coming for climate science.

DOEresponseSite

On July 29, 2025, the Department of Energy (DOE) published a report from its Climate Working Group (CWG). This report features prominently in the EPA's reconsideration of its 2009 Endangerment Finding. In response, over 85 scientists have come together to write a comprehensive review, which is

sites.google.com

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Reposted by Dr Theodosios Chatzistergos

Zeke Hausfather @hausfath.bsky.social · Sep 2

Proud to be part of an effort by 85 scientists from around the world to respond to a misleading DOE climate science report last month.

The fact that our rebuttal is more than 3x the length of the DOE report is a good example of Brandolini's Law in action...

DOEresponseSite

On July 29, 2025, the Department of Energy (DOE) published a report from its Climate Working Group (CWG). This report features prominently in the EPA's reconsideration of its 2009 Endangerment Finding. In response, over 85 scientists have come together to write a comprehensive review, which is

sites.google.com

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Chris Colose @ccolose.bsky.social · Sep 2

There's a lot of very interesting material in the response from experts across many domains if you want to learn something solar reconstructions, coral reefs, U.S. temperature data, atmospheric temperature trends, climate models, etc. Andrew did a great job organizing with a very small (30d) window.

Andrew Dessler @andrewdessler.com · Sep 2

On The Climate Brink, I write about the DOE report and our response.

The merchants of doubt are back

But this time, it's the U.S. government pushing doubt

www.theclimatebrink.com

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Reposted by Dr Theodosios Chatzistergos

Andrew Dessler @andrewdessler.com · Sep 2

Great article in the NYTimes about our comment to the DOE about their climate report.

Gift link:
www.nytimes.com/2025/09/02/c...

Scientists Denounce Trump Administration’s Climate Report

www.nytimes.com

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Andrew Dessler @andrewdessler.com · Sep 2

Our 400+ page comment on the DOE climate working group report is now out.

Our conclusion: The merchants of doubt are back, and they're coming for climate science.

DOEresponseSite

On July 29, 2025, the Department of Energy (DOE) published a report from its Climate Working Group (CWG). This report features prominently in the EPA's reconsideration of its 2009 Endangerment Finding. In response, over 85 scientists have come together to write a comprehensive review, which is

sites.google.com

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Bob Kopp @bobkopp.net · Sep 2

The Department of Energy hired five academics to raise doubts about climate change. 85+ climate experts (organized by @andrewdessler.com) reviewed their report. Our conclusion, detailed in 450 pages of analysis: it is biased, full of errors, and not fit to inform policy making.

DOEresponseSite

On July 29, 2025, the Department of Energy (DOE) published a report from its Climate Working Group (CWG). This report features prominently in the EPA's reconsideration of its 2009 Endangerment Finding...

sites.google.com

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Sep 2

I don't think I have anything better than these threads. Otherwise the paper mentioned in this thread would be my suggestion.
Zharkova has made a number of nonsense claims, was it her failed prediction for a grand solar minimum, her miscalculation of Sun-Earth distance change, or something else?

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Andrew Dessler @andrewdessler.com · Aug 28

Our comment on the DOE CWG report is done. It tips the scales at 439 pages, approx. 3x longer than the DOE report.
This is related to Brandolini's law: The amount of energy needed to refute bullshit is an order of magnitude bigger than that needed to produce it.

Example: refuting one sentence.

DOE CWG STATEMENT (second paragraph of section 2.1.1, page 3): “Piao et al. (2020) noted
that greening was even observable in the Arctic.”
COMMENT: This statement implies that the Arctic greening signal was caused by elevated CO2
,
however that is not the scientific consensus. Piao et al. (2020) attribute the greening trend in the
Arctic predominantly to growing season length driven by warmer temperatures (see also Y.
Zhang et al., 2022). Piao et al. (2020) also note that this positive impact of increasing
temperatures appears to have weakened over the past four decades, “suggesting a possible
saturation of future greening in response to warmer temperature” (see also comment on
greenness trends related to Section 2.1.1, first sentence of Page 4). It is also important to put
Arctic greening more broadly into the context of the carbon cycle and other impacts. While
above-ground plants may have displayed more leaf area over the past decades, rising
temperatures also thaw permafrost and drive accelerated decomposition in highly carbon rich
soils (Turetsky et al., 2020), a process which is expected to accelerate as climate continues to
warm (Miner et al., 2022). Thus even with Arctic greening, high latitude terrestrial systems may
become net carbon sources to the atmosphere, causing an amplifying feedback (Braghiere et
al., 2023). Other risks to the Arctic linked to higher CO2

levels and rising temperatures are not
mentioned in this report (Virkkala et al., 2025). The Arctic is warming at a rate of 2 to 3 times the
global average, leading to thawing of permanently frozen soils (permafrost), with downstream
impacts including loss of structural support for buildings and subsidence, threatening
communities, roads, runways, and other assets across Alaska (Manos et al., 2025; University of
Alaska Fairbanks Institute of Northern Engineering US Army Corps of Engineers Alaska District
& Laboratory, 2019).

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Reposted by Dr Theodosios Chatzistergos

Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Feb 26

We are pleased to announce that the Topical Issue (TI) on “Space Climate: Solar Extremes, Long-Term Variability, and Impacts on Earth’s System” is now open for submissions at the Journal of Space Weather and Space Climate (JSWSC) site:
www.swsc-journal.org/topical-issu....
🧪🔭☀️

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Reposted by Dr Theodosios Chatzistergos

Max Planck Institute for Solar System Research @mpsgoettingen.bsky.social · Aug 22

Could the #Sun be responsible for #ClimateChange? In his #TEDx talk on the subject, #mpsgoettingen director Sami Solanki looks into our star’s capricious past, at its more recent behavior – and gives a clear and definite answer. View here: www.youtube.com/watch?v=bQ21...

Could the sun be responsible for climate change? | Dr. Sami K. Solanki | TEDxHHN

YouTube video by TEDx Talks

www.youtube.com

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Max Planck Institute for Solar System Research @mpsgoettingen.bsky.social · Aug 28

#ParkerSolarProbe was in the right place at the right time in Sept 2022: It passed through a magnetic reconnection region in the Sun's corona. #SolarOrbiter observed the event from a distance. Study led by #SwRI in
@natastron.nature.com
. #NASA
@science.esa.int

www.mps.mpg.de/flying-throu...

solar flare as seen by Solar Orbiter on September 5th and 6th, 2022

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Max Planck Institute for Solar System Research @mpsgoettingen.bsky.social · Aug 15

And here's a video of the flare!

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Max Planck Institute for Solar System Research @mpsgoettingen.bsky.social · Aug 15

Here are some great shots from our #GREGORSolarTelescope observation campaign in July. Peering into the #photosphere and #chromosphere, we caught several emerging active regions – and a #flare! This will help us study the plasma dynamics in active regions and how energy builds up to create a flare.

emerging active region as seen by GREGOR

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 30

I guess you can include us, too. Although the sentence in which they cite us is factually accurate in isolation, the surrounding text creates a misleading impression. More importantly, our review paper, which they cited, explains why their subsequent paragraph has misleading & wrong statements.

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 30

BTW the list at the end would now include also Grok+2025, Green & Soon 2025, Soon+2024, Connolly+2023,2024, Scafetta 2025 and some older ones by Soon+1996, 2005, 2013, 2015, 2019, 2021 & Scafetta 2013, 2019.
As well as "climate the movie" and "the great global warming swindle" disinformation videos.

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 30

A quick reminder that the claim that "TSI
variability can explain more than 70% of the temperature variability since preindustrial times" is based on outdated and implausible TSI models. Thus, it is a misleading statement.
link.springer.com/article/10.1...
www.sciencedirect.com/science/arti...

Screenshot from the conclusions of the Chatzistergos 2024 paper https://link.springer.com/article/10.1007/s11207-024-02262-6 . The included text is:
"Overall, our work highlighted issues with the original HS93 TSI series by identifying artefacts in the processing HS93 applied, while also discussing the issues with the arbitrary choice of activity indices used by this model. In addition, by updating the activity indices the model uses, we demonstrated that the original HS93 TSI series suggests an implausible magnitude of variations, which is incompatible with recent TSI data. We also showed that replicating and updating the HS93 model with recent data results in TSI variations since 1700 that are consistent with those by SATIRE-T and NRLTSI, that is those used by IPCC. In particular, the updated HS93 model suggests a TSI difference between the 1700s and 1986 of 0.5 W m−2, which is significantly lower than the 4 W m−2 suggested by the original HS93 series. Finally, we found the updated TSI series with the HS93 model exhibits a rather poor agreement with Earth’s temperature (linear correlation coefficients between 0.13 and 0.23 when considering the entire period of TSI reconstruction, 1700 – 2010). This demonstrates that the high agreement that was previously reported is due to artefacts in the processing applied by HS93 and the exaggerated magnitude of variations they imposed. As a consequence, this also renders void arguments about the solar influence on Earth’s climate that were drawn based on the original HS93 series (e.g. Connolly et al., 2020, 2021; Scafetta, 2023; Soon et al., 2023; Georgieva and Veretenenko, 2023)."

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Living Reviews | Solar Physics @livingrev-solphys.bsky.social · Jul 11

"It's Alive!" — Yes, after a break, Living Reviews in Solar Physics has resumed publication:

Greg Kopp. Solar irradiance measurements. #LivingRevSolPhys 22, 1 (2025). doi.org/10.1007/s411... #OpenAccess #Review @laspatcu.bsky.social

Space-borne TSI Record. The TSI has been measured from space via an uninterrupted series of overlapping instruments since 1978. Scale differences between instruments are due to calibration differences.

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Max Planck Institute for Solar System Research @mpsgoettingen.bsky.social · Jul 11

The German radio station "Bayern 2" has devoted the latest episode of its show “IQ” to the #Sun - and to Solar Orbiter’s first views of the solar poles. Interview partner is Sami Solanki of #mpsgoettingen : www.ardaudiothek.de/episode/urn:... In German. Enjoy!
#SolarOrbiter @science.esa.int

Podcast: Magnetfeld der Sonne - Ist das ihr letztes Rätsel?

Die Sonne ist ein lebendiger Stern: Die Oberfläche brodelt, Sonnenflecken tauchen auf und vergehen, Eruptionen schleudern Ströme geladener Teilchen ins All. Sogar ihr Magnetfeld dreht sich regelmäßig ...

www.ardaudiothek.de

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Nereide @drnereide.bsky.social · Jul 8

🧵
Did you know that sunspots, those dark "marks" on the Sun surface have been observed for over 400 years?

They are the key to studying solar activity, but combining them into a single story is a challenge!

A new study has tested methods for "calibrating" this historical data, collected by

🔭 🧪

Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 7

New paper alert 🧪☀️☄️
In this study, we assessed different methods of combining sunspot number records from various observers, which will strengthen our ability to construct a consistent solar activity history.
doi.org/10.1051/0004...

Screenshot of title and abstract of the paper.
title: Assessment of sunspot number cross-calibration approaches

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 7

The method by Velasco Herrera, Willie Soon, et al., 2024 stood out as particularly problematic due to serious methodological flaws.
In particular, for implicitly assuming a constant standard deviation in sunspot number, which in reality varies significantly over time.

Comparison of cross-calibration results with the different methods for synthetic data with different acuities, where cycle 19 (the strongest solar cycle, marked in dark grey) is not considered for the cross-calibration process.

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 7

The non-linear, non-parametric methods gave more accurate results across the different tests we did.
However, methods that rely on statistical assumptions rather than direct overlap generally performed worse.

Comparison of cross-calibration results with the different methods for synthetic data with different temporal coverages

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 7

We found that linear scaling (Hoyt & Schatten 1998, Svalgaard & Schatten 2016) tends to overestimate the peaks of strong cycles and underestimate those of weak ones.
This skews the overall results, and can significantly affect the long-term trends in solar activity.

Comparison of cross-calibration results with the different methods for synthetic data with different acuities

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Dr Theodosios Chatzistergos @damagedonegr.bsky.social · Jul 7

To test these methods, we created artificial data. This allowed us to understand the strengths and weaknesses of each approach.
We simulated observers with different abilities and tested how much overlap between them affected the calibration.

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