Johannes Quaas
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jquaas.bsky.social
Johannes Quaas
@jquaas.bsky.social
Theoretical Meteorology, Leipzig University
Clouds and climate, biodiversity and climate, aerosols and clouds
Great study by our iDiv colleagues: biodiversity in forests helps to mitigate impacts of climate change
New study led by @lsachsenmaier.bsky.social @agwirthweigelt.bsky.social shows: forest stands made up of tree species with different water-use strategies (not just many species) grow better in drought years. #iDivResearch #Biodiversity
www.idiv.de/diverse-fore...
Diverse forests are more resistant to climate change
www.idiv.de
November 14, 2025 at 6:06 AM
Reposted by Johannes Quaas
What if we had no electricity and everything ran on fossil fuels?

This ad keeps making me chuckle.

Enjoy if you have not seen it or rewatch as it is just gold.
November 11, 2025 at 8:04 AM
Dokumentation über Klima und Amazonas mit der super Kollegin Mira Pöhlker @tropos-de.bsky.social @meteoleipzig.bsky.social
November 10, 2025 at 9:19 PM
A joint job offer is open for Junior Professorship Financial Economics
@unileipzig.bsky.social together with the excellent @iwh-halle.bsky.social
Really interesting focus on sustainability, links to biodiversity and climate:
www.uni-leipzig.de/en/universit...
Junior Professorship in VWL, esp. Financial Economics (W1)
www.uni-leipzig.de
November 10, 2025 at 10:17 AM
Reposted by Johannes Quaas
It was a call I couldn't ignore.

I was formally invited by the Danish EU Presidency to Luxembourg to speak about industrial electrification and energy efficiency directly to the energy ministers from every single one of the 27 EU member states on the 20th of October.
www.youtube.com/watch?v=FO30...
Speaking at EU Energy Council
YouTube video by Jan Rosenow
www.youtube.com
October 20, 2025 at 11:10 AM
Reposted by Johannes Quaas
Last week the German Meteorological Society warned that "the 3-degree limit could be exceeded as early as 2050".

While not possible to fully rule out, the assessed warming scenarios we published in the IPCC AR6 report find this to be extremely unlikely.
September 28, 2025 at 8:47 PM
That's really great, congratulations! And I'm happy my colleague Made Maahn @meteoleipzig.bsky.social helps make it happen!
September 27, 2025 at 4:29 AM
The national project "WarmWorld" works on the new-generation global climate simulations at resolutions as high as 1 km. At @kit.edu a group of us met to discuss how to represent the cloud processes in clouds in such computationally-demanding models, to account for pollution effects on climate.
September 26, 2025 at 2:59 PM
Currently at the annual meeting of the "Arctic amplification" collaborative research project. Discussion on how increases in convection in the Arctic make it more "tropical" with warming. ac3-tr.de funded by @dfg.de, partners @meteoleipzig.bsky.social, U Bremen, Köln, @awi.de, @tropos-de.bsky.social
September 24, 2025 at 4:55 PM
Reposted by Johannes Quaas
In a UN speech today, President Trump said that "all of these [climate] predictions were wrong".

Back in 2019 I led a research effort to digitize old climate model projections and assess how well they did. Turns out they got future warming pretty spot on!
September 23, 2025 at 5:01 PM
Since one year, the Research Training Group "Economics of connected natural commons" studies the challenges of sustainably using ecosystems and the climate system as commons. We just come back from the first retreat between the 14 PhD candidates, advisers, and excellent invited external speakers.
September 12, 2025 at 6:57 PM
The current Advanced Training Module on "Climate Attribution", joinly by our interdisciplinary research training group "Economics of Connected Natural Commons" and the Leipzig Graduate school on Clouds, aerosols and radiation sparked large interest: 65 PhD researchers from 7 countries!
September 4, 2025 at 9:03 AM
Great piece from Nadir Jeevanjee. As a meteorologist I of course love it when forecasts prove correct but as a citizen I would have preferred it if climate change had been prevented on the basis of the forecasts
nice article from Nadir Jeevanjee (is he on bluesky?) about predictions climate models got right. successful predictions are the gold standard of science.

5 forecasts early climate models got right – the evidence is all around you
theconversation.com/5-forecasts-...
5 forecasts early climate models got right – the evidence is all around you
From rising global temperatures to the fast-warming Arctic, early climate models predicted the changes half a century ago.
theconversation.com
September 4, 2025 at 5:18 AM
Cloud drop number is a key quantity to understand cloud processes. Getting it from satellites so far was very indirect. Gonzalez et al. @meteoleipzig.bsky.social @scadsai.bsky.social now created a machine-learning method to get it directly from satellite radiances ieeexplore.ieee.org/document/111...
August 28, 2025 at 8:15 AM
I'm glad to contribute again!
The #IPCC has announced the authors selected for its Seventh Assessment Report.

664 experts from 111 countries have been invited to participate as Coordinating Lead Authors, Lead Authors, & Review Editors.

🌍 51% from developing countries
🚺 46% women

🔗 bit.ly/AR7AuthorsPR
August 18, 2025 at 9:19 PM
Reposted by Johannes Quaas
Imagine all cars were electric, and then one Volkswagen engineer comes up with another idea …

#EMobility
August 11, 2025 at 10:46 AM
How does cloud drop size distribution respond to aerosol? Hengqi Wang, visiting PhD researcher from Tsinghua university, used new data from satellite measurements of polarization from SRON/Netherlands to quantify the effect. Offsets systematically 7% of the aerosol-cloud forcing. rdcu.be/ezaeX
August 4, 2025 at 1:27 PM
Reposted by Johannes Quaas
As @pkrugman.bsky.social writes, this is a deliberate effort to destroy science.
For MAGA, Ignorance is Strength
Research cuts aren’t about shrinking government, they’re about killing science
paulkrugman.substack.com
July 16, 2025 at 4:53 AM
Übersicht zum Thema Aerosole und Klima, gemeinsam mit Mira Pöhlker @tropos-de.bsky.social , deutschsprachig, an physik-interessierte Leserschaft gerichtet:

Bessere Luftqualität erwärmt die Erde: Aerosole und Klima - Quaas - Physik in unserer Zeit onlinelibrary.wiley.com/doi/10.1002/...
Bessere Luftqualität erwärmt die Erde: Aerosole und Klima
Aerosolpartikel in der Atmosphäre wirken kühlend auf das Klima, weil sie Sonnenlicht reflektieren und auch Wolken mehr reflektieren lassen. Eine Verbesserung der Luftqualität wirkt deswegen, relativ ...
onlinelibrary.wiley.com
June 24, 2025 at 6:12 PM
Reposted by Johannes Quaas
We have a PhD position in Meteorology open at the University of Bergen. Join us to study the moisture transport in extratropical cyclone families using reanalysis data, water tracer simulations, and stable water isotopes. Application deadline 24 June 2025: www.jobbnorge.no/en/available...
PhD Research Fellow in Meteorology (281744) | University of Bergen
Job title: PhD Research Fellow in Meteorology (281744), Employer: University of Bergen, Deadline: Tuesday, June 24, 2025
www.jobbnorge.no
June 6, 2025 at 4:27 PM
Reposted by Johannes Quaas
This is great! And yes we should f***ing swear more about how we are still neither reducing global emissions to meet agreed targets nor adapting to increasing extreme weather already now happening
US climate scientists need all the help they can get. Including from foul-mouthed comedians! 🤡😱😱

Watch Emmy Award-Winning David Cross team up with Prof Michael Oppenheimer in the US launch of the hit series "Climate Science Translated".

#climate #arresteddevelopment #climatescience
June 3, 2025 at 11:02 AM
Reposted by Johannes Quaas
The people telling you climate change isn’t real would also like you to believe that paying rent on an empty building saves money
www.nytimes.com/2025/05/16/n...
NASA Office Above ‘Seinfeld’ Diner Is a Target of Trump Budget Shrinkage
www.nytimes.com
May 16, 2025 at 11:28 AM
Reposted by Johannes Quaas
We will have talks from @andrewdessler.com, @drkatemarvel.bsky.social, @johnmoralestv.bsky.social, Kerry Emanuel, Bernadette Woods Placky, Ralph Keeling, Ben Santer, and many more! Sign up and learn more at wclivestream.com
The Weather & Climate Livestream
Join us starting May 28th, as meteorologists and climate scientists from across the US share their research and answer your questions.
wclivestream.com
May 14, 2025 at 10:14 PM
Reposted by Johannes Quaas
Hommage aux chercheurs de l'Agence américaine d'observation océanique et atmosphérique (NOAA), licenciés en 2025 sous l’administration Trump. Merci pour votre travail en sciences du climat, votre engagement, vos découvertes.
#StandUpForScience
Dear NOAA: Thank You
YouTube video by Cole Vaughn
youtu.be
May 1, 2025 at 7:23 AM