Excellent idea @mikarantane.bsky.social . We currently have a setup that would be very well suited to test this in a coupled model, (a) whether it can even reproduce this and (b) what the impacts may look like. We will think about it, great idea.
Honored and excited to contribute to the important work of @carbonbrief.org as a contributing editor
Can AI weather models predict out-of-distribution gray swan extremes? We report @pnas.org that the answer is NO for global gray swans, YES for regional ones: AI models can't extrapolate from weaker events but can learn from similar events in other regions during training! doi.org/10.1073/pnas...
Graph of daily sea surface temperature averaged from 60°S to 60°N. 2026 has just edged into record territory. Data from NOAA OISST v2.1
Graph of daily sea surface temperature averaged from 60°S to 60°N. 2026 has just edged into record territory. Data from ERA5.
Almost-global-average sea-surface temperatures are creeping up to record levels again and we’re still in La Niña (according to NOAA).
There’s some uncertainty though as you can see from these two datasets..
Cloudiness has been declining globally for the last two decades. Why is this and how does it matter for global warming?
Read our new article to find out! 👇
doi.org/10.5194/acp-26-4153-2026
And see the @carbonbrief.org post summarising the key findings buff.ly/oLxKacO
Excellent summary on our study in @nature.com by @ayeshatandon.carbonbrief.org (@carbonbrief.org) with comments from Rowan Sutton, Karen McKinnon and @robertvautard.bsky.social
www.carbonbrief.org/limiting-glo...
Fair point. We argue it is often perceived as moderate warming but our paper suggests that indeed the regional changes could well be extremely severe.
Extreme global climate outcomes are possible even at 2°C of warming
In our new Nature study led by @bevacquae.bsky.social with Jakob Zscheischler and @janasillmann.bsky.social, we show that even moderate warming of 2°C could lead to extreme outcomes.
www.nature.com/articles/s41...
Plot wrapping daily maximum temperature history for Phoenix, Arizona for every year since 1933, and showing the anomalously high temperatures in 2026.
The current heatwave in the US Southwest is utterly destroying many records for this time of year.
Phoenix, Arizona has ~90 years of daily temperature data, and yet recent temperatures beat the previous March record by 5 °F (2.8 °C), and would actually tie the record for April.
Map of the lower 48 United States showing 0.25° GFS run from 18z on 20 March 2026. The variable is the 500 hPa geopotential height percentile rank considering ERA5. There is a record-breaking ridge across the Western U.S.
Honestly, this historic heat dome across the West is really hard to put into words for me. Temperatures over 110°F (43°C) in March, shattering all-time monthly records on multiple consecutive days, and not just by a little.
➡️ I can confirm this is human-caused climate change.
polarwx.com/models/
New discussion paper just dropped that’s taken shall we say a little work to get this far … essd.copernicus.org/preprints/es... please be kind. Not on an at all sensitive topic in the slightest.
Globally, no single day in 2025 was cooler than its 1991-2020 average.
climate.copernicus.eu/global-clima...
Multi-dataset comparison of global temperatures from 1850-2025, with 2025 values highlighted in a separate panel for each individual dataset. Baseline is a combination of 1850-1900 means.
Most 2025 global temperatures are now out (degrees C above 1850-1900 baseline)
1.41 HadCRUT5
1.44 Berkeley
1.46 JRA-3Q
1.47 Copernicus
1.53 DCENT-I
NOAA and NASA GISS values will be public at 2pm UK time and but based on already public Jan-Nov data they will likely be between 1.3 and 1.4 degC.
2025 global climate highlights are out:
🌡️ 2025 was 3rd warmest year on record, 1.47ºC above the preindustrial level
📈 2023-2025 is the first three year period above 1.5ºC (according to ERA5)
🌍 The last 11 years have been the warmest 11 years on record
See: climate.copernicus.eu/global-clima...
⚒️🧪🌊
Hot off the press in the journal Science Advances:
A new era of bioclimatic extremes in the terrestrial Arctic
www.science.org/doi/10.1126/...
Our new paper was published today!
The Trump Administration's plan to dismantle the @ncar-ucar.bsky.social is senseless & dangerous.
It would weaken weather forecasting, climate research, & the science that keeps people safe.
We urge that this plan be abandoned.
Call Congress to #SaveNCAR today. buff.ly/7ka1BQA
Snapshot of US EPA's "causes of climate change" webpage as of 12/8/2025. Human causes are no longer mentioned anywhere on the page.
It appears that the U.S. Environmental Protection Agency (EPA) has, within the past week, scrubbed a large amount of climate change content from its official website, as well as *removed human-caused warming* from the discussion on its "causes of climate change" page.
Starting the first lead author meeting of the @Ipcc #AR7 report in Paris! For the first time, WG1, WG2 and WG3 meet together in a lead author meeting. Great to see so much expertise and enthusiasm to kick off the next report.
Many thanks to the fantastic team of PhD and MSc students, postdocs, IT and administrative staff and colleagues at @ethz.ch and across the world who helped to make this possible. I am very honored to be listed again. Special thanks to the @usyseth.bsky.social for the excellent research environment.
Climate skeptics have long been obsessed with corrections to temperature records for changes in measurement techniques and instruments over time.
But it turns out that if we just used the raw data we'd see more warming. My latest at The Climate Brink: www.theclimatebrink....
Snapshot from ECMWF ensemble depicting an extreme and record-breaking ridge near British Columbia in ~6 days.
A bit farther ahead, it's increasingly looking like a rather extreme late-season ridge & heatwave event may develop over Pacific NW & British Columbia in about a week--with some degree of anomalous warmth extending across most of the West (including California). #CAwx #ORwx #WAwx
Numerical weather prediction models (ECMWF IFS) still outperform AI weather models in forecasting record-breaking hot and cold extremes and unseen wind extremes
Preprint
arxiv.org/abs/2508.15724
with Zhongwei Zhang @erichfischer.bsky.social @zscheischlerjak.bsky.social and Sebastian Engelke
Wetterextreme und Sommer 2025
Ich war gestern Gast im SRF Tagesgespräch bei Karoline Arn. Ich habe die Wetterereignisse des Sommers 2025 eingeordnet und über unsere laufende Forschung am @usyseth.bsky.social
der @ethz.ch gesprochen.
www.srf.ch/audio/tagesg...
Honoured to be appointed Lead Author of IPCC #AR7 for the chapter 7 on "Projections of regional climate and extremes".
I am looking forward to contribute together with my @usyseth.bsky.social colleague @lukasgudmundsson.bsky.social
and IPCC WG1 vice-chair @soniaseneviratne.bsky.social
Showing the rainfall of 14th July 2021 (upper left) and 5 alternative scenarios derived from a climate model, conditioned to the atmospheric circulation patterns of the observed event. Similar to fig.6 of https://www.nature.com/articles/s43247-025-02386-y
📣 New paper:
💧💧💧 In July 2021 record breaking rainfall hit western Europe, we use ensemble boosting to explore different plausible storylines. These show it could have rained for longer, or over a larger area, or in a different place. Are we prepared?
doi.org/10.1038/s432...
🌧️The July 2021 extreme rainfall in Western Europe was near the upper bound of plausibility in the current climate, though alternative storylines reveal more severe potential outcomes.
@vikkithompson.bsky.social @hancloke.bsky.social @erichfischer.bsky.social
👉
www.nature.com/articles/s43...
Schon 34.5°C um 13:40 in Basel! Ohne Gewitter dürfte es ein sehr warmes Eröffnungsspiel der Schweiz an der #WEURO2025 werden.
In about 4 days from now, we are going to hit the #Glacier Loss Day in Switzerland! All melting from this point onwards till next winter is unsustainable, i.e. is long-term mass loss.
This is extremely early in the season! And just a bit behind the record-shattering year 2022...
In den letzten 75 Jahren sind mehr Hitzerekorde aufgetreten, als man eigentlich in 100'000 Jahren erwarten würde. Verantwortlich dafür ist die aussergewöhnlich hohe Erwärmungsrate. Es gilt: Je schneller die Erwärmung, desto häufiger die Hitzerekorde.
Die Hitze bricht schon wieder Rekorde: 46 °C in Spanien und Schmelztemperaturen auf dem Mont Blanc. Was früher Ende Juli oder Anfang August extrem war, tritt heute schon im Juni auf.
Heute treten jährlich mehr als viermal so viele Hitzerekorde auf, wie man es ohne den Klimawandel erwarten würde.
