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Ketil Isaksen

@ketilisaksen.bsky.social
590 followers 721 following 54 posts

Senior scientist at the Norwegian Meteorological Institute. Focusing on permafrost thermal dynamics and climate change in the Arctic and European mountain areas. Long-term permafrost monitoring

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Ketil Isaksen @ketilisaksen.bsky.social · 01/10/2026
‘Explosion of melt rates’: 20% of Swiss glaciers lost in five years www.theguardian.com/environment/...
theguardian.com
‘Explosion of melt rates’: 20% of Swiss glaciers lost in five years
Alpine regions in Europe experiencing extreme glacier collapse due to heat-trapping effects of fossil fuel pollution
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Matthias Huss @matthias-huss.bsky.social · 01/10/2025
Remember the catastrophic rock-ice avalanche of Blatten 🇨🇭 this May? This incredible image comparison shows like nothing else the darkening of mountain peaks. And along with the disappearance of snow, ice and permafrost, new hazards come along @vaw-glaciology.bsky.social
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Melaine Le Roy @subfossilguy.bsky.social · 12/09/2026
Mont Blanc this morning! 😍 After this terrible summer 'La Jonction' between Grands Mulets and Bossons Glaciers (lower left) doesn't exist anymore... 🧊🔥😭
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Ketil Isaksen @ketilisaksen.bsky.social · 10/09/2026
August 2026 was the warmest August on record globally - climate.copernicus.eu/surface-air-...
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Rick Thoman @alaskawx.bsky.social · 06/09/2026
The #Arctic (land & seas poleward north of 60ºN) finished up with the warmest summer on record in ERA5 data from @copernicusecmwf.bsky.social. The five warmest summers all since 2016. However, within 1100km (700 miles) of the North Pole (80° to 90°N) this was the coolest summer since 2014. #Climate
Time series graphic plotting the June through August average temperature in the Arctic each year 1950 to 2026. The five highest and lowest values are highlighted, and an estimate of the time varying average is also shown.
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Prof Ian Hall @ianhall.bsky.social · 30/08/2026
Permafrost is thawing deeper and it’s happening worldwide. A new study of 156 monitoring sites found that the active layer, the soil that thaws each summer, increased significantly at many sites from 2000–2024. www.nature.com/articles/s43...
nature.com
Long-term monitoring of active layer thickness confirms global permafrost degradation - Communications Earth & Environment
Active-layer thickness increased at 55% and 38% of Arctic and Antarctic sites, and >90% in European, Asian, and South American mountains, driven by increasing thawing degree-days and rainfall, acco...
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Dr. Twila Moon @drtwilamoon.bsky.social · 20/08/2026
Here's the direct-to-slides re: 3 consequences of losing US Federal support for the NOAA Arctic Report Card. ⬇️
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Luke LeBrun @lukelebrun.ca · 15/07/2026
These images of First Nations community members evacuating Collins, Ontario on motorboats are absolutely surreal www.facebook.com/reel/1548244...
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Daan van den Broek @daanvandenbroek.com · 01/07/2026
Longyearbyen (Svalbard) measured it's warmest June on record. 🌡️ Monthly mean temperature: 6.4°C Already surpassing the June of the record summer 2024 (6.1°C)
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Zack Labe @zacklabe.com · 01/07/2026
"Climate Shift Index (CSI) levels of 5 — the highest possible — are forecast across the eastern U.S., meaning human-caused climate change made this extreme heat at least 5x more likely. This signals an exceptional climate-influenced event." 🔥 ➡️ Learn more: www.climatecentral.org/climate-shif...
Graphic showing the Climate Shift Index for July 2, 2026 using data from the 18z GFS model for minimum temperatures. The graphic shows the change in likelihood due to climate change. Many areas are seeing a maximum of temperatures being at least 5x more likely due to climate change. This tool is available at https://csi.climatecentral.org/climate-shift-index.
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Ketil Isaksen @ketilisaksen.bsky.social · 01/07/2026
🌡️ Unprecedented June heat across Svalbard, led by extreme spikes at the highest latitudes! Final monthly data shows Karl XII-øya (80.65N) shattered its June record reaching 0.8°C (prev 0.2°C), while Verlegenhuken (80.05N) crushed its 2024 record by a massive 0.8°C, hitting 3.2°C.
Data from frost.met.no, The Norwegian Meteorological Institute
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Melaine Le Roy @subfossilguy.bsky.social · 29/06/2026
We are late June, and while we should be admiring snow-capped 4,000ers peaks, there is absolutely no snow left even at the highest elevations! ❄️🧊🔥 Here electric light over Moming Glacier few minutes before a large storm ⚡ Zinalrothorn (4,221 m asl) at the background 🏔️
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Zack Labe @zacklabe.com · 29/06/2026
My next “climate viz of the month” blog is out, which describes a historic extreme event for sea ice conditions in the Barents Sea region of the Arctic this summer: zacklabe.com/climate-viz-... #DataViz #SciComm #OpenScience #OpenData
zacklabe.com
Climate Viz of the Month
May 2026 Hi! And thanks for visiting! My next ‘climate viz of the month’ blog highlights a region of the Arctic that is no stranger to extreme events or climate change: the Barents Sea. In fact, th…
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Ketil Isaksen @ketilisaksen.bsky.social · 02/06/2026
Svalbard just shattered its spring temperature record 🚨 Average spring temperature (Mar-May) at Svalbard Airport ended at an unprecedented -2.9 °C - beating the previous 2016 record by 1.0 °C. The new Top 3 warmest springs since 1899: 1. 2026: -2.9°C 2. 2016: -3.9°C 3. 2006: -4.0°C
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Met Office - weather and climate @metoffice.gov.uk · 25/05/2026
Today has been the hottest day in May on record with Kew Gardens provisionally reaching 34.8°C - exceeding the previous highest May temperature in the UK by a full 2 degrees Celsius🌡️ This heat would be exceptional in the UK even in mid summer, let alone in May📈
A map of the UK showing a temperature of 34.8 degrees Celsius, recorded in Kew Gardens, London on Monday 25 May 2026
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David Ho @davidho.bsky.social · 12/05/2026
None of us alive will experience climate better than what we have now. How much worse it gets is up to us.
eos.org
2026 Has Already Broken Climate Records. El Niño Could Break More. - Eos
As the midpoint of the year approaches, several climate records have already been broken. Arctic winter sea ice extent reached a record low. Several countries saw record-breaking winter heat waves. An...
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Copernicus ECMWF @copernicusecmwf.bsky.social · 29/04/2026
📣Out now! We are pleased to release the European State of the Climate 2025 report, published jointly by #CopernicusClimate @ecmwf.int & @wmo-global.bsky.social. Explore climate conditions, key events of 2025 in Europe, long-term climate indicators, climate policy and action for biodiversity, more! ⬇️
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Ketil Isaksen @ketilisaksen.bsky.social · 21/04/2026
Svalbard is thawing in April, and it’s not supposed to. 2026 ground temperatures at 0.2m depth in Svalbard spiking to 0°C in April, far exceeding the 1998-2025 median and maximum
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evgyrt.bsky.social @evgyrt.bsky.social · 10/03/2026
An exceptionally strong storm in the Norwegian Arctic zone, with wave heights exceeding 10 m. 🌊🧊 #Sentinel-1 data shows how the storm pushed the ice edge over 100 km northward over a couple of days! gif 👉 #CDSE
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Meteorologisk institutt @met.no · 08/01/2026
Aldri før har vi registrert et så varmt år som 2025🌡️ De høye temperaturene er sterkt knyttet til menneskeskapte klimaendringer, ifølge en helt ny rapport. Sammenligner vi temperaturen i 2025 med før-industriell tid (1871-1900), var det 2,8 grader varmere i 2025. 👉 www.met.no/nyhetsarkiv/...
Trekantene viser hvor sannsynlig temperaturen vi opplevde i 2025 var i et førindustrielt klima. Alle fylker i Norge viser at sannsynligheten var “nesten aldri”. Sirkelen viser hvor sannsynlig temperaturen vi opplevde i 2025 er i dagens klima. Firkanten viser hvor sannsynlig temperaturen vi opplevde i 2025 kan bli mot midten av århundret.
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Copernicus ECMWF @copernicusecmwf.bsky.social · 10/12/2025
#CopernicusClimate has released its first data from the Copernicus pan-Arctic Regional Reanalysis (CARRA2): 2.5 km pan‑Arctic coverage, 24 years of data in the Climate Data Store, more realistic physics & improved details for local extremes, lots of added details with respect to ERA5. ⬇️
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Zack Labe @zacklabe.com · 18/10/2025
Record warm conditions continue in the northernmost portions of the #Arctic Ocean, near the North Pole. This anomalous warmth is forecast to continue over the next week or so too. More graphics: zacklabe.com/arctic-tempe...
Line graph time series of 2025's daily 2-m temperature in the Arctic compared to each year from 1958 through 2024. There is a long-term warming trend for every day of the year. There is also large interannual variability and a clear seasonal cycle.
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Anine Hartmann @aninehartmann.bsky.social · 01/10/2025
Jeg tror dette er godt kjent blant alle som jobber med planlegging i Norge: Vi er verst i Europa på å bygge ned natur.
nrk.no
NRK avslører europeisk naturtap: Norge topper verstingliste
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VAW Glaciology @vaw-glaciology.bsky.social · 16/09/2025
Incredible ice loss measured again at #Konkordiaplatz on the #Aletsch #Glacier, home to the thickest ice in the #Alps (still about 800 m!). Yesterday’s survey revealed another –4.6 m of ice gone in just one year. :( Measurements by @matthias-huss.bsky.social for GLAMOS
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Ketil Isaksen @ketilisaksen.bsky.social · 21/08/2025
Witnessing the rapid and extensive thawing of permafrost in Svalbard is truly impressive but deeply concerning
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Michael E. Mann @michaelemann.bsky.social · 20/08/2025
"Melting on the Arctic’s Svalbard Islands Shows the Climate Future Is Now" by @bberwyn.bsky.social for @insideclimatenews.org: insideclimatenews.org/news/1908202...
insideclimatenews.org
Melting on the Arctic’s Svalbard Islands Shows the Climate Future Is Now - Inside Climate News
The rapid disintegration of glaciers on the islands north of Norway foreshadows a catastrophic future for the Arctic, scientists warn.
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Ketil Isaksen @ketilisaksen.bsky.social · 20/08/2025
Ice melt records set in 2020 and 2022 were just marginally greater than previous years, but an extreme and long Arctic heat wave last summer, intensified by weather patterns disrupted by climate change, opened a new page in the record books insideclimatenews.org/news/1908202...
insideclimatenews.org
Melting on the Arctic’s Svalbard Islands Shows the Climate Future Is Now - Inside Climate News
The rapid disintegration of glaciers on the islands north of Norway foreshadows a catastrophic future for the Arctic, scientists warn.
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New Scientist @newscientist.com · 19/08/2025
During the summer of 2024, six weeks of record-smashing heat led to a record-obliterating amount of ice melting on the islands of Svalbard in the Arctic.
newscientist.com
Unprecedented Arctic heatwave melted 1 per cent of Svalbard's ice
A six-week period of extraordinary heat in 2024 melted 62 gigatonnes of ice on the Arctic archipelago of Svalbard, obliterating all previous melt records
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Mika Rantanen @mikarantane.bsky.social · 19/08/2025
Summer 2024 featured unprecedented warmth in the European Arctic, causing melting of 1 % of the total ice volume on Svalbard. Bad news is that in 2100 and even in the optimistic SSP1-2.6 emission scenario, 50% of the future summers will be warmer than 2024. www.pnas.org/doi/10.1073/...
Fig. 4a of the paper. The caption of the paper: Projected temperature evolution until 2100. (A) shows JJA air temperature measured at Svalbard Airport (black) and corresponding downscaled statistics from CMIP6 multimodel ensembles for four different SSPs. The shaded regions mark the 5 to 95% CI for the respective SSP, and the solid lines show the ensemble means. The level of the observed value for 2024 is indicated by the horizontal dashed line, and the yellow horizontal bar indicates the mean value of the 1991–2020 climatology. Vertical bars indicate the time when the ensemble means reach the observed 2024 level.Fig. S3a of the paper. Cumulative CMB for all Svalbard glaciers for the season 2023/24 (blue), compared to the mean (black) and range of the 1991-2020 climatology (gray).
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James Kirkham @jdkirkham.bsky.social · 19/08/2025
Shocking stats from this paper on the extreme 2024 summer heat in Arctic Svalbard, which lost 1% of its total ice volume in just ~6 weeks. 🔥 In fact, Svalbard's 2024 glacier mass loss actually exceeded that of the Greenland Ice Sheet, which is 50 times larger!!! 😱 www.pnas.org/doi/10.1073/... ❄️🧪🌊
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Melaine Le Roy @subfossilguy.bsky.social · 19/08/2025
2024 glacier loss in Svalbard was beyond imagination! 😱 - Anomaly of up to 4 SD! - Amounts to ~61.7 Gt => 1% of the total ice volume - Comparable to that of the Greenland ice sheet (55 Gt), which is 50 x larger! ... Otherworldly! 🪐 www.pnas.org/doi/10.1073/...
pnas.org
Svalbard’s 2024 record summer: An early view of Arctic glacier meltdown? | PNAS
A record-breaking melt season affected the Arctic glaciers of Svalbard in summer 2024 by a substantial margin. Across the entire archipelago, glaci...
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Ketil Isaksen @ketilisaksen.bsky.social · 18/08/2025
Our latest research investigates the remarkable heatwave that affected part of the Arctic in the summer of 2024. It caused a 1 percent loss in Svalbard's ice, making this region one of the most significant contributors to global sea-level rise last year www.pnas.org/doi/10.1073/...
pnas.org
PNAS
Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS) - an authoritative source of high-impact, original research that broadly spans...
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Ketil Isaksen @ketilisaksen.bsky.social · 14/08/2025
This July reminded us that in the north, heat is not a distant threat but is seeping into hospitals, care facilities & homes. Our infrastructure was not built to withstand these extreme temperatures and our population is increasingly susceptible to dangerous heat www.theguardian.com/environment/...
theguardian.com
‘No country is safe’: deadly Nordic heatwave supercharged by climate crisis, scientists say
Historically cool nations saw hospitals overheating and surge in drownings, wildfires and toxic algal blooms
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Matthias Huss @matthias-huss.bsky.social · 11/08/2025
Getting used to this image: #glaciers almost completely naked - unprotected by the white snow - in August... While July was good for glaciers after record-melt in June, the new heat wave again results in major ice loss @vaw-glaciology.bsky.social
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Nahel Belgherze @wxnb.bsky.social · 06/08/2025
This is unbelievable. The high temperature at one of Finland’s northernmost weather stations, in the municipality of Sodankylä (Lapland region) within the Arctic Circle at latitude 67.3°N, reached at least 25°C for 26 days in a row. Records date back to 1908.
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Mika Rantanen @mikarantane.bsky.social · 04/08/2025
Inspired by @ketilisaksen.bsky.social post, I did the same analysis for Finland. In terms of 14-day average temperatures, the 2025 heatwave in Finland did not quite surpass the well-known 1972 and 2018 heatwaves. This is based on 10 km gridded observations.
Bar chart showing the top ten warmest 14-day periods in Finland, as measured by area average temperature for Finland. The data is based FMI ClimGrid temperature which is gridded 10 km dataset for Finland.
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Ketil Isaksen @ketilisaksen.bsky.social · 03/08/2025
Melting glaciers threaten to wipe out European villages - is the steep cost to protect them worth it? www.bbc.com/news/article...
bbc.com
Why glaciers are threatening to wipe out more mountain villages
Switzerland spends almost $500m a year on protective structures. Is it worth it - or, as some suggest, should people move away from the mountain villages at risk?
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Ketil Isaksen @ketilisaksen.bsky.social · 02/08/2025
En sommer med ekstremvær www.nrk.no/klima/ekstre...
nrk.no
Ekstremværsommeren 2025
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Signe Aaboe @signeaaboe.bsky.social · 02/08/2025
Disregarding the extreme and record-low sea-ice extent in Antarctic the last two years, this year's July extent is exceptionally low, ranking as the 3rd lowest on record. The July extent over the last four years differs significantly from that of the previous four decades. @osi-saf.eumetsat.int
Map showing the Antarctic anomaly of the July 2025 sea-ice concentration relative to the mean July ice concentration in 1981-2010. Especially, the sea ice around the Antarctic Peninsula, and in the King Haakon VII sea, shows large areas of negative anomaly (red colour).
Source data is OSI SAF sea-ice concentration CDR v3.0.The line graph displays the monthly sea-ice extent in the Antarctic for July from 1979 to 2025. In 2025, the July extent ranked as the third lowest on record.
Source data is OSI SAF sea-ice index.
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Ketil Isaksen @ketilisaksen.bsky.social · 02/08/2025
Nordic countries hit by ‘truly unprecedented’ heatwave www.theguardian.com/environment/...
theguardian.com
Nordic countries hit by ‘truly unprecedented’ heatwave
Scientists record longest streak of temperatures higher than 30C in region in records going back to 1961
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Mika Rantanen @mikarantane.bsky.social · 31/07/2025
20 straight days with 30 °C in Finland! Truly unprecedented heatwave still in full swing with maximum today about 32-33 degrees. Even the Arctic regions (e.g. Sodankylä Tähtelä) have seen three weeks above 25 °C, and may rival tomorrow their August heat records.
Forecast 2-m temperatures today in Finland, based on the MEPS regional model.
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Mika Rantanen @mikarantane.bsky.social · 27/07/2025
The heatwave in Finland could last another week or so as the Omega pattern strengthens over northeast Europe. The persistence of the heatwave will make it definitely one of the strongest on record in Finland, if not the strongest.
500 hPa geopotential height & anomaly forecast for Thu 31 July for Europe. The map is from wxcharts.com.
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Ketil Isaksen @ketilisaksen.bsky.social · 30/07/2025
Temperaturen under den varmeste 14-dagers perioden i juli 2025 er den desidert høyeste som er registrert for Norge
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Martin Stendel @martinstendel.bsky.social · 25/07/2025
Melting over 80.6% of the area of the Greenland Ice Sheet. This is the highest value in our data set, which starts in 1981. @polarportal.bsky.social
Screenshot from polarportal.dk, a website that makes research on the Arctic research conducted by Danish institutions available to the public and researchers. The image shows Greenland in tan and the Greenland Ice Sheet in red and white. The red part indicates melting and covers all except about 20% in the northeast, which is roughly the area higher than 2500 m above Se level.

Below the map is a chart that compares 2025 melting to the 1981-2010 average. The average melting peaks in mid-July at about 35%. For the last few days, melting has occurred over roughly 80% of the area of Greenland, with a maximum melt area of 80.6% on 24 July 2025. This is the highest value in our dataset, which starts in 1981.
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Zeke Hausfather @zekehausfather.com · 26/06/2025
Great piece in today's NYTimes on the recent acceleration of global warming (and its impacts), featuring comments from Kate Marvel, Daniel Swain, Cecilia Bitz, and me: www.nytimes.com/2025...
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Zack Labe @zacklabe.com · 05/06/2025
Changes in June temperatures in the #Arctic by decade... check out Siberia! Data from @copernicusecmwf.bsky.social ERA5 reanalysis (doi.org/10.24381/cds...).
Four polar stereographic maps showing Arctic near-surface air temperature anomalies for the month of June in 1985-1994, 1995-2004, 2005-2014, and 2015-2024. Most all areas are observing long-term warming, which is largest at the edges of the Arctic Ocean on the Atlantic and Pacific facing marginal seas.
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Ketil Isaksen @ketilisaksen.bsky.social · 03/06/2025
Spring 2025 is the second warmest for mainland Norway. Certain regions in Southern Norway have noted their highest mean temperature for spring since the series began in 1901, exceeding the prior record set in 2024 www.met.no/nyhetsarkiv/...
Spring air temperature (March-April-May) for Norway, deviation from 1991-2020 normal. Source: MET Norway
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WSL Institute for Snow and Avalanche Research SLF @slfdavos.bsky.social · 28/05/2025
Stop! Danger! #Permafrost is thawing, mountains are crumbling: Combined with extreme weather, these and other processes are leading to more #naturalhazards. More in the latest issue of Diagonal magazine: www.slf.ch/en/publicati... #WSL #SLF #CCAMM #CERC #climatechange 📹 R. Oester
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Katharine Hayhoe @katharinehayhoe.com · 29/05/2025
We must wait for detailed attribution to determine exactly how much climate change accelerated the timeline of this collapse. However, the balance of the evidence (given the impact of warming on ice and permafrost) suggests a number is greater than zero, and this was a climate-enhanced event. //
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