Mika Rantanen
@mikarantane.bsky.social
Researcher in Finnish Meteorological Institute. Climate change, extreme weather, and attribution of extreme events. PhD in meteorology in University of Helsinki.
Pinned
Mika Rantanen
@mikarantane.bsky.social
· Apr 28
Summer 2024 in northern Fennoscandia was very likely the warmest in 2000 years - npj Climate and Atmospheric Science
npj Climate and Atmospheric Science - Summer 2024 in northern Fennoscandia was very likely the warmest in 2000 years
doi.org
Excited to share that our new paper
“Summer 2024 in northern Fennoscandia was very likely the warmest in 2000 years”
has been published in npj Climate and Atmospheric Science!
See the open-access paper from doi.org/10.1038/s416...
Short thread 👇
“Summer 2024 in northern Fennoscandia was very likely the warmest in 2000 years”
has been published in npj Climate and Atmospheric Science!
See the open-access paper from doi.org/10.1038/s416...
Short thread 👇
Extremely cold conditions have prevailed under surface inversion in Lapland now for several days. Some stations have not risen above -25 °C even in the daytime, which is exceptional for the time of the year.
For example, Kittilä Lompolonvuoma *highest* today is -27.1 °C.
For example, Kittilä Lompolonvuoma *highest* today is -27.1 °C.
November 21, 2025 at 10:29 AM
Extremely cold conditions have prevailed under surface inversion in Lapland now for several days. Some stations have not risen above -25 °C even in the daytime, which is exceptional for the time of the year.
For example, Kittilä Lompolonvuoma *highest* today is -27.1 °C.
For example, Kittilä Lompolonvuoma *highest* today is -27.1 °C.
Reposted by Mika Rantanen
Can simple circulation analogues detect observed changes in extreme rainfall?
In many cases, no. Rainfall is too complex and circulation alone cannot predict it. 🧵1/2
🌧️ New paper 🌧️
iopscience.iop.org/article/10.1...
In many cases, no. Rainfall is too complex and circulation alone cannot predict it. 🧵1/2
🌧️ New paper 🌧️
iopscience.iop.org/article/10.1...
November 19, 2025 at 9:19 AM
Can simple circulation analogues detect observed changes in extreme rainfall?
In many cases, no. Rainfall is too complex and circulation alone cannot predict it. 🧵1/2
🌧️ New paper 🌧️
iopscience.iop.org/article/10.1...
In many cases, no. Rainfall is too complex and circulation alone cannot predict it. 🧵1/2
🌧️ New paper 🌧️
iopscience.iop.org/article/10.1...
Now, a majority of the 101 ensemble members in the ECMWF subseasonal forecast are indicating a major sudden stratospheric warming (SSW) event next week.
November SSWs are extremely rare: over the last 67 years, there is only one known event (Nov 1968).
November SSWs are extremely rare: over the last 67 years, there is only one known event (Nov 1968).
November 19, 2025 at 8:26 AM
Now, a majority of the 101 ensemble members in the ECMWF subseasonal forecast are indicating a major sudden stratospheric warming (SSW) event next week.
November SSWs are extremely rare: over the last 67 years, there is only one known event (Nov 1968).
November SSWs are extremely rare: over the last 67 years, there is only one known event (Nov 1968).
Reposted by Mika Rantanen
The global record 134 °F surface temp, measured in Death Valley in 1913, is "implausible" based on other records from that date, claims a paper in #BulletinAMS. The authors suggest the temperature was recorded at an improper location.
More on the blog: https://bit.ly/3LCKPgS
More on the blog: https://bit.ly/3LCKPgS
Global Record in Question: Could Death Valley lose its claim to “world’s hottest place”?
New analysis of the Death Valley record for hottest weather-related air-surface temperature recorded on Earth suggests the record is “implausible.”…
bit.ly
November 18, 2025 at 5:44 PM
The global record 134 °F surface temp, measured in Death Valley in 1913, is "implausible" based on other records from that date, claims a paper in #BulletinAMS. The authors suggest the temperature was recorded at an improper location.
More on the blog: https://bit.ly/3LCKPgS
More on the blog: https://bit.ly/3LCKPgS
Reposted by Mika Rantanen
It’s almost like something dramatically changed after the Industrial Revolution! (figure via Ed Hawkins)
November 18, 2025 at 4:53 PM
It’s almost like something dramatically changed after the Industrial Revolution! (figure via Ed Hawkins)
Reposted by Mika Rantanen
📈🚨NEW: Extreme heat events are increasingly threatening to become mass mortality events. In @natclimate.nature.com today, we project tens of thousands of deaths in a single week across Europe if extreme heat domes coincide with rising global temperatures.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Increasing risk of mass human heat mortality if historical weather patterns recur - Nature Climate Change
The authors couple calculations of historical heatwave intensity at present and future global temperatures with exposure–response functions to quantify mortality from extreme heat events in Europe. Th...
www.nature.com
November 18, 2025 at 1:06 PM
📈🚨NEW: Extreme heat events are increasingly threatening to become mass mortality events. In @natclimate.nature.com today, we project tens of thousands of deaths in a single week across Europe if extreme heat domes coincide with rising global temperatures.
www.nature.com/articles/s41...
www.nature.com/articles/s41...
"For example, if August 2003 meteorological conditions recur at the recent annual global temperature anomaly of 1.5 °C, we project 17,800 excess deaths across Europe in one week, rising to 32,000 at 3 °C."
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Increasing risk of mass human heat mortality if historical weather patterns recur - Nature Climate Change
The authors couple calculations of historical heatwave intensity at present and future global temperatures with exposure–response functions to quantify mortality from extreme heat events in Europe. Th...
www.nature.com
November 18, 2025 at 11:54 AM
"For example, if August 2003 meteorological conditions recur at the recent annual global temperature anomaly of 1.5 °C, we project 17,800 excess deaths across Europe in one week, rising to 32,000 at 3 °C."
www.nature.com/articles/s41...
www.nature.com/articles/s41...
Some kind of quasi-stationary "sea-effect rain" hit yesterday in SE-Finland, producing an extremely localized total of 79 mm in Virolahti Koivuniemi.
This is the highest daily rainfall ever recorded in Finland for the Oct–Dec period.
Radar products indicate even higher amounts, up to 100 mm.
This is the highest daily rainfall ever recorded in Finland for the Oct–Dec period.
Radar products indicate even higher amounts, up to 100 mm.
November 17, 2025 at 8:24 AM
Some kind of quasi-stationary "sea-effect rain" hit yesterday in SE-Finland, producing an extremely localized total of 79 mm in Virolahti Koivuniemi.
This is the highest daily rainfall ever recorded in Finland for the Oct–Dec period.
Radar products indicate even higher amounts, up to 100 mm.
This is the highest daily rainfall ever recorded in Finland for the Oct–Dec period.
Radar products indicate even higher amounts, up to 100 mm.
Reposted by Mika Rantanen
Vaihtelua piisaa Suomen säässä. Pohjoiseen napakoita pakkaslukemia. Etelärannikolle rankkoja sateita.
Savukosken -28,3 °C on talvikauden kylmin mittaus tähän mennessä.
Virolahdella vettä on tullut 12 tunnin aikana jo liki 55 mm.
Savukosken -28,3 °C on talvikauden kylmin mittaus tähän mennessä.
Virolahdella vettä on tullut 12 tunnin aikana jo liki 55 mm.
November 16, 2025 at 6:54 PM
Vaihtelua piisaa Suomen säässä. Pohjoiseen napakoita pakkaslukemia. Etelärannikolle rankkoja sateita.
Savukosken -28,3 °C on talvikauden kylmin mittaus tähän mennessä.
Virolahdella vettä on tullut 12 tunnin aikana jo liki 55 mm.
Savukosken -28,3 °C on talvikauden kylmin mittaus tähän mennessä.
Virolahdella vettä on tullut 12 tunnin aikana jo liki 55 mm.
Breaking: Virolahti Koivuniemi in SE-Finland has provisionally broken the national daily rainfall record for November with 58.2 mm by 21.00 local time and still counting.
www.ilmatieteenlaitos.fi/saa/virolahti
www.ilmatieteenlaitos.fi/saa/virolahti
November 16, 2025 at 7:08 PM
Breaking: Virolahti Koivuniemi in SE-Finland has provisionally broken the national daily rainfall record for November with 58.2 mm by 21.00 local time and still counting.
www.ilmatieteenlaitos.fi/saa/virolahti
www.ilmatieteenlaitos.fi/saa/virolahti
Reposted by Mika Rantanen
Now that the Sept and Oct data are (belatedly) in, it looks like 2025 will be the second warmest year in the record (~80% probability). The last three years are in a class of their own.
November 15, 2025 at 4:54 PM
Now that the Sept and Oct data are (belatedly) in, it looks like 2025 will be the second warmest year in the record (~80% probability). The last three years are in a class of their own.
Winter tightens its hold in Lapland. At the moment -28.3 °C in Savukoski Tulppio with > 20 cm of snow. The coldest so far this winter in Finland.
However, much like in 2023, large parts of the northern hemisphere are unusually warm again (except Fennoscandia).
However, much like in 2023, large parts of the northern hemisphere are unusually warm again (except Fennoscandia).
November 16, 2025 at 8:31 AM
Winter tightens its hold in Lapland. At the moment -28.3 °C in Savukoski Tulppio with > 20 cm of snow. The coldest so far this winter in Finland.
However, much like in 2023, large parts of the northern hemisphere are unusually warm again (except Fennoscandia).
However, much like in 2023, large parts of the northern hemisphere are unusually warm again (except Fennoscandia).
Lokakuun Ilmastokatsaus-lehdessä on kansankielinen artikkeli uudesta tutkimuksestamme Lapin kesälämpötiloista vuosilustoaineistojen valossa, ja siitä miten kesä 2024 oli alueella lämpimin 2000 vuoteen.
www.ilmastokatsaus.fi/lapin-vuosil...
www.ilmastokatsaus.fi/lapin-vuosil...
Lapin vuosilustoaineistot kertovat menneiden kesien lämpötiloista | Ilmastokatsaus – Ilmatieteen laitos
www.ilmastokatsaus.fi
November 15, 2025 at 12:26 PM
Lokakuun Ilmastokatsaus-lehdessä on kansankielinen artikkeli uudesta tutkimuksestamme Lapin kesälämpötiloista vuosilustoaineistojen valossa, ja siitä miten kesä 2024 oli alueella lämpimin 2000 vuoteen.
www.ilmastokatsaus.fi/lapin-vuosil...
www.ilmastokatsaus.fi/lapin-vuosil...
Consequences of the cold air outbreak. First snow of the winter now in Lahti, Finland 🌨️
November 14, 2025 at 4:45 PM
Consequences of the cold air outbreak. First snow of the winter now in Lahti, Finland 🌨️
Reposted by Mika Rantanen
Published today in Earth System Science Data: The Global Carbon Budget 2025
essd.copernicus.org/preprints/es...
essd.copernicus.org/preprints/es...
Global Carbon Budget 2025
Abstract. Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to bette...
essd.copernicus.org
November 13, 2025 at 3:07 PM
Published today in Earth System Science Data: The Global Carbon Budget 2025
essd.copernicus.org/preprints/es...
essd.copernicus.org/preprints/es...
Reposted by Mika Rantanen
The ensemble mean from today's IFS subseasonal run almost predicts the earliest major sudden stratospheric warming on record 😮
Will be interesting to see if this signal progresses as it is just on the cusp of typical SSW prediction lead-times – daily runs of 101 members can still vary a fair bit
Will be interesting to see if this signal progresses as it is just on the cusp of typical SSW prediction lead-times – daily runs of 101 members can still vary a fair bit
November 12, 2025 at 8:32 PM
The ensemble mean from today's IFS subseasonal run almost predicts the earliest major sudden stratospheric warming on record 😮
Will be interesting to see if this signal progresses as it is just on the cusp of typical SSW prediction lead-times – daily runs of 101 members can still vary a fair bit
Will be interesting to see if this signal progresses as it is just on the cusp of typical SSW prediction lead-times – daily runs of 101 members can still vary a fair bit
Reposted by Mika Rantanen
📢Global Carbon Budget 2025📢
Fossil CO2 emissions continue to rise in 2025 while the terrestrial carbon sink recovers to pre-El Niño strength.
The key findings are covered in two reports this year:
* ESSDD (preprint): essd.copernicus.org/preprints/es...
* Nature: www.nature.com/articles/s41...
1/
Fossil CO2 emissions continue to rise in 2025 while the terrestrial carbon sink recovers to pre-El Niño strength.
The key findings are covered in two reports this year:
* ESSDD (preprint): essd.copernicus.org/preprints/es...
* Nature: www.nature.com/articles/s41...
1/
November 13, 2025 at 7:07 AM
📢Global Carbon Budget 2025📢
Fossil CO2 emissions continue to rise in 2025 while the terrestrial carbon sink recovers to pre-El Niño strength.
The key findings are covered in two reports this year:
* ESSDD (preprint): essd.copernicus.org/preprints/es...
* Nature: www.nature.com/articles/s41...
1/
Fossil CO2 emissions continue to rise in 2025 while the terrestrial carbon sink recovers to pre-El Niño strength.
The key findings are covered in two reports this year:
* ESSDD (preprint): essd.copernicus.org/preprints/es...
* Nature: www.nature.com/articles/s41...
1/
Reposted by Mika Rantanen
Looking for a PhD in climate science?
Great opportunity to help modernise one of the iconic climate time series - Central England Temperature.
Led by @timosbornclim.bsky.social, with myself and Met Office collaborators: www.uea.ac.uk/course/phd-d...
Great opportunity to help modernise one of the iconic climate time series - Central England Temperature.
Led by @timosbornclim.bsky.social, with myself and Met Office collaborators: www.uea.ac.uk/course/phd-d...
PhD Redeveloping Central England Temperature: Modernising a Historic Climate Series, CASE project with Met Office (OSBORNT_U26SCI) 2026/27 | UEA
PhD Redeveloping Central England Temperature: Modernising a Historic Climate Series, CASE project with Met Office (OSBORNT_U26SCI) 2026/27 | UEA
www.uea.ac.uk
November 12, 2025 at 5:38 PM
Looking for a PhD in climate science?
Great opportunity to help modernise one of the iconic climate time series - Central England Temperature.
Led by @timosbornclim.bsky.social, with myself and Met Office collaborators: www.uea.ac.uk/course/phd-d...
Great opportunity to help modernise one of the iconic climate time series - Central England Temperature.
Led by @timosbornclim.bsky.social, with myself and Met Office collaborators: www.uea.ac.uk/course/phd-d...
Syksy on ollut lähes koko maassa ja myös koko maan keskiarvoa tarkastellessa ennätyksellisen lämmin. Lämmin suursäätyyppi muuttuu kuitenkin tällä viikolla.
suomenluonto.fi/ennatyslammi...
@suomenluonto.bsky.social
suomenluonto.fi/ennatyslammi...
@suomenluonto.bsky.social
November 12, 2025 at 1:52 PM
Syksy on ollut lähes koko maassa ja myös koko maan keskiarvoa tarkastellessa ennätyksellisen lämmin. Lämmin suursäätyyppi muuttuu kuitenkin tällä viikolla.
suomenluonto.fi/ennatyslammi...
@suomenluonto.bsky.social
suomenluonto.fi/ennatyslammi...
@suomenluonto.bsky.social
Came across what appears to be the 1st peer-reviewed paper against the world record temperature of 56.7 °C (134 °F) in Death Valley in 1913: journals.ametsoc.org/view/journal...
They present evidence that the reading should be in reality 7.8 °C lower, 48.9 °C (120 °F).
They present evidence that the reading should be in reality 7.8 °C lower, 48.9 °C (120 °F).
journals.ametsoc.org
November 11, 2025 at 10:20 AM
Came across what appears to be the 1st peer-reviewed paper against the world record temperature of 56.7 °C (134 °F) in Death Valley in 1913: journals.ametsoc.org/view/journal...
They present evidence that the reading should be in reality 7.8 °C lower, 48.9 °C (120 °F).
They present evidence that the reading should be in reality 7.8 °C lower, 48.9 °C (120 °F).
Elämäni ensimmäinen akatemiatutkijan hakemus Suomen Akatemialle jätetty! Ja jopa päivä ennen takarajaa.
Olihan siinä hommaa paketoida päässä oleva idea äärisäätutkimuksesta 12 sivun tutkimussuunnitelmaksi, mutta lopulta olin tyytyväinen lopputulokseen. Toivotaan että se näkyy arvioitsijoille 🤞
Olihan siinä hommaa paketoida päässä oleva idea äärisäätutkimuksesta 12 sivun tutkimussuunnitelmaksi, mutta lopulta olin tyytyväinen lopputulokseen. Toivotaan että se näkyy arvioitsijoille 🤞
November 11, 2025 at 8:32 AM
Elämäni ensimmäinen akatemiatutkijan hakemus Suomen Akatemialle jätetty! Ja jopa päivä ennen takarajaa.
Olihan siinä hommaa paketoida päässä oleva idea äärisäätutkimuksesta 12 sivun tutkimussuunnitelmaksi, mutta lopulta olin tyytyväinen lopputulokseen. Toivotaan että se näkyy arvioitsijoille 🤞
Olihan siinä hommaa paketoida päässä oleva idea äärisäätutkimuksesta 12 sivun tutkimussuunnitelmaksi, mutta lopulta olin tyytyväinen lopputulokseen. Toivotaan että se näkyy arvioitsijoille 🤞
Vierailin tänään Ari-Juhani Punkan vieraana myrskyvaroitus-videoblogissa. Juteltiin kesäkaudesta, pitkistä ennusteista ja tulevasta polaaripyörteen heikkenemisestä. Käy kuuntelemassa: youtu.be/kVnWPLge81I?...
youtu.be
November 10, 2025 at 4:40 PM
Vierailin tänään Ari-Juhani Punkan vieraana myrskyvaroitus-videoblogissa. Juteltiin kesäkaudesta, pitkistä ennusteista ja tulevasta polaaripyörteen heikkenemisestä. Käy kuuntelemassa: youtu.be/kVnWPLge81I?...
Latest ECMWF subseasonal forecast shows ensemble mean zonal wind of about 5 m/s at 10 hPa in late November, with roughly 20–30 % of ensemble members indicating a reversal to easterlies (i.e. going < 0 m/s).
This suggests a non-zero probabilty for a major SSW event!
This suggests a non-zero probabilty for a major SSW event!
November 10, 2025 at 11:52 AM
Latest ECMWF subseasonal forecast shows ensemble mean zonal wind of about 5 m/s at 10 hPa in late November, with roughly 20–30 % of ensemble members indicating a reversal to easterlies (i.e. going < 0 m/s).
This suggests a non-zero probabilty for a major SSW event!
This suggests a non-zero probabilty for a major SSW event!
The first week of November (1.-7.11.) was record-warm in Helsinki, Finland. The average temperature was 9.3 °C.
Records have been kept since 1882.
Records have been kept since 1882.
November 8, 2025 at 3:26 PM
The first week of November (1.-7.11.) was record-warm in Helsinki, Finland. The average temperature was 9.3 °C.
Records have been kept since 1882.
Records have been kept since 1882.
Reposted by Mika Rantanen
Vuodesta 2025 on tulossa maailmanlaajuisesti mittaushistorian toiseksi tai kolmanneksi lämpimin vuosi, selviää WMO:n State of the Global Climate Update 2025 -raportista. Seuraukset ovat näkyneet vuoden aikana esimerkiksi sään ääri-ilmiöinä.
www.ilmatieteenlaitos.fi/tiedote/3O5H...
www.ilmatieteenlaitos.fi/tiedote/3O5H...
Ilmaston lämpeneminen jatkuu poikkeuksellisena – vuodesta 2025 on
Vuodesta 2025 on tulossa maailmanlaajuisesti mittaushistorian toiseksi tai kolmanneksi lämpimin vuosi, selviää Maailman ilmatieteen järjestö WMO:n State of the Global Climate Update 2025 -raportista.
www.ilmatieteenlaitos.fi
November 6, 2025 at 3:03 PM
Vuodesta 2025 on tulossa maailmanlaajuisesti mittaushistorian toiseksi tai kolmanneksi lämpimin vuosi, selviää WMO:n State of the Global Climate Update 2025 -raportista. Seuraukset ovat näkyneet vuoden aikana esimerkiksi sään ääri-ilmiöinä.
www.ilmatieteenlaitos.fi/tiedote/3O5H...
www.ilmatieteenlaitos.fi/tiedote/3O5H...