Mika Rantanen
@mikarantane.bsky.social
Researcher at the Finnish Meteorological Institute. Climate change, extreme weather and attribution of extreme events. PhD in meteorology from the 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 👇
January is soon in the books, and what an exceptionally cold month it has been in northern Fennoscandia!
The monthly mean temperature in Sodankylä Tähtelä will be -21.2 °C. This means coldest January since 1987 and 5th coldest overall.
The monthly mean temperature in Sodankylä Tähtelä will be -21.2 °C. This means coldest January since 1987 and 5th coldest overall.
January 31, 2026 at 11:35 AM
January is soon in the books, and what an exceptionally cold month it has been in northern Fennoscandia!
The monthly mean temperature in Sodankylä Tähtelä will be -21.2 °C. This means coldest January since 1987 and 5th coldest overall.
The monthly mean temperature in Sodankylä Tähtelä will be -21.2 °C. This means coldest January since 1987 and 5th coldest overall.
Reposted by Mika Rantanen
I've seen several Big Climate Accounts™ post about how the recent winter storm was made worse by climate change. It's a convenient narrative.
s
But what is "worse"? Colder temperatures? More snow? More freezing rain? Is there any primary literature supporting the idea of worse snowstorms?
1/
s
But what is "worse"? Colder temperatures? More snow? More freezing rain? Is there any primary literature supporting the idea of worse snowstorms?
1/
January 31, 2026 at 3:29 AM
I've seen several Big Climate Accounts™ post about how the recent winter storm was made worse by climate change. It's a convenient narrative.
s
But what is "worse"? Colder temperatures? More snow? More freezing rain? Is there any primary literature supporting the idea of worse snowstorms?
1/
s
But what is "worse"? Colder temperatures? More snow? More freezing rain? Is there any primary literature supporting the idea of worse snowstorms?
1/
Extreme seasons recently in Finnish Lapland: both summer 2025 and winter 2026 featured the 3rd hottest and 3rd coldest two-week periods on record.
Data is based on FMI ClimGrid (available since 1961).
Data is based on FMI ClimGrid (available since 1961).
January 30, 2026 at 9:17 AM
Extreme seasons recently in Finnish Lapland: both summer 2025 and winter 2026 featured the 3rd hottest and 3rd coldest two-week periods on record.
Data is based on FMI ClimGrid (available since 1961).
Data is based on FMI ClimGrid (available since 1961).
The Bothnian Bay is completely frozen. The ongoing high-pressure dominated and cold weather type will continue to favour sea ice formation in the Baltic Sea.
www.ilmatieteenlaitos.fi/jaatilanne
www.ilmatieteenlaitos.fi/jaatilanne
January 29, 2026 at 1:11 PM
The Bothnian Bay is completely frozen. The ongoing high-pressure dominated and cold weather type will continue to favour sea ice formation in the Baltic Sea.
www.ilmatieteenlaitos.fi/jaatilanne
www.ilmatieteenlaitos.fi/jaatilanne
Arktinen kiihdytyskaista vauhdittaa koko maapallon lämpenemistä – neljä tutkijaa kertoo, mistä on kyse
yle.fi/a/74-20202928
yle.fi/a/74-20202928
Arktinen kiihdytyskaista vauhdittaa koko maapallon lämpenemistä – neljä tutkijaa kertoo, mistä on kyse
Ilmasto lämpenee pohjoisella napa-alueella jopa neljä kertaa nopeammin kuin maapallolla keskimäärin. Lapissa nousu on jo 2,5 astetta. Ja vauhti vain kiihtyy.
yle.fi
January 28, 2026 at 5:08 PM
Arktinen kiihdytyskaista vauhdittaa koko maapallon lämpenemistä – neljä tutkijaa kertoo, mistä on kyse
yle.fi/a/74-20202928
yle.fi/a/74-20202928
Reposted by Mika Rantanen
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.
How well can we quantify when 1.5 °C of global warming has been exceeded?
Abstract. Parties to the 2015 Paris Agreement agreed to limit the long-term increase in global average temperature to well below 2 °C and pursue efforts to keep temperatures below 1.5 °C relative to p...
essd.copernicus.org
January 28, 2026 at 8:48 AM
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.
Ehkä vähemmälle huomiolle on jäänyt se, että Lapissa alkuvuoden kahden viikon ajanjakso oli paikoin jopa ennätyksellisen kylmä.
Ylitornion Meltosjärvellä 14 vrk keskilämpötila oli -29,8 astetta (!), joka oli aseman mittaushistorian kylmin kaksiviikkoinen.
Ylitornion Meltosjärvellä 14 vrk keskilämpötila oli -29,8 astetta (!), joka oli aseman mittaushistorian kylmin kaksiviikkoinen.
January 27, 2026 at 11:59 AM
Ehkä vähemmälle huomiolle on jäänyt se, että Lapissa alkuvuoden kahden viikon ajanjakso oli paikoin jopa ennätyksellisen kylmä.
Ylitornion Meltosjärvellä 14 vrk keskilämpötila oli -29,8 astetta (!), joka oli aseman mittaushistorian kylmin kaksiviikkoinen.
Ylitornion Meltosjärvellä 14 vrk keskilämpötila oli -29,8 astetta (!), joka oli aseman mittaushistorian kylmin kaksiviikkoinen.
Due to current weather pattern, the sea level in the Baltic Sea is about half a meter lower than normally.
At the Föglö tide gauge, that is located in the northern part of the main basin, the observed -53 cm is the lowest since 2018.
At the Föglö tide gauge, that is located in the northern part of the main basin, the observed -53 cm is the lowest since 2018.
January 26, 2026 at 5:36 PM
Due to current weather pattern, the sea level in the Baltic Sea is about half a meter lower than normally.
At the Föglö tide gauge, that is located in the northern part of the main basin, the observed -53 cm is the lowest since 2018.
At the Föglö tide gauge, that is located in the northern part of the main basin, the observed -53 cm is the lowest since 2018.
Reposted by Mika Rantanen
Really excited to see this paper out!! Led by @vtcoop.bsky.social we show that if you use cold and warm paleoclimates together, you can reduce uncertainty in Earth's climate sensitivity by quantifying the pattern effect and more precisely constrain future climate change www.pnas.org/doi/10.1073/...
Paleoclimate pattern effects help constrain climate sensitivity and 21st-century warming | PNAS
Paleoclimates provide examples of past climate change that inform estimates of modern
warming from greenhouse-gas emissions, known as Earth’s clima...
www.pnas.org
January 23, 2026 at 3:36 PM
Really excited to see this paper out!! Led by @vtcoop.bsky.social we show that if you use cold and warm paleoclimates together, you can reduce uncertainty in Earth's climate sensitivity by quantifying the pattern effect and more precisely constrain future climate change www.pnas.org/doi/10.1073/...
Well that's an impressive negative North Atlantic Oscillation signal in the ECMWF weather regime forecast. The ensemble mean forecast resembles NAO- regime well into mid-February.
January 23, 2026 at 7:27 AM
Well that's an impressive negative North Atlantic Oscillation signal in the ECMWF weather regime forecast. The ensemble mean forecast resembles NAO- regime well into mid-February.
Reposted by Mika Rantanen
Käynnissä oleva avaruusmyrsky on protonivuolla mitattuna voimakkain hiukkasmyrsky sitten vuoden 1991 ja luokitukseltaan voimakkain (S4) sitten vuoden 2003. Myrskyn näkyvin vaikutus ovat tavanomaista eteläisemmillä alueilla loimottavat revontulet.
www.ilmatieteenlaitos.fi/tiedote/17u8...
www.ilmatieteenlaitos.fi/tiedote/17u8...
Käynnissä on harvinainen avaruusmyrsky - Ilmatieteen laitos
Revontulia on nähty Keski-Eurooppaa myöten. Suomessa pilvisyys voi estää revontulien näkemisen suuressa osassa maata.
www.ilmatieteenlaitos.fi
January 20, 2026 at 1:13 PM
Käynnissä oleva avaruusmyrsky on protonivuolla mitattuna voimakkain hiukkasmyrsky sitten vuoden 1991 ja luokitukseltaan voimakkain (S4) sitten vuoden 2003. Myrskyn näkyvin vaikutus ovat tavanomaista eteläisemmillä alueilla loimottavat revontulet.
www.ilmatieteenlaitos.fi/tiedote/17u8...
www.ilmatieteenlaitos.fi/tiedote/17u8...
Reposted by Mika Rantanen
Global mean temperature 2025: 1.44 ± 0.13 °C above the 1850-1900 average, based on a synthesis of eight international datasets.
2025 was the second or third warmest year on record. 2024 remains the warmest.
That makes the past 3 years are the 3 warmest years on record.
wmo.int/news/media-c...
2025 was the second or third warmest year on record. 2024 remains the warmest.
That makes the past 3 years are the 3 warmest years on record.
wmo.int/news/media-c...
WMO confirms 2025 was one of warmest years on record
wmo.int
January 14, 2026 at 2:06 PM
Global mean temperature 2025: 1.44 ± 0.13 °C above the 1850-1900 average, based on a synthesis of eight international datasets.
2025 was the second or third warmest year on record. 2024 remains the warmest.
That makes the past 3 years are the 3 warmest years on record.
wmo.int/news/media-c...
2025 was the second or third warmest year on record. 2024 remains the warmest.
That makes the past 3 years are the 3 warmest years on record.
wmo.int/news/media-c...
Reposted by Mika Rantanen
Copernicus-ilmastopalvelun mukaan vuosi 2025 oli maailmanlaajuisesti mittaushistorian kolmanneksi lämpimin. Kolmen vuoden jakson keskilämpötila ylitti 1,5 asteen tason ensimmäistä kertaa.
www.ilmatieteenlaitos.fi/tiedote/58Dc...
www.ilmatieteenlaitos.fi/tiedote/58Dc...
Vuosi 2025 oli mittaushistorian kolmanneksi lämpimin – 1,5 asteen
Copernicus-ilmastopalvelun mukaan vuosi 2025 oli maailmanlaajuisesti mittaushistorian kolmanneksi lämpimin. Kolmen vuoden jakson keskilämpötila ylitti 1,5 asteen tason ensimmäistä kertaa. Merien
www.ilmatieteenlaitos.fi
January 14, 2026 at 6:24 AM
Copernicus-ilmastopalvelun mukaan vuosi 2025 oli maailmanlaajuisesti mittaushistorian kolmanneksi lämpimin. Kolmen vuoden jakson keskilämpötila ylitti 1,5 asteen tason ensimmäistä kertaa.
www.ilmatieteenlaitos.fi/tiedote/58Dc...
www.ilmatieteenlaitos.fi/tiedote/58Dc...
Reposted by Mika Rantanen
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...
⚒️🧪🌊
🌡️ 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...
⚒️🧪🌊
January 14, 2026 at 6:34 AM
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...
⚒️🧪🌊
🌡️ 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...
⚒️🧪🌊
Reposted by Mika Rantanen
📢 The Global Climate Highlights report is OUT 📢
climate.copernicus.eu/global-clima...
@copernicusecmwf.bsky.social
🌡️ 2025 was 3rd warmest year on record and the warmest La Niña year on record
📈 2023-2025 is the first three year period above 1.5ºC (according to ERA5)
#dataviz #dataviz4climate
climate.copernicus.eu/global-clima...
@copernicusecmwf.bsky.social
🌡️ 2025 was 3rd warmest year on record and the warmest La Niña year on record
📈 2023-2025 is the first three year period above 1.5ºC (according to ERA5)
#dataviz #dataviz4climate
January 14, 2026 at 8:00 AM
📢 The Global Climate Highlights report is OUT 📢
climate.copernicus.eu/global-clima...
@copernicusecmwf.bsky.social
🌡️ 2025 was 3rd warmest year on record and the warmest La Niña year on record
📈 2023-2025 is the first three year period above 1.5ºC (according to ERA5)
#dataviz #dataviz4climate
climate.copernicus.eu/global-clima...
@copernicusecmwf.bsky.social
🌡️ 2025 was 3rd warmest year on record and the warmest La Niña year on record
📈 2023-2025 is the first three year period above 1.5ºC (according to ERA5)
#dataviz #dataviz4climate
Vuosi 2025 oli mittaushistorian kolmanneksi lämpimin – 1,5 asteen lämpeneminen saavutetaan noin 10 vuotta aiemmin kuin Pariisin sopimuksen aikaan arvioitiin
www.ilmatieteenlaitos.fi/tiedote/58Dc...
(lyhyt ketju alla)
www.ilmatieteenlaitos.fi/tiedote/58Dc...
(lyhyt ketju alla)
Vuosi 2025 oli mittaushistorian kolmanneksi lämpimin – 1,5 asteen
Copernicus-ilmastopalvelun mukaan vuosi 2025 oli maailmanlaajuisesti mittaushistorian kolmanneksi lämpimin. Kolmen vuoden jakson keskilämpötila ylitti 1,5 asteen tason ensimmäistä kertaa. Merien
www.ilmatieteenlaitos.fi
January 14, 2026 at 7:58 AM
Vuosi 2025 oli mittaushistorian kolmanneksi lämpimin – 1,5 asteen lämpeneminen saavutetaan noin 10 vuotta aiemmin kuin Pariisin sopimuksen aikaan arvioitiin
www.ilmatieteenlaitos.fi/tiedote/58Dc...
(lyhyt ketju alla)
www.ilmatieteenlaitos.fi/tiedote/58Dc...
(lyhyt ketju alla)
The beginning of January in Lapland has been strikingly cold: there are several weather stations recording 12-day mean temperatures below −30 °C.
In Sodankylä Tähtelä, the coldest start of the year since the infamous 1987 cold spell, and overall the 2nd coldest on record!
In Sodankylä Tähtelä, the coldest start of the year since the infamous 1987 cold spell, and overall the 2nd coldest on record!
January 13, 2026 at 10:52 AM
The beginning of January in Lapland has been strikingly cold: there are several weather stations recording 12-day mean temperatures below −30 °C.
In Sodankylä Tähtelä, the coldest start of the year since the infamous 1987 cold spell, and overall the 2nd coldest on record!
In Sodankylä Tähtelä, the coldest start of the year since the infamous 1987 cold spell, and overall the 2nd coldest on record!
That's pretty "perfect" cold spell simulated by ECMWF deterministic run at +324 h.
This is not a forecast, but a simulated weather evolution that is strikingly beautiful (and in theory possible).
This is not a forecast, but a simulated weather evolution that is strikingly beautiful (and in theory possible).
January 12, 2026 at 2:08 PM
That's pretty "perfect" cold spell simulated by ECMWF deterministic run at +324 h.
This is not a forecast, but a simulated weather evolution that is strikingly beautiful (and in theory possible).
This is not a forecast, but a simulated weather evolution that is strikingly beautiful (and in theory possible).
Reposted by Mika Rantanen
📆 Mark your calendars!
On 14 January, WMO will release global temperature figures for 2025, consolidating multiple international datasets to provide a single, authoritative source of information to support climate monitoring and decision-making.
More details below:
🔗 https://bit.ly/3Ysu9vE
On 14 January, WMO will release global temperature figures for 2025, consolidating multiple international datasets to provide a single, authoritative source of information to support climate monitoring and decision-making.
More details below:
🔗 https://bit.ly/3Ysu9vE
January 12, 2026 at 6:26 AM
📆 Mark your calendars!
On 14 January, WMO will release global temperature figures for 2025, consolidating multiple international datasets to provide a single, authoritative source of information to support climate monitoring and decision-making.
More details below:
🔗 https://bit.ly/3Ysu9vE
On 14 January, WMO will release global temperature figures for 2025, consolidating multiple international datasets to provide a single, authoritative source of information to support climate monitoring and decision-making.
More details below:
🔗 https://bit.ly/3Ysu9vE
Reposted by Mika Rantanen
The current cold in Northern Finland is remarkable, both in terms of severity, as well as in terms of persistence.
The first 10 days of the year had an average temperature below -30°C (!!) in Muonio Oustajärvi, by far the coldest start of the year in its (short) measurement history. 🥶
🧵(1/4)
The first 10 days of the year had an average temperature below -30°C (!!) in Muonio Oustajärvi, by far the coldest start of the year in its (short) measurement history. 🥶
🧵(1/4)
January 10, 2026 at 1:45 PM
The current cold in Northern Finland is remarkable, both in terms of severity, as well as in terms of persistence.
The first 10 days of the year had an average temperature below -30°C (!!) in Muonio Oustajärvi, by far the coldest start of the year in its (short) measurement history. 🥶
🧵(1/4)
The first 10 days of the year had an average temperature below -30°C (!!) in Muonio Oustajärvi, by far the coldest start of the year in its (short) measurement history. 🥶
🧵(1/4)
Reposted by Mika Rantanen
Nature research paper: Climate change shifts the North Pacific storm track polewards
go.nature.com/4jy48Vh
go.nature.com/4jy48Vh
Climate change shifts the North Pacific storm track polewards - Nature
An observation-based storm-track proxy shows that the winter North Pacific storm track has shifted substantially polewards, suggesting regional impacts on precipitation and warming patterns, with implications for temperature variability and extreme events.
go.nature.com
January 9, 2026 at 11:56 AM
Nature research paper: Climate change shifts the North Pacific storm track polewards
go.nature.com/4jy48Vh
go.nature.com/4jy48Vh
Reposted by Mika Rantanen
-40 °C in Sodankylä Tähtelä! Below -40 °C in several other stations too, with the lowest -42.8 °C in Savukoski Tulppio.
January 2025 cold spell is shaping up to be quite intensive in Lapland!
January 2025 cold spell is shaping up to be quite intensive in Lapland!
January 9, 2026 at 10:31 AM
-40 °C in Sodankylä Tähtelä! Below -40 °C in several other stations too, with the lowest -42.8 °C in Savukoski Tulppio.
January 2025 cold spell is shaping up to be quite intensive in Lapland!
January 2025 cold spell is shaping up to be quite intensive in Lapland!
One of those rare occasions when -40 °C mark is reached in Finland.
Today morning -41.5 °C in Savukoski Tulppio (station established in 2022).
Sodankylä Tähtelä -39.1 °C, the coldest morning since January 2017.
Today morning -41.5 °C in Savukoski Tulppio (station established in 2022).
Sodankylä Tähtelä -39.1 °C, the coldest morning since January 2017.
January 8, 2026 at 8:45 AM
One of those rare occasions when -40 °C mark is reached in Finland.
Today morning -41.5 °C in Savukoski Tulppio (station established in 2022).
Sodankylä Tähtelä -39.1 °C, the coldest morning since January 2017.
Today morning -41.5 °C in Savukoski Tulppio (station established in 2022).
Sodankylä Tähtelä -39.1 °C, the coldest morning since January 2017.
Mediatiedote uudesta tutkimuksesta: sään ääri-ilmiöt ovat yleistyneet arktisella alueella
www.ilmatieteenlaitos.fi/tiedote/30cH...
www.ilmatieteenlaitos.fi/tiedote/30cH...
Sään ääri-ilmiöt ovat yleistyneet arktisella alueella - Ilmatieteen
Sään ääri-ilmiöillä voi olla merkittävä vaikutus arktiseen luontoon, mutta niiden pitkän ajan muutoksia ei ole aiemmin ymmärretty kattavasti. Uuden tutkimuksen mukaan sään ääri-ilmiöt ovat
www.ilmatieteenlaitos.fi
January 8, 2026 at 8:00 AM
Mediatiedote uudesta tutkimuksesta: sään ääri-ilmiöt ovat yleistyneet arktisella alueella
www.ilmatieteenlaitos.fi/tiedote/30cH...
www.ilmatieteenlaitos.fi/tiedote/30cH...