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 👇
Alhainen vedenkorkeus ja jäätilanne muuttavat saariston lauttareittejä – osa ajetaan nyt ilmatyynyaluksilla
yle.fi/a/74-2020832...
yle.fi/a/74-2020832...
Alhainen vedenkorkeus ja jäätilanne muuttavat saariston lauttareittejä – osa ajetaan nyt ilmatyynyaluksilla
Lautta- ja yhteysalusliikennettä operoivan Finferries-yhtiön liikennepäällikkö ei muista yhtä pahaa tilannetta yli kaksikymmentävuotisen uransa ajalta.
yle.fi
February 4, 2026 at 5:04 PM
Alhainen vedenkorkeus ja jäätilanne muuttavat saariston lauttareittejä – osa ajetaan nyt ilmatyynyaluksilla
yle.fi/a/74-2020832...
yle.fi/a/74-2020832...
New all-time minimum sea level in the Baltic Sea!
The Föglö tide gauge measured just -71.6 cm below the mean level which is the lowest value ever recorded there. Records have been kept over 100 years, since 1924 (!).
The sea level is still decreasing. (1/3)
The Föglö tide gauge measured just -71.6 cm below the mean level which is the lowest value ever recorded there. Records have been kept over 100 years, since 1924 (!).
The sea level is still decreasing. (1/3)
February 4, 2026 at 10:12 AM
New all-time minimum sea level in the Baltic Sea!
The Föglö tide gauge measured just -71.6 cm below the mean level which is the lowest value ever recorded there. Records have been kept over 100 years, since 1924 (!).
The sea level is still decreasing. (1/3)
The Föglö tide gauge measured just -71.6 cm below the mean level which is the lowest value ever recorded there. Records have been kept over 100 years, since 1924 (!).
The sea level is still decreasing. (1/3)
When I hear these cold extremes are associated to climate change, I often make a thought experiment in my head: imagine a counterfactual world in which climate change were causing global *cooling* rather than warming, and the Arctic would be cooling 4x faster than the global mean. 1/2
Is climate change responsible for increasingly frequent or severe cold events?
The evidence suggests it is not.
Instead, the impact of climate change is warmer winters and less severe cold events.
@hausfath.bsky.social has a great post on The Climate Brink talking about this.
The evidence suggests it is not.
Instead, the impact of climate change is warmer winters and less severe cold events.
@hausfath.bsky.social has a great post on The Climate Brink talking about this.
Fact check: Climate change is not making extreme cold more common
Sometimes it just gets cold
substack.com
February 3, 2026 at 7:10 PM
When I hear these cold extremes are associated to climate change, I often make a thought experiment in my head: imagine a counterfactual world in which climate change were causing global *cooling* rather than warming, and the Arctic would be cooling 4x faster than the global mean. 1/2
Reposted by Mika Rantanen
While there *is* evidence of both "wetter wets" & "drier dries" in warming climate, temperatures are going almost universally in one direction: Up. We're just not seeing "colder colds."
Some interesting potential Arctic-related caveats still remain TBD, but that doesn't change big picture.
Some interesting potential Arctic-related caveats still remain TBD, but that doesn't change big picture.
Is climate change responsible for increasingly frequent or severe cold events?
The evidence suggests it is not.
Instead, the impact of climate change is warmer winters and less severe cold events.
@hausfath.bsky.social has a great post on The Climate Brink talking about this.
The evidence suggests it is not.
Instead, the impact of climate change is warmer winters and less severe cold events.
@hausfath.bsky.social has a great post on The Climate Brink talking about this.
Fact check: Climate change is not making extreme cold more common
Sometimes it just gets cold
substack.com
February 3, 2026 at 1:57 AM
While there *is* evidence of both "wetter wets" & "drier dries" in warming climate, temperatures are going almost universally in one direction: Up. We're just not seeing "colder colds."
Some interesting potential Arctic-related caveats still remain TBD, but that doesn't change big picture.
Some interesting potential Arctic-related caveats still remain TBD, but that doesn't change big picture.
Reposted by Mika Rantanen
The weather regime that on average brings the coldest weather is warming the fastest in a large part of northern Europe. In contrast, the weather regime that typically brings the warmest weather has warmed the slowest.
doi.org/10.1002/asl.... @mikarantane.bsky.social
doi.org/10.1002/asl.... @mikarantane.bsky.social
Is climate change responsible for increasingly frequent or severe cold events?
The evidence suggests it is not.
Instead, the impact of climate change is warmer winters and less severe cold events.
@hausfath.bsky.social has a great post on The Climate Brink talking about this.
The evidence suggests it is not.
Instead, the impact of climate change is warmer winters and less severe cold events.
@hausfath.bsky.social has a great post on The Climate Brink talking about this.
Fact check: Climate change is not making extreme cold more common
Sometimes it just gets cold
substack.com
February 3, 2026 at 2:59 PM
The weather regime that on average brings the coldest weather is warming the fastest in a large part of northern Europe. In contrast, the weather regime that typically brings the warmest weather has warmed the slowest.
doi.org/10.1002/asl.... @mikarantane.bsky.social
doi.org/10.1002/asl.... @mikarantane.bsky.social
Cold January! The wind rose from Helsinki Kaisaniemi shows that the most common wind direction so far this year has been from the northeast.
Wind has blown from that direction almost half (44%) of the time.
Wind has blown from that direction almost half (44%) of the time.
February 2, 2026 at 2:22 PM
Cold January! The wind rose from Helsinki Kaisaniemi shows that the most common wind direction so far this year has been from the northeast.
Wind has blown from that direction almost half (44%) of the time.
Wind has blown from that direction almost half (44%) of the time.
January climate statistics are out. Remarkably in Lapland, January 2026 was the coldest month since January 1987!
www.ilmatieteenlaitos.fi/tiedote/1GU2...
www.ilmatieteenlaitos.fi/tiedote/1GU2...
February 2, 2026 at 9:21 AM
January climate statistics are out. Remarkably in Lapland, January 2026 was the coldest month since January 1987!
www.ilmatieteenlaitos.fi/tiedote/1GU2...
www.ilmatieteenlaitos.fi/tiedote/1GU2...
The total water volume in the Baltic Sea continues to drop. The mean water level dropped to -62.0 cm at the Föglö tide gauge today morning.
This is now the 2nd lowest reading in the 21st century, surpassed only by the March 2013 cold wave (-63.4 cm).
en.ilmatieteenlaitos.fi/sea-level?se...
This is now the 2nd lowest reading in the 21st century, surpassed only by the March 2013 cold wave (-63.4 cm).
en.ilmatieteenlaitos.fi/sea-level?se...
February 2, 2026 at 7:20 AM
The total water volume in the Baltic Sea continues to drop. The mean water level dropped to -62.0 cm at the Föglö tide gauge today morning.
This is now the 2nd lowest reading in the 21st century, surpassed only by the March 2013 cold wave (-63.4 cm).
en.ilmatieteenlaitos.fi/sea-level?se...
This is now the 2nd lowest reading in the 21st century, surpassed only by the March 2013 cold wave (-63.4 cm).
en.ilmatieteenlaitos.fi/sea-level?se...
Reposted by Mika Rantanen
Helsinki saw its coldest January since 2016 with a mean temperature of -7.4°C.
February 1, 2026 at 1:20 PM
Helsinki saw its coldest January since 2016 with a mean temperature of -7.4°C.
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)