Anna Virkkala
@annvirkk.bsky.social
Research scientist @Woodwell Climate Research Center and @University of Helsinki. Arctic, carbon, climate change.
Pinned
Anna Virkkala
@annvirkk.bsky.social
· Jan 28
Wildfires offset the increasing but spatially heterogeneous Arctic–boreal CO2 uptake - Nature Climate Change
How the carbon stocks of the Arctic–Boreal Zone change with warming is not well understood. Here the authors show that wildfires and large regional differences in net carbon fluxes offset the overall ...
www.nature.com
Last week's highlight was our study in @natclimchange.bsky.social showing over 30% of the Arctic-boreal region as a CO2 source: www.nature.com/articles/s41...
It has taken more than two years (plus all the years data contributors have spent on their data collection), but finally our data descriptor manuscript preprint on Arctic-boreal carbon fluxes across terrestrial and freshwater ecosystems is out: essd.copernicus.org/preprints/es... Go have a look!
ABCFlux v2: Arctic–boreal CO2 and CH4 monthly flux observations and ancillary information across terrestrial and freshwater ecosystems
Abstract. Measurements of surface-atmosphere carbon dioxide (CO2) and methane (CH4) fluxes have been relatively sparse across the Arctic tundra and boreal biomes, causing significant uncertainties in ...
essd.copernicus.org
October 21, 2025 at 6:37 PM
It has taken more than two years (plus all the years data contributors have spent on their data collection), but finally our data descriptor manuscript preprint on Arctic-boreal carbon fluxes across terrestrial and freshwater ecosystems is out: essd.copernicus.org/preprints/es... Go have a look!
Reposted by Anna Virkkala
Hot off the presses! Abrupt permafrost thaw is a critical climate feedback but is poorly defined & understood. In an awesome collaboration between my team & the Permafrost Carbon Network, PhD student Hailey Webb provides a formal definition to guide future studies. link.springer.com/article/10.1...
A Review of Abrupt Permafrost Thaw: Definitions, Usage, and a Proposed Conceptual Framework - Current Climate Change Reports
Purpose of Review We review how ‘abrupt thaw’ has been used in published studies, compare these definitions to abrupt processes in other Earth science disciplines, and provide a definitive framework f...
link.springer.com
July 24, 2025 at 3:43 PM
Hot off the presses! Abrupt permafrost thaw is a critical climate feedback but is poorly defined & understood. In an awesome collaboration between my team & the Permafrost Carbon Network, PhD student Hailey Webb provides a formal definition to guide future studies. link.springer.com/article/10.1...
Reposted by Anna Virkkala
Congratulations to Dr. Ying and all co-authors, including @benpoulter.bsky.social @profdesai.bsky.social and @woodwellclimate.bsky.social @permafrostpathways.bsky.social's Jennifer Watts, Kyle Arndt, @annvirkk.bsky.social, Brendan Rogers, and Sue Natali. essd.copernicus.org/articles/17/...
WetCH4: a machine-learning-based upscaling of methane fluxes of northern wetlands during 2016–2022
Abstract. Wetlands are the largest natural source of methane (CH4) emissions globally. Northern wetlands (>45° N), accounting for 42 % of global wetland area, are increasingly vulnerable to carbon los...
essd.copernicus.org
June 17, 2025 at 5:03 PM
Congratulations to Dr. Ying and all co-authors, including @benpoulter.bsky.social @profdesai.bsky.social and @woodwellclimate.bsky.social @permafrostpathways.bsky.social's Jennifer Watts, Kyle Arndt, @annvirkk.bsky.social, Brendan Rogers, and Sue Natali. essd.copernicus.org/articles/17/...
If you need land cover datasets for the Arctic-boreal region, here is one great option for you at 1-km resolution: essd.copernicus.org/preprints/es.... It merges several regional products and separates dozens of key land cover types (e.g. bogs, fens, pine forest, spruce forest). 🌎🏞🏔
Fusing Regional and Global Datasets to Develop a Composite Land Cover Product Across High Latitudes
Abstract. Rapid warming across the Arctic is the primary driver of widespread permafrost thaw, with far-reaching consequences for local ecosystem resilience, the regional carbon budget, and the global...
essd.copernicus.org
May 15, 2025 at 11:48 AM
If you need land cover datasets for the Arctic-boreal region, here is one great option for you at 1-km resolution: essd.copernicus.org/preprints/es.... It merges several regional products and separates dozens of key land cover types (e.g. bogs, fens, pine forest, spruce forest). 🌎🏞🏔
Reposted by Anna Virkkala
Make a difference this summer -- Join @cmshintani.bsky.social and me for an internship at @woodwellclimate.bsky.social and contribute to critical research on climate change.
Apply now: bit.ly/4l5D93W
Apply now: bit.ly/4l5D93W
March 25, 2025 at 7:01 PM
Make a difference this summer -- Join @cmshintani.bsky.social and me for an internship at @woodwellclimate.bsky.social and contribute to critical research on climate change.
Apply now: bit.ly/4l5D93W
Apply now: bit.ly/4l5D93W
First circumpolar maps of aboveground tundra biomass at 30 m resolution 💪 www.sciencedirect.com/science/arti...
These new estimates show that in total tundra plants (above-and belowground) store around 8 Pg C while the upper 30 cm soils store ca 53 Pg C.
These new estimates show that in total tundra plants (above-and belowground) store around 8 Pg C while the upper 30 cm soils store ca 53 Pg C.
Next generation Arctic vegetation maps: Aboveground plant biomass and woody dominance mapped at 30 m resolution across the tundra biome
The Arctic is warming faster than anywhere else on Earth, placing tundra ecosystems at the forefront of global climate change. Plant biomass is a fund…
www.sciencedirect.com
April 1, 2025 at 5:24 PM
First circumpolar maps of aboveground tundra biomass at 30 m resolution 💪 www.sciencedirect.com/science/arti...
These new estimates show that in total tundra plants (above-and belowground) store around 8 Pg C while the upper 30 cm soils store ca 53 Pg C.
These new estimates show that in total tundra plants (above-and belowground) store around 8 Pg C while the upper 30 cm soils store ca 53 Pg C.
Reposted by Anna Virkkala
" The sooner we reduce global greenhouse gas emissions, the sooner we can get the permafrost to refreeze," said Sue Natali.
Thanks @vivianla.bsky.social for covering this study!
Thanks @vivianla.bsky.social for covering this study!
"Significant and alarming" -- @vivianla.bsky.social's first piece for @wbur.org
www.wbur.org/news/2025/01...
www.wbur.org/news/2025/01...
A third of the Arctic is now a greenhouse gas emitter, Mass. study finds
A third of the Arctic is now emitting climate-changing greenhouse gasses after thousands of years of storing them, according to a new study from the Falmouth-based Woodwell Climate Research Center.
www.wbur.org
January 30, 2025 at 4:31 PM
" The sooner we reduce global greenhouse gas emissions, the sooner we can get the permafrost to refreeze," said Sue Natali.
Thanks @vivianla.bsky.social for covering this study!
Thanks @vivianla.bsky.social for covering this study!
Reposted by Anna Virkkala
Vuoden 2024 ilmastovuosikatsaus on julkaistu!
www.ilmastokatsaus.fi/2025/01/30/i...
Katsauksesta löydät muun muassa:
- Säätapahtumat Suomessa ja maailmalla vuonna 2024
- Keskilämpötilan kehitys pitkällä aikavälillä Suomessa
- Myrskypäivät Suomen merialueilla
- Itämeren merilämpöaallot
www.ilmastokatsaus.fi/2025/01/30/i...
Katsauksesta löydät muun muassa:
- Säätapahtumat Suomessa ja maailmalla vuonna 2024
- Keskilämpötilan kehitys pitkällä aikavälillä Suomessa
- Myrskypäivät Suomen merialueilla
- Itämeren merilämpöaallot
January 30, 2025 at 4:48 PM
Vuoden 2024 ilmastovuosikatsaus on julkaistu!
www.ilmastokatsaus.fi/2025/01/30/i...
Katsauksesta löydät muun muassa:
- Säätapahtumat Suomessa ja maailmalla vuonna 2024
- Keskilämpötilan kehitys pitkällä aikavälillä Suomessa
- Myrskypäivät Suomen merialueilla
- Itämeren merilämpöaallot
www.ilmastokatsaus.fi/2025/01/30/i...
Katsauksesta löydät muun muassa:
- Säätapahtumat Suomessa ja maailmalla vuonna 2024
- Keskilämpötilan kehitys pitkällä aikavälillä Suomessa
- Myrskypäivät Suomen merialueilla
- Itämeren merilämpöaallot
Reposted by Anna Virkkala
We are so grateful for everyone's engagement and great questions on this study! We want to address a few of the main ones that have appeared 🧵
🧊🔥 New paper @natclimchange.bsky.social: After millennia as a carbon deep-freezer for the planet, a third of the Arctic-boreal zone is now a CO2 source to the atmosphere. The int’l research team was led by @annvirkk.bsky.social
⬇️ Learn more:
permafrost.woodwellclimate.org/after-millen...
⬇️ Learn more:
permafrost.woodwellclimate.org/after-millen...
January 29, 2025 at 4:15 PM
We are so grateful for everyone's engagement and great questions on this study! We want to address a few of the main ones that have appeared 🧵
We are looking for a grant-funded doctoral resarcher on a project focusing on how tree and shrub expansion into the tundra impact biodiversity and carbon balance @Department of Geosciences and Geography @helsinkiuni.bsky.social! DM me if you are interested, and please share!
January 28, 2025 at 10:58 AM
We are looking for a grant-funded doctoral resarcher on a project focusing on how tree and shrub expansion into the tundra impact biodiversity and carbon balance @Department of Geosciences and Geography @helsinkiuni.bsky.social! DM me if you are interested, and please share!
Last week's highlight was our study in @natclimchange.bsky.social showing over 30% of the Arctic-boreal region as a CO2 source: www.nature.com/articles/s41...
Wildfires offset the increasing but spatially heterogeneous Arctic–boreal CO2 uptake - Nature Climate Change
How the carbon stocks of the Arctic–Boreal Zone change with warming is not well understood. Here the authors show that wildfires and large regional differences in net carbon fluxes offset the overall ...
www.nature.com
January 28, 2025 at 8:52 AM
Last week's highlight was our study in @natclimchange.bsky.social showing over 30% of the Arctic-boreal region as a CO2 source: www.nature.com/articles/s41...
First PhD paper (preprint) from a collaborator Nathalie Triches on some methodological tips related to Arctic N2O flux measurements: amt.copernicus.org/preprints/am... 🧐🏔🛢
Advancing N2O flux chamber measurement techniques in nutrient-poor ecosystems
Abstract. Nitrous oxide (N2O) is the third most important greenhouse gas, with its atmospheric concentration rising from 273 parts per billion (ppb) to 336 ppb since 1800, primarily due to agricultura...
amt.copernicus.org
January 28, 2025 at 8:48 AM
First PhD paper (preprint) from a collaborator Nathalie Triches on some methodological tips related to Arctic N2O flux measurements: amt.copernicus.org/preprints/am... 🧐🏔🛢
Reposted by Anna Virkkala
📢New paper🚨Excited to share our new review paper in @plosclimate.org on Browning events in Arctic ecosystems! 🌿❄️ A wonderful collaboration, brilliantly led by @garethphoenix.bsky.social. 🌿@naturvetenskap.bsky.social @vetenskapsradet.bsky.social
A new PLOS Climate Review article by @garethphoenix.bsky.social and colleagues brings together understanding of browning events in Arctic ecosystems to compare their impacts and rates of recovery, and likely future changes in frequency and distribution
journals.plos.org/climate/arti...
journals.plos.org/climate/arti...
Browning events in Arctic ecosystems: Diverse causes with common consequences
Arctic ecosystems are experiencing extreme climatic, biotic and physical disturbance events that can cause substantial loss of plant biomass and productivity, sometimes at scales of >1000 km2. Collect...
journals.plos.org
January 27, 2025 at 8:35 PM
📢New paper🚨Excited to share our new review paper in @plosclimate.org on Browning events in Arctic ecosystems! 🌿❄️ A wonderful collaboration, brilliantly led by @garethphoenix.bsky.social. 🌿@naturvetenskap.bsky.social @vetenskapsradet.bsky.social
Reposted by Anna Virkkala
Filling the Gaps: Context and Design of Arctic Carbon Flux Measurement Networks eos.org/editor-highl... -- an Editor's Highlight in @jgrbiogeo.bsky.social
Filling the Gaps: Context and Design of Arctic Carbon Flux Measurement Networks - Eos
Large scale observational networks are necessary for understanding the impact of a warming climate in the Arctic, but critical tools are crucial to how those networks are designed.
eos.org
January 24, 2025 at 2:07 PM
Filling the Gaps: Context and Design of Arctic Carbon Flux Measurement Networks eos.org/editor-highl... -- an Editor's Highlight in @jgrbiogeo.bsky.social
Reposted by Anna Virkkala
🧊🔥 New paper @natclimchange.bsky.social: After millennia as a carbon deep-freezer for the planet, a third of the Arctic-boreal zone is now a CO2 source to the atmosphere. The int’l research team was led by @annvirkk.bsky.social
⬇️ Learn more:
permafrost.woodwellclimate.org/after-millen...
⬇️ Learn more:
permafrost.woodwellclimate.org/after-millen...
January 21, 2025 at 5:32 PM
🧊🔥 New paper @natclimchange.bsky.social: After millennia as a carbon deep-freezer for the planet, a third of the Arctic-boreal zone is now a CO2 source to the atmosphere. The int’l research team was led by @annvirkk.bsky.social
⬇️ Learn more:
permafrost.woodwellclimate.org/after-millen...
⬇️ Learn more:
permafrost.woodwellclimate.org/after-millen...
Reposted by Anna Virkkala
New paper in @agu.org Geophysical Research Letters: Detecting #Arctic hotspots using satellite and temp records shows extreme warming, drying and browning in Siberian forests and other areas of high ecosystem #climate stress in northern #Alaska & Northwest Territories of #Canada. #AGUPubs #GIS
a 🧵:
a 🧵:
January 16, 2025 at 2:33 PM
Reposted by Anna Virkkala
📣 Open PhD position in new #ERCStG project COLDSPOT. Are you interested in exploring processes regulating CH4 and N2O sinks in #permafrost soils? Excited to join Arctic field campaigns? Applying biogeochemical and microbial techniques? Come work with us! tinyurl.com/mu8fhscm
@cenunihh.bsky.social
@cenunihh.bsky.social
Job advertisement
tinyurl.com
November 28, 2024 at 10:39 AM
📣 Open PhD position in new #ERCStG project COLDSPOT. Are you interested in exploring processes regulating CH4 and N2O sinks in #permafrost soils? Excited to join Arctic field campaigns? Applying biogeochemical and microbial techniques? Come work with us! tinyurl.com/mu8fhscm
@cenunihh.bsky.social
@cenunihh.bsky.social