Anna Virkkala

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 ...

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!

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...

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...

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...

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/...

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...

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). 🌎🏞🏔

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

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…

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.

" 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!

Sinisellä pohjalla oleva Suomen maan äärirajat jonne on viivoilla lisätty tietoa eri säätapahtumista. Esim. vuoden alin lämpötila, vuoden suurin lumensyvyys ja vuoden kovin tuulennopeus.

Pylväsdiagrammi Suomen keskilämpötilasta. Keskimääräistä kylmemmät vuodet ovat sinisellä ja lämpimämmät punaisella. Musta viiva kuvaa liukuvaa 10 vuoden keskiarvoa.

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

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!

After millennia as carbon dioxide sink, more than one-third of Arctic-boreal region is now a source - Permafrost Pathways

A story summrizing the key results put together by @k8petersen.bsky.social here: permafrost.woodwellclimate.org/after-millen...

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 ...

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... 🧐🏔🛢

📢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

That's terrible!

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.

Filling the Gaps: Context and Design of Arctic Carbon Flux Measurement Networks eos.org/editor-highl... -- an Editor's Highlight in @jgrbiogeo.bsky.social

🧊🔥 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...

Map of areas that experienced ecosystem climate stress in the Arctic-boreal region between 1997-2020 as detected by multiple variables including satellite data and long-term temperature records. Watts et al., 2025, Geophysical Research Letters

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 🧵:

Job advertisement

📣 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