Dr. Merritt Turetsky Profile picture
Director of Arctic National Security, CU Boulder. Ecologist & chaser of permafrost & fires. In love with boglands. Represented by @zcosini
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Sep 23, 2023 5 tweets 2 min read
There is a ton of misinformation in my replies so here is a primer on permafrost carbon. Permafrost stores a HUGE amount of carbon because ancient life took up CO2, built biomass, then died. That organic matter (~50% C) slowly accrued in Earth's best freezer for 1000s of yrs. 1/ Photograph of a man wearing a baseball hat and a blue t shirt with overalls holding up a permafrost core while kneeling on the ground in a forest. When frozen organic matter in permafrost warms, microbial activity speeds up. Microbes use the organic matter in their respiratory processes, which can release a variety of GHGs as byproducts, mostly CO2 but also methane, which make their way to the atmosphere. 2/ Image of a permafrost peat core with brown markings denoting ancient vegetation patterns.
Jun 16, 2023 10 tweets 4 min read
Fire Facts from a Boreal 🔥 Ecologist to help you understand what is really going on in Canada.

Fire Fact 1: The term “forest fire” is misleading in boreal regions. Also burning are peatlands and permafrost ecosystems, which store LOTS of ancient carbon. 1/ Fire Fact 2: We tend to picture crown fires, with flames leaping up into tall trees. However, the majority of what burns and fuels boreal fires is ON THE GROUND. More than 80% of what burns and emits greenhouse gas is moss, peat, and litter. 2/ Photograph of red Sphagnum ...
Dec 21, 2022 6 tweets 3 min read
False narratives about the #Arctic & #permafrost are being driven by the media. Here are some facts from science. 1) permafrost underlies 1/4 of N hemisphere land and 1/2 of Canada. Frozen ground is a backbone for ecosystems and infrastructure. 1/ fediscience.org/@queenofpeat/1… Fact 2: It’s false to say thaw is unprecedented as it has happened in the past. However, rates of thaw are getting faster w/ warming, and because of climate change some permafrost will never return. Here is a video of me realizing ancient permafrost in Alaska is gone forever. 2/
Jan 5, 2022 4 tweets 2 min read
I am seeing and receiving pushback for being a climate scientist speaking out about the #MarshallFire. I understand this perspective. 1) It's difficult to attribute the #ClimateCrisis to any single event, and 2) this event was extremely complex. But hear me out. 1/ 1) The #MarshallFire was either a reminder or a wakeup call that whether you live up the canyon (like I do) or on the plains, 🔥 is an ongoing threat.
2) Climate-fire relationships are complex, but due to the #ClimateCrisis, we need to learn to live with 🔥 more than ever. 2/
Dec 31, 2021 7 tweets 2 min read
~30,000 people fled the #MarshallFire, one of the most terrifying experiences we can face. Today I am reflecting on the added anxiety and consequences of fleeing a #climatemergency disaster during the COVID pandemic. Here I'll share a personal story w/ a tiny bit of insight. 1/ Just outside Boulder, circa January 2021

Normally I love the sound of wind in the trees. But the winds were howling that day. It was difficult to ignore. The house was groaning, shifting. We were in full lockdown due to COVID-19. I was trying to stay busy. 2/
Dec 22, 2021 7 tweets 3 min read
Permafrost stores 2x the amount of carbon in the atmosphere yet is not considered by many climate models. Are we totally screwed??? Here I will explain what we know and why I promote #ClimateActionNow but not panic. 1/ Schematic of global carbon pools showing that permafrost sto The Arctic (and its permafrost soils) is not a missing black box in any climate model, which all include Arctic soils. Until we explicitly include permafrost in these models, it is difficult to know what climate feedbacks we are missing. Likely to be in the middle. 2/ Image of a permafrost core laying on the ground of a black s
Nov 11, 2021 4 tweets 3 min read
Permafrost stores >2x as much as carbon as is in the atmosphere. The most carbon-rich permafrost is associated with ground ice, yet climate models don't account for ice-rich permafrost thaw (Turetsky et al. @Nature 2019). This WICKED problem underestimates Arctic emissions. 1/ Map showing the colocation of carbon rich permafrost soils w In my @CUBoulder lecture today I outlined a trifecta of uncertainties related to permafrost & carbon.
1) We know plants and new biomass will offset some permafrost soil carbon losses with thaw, but how much? And will that "green carbon" last in the face of 🔥🔥👇 2/ Photograph of a wildfire in a permafrost wetland complex sho
Nov 4, 2021 12 tweets 6 min read
Please share to build awareness! Permafrost is being featured today at #COP26Glasgow. Here I will explain why this is SO important to our future climate and everything we know and love about the Arctic. Stick with me for a cooler than cool 🧵. Photo @grosse_guido 1/ Photograph of a permafrost cliff showing exposed permafrost Permafrost is diverse, comprised of frozen earth (rock, soil, sediment...). It often contains pockets of ice of all sizes. For many many 1000s of yrs, permafrost has been quietly doing its thing. Aggrading & locking atmospheric carbon into frozen ground. A true climate champ! 2/ Photograph of a permafrost core with layers of frozen peat a
Sep 30, 2021 11 tweets 3 min read
Big Run Bog, West Virginia. circa 1995

This is a true story, but also science legend. When bogs want to share their secrets, they delight with sunlight & spider webs glistening on wet stems, dragonflies feasting. But a bog can turn on you at any moment, as I learned. 1/ Image of sundews, moss, and sedges in a bog. The drive was fueled by stories and big laughter from our guests. Approaching the rolling hills of West Virginia, the Czech scientists pressed their faces against the warm windows. We rolled into motel rooms eager to greet the morning. Such perfect field conditions we thought. 2/
Aug 27, 2021 14 tweets 6 min read
This is a story about one of the most powerful plants on Earth, the climate champion Sphagnum moss. This story is about science, discovery, & how much we have left to learn. Not about a distant planet, but a group of plants millions of years old that continues to astound us. 1/ Photograph of red Sphagnum capitula. Sphagnum are infamous for storing carbon from the atmosphere via thick layers of peat. Sphagnum tissue decomposes slowly, sometimes more slowly than wood! As a result Sphagnum & peatlands have cooled our climate for millennia. So please thank Sphagnum moss! 2/ Image of permafrost peat including some Sphagnum remains.
Jul 15, 2021 7 tweets 3 min read
In @NMNH's panel on vicious #climate cycles, I was asked why permafrost is important. Here I'll give my top reasons from carbon to caribou. #1 For millenia, permafrost has been Earth's freezer for ancient C. Permafrost stores more C than global forests; on par w/ fossil fuels. 1/ Cartoon of global carbon pools showing that permafrost store Reason #2. Permafrost is the backbone of the Arctic. Thaw can trigger sinking or erosion that kills vegetation & makes ground dangerous for travel. The loss of frozen ground means the loss of stability. Travel routes, hunting grounds, animal migration - all unreliable w/ thaw. 2/ Panorama of permafrost thaw in northwestern Canada showing s
Mar 27, 2021 5 tweets 2 min read
A wee history lesson on wetlands as wastelands. This philosophy dominated colonialism in the 🇺🇸 as wetlands were seen as a barrier to “building the country”. Early settlers lacked resources to drain wetlands, but this changed w/ the Swamp Land Act passed by Congress in 1849. 1/ States gained the right to sell wetlands, w/ profit intended to fund “dehydration” of the land. This Act decimated wetlands throughout #Louisiana & #Florida but also #Minnesota & #Oregon. It also set the stage for toll-use of canals, privatizing travel in the U.S. 2/
Mar 3, 2021 15 tweets 5 min read
Have a job offer? Need to negotiate but not sure how? Negotiating wisely has long-term $ impacts, yet often is considered a taboo topic. No more! Here I'll share some advice as someone who has sat on both sides. Please share to help out early career colleagues in any field! 1/ Why is negotiating a taboo subject? Many orgs (including universities) have convinced us that we should feel honored & lucky to receive a job offer. I call bullshit. We all worked too hard for that. Rule 1: the minute you have a job offer, you are in the driver's seat. 2/
Mar 1, 2021 10 tweets 5 min read
Permafrost thaw is about WAY more than carbon and climate. From impacting caribou to mobilizing mercury and legacy arsenic from gold mining, many thaw impacts are not conceptualized yet let alone understood. Below shows how pockmarks of thaw can consume entire forests. 1/ Photograph of wet thaw features within permafrost forest. How can permafrost thaw consume whole forests or trigger landslides? The answer is simple yet so complex. Ground ice. Thaw of ice-rich permafrost causes drama. Peek inside permafrost to view gorgeous ice wedges in Alaska's #permafrosttunnel. Stunning. 2/
Jan 13, 2021 6 tweets 3 min read
In case you thought Sphagnum was only found in boreal peatlands. This is one of my most favorite discoveries, carved into a Sphagnum hill on Basse-Terre, Guadeloupe. I've imagined all sorts of stories....someone loves this place. Sphagnum hill and door in Guadeloupe. My 5 favorite Sphagnum facts:
1) Sphagnum is a genus with >350 species thriving all over the world.
2) Sphagnum is THE most important genus for carbon in the biosphere. Its biomass stores more carbon (once in the atmosphere) than any other genus of life. 2/ Photograph of Sphagnum mosses
Dec 1, 2020 7 tweets 3 min read
Pimples or pingos? Thoughts on thawing permafrost and explosive craters in Siberia, starting with this nice @BBC_Future article. 1/ bbc.com/future/article… Pingo means small hill in Inuvialuit (Yakut: bulgunnyakh). For years, permafrost scientists wondered if these explosive craters were the remnants of pingos collapsing (sometimes called ognips). Check out my entire list of favorite permafrost terms. 2/
Nov 14, 2020 10 tweets 7 min read
With a lot of debate this week on how models simulate permafrost thaw & climate impacts, I want to explain how we actually MEASURE permafrost change. Follow this thread for the pretty scenes or the weird science. Here is me caught in a surprise ❄️ squall w/ permafrost gear. 1/ Picture of Dr. Turetsky holding metal field equipment on a r The traditional method of monitoring permafrost change is through the trusty frost probe. In this quick video I explain our work on 🔥-permafrost interactions while taking a frost probe measurement. 2/
Nov 12, 2020 5 tweets 5 min read
@ClimateOfGavin @mammuthus @theresphysics Buckle up for a permafrost ride! This paper is a thought experiment that relies on my empirical & modeling work on permafrost C release. First, I ♥️ using models for thought experiments so that is a positive here. Below is what permafrost THAW looks like - it's complicated! 1/ Image @ClimateOfGavin @mammuthus @theresphysics Permafrost is represented very crudely in most models to date. We know these frozen soils store a lot of C, but we know that only a fraction of that C is vulnerable to decomposition post-THAW. As temp constraints are released, there are other mechanisms that protect that C. 2/ Image
Nov 2, 2020 20 tweets 12 min read
It's a great day for a permafrost mash-up! Let's combine a few things I love - permafrost, language, & culture. Follow this thread if you want to learn some *cool* words from across the Arctic. Great for Scrabble or your next northern adventure. My top 10 #Permaterms 1/ My first #permaterm is pingo, which means small hill in Inuvialuit. A pingo is a mound in the permafrost region that has a core of massive ice & covered w/ soil & vegetation. Several are protected in the Pingo National Landmark area,Tuktoyaktuk Northwest Terroritories Canada. 2/ Pingo National Landmark area,Tuktoyaktuk Northwest Terrorito
Oct 9, 2020 19 tweets 10 min read
Welcome to my dive into #MarvelousMoss. Most of what we know about plants centers on vascular plants. But there is this incredibly rich & interesting lineage(s) of nonvascular plants or bryophytes. These plants are other-worldly, create habitat & be habitat, & defy physics! 1/ Image Bryophytes=liverworts, hornworts, mosses are often referred to as cryptogams (meaning hidden reproduction). But I think about cryptic diversity. Most of the plant diversity in northern ecosystems is on the ground, difficult to ID, but provides loads of important functions. 2/ Arctic mosses and ground co...
Sep 28, 2020 7 tweets 4 min read
🔥is now shaping the Arctic. In @NatureGeosci
we outline a call to action. Key messages - 1) a global climate problem requires a global scale solution, 2) western science can't tackle this without Indigenous knowlege holders. w/ @jmccarty_geo @DrTELS instaar.colorado.edu/news-events/in… 2/ Will Arctic 🔥 burn into ancient carbon stored in peat & permafrost? We conclude that the 2020 fires in Siberia showed signs of holdover or zombie fires, which can overwinter in deep peat & influence burning the following season. This represents momentum in the climate system.