David Harning

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...

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.

Would love to get involved!

Quaternary geochronology This Collection invites submissions on the latest advances in quaternary geochronology.

Calling all Quaternary Geochronology enthusiasts! I'm serving as a Guest Editor for @natureportfolio.nature.com (Scientific Reports) upcoming special issue and would be excited to see your submission. Learn more about the collection and how to contribute👇
www.nature.com/collections/...

Statement from U.S. Scientists in Solidarity with Greenland STATEMENT FROM U.S. SCIENTISTS IN SOLIDARITY WITH GREENLAND Amerikarmiut Kalaallit Nunaanut misissuiartortartut nunatsinnut ataqatigiinerannu...

To Greenlanders: thank you for years of friendship and partnership; we stand with you. Qujanaq, ilagaasi.

U.S. scientists: Write your reps in D.C. TODAY. Urge them to support Greenland's right to self-determination. Insist the U.S. engage respectfully and peacefully with our ally. bit.ly/3LjITdm

I’m interested! Will follow up by email.

New paper alert ! 🙂
Happy to share our new study published in The Cryosphere !
doi.org/10.5194/tc-1...
We modelled the evolution of the Greenland Ice Sheet from the LGM (24 ka) to the present and learned a lot on its former history and dynamics !
@jeremyely.bsky.social @chrisdclark.bsky.social

Postdoctoral Research Associate - Earth, Environmental, and Planetary Sciences Position Summary The Climate and Paleoclimate Lab in the Department of Earth, Environmental, and Planetary Sciences at WashU in St. Louis seeks a Postdoctoral Research Associate in tropical climate/pa...

We're hiring! I'm recruiting a Postdoctoral Research Associate in climate & paleoclimate modeling of the tropical Americas. Come obsess over the tropical rain belt with me! :) Please share w/folks who may be interested. Ad here: wustl.wd1.myworkdayjobs.com/en-US/Extern...

Congrats, great to see this progress - let’s do some lipids!

Cosmic dust reveals dynamic shifts in central Arctic sea-ice coverage over the past 30,000 years Arctic sea-ice loss affects biological productivity, sustenance in coastal communities, and geopolitics. Forecasting these impacts requires mechanistic understanding of how Arctic sea ice responds to ...

Huge paper for the Arctic Ocean published today in @science.org - a new 30,000 year history of Arctic Ocean sea-ice cover reconstructed from the accumulation of cosmic dust-derived helium-3! www.science.org/doi/10.1126/... (1/n)

PNAS: Six-million-year-old ice discovered in Antarctica offers unprecedented window into a warmer Earth via our NSF COLDEX & US Antarctic Program. ❄️ www.pnas.org/doi/10.1073/...

Not sure if I’m supposed to promote my work as a furloughed government employee, but our paper comparing vegetation communities of the now-submerged central Bering land bridge and modern (Holocene) Bering Sea islands, with implications for the timing of sea-level transgression, is out!

miriamcjones.bsky.social et al.’s #newarticle on Bering Land Bridge (BLB) climate & vegetation during the Last Glacial Maximum shows Bering Sea island vegetation communities reflect the timing of their isolation from the BLB with sea level transgression: doi.org/10.1080/15230430.2025.2557062

Global mean sea level over the past 4.5 million years Changes in global mean sea level (GMSL) during the late Cenozoic remain uncertain. We use a reconstruction of changes in δ18O of seawater to reconstruct GMSL since 4.5 million years ago (Ma) that acco...

It definitely piqued my interest to see Clark et al's reconstruction of sea level for the past 4.5 million years, something I first heard about several years ago. However, upon reading it, I am very surprised that this was published. 🧵 1/11

doi.org/10.1126/scie...

Earth scientists Maggie Osburn and Mia Tuccillo bag up plant samples in a rocky Greenland landscape, with an iceberg-spotted fjord and glacier-covered mountains in the background.

New paper! PhD student Mia Tuccillo has uncovered another big impact of past warming in Greenland: lakes lost oxygen for thousands of years and cyanobacteria took over 🦠 🧪 🦠. It's kinda yikes...
With collaborator @geobiomaggie.bsky.social (1/3)

🚨 New paleoclimate proxy paper from a team of INSTAARs, working with colleagues from UC Santa Cruz & U of Iceland. 1st author David Harning now works with CIRES & NOAA, but remains an INSTAAR Affiliate. Congrats all! 👏🏽

Both redox potential and climate control molecular proxies in Icelandic Holocene lake sediments Communications Earth & Environment - Recovery of complementary materials from well-ventilated and seasonally stratified lakes can allow reliable reconstruction of local temperature and...

New paper on ancient DNA and lipids from Icelandic lakes. This one threw some unexpected results and now has me thinking a lot about lake oxygen’s role in organic matter preservation, the climate proxies derived from them, and past methane cycling. #Paleosky www.nature.com/articles/s43...

Registration for experts interested in serving as Expert Reviewers and providing scientific comments on the First Order Draft of the Special Report on Climate Change and Cities is now open!

Register here: apps.ipcc.ch/comments/src...
⚠️ Registration closes 30 Nov2025

🔗 www.ipcc.ch/2025/09/17/p...

Development of new global lake brGDGT-temperature calibrations: advances, applications, challenges, and recommendations Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a group of temperature-sensitive membrane lipids found in bacteria that have been widely …

🚨New paper!🚨🥳

Delighted to share our new paper out now on global lake brGDGT temperature calibrations: advances, applications and challenges:

www.sciencedirect.com/science/arti...

@hassfacultyncl.bsky.social @bas.ac.uk @ogu-bristol.bsky.social

Reminder: Applications are open until October 31st! 📣

Alpine wildflowers bloom on the tundra of Niwot Ridge. Photo by William Bowman.

Know a CU Boulder undergrad who might want to be an Ecology Lab Technician for 8-10 hrs/wk?
• Process alpine plant seeds collected in Colorado.
• Ideal start date: Oct 1 (or as soon as possible).
• Application deadline: Sep 19.
Look for student jobs at www.colorado.edu/instaar/jobs

🦣🍖🧬 Fully funded 3-yr PhD in palaeogenomics & bioinformatics! Help me push non-model palaeogenomes beyond their limits @DTU in Denmark.

Start: Feb 2026 (flexible)
Application deadline: 24 Oct 2025

For details click here: tinyurl.com/BioExtPhD

Reposts appreciated 😁

A grassland on a sunny day near Boulder, CO

We're recruiting!! Myself along with Nathan Gill, Dylan Schwilk @schwilk.org, and Katharine Suding are recruiting people for Master's, PhD, and postdoc positions in GrassFire, an NSF funded project examining fuels and fire risk in grassland ecosystems across the Southern Great Plains! 🔥🌿🐮

"mentorship is a two-way exchange that energizes and inspires all participants to become active agents of change"
tos.org/oceanography...

I'm looking for a driven PhD student to join us at @au.dk and to both generate new paleoclimate data in the lab and work on computational problems to understand climate relationships across timescales.

Get in touch if you'd like to hear more, and apply by Nov 1!

phd.nat.au.dk/for-applican...

Journal of Quaternary Science Call for Papers Beyond the Eruption: Advances and applications in distal tephra analysis across the Geosciences <em>Journal of Quaternary Science</em> publishes papers on any field of Quaternary research, advancing understanding of earth's history over the last 2.58 million years.

🌋📢 Calling all #tephra researchers!
Join us in shaping this new JQS Special Issue.

"Beyond the #Eruption – Advances and Applications in Distal Tephra Analysis Across the Geosciences"

Deadline: 2 Jan 2026.

Further details below: onlinelibrary.wiley.com/page/journal...

Cosmogenic Isotope Laboratory Manager in Doerr School of Sustainability, Stanford, California, United States The Stanford Cosmogenic Isotope shared laboratory within Stanford University’s Doerr School of Sustainability (SDSS) is seeking an experienced.....

The Stanford Cosmogenic Isotope Lab is hiring a new (permanent) Lab Manager. Please share and apply if you are qualified. phxc1b.rfer.us/STANFORDSD1UPF

Converging evidence constrains late pleistocene bering land bridge history The Bering Land Bridge was an important biotic corridor and climatic modifier during the Pleistocene (2.58 million to 11,700 thousand years ago [ka]).…

Out today in Quaternary Science Advances! @cwanket.bsky.social's paper linking terrestrial, marine, and GIA model results to constrain the last (most recent) formation of the Bering Land Bridge to between 40 and 35 thousand years ago:
www.sciencedirect.com/science/arti...

Abrupt weakening of deep Atlantic circulation at the last glacial inception - Nature Communications Zhou et al. report an abrupt weakening of the Atlantic Meridional Overturning Circulation at the last glacial inception. The observed circulation slowdown could explain the delayed timing of the atmos...

Earth scientists know a lot more about getting out of an ice age than going into one. We report an episode of AMOC slowdown at 115 thousand years ago that's likely astronomically forced (via sea-ice) and coincides with a delayed drawdown of atmospheric CO2 @natcomms.nature.com rdcu.be/eALD1

#PaleoSky