screenshot of a resignation letter expressing sadness at leaving NASA

My resignation letter

Time series plot depicting predicted Nino 3.4 region ocean temperature anomalies from the latest (Mar 2026) ECMWF ensemble. It depicts an extremely rapid rise in such temperatures, from modest negative anomalies to strong positive anomalies, by mid-summer 2026--indicative of a transition from weak-moderate La Nina conditions to moderate-strong El Nino conditions over just a few months.

Whew.

All signs are increasingly pointing to a significant, if not strong to very strong, El Niño event. I'll have more to say in coming weeks & months, but for now I'll just say that this is increasingly likely to become a major regional-to-global climate driver in 2026-2027.

Oxygen Isotopes in Tree Rings Track Neotropical Climate Dynamics Tree-ring δ18O from Abies guatemalensis in Central America captures interannual variations in boreal summer rainfall Lighter δ18O years are associated with a weakening of the Caribbean Low-Level ...

Excited to have this paper out showing a strong coupling between Central American tree-ring oxygen isotopes and ocean–atmosphere dynamics (interbasin SST gradients, ITCZ, CLLJ... ). Many thanks to all co-authors!

agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Caroline Leland at AGU: Temperature Signals of Siberian Pine and Larch in North-central Mongolia YouTube video by Lamont-Doherty Earth Observatory

At #AGU25, tree ring scientist Caroline Leland of LDEO shared her research on dshared research on climate sensitivity of wood from Siberian Pine and Larch in North-central Mongolia to improve or build upon reconstructions of long-term climate. ➡️ Lamont at AGU25: https://lamont.columbia.edu/agu25

From @AGU.org: Senators are working on legislation to save NCAR, but we need extra support for these 8 states. Your Senators in Alabama, Alaska, Florida, Louisiana, Mississippi, North Carolina, Texas, and Wyoming need to hear from you.

Upcoming atmospheric river approaching California could be attached to a “bomb cyclone”…

But here ‘s the current flood fcasts (surely not the final word but), for now broadly not as dire as could be.

www.sfchronicle.com/weather-fore...

An atmospheric river continues to drench the Pacific Northwest in heavy rainfall, resulting in a widespread flooding threat across western Washington.

This timelapse since the beginning of the week shows the relentless plume of moisture that has soaked the region.

Please contribute! We neex broad input, different forest types, and an array of natural disturbances to see how disturbance regimes are changing.

Excited for this paper to be out! With the collaboration of met services from Central America, we evaluate in detail the biases in gridded products that arise from the underlying station data, and the effect this has on the apparent emergence of regional drying trends. Thanks to all the co-authors!

Impacts of Spatial and Temporal Station Availability on Gridded Precipitation Products in Central America There are significant differences between gridded precipitation products in Central America in both variability and trends CHIRPS consistently outperforms Global Precipitation Climatology Centre ...

Rainfall data can be hard to come by in the tropics. @anaigmendez.bsky.social leads a new paper taking a deep dive into the quality and potential biases in gridded precipitation data in Central America. CHIRPS comes out ahead, but be wary of trends! agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Disturbance interactions have profound consequences for forest health, yet remain poorly understood.

Here we use DAGs to differentiate #Synergisms, #CompoundDisturbances & #NetworkEffects and review the impacts of climate change.

Final version out now! 🧪🌐🍁🌱
www.annualreviews.org/content/jour...

Join the Laboratory of Tree-Ring Research at the University of Arizona for our 2026 Dendrochronology Intensive Summer Course (DISC)! Spend 3 great weeks (May 18th to June 5, 2026) in the field, lab, and classroom learning first-hand how tree-ring research is done! ltrr.arizona.edu/summerschool

UC to Stop Funding Systemwide Postdoc Program Established in 1984 to encourage women and minority Ph.D.s to pursue academia, the program has attracted right-wing criticism for prioritizing diverse candidates.

A devastating set of decisions on the part of UC leadership to withdraw support from our nationally recognized postdoc program that prioritizes research excellence combined with addressing our university public service mission. www.insidehighered.com/news/faculty...

Resolution and Frequency‐Dependent Climate Signals in an Arctic Tree‐Ring Temperature Reconstruction of the Last Millennium Tree-ring density measurement resolution affects low-frequency trends in temperature reconstructions High-resolution anatomical maximum latewood density has stronger correlations with instrumenta...

Dr. Julie Edwards (@julieedtree.bsky.social) leads a new paper showing that high-resolution cellular-scale measurements (Quantitative Wood Anatomy) yield better temperature signals in Alaskan tree rings than even conventional MXD across all frequencies agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Thrilled our #AREES review on #Disturbance #Interactions is out! #ClimateChange = MAJOR DISRUPTER, but not how you’d expect 👀

#NewFramework: #CC effects on interactions🧪🌐🍁🌱
HUGE🙏4 legendary efforts: @rupertseidl.bsky.social @brian-j-harvey.bsky.social @julieedtree.bsky.social

tinyurl.com/3p97ztr5

Climate change increasingly alters the interactions between forest disturbances. Here we present a framework for quantifying dist. interactions and compile evidence for their impacts. Led by @dudney-joan.bsky.social with @brian-j-harvey.bsky.social & @julieedtree.bsky.social doi.org/10.1146/annu...

It's been a blast kicking off my first research project in Yosemite this summer. I am so thankful to continue learning about the Sierra Nevada and for our outstanding team!

If you have cool research about climate over the last 2000 years, consider submitting your abstract to our session Climate of the Common Era at the 2025 AGU Fall Meeting #AGU25 #paleoclimate. The abstract submission deadline is Wednesday, July 30 at 23:59 EDT.

agu.confex.com/agu/agu25/pr...

The Influence of Carbon Dioxide and Precession on Western North American Hydroclimate and Pacific Sea Surface Temperature During the Holocene A network of proxy records shows western North American hydroclimate and Pacific sea surface temperature co-evolved during the Holocene The western North America became wetter while the eastern e...

Excited to (finally) share my new paper on Pacific SST and western North America hydroclimate during the Holocene! TL;DR They are connected, CO2 and precession both affect hydroclimate. Thanks @xiaojingdu.bsky.social @meredithparish.bsky.social @baylorfk.bsky.social+others
dx.doi.org/10.1029/2024...

Contrasting effects of warming and drought on autumn phenology of photosynthesis and growth in white spruce Warming delays the autumn downregulation of photosynthesis in white spruce; however, local adaptation to photoperiod constrains the timing of growth cessat

The first chapter of my PhD thesis is officially published. If you're into conifers, climate change or cold acclimation then this paper is for you 🌿❄️

academic.oup.com/plphys/artic...

As I wrap up my PhD this year, I'm also beginning the search for postdoc opportunities so keep me in mind

Final fieldwork of the season at Big Rock Creek in SoCal was made much cooler by the monsoon rolling in! This site is part of my project using tree rings to reconstruct atmospheric rivers in SoCal, but maybe there’s a monsoon story hiding in the wood too 👀

A Nutrient Effect on the TEX86 Paleotemperature Proxy Nutrient stress alters GDGT distributions in marine sediments, resulting in elevated TEX86 ${\text{TEX}}_{86}$ values beyond those related to thermal effects Paleoclimate case studies from the Ar...

Now published in @agu.org Geophysical Research Letters!

What happens to marine archaea when they’re hungry? And what does that mean for the TEX₈₆ paleothermometer?

Full paper here: doi.org/10.1029/2025...

Thanks to my coauthors and mentors for their support — and stay tuned, more is coming!

Resolving troubling discord in Boreal versus Austral late Holocene temperature history | BOREAUSTRALIS | Projekt | Fact Sheet | HORIZON | CORDIS | European Commission According to temperature reconstructions based on natural climate proxy archives (ice cores, lake sediments, tree rings etc.), Northern and Southern Hemisphere (NH, SH) temperature histories differ in...

2 PhD positions in dendroclimatology! cordis.europa.eu/project/id/1...
The project is centered around working up millennium-long wood anatomical datasets to reconstruct temperature.
web103.reachmee.com/ext/I005/103...
Deadline 30th of June. For questions, contact: jesper.bjorklund@gu.se

Epic (hot!!) day on #MtFig coring bigcone Douglas-fir for @julieedtree.bsky.social amazing #NSF postdoc research! These ladies are such badasses (and such good vibes!). W/ @michelledmohr.bsky.social @olross.bsky.social Stay tuned for updates on historical patterns of atmospheric rivers in #socal!

Tree‐Ring Anatomy Improves the Reliability of Temperature Reconstructions Using Relict Wood Cell wall dimensions: Subfossil wood cell wall measurements are less affected by degradation than MXD from X-ray densitometry Identifying degradation: The holo-cellulose-to-wood ratio in low-dens...

Quantitative wood anatomy measurements for the win! This time when using subfossil wood - 'Tree-Ring Anatomy Improves the Reliability of Temperature Reconstructions Using Relict Wood' agupubs.onlinelibrary.wiley.com/doi/full/10....

Olivia coring a large big-cone Douglas fir tree on a shady slope with smaller firs, oaks, and cedars in the surrounding area.

A vista of the Peninsular Ranges in northern San Diego County near Palomar Mountain, an oak woodland is in the foreground.

Olivia cores a big-cone Douglas fir tree on a shady slope. Leaf litter covers the ground and small oaks are in the background

Dervla smiles while coring a big-cone Douglas fir tree on a rocky slope. Large granite(?) rocks covered in moss are behind her

Fieldwork this past weekend with the AMAZING @olross.bsky.social and Dervla Meegan-Kumar in the Cleveland National Forest. NSF-funded, I’m using tree-ring width to reconstruct atmospheric river variability in Southern California, which will help us better prepare for future storms in the region.

Global Warming Is Likely Affecting Regional Drought Across Eurasia Rigorous climate change detection and attribution is possible without the use of general circulation model simulations 21st century Eurasian hydroclimate patterns are incompatible with pre-indust...

Can we use paleo for detection and attribution of drought without a climate model? Yes!

New work led by @drkatemarvel.bsky.social, with me and some old guy.

agupubs.onlinelibrary.wiley.com/doi/10.1029/...

Tree-ring evidence of the elusive 1959 summer cold event in northwestern North America Tree-ring records in northwestern North America suggest that the year 1959 was anomalously cold relative to the last several centuries. Here, we investigate the spatial characteristics, specific ti...

And in another new paper out today, lead author Cari Leland shows how tree-ring proxies and wood anatomy track a transient synoptic scale cold snap across northwestern North American in the late summer (late July to early August) of 1959 www.tandfonline.com/doi/full/10....

Climate Variability in the Gulf of California Over the Last 1,300 years Sea surface temperatures in the Gulf of California (GoC) have varied on multidecadal to multicentennial time scales over the Common Era There is no one-to-one relationship between reconstructed S...

Congratulations to @kiradharris.bsky.social who leads a new paper in Paleoceanography and Paleoclimatology on last millennium SSTs in the Gulf of California and leaf wax evidence for North American Monsoon variability agupubs.onlinelibrary.wiley.com/doi/full/10....

National Science Foundation suspends salary payments, leaving researchers unable to pay their bills An NSF online payment system remained down after the federal funding freeze was lifted, leaving early-career scientists scrambling to pay bills

National Science Foundation suspends salary payments, leaving researchers unable to pay their bills www.statnews.com/2025/01/30/t...
Story by @ericboodman.bsky.social