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Jessica Tierney

@leafwax.bsky.social

1.5K followers 130 following 64 posts

Climate scientist living in the Sonoran Desert. Analyzer of leaf waxes to learn about past climate change. Professor at the University of Arizona. I also like birds, nature, pets🦉🌿🐕 | Opinions are mine, not those of my employer .. more

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Jessica E. Tierney (born 1982) is an American paleoclimatologist who has worked with geochemical proxies such as marine sediments, mud, and TEX86, to study past climate in East Africa. Her papers have been cited more than 2,500 times; her most cited work is Northern Hemisphere Controls on Tropical Southeast African Climate During the Past 60,000 Years. Tierney is currently a professor of geosciences and the Thomas R. Brown Distinguished Chair in Integrative Science at the University of Arizona and faculty affiliate in the University of Arizona School of Geography, Development and Environment Tierney is the first climatologist to win NSF's Alan T Waterman Award (2022) since its inception in 1975. .. more

Environmental science 43%

Geology 26%

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Jessica Tierney @leafwax.bsky.social · 23d

The special issue @quantamagazine.bsky.social on Climate Science just dropped and I know what my weekend readings is gonna be 👍🏻 www.quantamagazine.org/how-we-came-...

How We Came To Know Earth | Quanta Magazine

Climate science is the most significant scientific collaboration in history. This series from Quanta Magazine guides you through basic climate science — from quantum effects to ancient hothouses, from...

www.quantamagazine.org

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Jessica Tierney @leafwax.bsky.social · Sep 8

I do love Reddit for so many reasons. Thanks for accepting me bros!

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Reposted by Kevin J. Anchukaitis

Jessica Tierney @leafwax.bsky.social · Sep 4

I stand by my offer to appear on Joe Rogan and set the record straight about our half-billion-year temperature reconstruction www.theguardian.com/environment/...

Joe Rogan claims study shows Earth cooling – but report’s authors say he’s wrong

Scientists say ‘old-school denier nonsense’ isn’t helpful as podcaster repeatedly airs false claim on his show

www.theguardian.com

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Jessica Tierney @leafwax.bsky.social · Aug 7

A proposed Amazon data center in Tucson (“Project Blue”, FFS) that would have sapped power and water from the city has been REJECTED thanks to amazing community solidarity. The people of the desert have spoken and won ✊🌵🏜️

Yana Kunichoff @yanak.bsky.social · Aug 6

The Tucson city council unanimously rejected the Project Blue data center today.

That comes after weeks of dogged organizing plus our little team @azluminaria.org going hard on helping Tucson understand who was behind this project and its impact on our community

azluminaria.org/2025/08/06/t...

Tucson City Council rejects Project Blue data center amid intense community pressure - AZ Luminaria

The Tucson city council voted unanimously Wednesday against bringing the massive and water-devouring Project Blue data center — tied to tech giant Amazon — into city limits. After weeks of escalating ...

azluminaria.org

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Reposted by Jessica E. Tierney

Yana Kunichoff @yanak.bsky.social · Aug 6

Tucson City Council rejects Project Blue data center amid intense community pressure - AZ Luminaria

azluminaria.org

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Reposted by Peter Thorne, Jessica E. Tierney, Keith S. Taber , and 3 more Peter Thorne, Jessica E. Tierney, Keith S. Taber, Christopher Wright, Gernot Wagner, Cheryl Peters

Christopher Mims @mims.bsky.social · Jul 31

struggling with an analogy here but imagine NASA posting a meme about how excited they are to return aviation to the pre-jet age

u.s. department of energy post on x praising coal:

"She's an icon
She's a legend
And she is the moment

[sparkly picture of coal]

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Reposted by Jessica E. Tierney

Joshua Weitz @joshuasweitz.bsky.social · Jan 27

It's Monday morning. Instead of advancing its leadership role in science, the current administration seems to be continuing its move of putting sand in the gears, NSF panel edition.

More via @pleunipennings.bsky.social, @cabarbieri.bsky.social and @robp.bsky.social.

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Reposted by Jessica E. Tierney

Huw Griffiths @huwiceandstuff.bsky.social · Mar 12

Another berg faces the storm! #biopole2
@bas.ac.uk @biopole.bsky.social

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Reposted by Jessica E. Tierney

High Country News @highcountrynews.org · Mar 13

Spitfire Raul Grijalva, a congressman from Arizona for more than 40 years, advocate for public lands and fighter against climate change, has died at age 77 in a major loss for the West. 🧵👇

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Reposted by Jessica E. Tierney

WIRED @wired.com · Jul 24

AI this, AI that, what about how much energy AI actually uses?

“It blows my mind that you can buy a car and know how many miles per gallon it consumes, yet we use all these AI tools every day and we have absolutely no efficiency metrics, emissions factors, nothing." From the experts:

How Much Energy Does AI Use? The People Who Know Aren’t Saying

A growing body of research attempts to put a number on energy use and AI—even as the companies behind the most popular models keep their carbon emissions a secret.

www.wired.com

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Jessica Tierney @leafwax.bsky.social · Jul 24

Here's some lovely artwork from the no desert data center (www.instagram.com/no_desert_da...) coalition that captures our feelings ⛈️

It would be great if a national news outlet picked up this story - its a type case for something that is increasingly an issue in the West. /fin

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Jessica Tierney @leafwax.bsky.social · Jul 24

The good news is that Tucsonians are organized ✊ and are asking tough questions. azluminaria.org/2025/07/21/t...

The Project Blue data center proposal sprang up fast — so did the organizing - AZ Luminaria

Until the first heady weeks of Tucson’s scorching summer, Vivek Bharathan and Elaina Richards had never worked or campaigned together, let alone been on a shared Google document. One month into coord...

azluminaria.org

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Jessica Tierney @leafwax.bsky.social · Jul 24

AI data centers are just the latest put your junk in the desert thing. But we as desert dwellers don't need to stand for it. Why would we repeat the past's mistakes? All for an AI response for a search (that sometimes you didn't ask for and don't really need!).

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Jessica Tierney @leafwax.bsky.social · Jul 24

There is a long history in the American West of putting our country's junk in the desert. c.f. a large portion of the State of Nevada (incl. the nuclear test range) and Dugway Proving Ground in Utah, where chemical and biological weapons were tested en.wikipedia.org/wiki/Dugway_...

Dugway Proving Ground - Wikipedia

en.wikipedia.org

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Jessica Tierney @leafwax.bsky.social · Jul 24

It seems to me that data centers in the desert is the new "growing alfalfa in the desert." It makes more sense to put these in places with more water...but land is cheap in the desert and local cities might be more amenable to the deal...

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Jessica Tierney @leafwax.bsky.social · Jul 24

Economically the boost of the data center would be the construction jobs, and there is no denying that, hence for trade unions this is a really good thing. But in the long-term, there are almost no people working at places like this. www.kold.com/2025/07/24/e...

Emotions run high in public meeting held by City of Tucson over Project Blue

The project has drawn a lot of attention around Pima County

www.kold.com

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Jessica Tierney @leafwax.bsky.social · Jul 24

The city claims the River won't be affected, but it's hard to imagine how, since water diverted to the data center means less outflow on the river at one of the flow stations no matter where it occurs. Prof. Michael Bogan at @uarizona.bsky.social crunched the math drive.google.com/file/d/1sSAp...

ProjectBlue_SantaCruzImpacts_11Jul2025.pdf

drive.google.com

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Jessica Tierney @leafwax.bsky.social · Jul 24

Reclaimed water is used to restore the Santa Cruz River, which was in the early 20th century an actual flowing river but due to ground water pumping no longer flows on its own. But thanks to reclaimed water we now have these beautiful riparian areas coming back www.azcentral.com/story/news/l...

Proposed data center raises concerns about drying up this Arizona river

The Santa Cruz River, dried up and polluted, came back to life recently, sustained by highly treated wastewater from two water reclamation facilities.

www.azcentral.com

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Jessica Tierney @leafwax.bsky.social · Jul 24

The water would rely on extending Tucson's reclaimed water system to the build to supply an estimated 0.8 million gallons per day (data centers in Phoenix use more than this). The problem is, reclaimed water demand is already very high in the city, and...

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Jessica Tierney @leafwax.bsky.social · Jul 24

As far as power goes, the project is estimated to require 400-600 MW at full build. It's not clear yet how TEP our power supplier will meet that. Current peak energy demand is 2400 MW so this is non-trivial. It could involve keeping coal-fired plants up and running past their expiration date.

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Jessica Tierney @leafwax.bsky.social · Jul 24

"Project Blue" is some (read: greenwashing) name for a data center that would be roughly the size of downtown Tucson, eat power and water, and provide only 180 jobs. For perspective, my department alone at the @uarizona.bsky.social employs about 130 people within 3-4 floors of a single building.

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Jessica Tierney @leafwax.bsky.social · Jul 24

This summer Tucsonians started to hear about something called "Project Blue", a proposal to build data centers on our outskirts. The city officials signed a NDA to not disclose the company❗but thanks to @azluminaria.org the company was outed this week as Amazon 🤡 azluminaria.org/2025/07/21/a...

Amazon Web Services is company behind Tucson’s Project Blue, according to 2023 county memo - AZ Luminaria

Amazon Web Services is revealed to be the company behind the Project Blue data center proposed for Tucson.

azluminaria.org

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Jessica Tierney @leafwax.bsky.social · Jul 24

This @wired.com article is extremely timely for those of us in Tucson, Arizona, as we face the possibility of Amazon Web Services building a huge data center at our outskirts. Energy and water use for AI data centers are non-trivial. Read my thread below if you want to hear about our local story ⬇️

WIRED @wired.com · Jul 24

How Much Energy Does AI Use? The People Who Know Aren’t Saying

A growing body of research attempts to put a number on energy use and AI—even as the companies behind the most popular models keep their carbon emissions a secret.

www.wired.com

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Jessica Tierney @leafwax.bsky.social · Jul 24

Several Fellows I talked to have decided to leave the US and seek science positions in Europe, citing the lack of positions here and negative attitude towards science 😞 Brain drain is a real thing that will have lasting impacts on US scientific strength.

Jessica Tierney @leafwax.bsky.social · Jul 24

Also, while temporary, the furlough caused a lot of stress for the Fellows, who scrambled to file for unemployment or get temporary positions since no one knew when it would end.

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Jessica Tierney @leafwax.bsky.social · Jul 24

Update on the NOAA Fellows situation: as of late last week the furlough has been lifted (phew!). However, there are no new Fellows this year, and we still don't know the future of this program.

Jessica Tierney @leafwax.bsky.social · Jul 7

As of today, all current NOAA Climate and Global Change postdoctoral fellows have been furloughed due to the Dept of Commerce not releasing the funding for the program. In addition no new Fellows were awarded this year. cpaess.ucar.edu/cgc

NOAA Climate & Global Change (C&GC) Postdoctoral Program | Cooperative Programs for the Advancement of Earth System ScienceNOAA Climate & Global Change (C&GC) Postdoctoral Program | Cooperative Progra...

cpaess.ucar.edu

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Reposted by Kevin J. Anchukaitis, Jessica E. Tierney

Becca Dzombak @rdzombak.bsky.social · Jul 10

The Trump administration's proposed budget would slash NOAA's climate research funds.

It still has to pass Congress, but it's already affecting scientists. A program supporting promising new climate scientists furloughed its current cohort and canceled 2025 awards.

www.nytimes.com/2025/07/09/c...

Recipients of a U.S. Climate Science Fellowship Are Put on Unpaid Leave

www.nytimes.com

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Jessica Tierney @leafwax.bsky.social · Jul 9

So bummed you are leaving - but it's probably a good choice

Jessica Tierney @leafwax.bsky.social · Jul 7

Unsure who to contact or pressure (ideas?), but pls spread the word on this issue.

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Jessica Tierney @leafwax.bsky.social · Jul 7

One of the things that makes this Fellowship special is that unlike NSF fellowships it is open to non-citizens, with the aim of retaining climate science talent in the US. The furlough creates significant problems for non-US postdocs in how it complicates visa status 😳

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