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Ariel Ortiz-Bobea

@arielob.bsky.social
11K followers 538 following 291 posts

Applied econ & policy prof at Cornell. Researching how people cope w/ environmental change. Posts about climate, agriculture, environment & academia. arielortizbobea.github.io

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Ariel Ortiz-Bobea @arielob.bsky.social · 09/10/2026
Gains in land productivity also track emission reductions more closely than gains in labor productivity. Free to read: onlinelibrary.wiley.com/share/author... Code and data: doi.org/10.5281/zeno...
onlinelibrary.wiley.com
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Ariel Ortiz-Bobea @arielob.bsky.social · 09/10/2026
TFP growth historically slowed U.S. agricultural emissions, but that contribution has weakened as U.S. farm productivity growth slows down. Falling emission intensity of inputs is now the main factor holding emissions down, and that decline is concentrated in the Southeast.
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Ariel Ortiz-Bobea @arielob.bsky.social · 09/10/2026
Earlier this year, Simone and I published a paper showing that productivity growth has been one of the main forces slowing agricultural emissions worldwide since 1961. This paper applies the same decomposition to U.S. states, linking EPA emissions inventories to USDA state productivity accounts.
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Ariel Ortiz-Bobea @arielob.bsky.social · 09/10/2026
New paper in AEPP with Simone Pieralli and Jeisson Prieto: "Growing more while emitting less? Decoupling U.S. agricultural production and greenhouse gas emissions." We split each state's farm emissions growth over 1990–2015 into output, emission intensity of inputs, and TFP. 🧵
Hexagon maps of U.S. states showing average annual growth from 1990 to 2015 in agricultural greenhouse gas emissions (large map), and in its three components: output, emissions per unit of input, and the negative of total factor productivity growth (three small maps). Colors run from blue for declines to red for increases.
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Ariel Ortiz-Bobea @arielob.bsky.social · 01/10/2026
John, I’m sure you’ve been asked this before, but do you have a sense of how much changes are driven by changes in the site composition of where jobs are posted (JOE vs AJO vs EconJobMarket)?
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John Cawley @johncawley.bsky.social · 30/09/2026
From our AEA cttee on the job market, here's the first update on the status of the job mkt for PhD economists of the 2026-27 cycle. A thread with graphs follows... #EconJobMarket #EconSky @aeainformation.bsky.social @aeacswep.bsky.social @joelistings.bsky.social 1/9
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Ariel Ortiz-Bobea @arielob.bsky.social · 30/09/2026
Finally, in moments like this I recall something my high school history teacher used to tell us: "Rights are not given to you. You take them."
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Ariel Ortiz-Bobea @arielob.bsky.social · 30/09/2026
Third, I'm glad this whole debacle is unfolding. I'm sure some of our admins are going through a rough patch. I don't rejoice in that. But deep and structural cultural change does not happen doing marginal work. My hope is that profound changes occur that make this impossible to happen again.
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Ariel Ortiz-Bobea @arielob.bsky.social · 30/09/2026
Second, I'm not surprised by the university's response. My view is that admins are inherently conservative & legalistic in how they operate. Admins seek to follow the rules & law and are advised against doing anything "above and beyond" if that increases legal risk. Those are the incentives.
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Ariel Ortiz-Bobea @arielob.bsky.social · 30/09/2026
First, I cannot hide feeling so proud of the student journalists at the Cornell Daily Sun, and of Jane Doe for coming forward to tell her story. To me this is the only bright spot in this whole story. I feel heartened we have such brave and tenacious young women on campus.
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Ariel Ortiz-Bobea @arielob.bsky.social · 30/09/2026
Starting to have friends and family ask how I feel about the alleged gang rape at Cornell as a faculty member. We'd like to believe our opinion does not matter, but it does enough to some that I'm compelled to share my views. Well, I'm pretty horrified. I'm sure I'm not the only one. A short thread.
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David Ho @davidho.bsky.social · 23/09/2026
Wtaf is this question my university just asked me about my project?
Does the project involve any work that could be interpreted as promoting DEIA, climate change research, or non-compliant to any Presidential Executive Orders?
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Bob Kopp @bobkopp.net · 22/09/2026
NEW PAPER: In a new paper, jointly published in @agu.org Earth's Future & @ametsoc.org BAMS, and co-led by Melissa Kenney, @costasamaras.com and me, 175 authors outline priorities to guide the future of scientific assessments of climate change in the United States. 🧵
doi.org
Research Priorities for Robust Climate Assessments in the United States
A network of climate assessments plays a critical role in synthesizing the state of science to support evidence-based decision-making To support future U.S. and sub-national climate assessments, ...
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Costa Samaras @costasamaras.com · 22/09/2026
Communities can't wait for the next National Climate Assessment to understand their climate risk. With leadership by Melissa Kenney, @bobkopp.net & I were lucky to work with 175 climate researchers to outline assessment priorities that folks can work on now: headlines.ametsoc.org/2026/09/22/f...
headlines.ametsoc.org
First Paper Published in the U.S. Climate Collection
The U.S. Climate Collection has published its first paper, with 175 authors outlining research priorities for future U.S.-focused climate assessments.
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
8/ This was joint work with Jeisson Prieto, Ziyi Lin, Kristan Reed and Chris Wolf. More details in the paper of course.
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
7/ We did a bunch of checks in this paper, and found the response function to be fairly stable by region, age of the cow, period in the sample, etc. While we see fat and protein content increase over time (with breeding progress), we could not detect any change in the sensitivity to heat over time.
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
6/ When you end up accounting for quality effects in addition to yield, we find the estimated heat damage doubles (!). Quality effects may appear subdued at first, but they end up counting more when you factor in it operates in temperature parts of the year.
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
5/ Second (& more interestingly), we find that higher THI essentially "dilutes" milk by reducing the proportion of fat and protein (panels B and C). Unlike the yield effect (sharp & concentrated in summer), this quality effect is gradual and widespread in the entire year.
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
4/ First, we recover pretty much the same nonlinear response documented in previous studies: milk *yield* declines sharply with exposure exceeding about 70 THI (panel A below).
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
3/ We rely on a massive dataset w/ daily snapshots of milk tests for millions of cows across the US. We link these tests with variables (bins) that capture how much time cows were exposed to various levels of the temperature-humidity-index (THI) the week prior to the test.
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
2/ Climate impact studies on ag typically focus on easily-measured metrics, like crop or milk yield. But heat could alter the composition (quality) of these products as well. We explore this in the context of US dairy where farmers are paid for milk fat and protein rather than volume.
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Ariel Ortiz-Bobea @arielob.bsky.social · 22/06/2026
1/ We have a new paper out showing that accounting for quality more than doubles the estimated heat damages on US dairy production. Story: news.cornell.edu/stories/2026... Paper: iopscience.iop.org/article/10.1... Code: doi.org/10.6077/COSA8S
news.cornell.edu
‘Double the damage’: Warming climate reduces milk quality and quantity | Cornell Chronicle
Heat stress on dairy cows not only decreases the amount of milk produced but also the fat and protein content, doubling the economic losses.
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Ariel Ortiz-Bobea @arielob.bsky.social · 21/05/2026
I wonder what editors of econ journals are seeing in terms of changes in the volume of submissions. As a reviewer I'm experiencing what feels like a doubling of reviewing requests. I'm not tracking my declines yet but will probably start soon.
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Ariel Ortiz-Bobea @arielob.bsky.social · 10/05/2026
Pineapples are just juicy bromeliads
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Ariel Ortiz-Bobea @arielob.bsky.social · 12/02/2026
Please share with potential solid candidates for this postdoc (academicjobsonline.org/ajo/jobs/31576). We start reviewing application next week! A data-savvy economist or data scientist with interest in agriculture and environment would be a good fit.
academicjobsonline.org
Cornell University, College of Business
Job #AJO31576, Postdoctoral Associate, Cornell University, College of Business, Cornell University, Ithaca, New York, US
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Ariel Ortiz-Bobea @arielob.bsky.social · 12/02/2026
academicjobsonline.org/ajo/jobs/31576
academicjobsonline.org
Cornell University, College of Business
Job #AJO31576, Postdoctoral Associate, Cornell University, College of Business, Cornell University, Ithaca, New York, US
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
Sure. You're referring to changes in the output mix (share of ruminant livestock in output). That's possible. Note that our study is historical and we don't see substantial changes in the output mix (share of livestock in output) across income regions (see below). More movements in input mix.
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
6/ Links: - press release: news.cornell.edu/stories/2026... - paper: www.science.org/doi/10.1126/... - code+data: data.socialsciences.cornell.edu/dataset.xhtm... thanks for reading!
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
5/ The bad news is that global TFP growth is slowing down, so a key driver keeping GHG emissions somewhat in check may not be as important moving forward... unless, of course, policy makers snap back and begin re-prioritizing public ag R&D.
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
4/ In the article we go a bit deeper and try to assess the role of land and labor inputs, and we find that stronger decoupling is associated with places with stronger gains in land productivity (Y/Xland) rather than gains in labor productivity (Y/Xlabor).
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
3/ You can reduce emissions by 1- reducing output (not a good idea), 2- reducing input emission intensity, or 3- increasing TFP. We find is that most of the historical reduction in ag GHG (ΔE) stem from increases in productivity (Δ(Y/X)) rather than reductions in input emission intensity (Δ(E/X)).
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
2/ There's been a lot of discussion about "decoupling" GHG and production. We take a historical look by decomposing the growth of GHG (ΔE) into a sum of growth in output (ΔY), growth in input emission intensity (Δ(E/X)) and growth in Total Factor Productivity (Δ(Y/X)): ΔE = ΔY + Δ(E/X) - Δ(Y/X)
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
1/ Lots going on these days, but I'm nonetheless happy to share a paper out today in Science Advances together with Simone Pieralli (European Commission Joint Research Centre) titled "Unpacking the growth of global agricultural greenhouse gas emissions". news.cornell.edu/stories/2026...
news.cornell.edu
More productive farming lowers global emissions | Cornell Chronicle
A new analysis shows that improved farm productivity has been the driving force in keeping global greenhouse gas emissions from agriculture in check, with implications for how countries support farmer...
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Ariel Ortiz-Bobea @arielob.bsky.social · 16/01/2026
Like boiling frogs
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Ariel Ortiz-Bobea @arielob.bsky.social · 14/01/2026
A little bit late, but I'm looking to hire a postdoc at Cornell to measure the private value of soil health improvements in US ag. A 2-year gig. Well suited for an ag/resource economist or data scientist w/ interests in soil health and solid programming & econometric chops. ad coming soon!
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Ariel Ortiz-Bobea @arielob.bsky.social · 20/12/2025
What can she see that everyone can see?
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Ariel Ortiz-Bobea @arielob.bsky.social · 11/12/2025
need to beef up the budget to welcome international visitors, just sayin'
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Ariel Ortiz-Bobea @arielob.bsky.social · 02/12/2025
Interesting. Is this the first time the AEA bans a member for life?
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Ariel Ortiz-Bobea @arielob.bsky.social · 01/12/2025
Proper use of a bar chart
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Richard Nerland @richardnerland.bsky.social · 27/11/2025
I'm excited, the RCT suggests Malengo increases psychological well‑being by about 0.36 standard deviations. As a reference point, this is similar in magnitude to the improvements after vision-restoring cataract surgery. This is not obvious a priori!
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Johannes Haushofer @johanneshaushofer.com · 27/11/2025
Exciting news on @malengo.org, the NGO that helps East African students move to Europe for education: Our research team has given us a glimpse of their early findings! Here is the full writeup, joint with @richardnerland.bsky.social: forum.effectivealtruism.org/posts/CpZYHk... Thread follows!
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Ariel Ortiz-Bobea @arielob.bsky.social · 25/11/2025
That’s what I imagined. I hope you keep at it. To me this is such a fundamental aspect of science. We (researchers) think we are immune to all sorts of biases, but we are subject to path dependence and what others before us chose to explore and “found” to be true.
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Ariel Ortiz-Bobea @arielob.bsky.social · 25/11/2025
We're going through the second 100-year shock to the academic job market in the past 5 years
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Ariel Ortiz-Bobea @arielob.bsky.social · 25/11/2025
We need candidates for AEA directors and presidents to be talking about concrete things like this, not how many top articles, cites or awards they have.
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Paul Goldsmith-Pinkham @paulgp.com · 24/11/2025
Update on the state of the job market courtesy of a nudge by @gottliebecon.bsky.social It's bad! paulgp.com/2025/11/24/j...
paulgp.com
Economics Job Market Update: November 2025 - A Historic Low
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Ariel Ortiz-Bobea @arielob.bsky.social · 25/11/2025
Eva, cool study. I imagine you've had this in the works for quite a while. So congrats! One point that I don't know if you can address here (or later) is to what extend people use previous published results as priors. i.e. does confidence and/or accuracy increase the more mature a literature is?
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JAERE @jaereaere.bsky.social · 13/11/2025
📢 Just accepted in #JAERE 📢 is now posted at @aereorg.bsky.social! 📍 Follow @aereorg.bsky.social to stay updated on all things REEP and JAERE. #EconSky 📈📉
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Ariel Ortiz-Bobea @arielob.bsky.social · 28/10/2025
Enough time for catcher to take a selfie
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Ariel Ortiz-Bobea @arielob.bsky.social · 28/10/2025
That was a poor pitch down the middle! You can’t do that with that guy
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Ariel Ortiz-Bobea @arielob.bsky.social · 20/10/2025
“If you can afford it”
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