Pierre Coster

In our model, a €100 carbon tax reproduces this leakage and modestly cuts emissions; adding a carbon tariff reverses leakage but raises prices. Overall, tax+tariff is about 7× more effective than the tax alone at reducing emissions. Full paper: costerpierre.github.io/files/CdGM_CBA…

In the paper, we study how firms adjust input sourcing when climate policy tightens. Using the EU ETS and French import/production data, we find clear carbon leakage: firms increasingly shifted ETS-regulated inputs toward non-EU suppliers, raising the outside-EU share by 4.3 p.p.

Happy to share our research with Julian di Giovanni & @IsabelleMejean on Liberty Street Economics—two short posts on what can undermine a carbon tax, and what a carbon tariff is and why the EU is imposing it: libertystreeteconomics.newyorkfed.org/2026/01/what-c… libertystreeteconomics.newyorkfed.org/2026/01/what-i…

Carbon leakage through firms’ supply chain adaptation Pierre Coster @USC, Julian Di Giovanni @NewYorkFed, Isabelle Mejean @IsabelleMejean @sciencespo @ScPoEcon ow.ly/Tllk50UyFrK

Full draft: costerpierre.github.io/files/Climate_…

Very happy to see our latest research with @IsabelleMejean and Julian di Giovanni featured on VoxEU. How do firms adapt their supply chains under carbon pricing, and does it lead to carbon leakage? Read more: cepr.org/voxeu/columns/…

Looking for a pre-doc to work with me and my co-authors on projects based in the DR Congo aimed at increasing tax capacity and fostering accountability. #predoc @econ_ra @predoc_org Deadline Dec 15th. Please share, retweet, and apply 👇

I am delighted that @USC_Econ will hire a junior macroeconomist. Progress not Regress! usccareers.usc.edu/job/los-angele…

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If you are applying to the @USC_Econ PhD program and are interested in applied micro (development, environmental, IO, labor, political economy, urban), please state what areas you'd like to work on and what professors you'd like to work with.

@AlisonSete98 @urbanthoughts11 🥲🥲🥲

@urbanthoughts11 @Pierre__Coster

30 people getting coffee. Sprawl vs. urbanism

@JoanMonrasEcon Amazing news! And welcome to the best coast ☺️

Just landed in SF! New adventures ahead! Let me know if in the area!

@AlisonSete98 @noticiaisbr Me very soon ahah

@noticiaisbr @Pierre__Coster

@s_mosquera_ @USC_Econ @bse_barcelona @ecb @ScPoEcon @santidemartini Indeed! Met him today :) Wonderful, let’s definitely keep in touch!

@Pierre__Coster @USC_Econ @bse_barcelona @ecb @ScPoEcon You'll be classmate of @santidemartini !! Congrats and enjoy LA!! I'll be there myself (another uni haha)! We can go surfing!

Delighted to share that today marks the first day of my PhD in Economics at @USC_Econ. Thanks to all those who helped me get here, at the @bse_barcelona, @ecb & @ScPoEcon! Can't wait to see what the next few years hold for me. If you ever are in LA, let me know! ☀️🌊

@alecauz1 @USC_Econ @bse_barcelona @ecb @ScPoEcon Thanks a lot Alessandro! I hope Toulouse is treating you well ;)

@Pierre__Coster @USC_Econ @bse_barcelona @ecb @ScPoEcon Congrats Pierre!

@goescarlos @USC_Econ @bse_barcelona @ecb @ScPoEcon Thanks a lot Carlos!

@Pierre__Coster @USC_Econ @bse_barcelona @ecb @ScPoEcon Congrats and enjoy SoCal! Life is happier in this part of the world.

@manimetrix @USC_Econ @bse_barcelona @ecb @ScPoEcon Thanks a lot. Now, let’s see where I end up in 20 years!

@Pierre__Coster @USC_Econ @bse_barcelona @ecb @ScPoEcon Welcome! Exactly 20 years ago, i could have wirtten something similar. Good luck.

@Marlon_Boarnet @USC_Econ @bse_barcelona @ecb @ScPoEcon @USC @USCPrice Thanks a lot for the warm welcome. Can’t wait to discover everything USC has to offer!

@Pierre__Coster @USC_Econ @bse_barcelona @ecb @ScPoEcon Welcome to @USC! Many of us @USCPrice collaborate with USC Econ. Reach out anytime. This is a great place. Enjoy your time here!

@aang_econ @USC_Econ @bse_barcelona @ecb @ScPoEcon Thank you! See you around :)

@Pierre__Coster @USC_Econ @bse_barcelona @ecb @ScPoEcon Welcome to USC!

@EmilyNix100 @RDMetcalfe @USC_Econ @bse_barcelona @ecb @ScPoEcon @USC Thanks a lot!!

@Pierre__Coster @RDMetcalfe @USC_Econ @bse_barcelona @ecb @ScPoEcon Welcome to @USC!!!