Peer Reviewed Publications

*undergraduate student author

  1. Zhang, X., Royer, D.L., Colombi, C.E., Drovandi, J.M., McElwain, J.C., Guignard, G., Leng, Q., Lomax, B.H., Sheldon, N.D., …Steinthorsdottir, M. (2025). Fossil leaf cuticle: Best practices for preparation and paleo-CO2 analysis. Earth-Science Reviews, p.105104.

  2. Cenozoic CO2 Proxy Integration Project (CenCO2PIP) Consortium, Hönisch, B., Royer, D.L., Breecker, D.O., Polissar, P.J., Bowen, G.J., ... Zhang, L. (2023). Toward a Cenozoic history of atmospheric CO2. Science, 382(6675), eadi5177.

  3. Milligan, J.N., Flynn, A.G., Kowalczyk, J.B., Barclay, R.S., *Geng, J., Royer, D.L., Peppe, D.J., 2022. Moderate to elevated atmospheric CO2 during the early Paleocene recorded by Platanites leaves of the San Juan Basin, New Mexico. Paleoceanography and Paleoclimatology, 37: e2021PA004408.

  4. Milligan, J.N., Flynn, A.G., Wagner, J.D., Kouwenberg, L.L.R., Barclay, R.S., Byars, B.W., Dunn, R.E., White, J.D., Zechmann, B., Peppe, D.J., 2021. Quantifying the effect of shade on cuticle morphology and carbon isotopes of sycamores: present and past. American journal of botany, 108(12): 2435-2451.

  5. Milligan, J.N., Royer, D.L., Franks, P.J., Upchurch, G.R., *McKee M.L., 2019. No Evidence for a Large Atmospheric CO2 Spike Across the Cretaceous‐Paleogene Boundary. Geophysical Research Letters, 46: 3462-3472.

  6. Milligan, G., Poulos, H., Gilmore, M., Berlyn, G., Milligan, J., Chernoff, B., 2019. Estimation of short-term C-fixation in a New England temperate tidal freshwater wetlands. Heliyon, 5: e01782.

Presentations and Conference Abstracts

  1. *Michel, N., *Morgen, R.C., Milligan, J.N., Burke, L., Barclay, R.S., Dunn, R.E., Wing, S.L., 2026. Leaf epidermal cells record the canopy response to changing climate during the late Paleocene to early Eocene in the Bighorn Basin, WY. Climatic and Biotic Events of the Paleogene.

  2. Flynn, A.G., Milligan, J.N., Peppe, D.J., Gygi, D., Secord, R., Williamson, T.E., Brusatte, S.L., Shelley, S.L., 2026. Prolonged terrestrial ecosystem instability following the Cretaceous-Paleogene (K/Pg) Boundary. Climatic and Biotic Events of the Paleogene.

  3. Milligan, J.N., Barclay, R.S., Butrim, M.J.., Shaherazade, K., Wilson., J., Scher, M., Baczynski, A., Lloyd. B., Smith., B.,….Wing, S.L., 2026. Response of Ginkgo to elevated CO2: implications for a leaf-gas exchange model for paleo-CO2 reconstruction. 43rd Midcontinent Paleobotanical Colloquium.

  4. *Morgen, R.C., Milligan, J.N., Burke, L., Barclay, R.S., Dunn, R.E., Wing, S.L., 2025. Leaf epidermal cells record the canopy response to changing climate during the late Paleocene to early Eocene in the Bighorn Basin, WY. 42nd Midcontinent Paleobotanical Colloquium.

  5. Morse, P.E., Vitek, N.S., Secord, R., Boyer, D.M., Milligan, J.N., Wing, S.L., Bloch, J.I., 2024. Thriving in the Bighorn Basin fifty-six million years ago: The story of the first primates. Washakie Museum Paleontology Symposium.

  6. Morse, P.E., Vitek, N.S., Secord, R., Boyer, D.M., Milligan, J.N., Wing, S.L., Bloch, J.I., 2024. A multiproxy approach to characterize the ecology of the earliest known crown primate from the Bighorn Basin, WY. North American Paleontological Convention.

  7. Milligan, J.N., Burke, L., Barclay, R.S., Dunn, R.E., Wing, S.L., 2024. Leaf epidermal cells record the canopy response to changing climate during the late Paleocene to early Eocene in the Bighorn Basin, WY. North American Paleontological Convention.

  8. Milligan, J.N., 2023. Reading the leaves: what fossil plants can tell us about climate change in deep time. Invited presentation to the Toll research program at Washington College, Md.

  9. Milligan, J.N., 2022. Leaf epidermal cells shine a light on ancient canopy structure: preliminary results from the Paleocene through Eocene of the western interior of North America. National Museum of Natural History Paleobiology seminar.

  10. Geng, J., Milligan, J.N., Thorne, D., Peppe, D.J., 2022. Reconstructing the pCO2 and climate record of the late Early Paleocene in the San Juan Basin, New Mexico. GSA Abstracts with Programs 54(4). doi: 10.1130/abs/2022AM-382796

  11. Thorne, D., Milligan, J.N., Geng, J., Hockaday, W.C., Peppe, D.J., 2022. Using Sycamore leaves to reconstruct ancient light environments. GSA Abstracts with Programs 54(4). doi: 10.1130/abs/2022AM-382712

  12. Milligan, J.N., Flynn, A.G., Peppe, D.J., Barclay, R., Dunn, R., 2022. Canopy structure of the early Paleocene, San Juan Basin, New Mexico from dispersed plant cuticle. Northeast-Midcontinent Paleobotanical Colloquium.

  13. Gygi, D., Milligan, J.N., Peppe, D.J., 2021. Early Paleocene plant community and paleoclimate reconstruction of the Nacimiento formation from the San Juan Basin, New Mexico. American Geophysical Union: PP55B-0653.

  14. Gygi, D., Milligan, J.N., Peppe, D.J., 2021. Early Paleocene plant community and paleoclimate reconstruction of the Nacimiento formation from the San Juan Basin, New Mexico. GSA Abstracts with Programs 53(6).

  15. Milligan, J.N., 2020. Sycamores shines a light on ancient canopy structure. Dallas Paleontological Society, Dallas, TX.

  16. Milligan, J.N., Barclay, R.S., Dunn, R.E., Flynn, A., Kouwenberg, L.L.R, Wagner, J., White, J.D., Zechmann, B., Peppe, D.J., 2020. Assessing the effects of shade on sycamore ecophysiology: present and past. GSA Abstracts with Programs 52(6).

  17. Milligan, J.N., Peppe, D.J., Zechmann, B., 2018. Assessing the effects of shade on sycamore ecophysiology: present and past. Green Life Sciences Symposium, Ann Arbor, MI.

  18. Milligan, J.N., Flynn, A.G., Peppe, D.J., Barclay, R., 2018. A multi proxy atmospheric CO2 reconstruction of the Early Paleocene from the San Juan Basin, New Mexico, USA. European Palaeobotany and Palynology Conference 2018: O016.

  19. Milligan, J., Royer, D., Franks, P., Upchurch, G., Flynn, A., Peppe, D., 2017. Revised estimates of atmospheric CO2 across the Cretaceous-Paleogene (K-Pg) boundary. Climatic and Biotic Events of the Paleogene.

  20. Peppe, D., Royer, D. Flynn, A., Milligan, J., 2017. The relationship between terrestrial climate and CO2 through the early Paleogene and its implications for Earth-system sensitivity. Climatic and Biotic Events of the Paleogene.

  21. Franks, P., Royer, D.L., Kowalczyk, J., Milligan, J., 2016. Phanerozoic pCO2 recorded by the plants that used it: refinement, independent validation and multi-proxy comparison of a physiological model. American Geophysical Union: PP41F-01.

  22. Royer, D.L., Franks, P.J., Milligan, J.N., Kowalczyk, J.B., Jaramillo, C.A., Londoño L, 2016.  A leaf gas-exchange model for reconstructing paleo-CO2: ground-truthing and fossil applications. International Organization of Paleobotany Conference Program.

  23. Milligan, J.N., Royer, D.L., 2016. Experimental constraints on a new leaf gas-exchange method for paleo-CO2 reconstruction. Northeast-Midcontinent Paleobotanical Colloquium.

  24. Milligan, J.N., Royer, D.L., 2015. Experimental constraints on a new leaf gas-exchange method for paleo-CO2 reconstruction. GSA Abstracts with Programs 47(7): Paper 264-9.

Nate presenting his summer research in 2026 at the CBEP meeting at the National Museum of Natural History.

Exploring the forest of Panama in a Canopy Crane at the MPC meeting in 2026.

Presenting a talk at MPC in Panama in 2026.