Scott J. Lehman

Scott J. Lehman

Senior Research Associate

  • Director, Laboratory for AMS Radiocarbon Preparation and Research (NSRL)


  • PhD: University of Colorado, 1989
  • Postdoctoral Scholar: Woods Hole Oceanographic Inst./MIT Joint Program in Oceanography, 1987

Contact Information

(Office) 303 492-8980


Paleoclimatology, paleoceanography, radiocarbon research.

Research Interests

The role of the oceans in climate change; cycling of heat, fresh water, and carbon by the oceans; dynamics and consequences of abrupt climate change; radiocarbon dating; 14C as a tracer in the carbon cycle.


Originally trained in Quaternary and glacial geology, my interests turned to oceanography after noting the profound influence of ocean heat transport on ice sheet growth and retreat in the Arctic. I was amongst the first to show that the timing and speed of changes in the large scale overturning circulation of the oceans matched that predicted by paleo-temperature records from Greenland ice cores and (the then) nascent numerical models of ocean circulation. In the run-up to the 1992 Rio Earth Summit (at which the United Nations Framework Convention on Climate Change was opened for signing) I gave testimony to the U.S. Senate warning that unmitigated warming could lead to changes in the overturning circulation of the northern North Atlantic—a phenomenon now clearly visible in regional air and sea temperatures 25 years later. For the last two decades my work has focused on studies of the ocean’s role in determining Ice Age (natural) CO2 variations and on the use of 14C as a tracer in the contemporary carbon cycle and for direct quantification of anthropogenic CO2 emissions.





Basu, S., Scott J. Lehman, Miller, J. B., Andrews, A. E., Sweeney, C., Gurney, K. R., Xu, X., Southon, J., Tans, P. P. 2020: Estimating US fossil fuel CO2 emissions from measurements of 14C in atmospheric CO2. Proceedings of the National Academy of Sciences, 117(24): 13,300-13,307. DOI: 10.1073/pnas.1919032117

Basu, S., Miller, J. B., Scott J. Lehman 2016: Separation of biospheric and fossil fuel fluxes of CO2 by atmospheric inversion of CO2 and 14CO2 measurements: Observation System Simulations. Atmospheric Chemistry and Physics, 16(9): 5665-5683. DOI: 10.5194/acp-16-5665-2016

Scott J. Lehman, Miller, J. B., Wolak, C., Southon J., Tans, P. P., Monzka, S. A., Sweeney, C., Andrews, A., LaFranchi, B., Guilderson, T. P., Fischer, M. A., Turnbull, J. C. 2013: Allocation of terrestrial carbon sources using 14CO2: Methods, measurement, and modeling. Radiocarbon, 55(2-3): 1484-1495. DOI: 10.2458/azu_js_rc.55.16392

Miller, J. B., Scott J. Lehman, Montzka, S. A., Sweeney, C., Miller, B. R., Karion, A., Chad Wolak, Dlugokencky, E. J., Southon, J., Turnbull, J. C., Tans, P. P. 2012: Linking emissions of fossil fuel CO2 and other anthropogenic trace gases using atmospheric (CO2)-C-14. Journal of Geophysical Research-Atmospheres, 117: D08302. DOI: 10.1029/2011JD017048

Hughen, K., Scott J. Lehman, Southon, J., Overpeck, J., Marchal, O., Herring, C., Turnbull, J. 2004: 14C activity and global carbon cycle changes over the past 50,000 years. Science, 303(5655): 202-207. DOI: 10.1126/science.1090300

Scott J. Lehman, Keigwin, L. D. 1992: Sudden changes in North Atlantic circulation during the last deglaciation. Nature, 356: 757-762. DOI: 10.1038/356757a0

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