understanding and constraining uncertainty in
climate variability, change, and impacts


The Dartmouth Climate Modeling & Impacts Group (CMIG) works to characterize the origins and consequences of climate variability and change.

In particular, our group is interested in where, when, and how climate affects people and the natural and managed systems they care about.

Beyond identifying the risks of various climate impacts, we work to understand the physical processes governing such impacts, and diagnose and improve model representations of the processes that generate uncertainty in climate risks.

Our research spans a number of projects, including the following:

Hydroclimatic variability and dynamics

What combinations of low- and high-frequency ocean-atmopshere variability generate droughts? Our work aims to understand the forcings of hydroclimatic variability using paleoclimate data, instrumental observations, and models. As part of this, we investigate and diagnose the drivers of historical hydroclimate changes and the consequences for terrestrial climate and hydrology — from low-frequency modes of internal variability to vegetation-atmosphere interactions. Current projects include examination of modes of variability and the land surface in shaping historical drought events and the drivers of persistent drought risks in forced versus unforced climates.


Model diagnosis and evaluation

How well do models simulate the real-world Earth system processes we care about and what are the model schemes responsible for structural uncertainties in such processes? There is a high degree of uncertainty in future climate changes, for example, due to the range of scales required to simulate things like precipitation and turbulent fluxes in models and the uncertainty inherent in a complex climate. Our work aims to understand the sources of model response uncertainty and constrain such uncertainty using data-model comparisons to improve model fidelity (and the prediction of the range of climate outcomes this coming century). Current projects include the role of land surface schemes and assumptions (pariticualry vegetation and snow) on hydroclimate and hydrology.


Human and ecosystem impacts of climate change

Translating the range of outcomes in physical climate impacts is insufficient to understand what such impacts imply for people and the systems they value. For example, snow is projected to melt in a warmer world, but the human impacts of reduced snowpack depends on where and how people use snow. The aim of this work is to incorporate other sciences, both social and natural, to translate physical climate impacts into impacts on people and ecosystems. Current projects include an examination of the risks of declines in future water availability given human water demands and reconciling top-down and bottom-up approaches to identifing climate-driven impacts on agriculture.


Adaptation decision-making

We know that model-simulated internal variability is sufficient to mask, amplify, or reverse the direction of anthropogenically-forced trends in temperature, circulation, and precipitation at large spatial and temporal scales, complicating adaptation decisions. Characterizing the most likely climate outcome is not sufficient for planning. Rather, quantifying the full extent of outcomes from internal variability under global warming is key to enable robust adaptation in the face of uncertain climate threats. Current projects include identification of the time of emergence and distribution of benefits of adaptations.



± denotes a graduate student/postdoc author
Bolded caps denotes CMIG member

Submitted or in revision

  1. ± COFFEL, E., R. M. Horton, J. M. Winter, J. S. MANKIN, Nonlinear increases in extreme temperatures paradoxically dampen increases in extreme humid-heat, submitted, Science Advances | Email to request copy

  2. ± Raymond, E. & J. S. MANKIN, Coastal moderation of extreme heat in the eastern United States, under review, Geophysical Research Letters | Email to request copy

  3. ± COFFEL, E., B Keith, C. Lesk, E. Bower, J. Lee, R. M. Horton, J. S. MANKIN, More concurently hot and dry years in the Nile Basin despite increasing precipitation, revising, Nature Climate Change | Email to request copy

  4. Schultz, K. & J. S. MANKIN, Sources of uncertainty in forecasting the climate-conflict relationship, revising | Email to request copy

Peer-reviewed journal articles

  1. Schultz, K. A. and J. S. MANKIN, (provisionally-accepted). Is Temperature Exogenous? The Impact of Civil Conflict on the Instrumental Climate Record in Sub-Saharan Africa, American Journal of Political Science | PDF
  2. ± Bishop, D. A., A. P. Williams, R. Seager, A. M. Fiore, B. I. Cook, J. S. MANKIN, D. Singh, J. E. Smerdon, M. P. Rao, (2018). Investigating the causes of increased 20th-century precipitation over the southeastern United States, Journal of Climate 10.1175/JCLI-D-18-0244.1 | PDF
  3. ± Trugman, A. T., D. Medvigy, J. S. MANKIN, W. R. L. Anderegg, (2018). Soil moisture drought as a major driver of carbon cycle uncertainty, Geophysical Research Letters 10.1029/2018GL078131 | PDF
  4. Cook, B. I., J. S. MANKIN, K. Anchukaitis, (2018). Climate change and drought: from past to future, Current Climate Change Reports 10.1007/s40641-018-0093-2 | PDF
  5. MANKIN, J. S. , R. Seager, J. E. Smerdon, B. I. Cook, A. P. Williams, R. M. Horton, (2018). Blue water tradeoffs with CO2-enriched ecosystems, Geophysical Research Letters 10.1002/2018GL077051 | PDF
  6. Skinner, C. B., C. J. Poulsen, J. S. MANKIN, (2018). Amplification of heat extremes by plant CO2 physiological forcing, Nature Communications 10.1038/s41467-018-03472-w | PDF
  7. Diffenbaugh, N. S., D. Singh, J. S. MANKIN, (2018). Probability of unprecedented climate events: comparing historical changes with the UN aspirational targets and NDC commitments, Science Advances 10.1126/sciadv.aao3354 | PDF
  8. Cook, B. I., A. P. Williams, J. S. MANKIN , R. Seager, J. E. Smerdon, D. Singh, (2018). Revisiting the leading drivers of Pacific coastal drought variability in the Contiguous United States, Journal of Climate 10.1175/JCLI-D-17-0172.1 | PDF
  9. Ault, T., S. St. George, J.E. Smerdon, S. Coats, J.S. MANKIN, C. Carrillo, B. I. Cook, S. Stevenson, (2018). A robust null hypothesis for the potential causes of megadrought in western North America, Journal of Climate 10.1175/JCLI-D-17-0154.1 | PDF
  10. Swain, D. L., D. Singh, D. Horton, J. S. MANKIN, T. Ballard, N. S. Diffenbaugh, (2017). Remote linkages to anomalous winter atmospheric ridging over the northeastern Pacific, Journal of Geophysical Research: Atmospheres 10.1002/2017JD026575 | PDF
  11. Williams, A. P., Cook, B. I., Smerdon, J. E., Bishop, D. A., Seager, R., MANKIN, J. S., (2017). The 2016 southeastern US drought: an extreme departure from centennial wetting and cooling, Journal of Geophysical Research: Atmospheres 10.1002/2017JD027523 | PDF
  12. Hydro2K Consortium - J. E. Smerdon, J. Luterbacher, S. Phipps, K.J. Anchukaitis, T.R. Ault, S. Coats, K.M. Cobb, B.I. Cook, C. Colose, T. Felis, A. Gallant, J.H. Jungclaus, B. Konecky, A. LeGrande, S. Lewis, A. S. Lopatka, W. Man, J.S. MANKIN, J.T. Maxwell, B.L. Otto-Bliesner, J.W. Partin, D. Singh, N.J. Steiger, S. Stevenson, J.E. Tierney, D. Zanchettin, H. Zhang, A. Atwood, L. Andreu-Hayles, S.H. Baek, B. Buckley, E.R. Cook, R. D'Arrigo, S.G. Dee, M. Griffiths, C. Kulkarni, Y. Kushnir, F. Lehner, C. Leland, H.W. Linderholm, A. Okazaki, J. Palmer, E. Piovano, C.C. Raible, M. P. Rao, J. Scheff, G.A. Schmidt, R. Seager, M. Widmann, A.P. Williams, E. Xoplaki, (2017). Comparing data and model estimates of hydroclimate variability and change over the Common Era, Climate of the Past 10.5194/cp-2017-37 | PDF
  13. MANKIN, J.S., J.E. Smerdon, B.I. Cook, A.P. Williams, and R. Seager, (2017). The curious case of projected 21st-century drying but greening in the American West, Journal of Climate 10.1175/JCLI-D-17-0213.1 | PDF
  14. Diffenbaugh, N.S., D. Singh, J.S. MANKIN, A. Charland, M. Haugen, D.E. Horton, D.L. Swain, D.E. Touma, M. Tsiang, B. Rajaratnam, (2017). Quantifying the influence of observed global warming on the probability of historically unprecedented extreme climate events, Proceedings of the National Academy of Sciences 10.1073/pnas.1618082114 | PDF
  15. MANKIN, J.S., D. Viviroli, A.Y. Hoekstra, R. Horton, J. Smerdon, and N.S. Diffenbaugh, (2017). Influence of internal variability on population exposure to hydroclimatic changes, Environmental Research Letters 10.1088/1748-9326/aa5efc | PDF
  16. Ault, T.R., J.S. MANKIN, B.I. Cook, J.E. Smerdon, (2016). Relative impacts of mitigation, temperature, and precipitation on 21st Century megadrought risk in the American Southwest, Science Advances 10.1126/sciadv.1600873 | PDF
  17. Coats, S. and J.S. MANKIN, (2016). The challenge of accurately quantifying future megadrought risk in the American Southwest, Geophysical Research Letters 10.1002/2016GL070445 | Email to request copy
  18. Singh, S., D. L. Swain, J.S. MANKIN, D.E. Horton, L. Thomas, N.S. Diffenbaugh, (2016). Recent amplification of the North American winter temperature dipole, Journal of Geophysical Research: Atmospheres 10.1002/2016JD025116 | PDF
  19. Horton, R., J.S. MANKIN, ± C. Lesk, ± E. COFFEL, ± C. Raymond, (2016). A Review of Recent Advances in Research on Extreme Heat Events, Current Climate Change Reports 10.1007/s40641-016-0042-x | PDF
  20. MANKIN, J.S., D. Viviroli, D. Singh, A.Y. Hoekstra, N.S. Diffenbaugh, (2015). The potential for snow to supply human water demand in the present and future, Environmental Research Letters 10.1088/1748-9326/10/11/114016 | PDF
  21. MANKIN, J.S., N.S. Diffenbaugh, (2015). Influence of temperature and precipitation variability on near-term snow trends, Climate Dynamics 10.1007/s00382-014-2357-4 | PDF
  22. Siegfried, T., T. Bernauer, R. Guiennet, S. Sellars, A.W. Robertson, J.S. MANKIN, P. Bauer-Gottwein, (2011). Will Climate Change Exacerbate or Mitigate Water Stress in Central Asia?, Climatic Change 10.1007/s10584-011-0253-z | PDF
  23. MANKIN, J.S., (2009). Gaming the system: how Afghan opium underpins local power, Journal of International Affairs, Vol. 63, No. 1. | PDF

Peer-reviewed book chapters

  1. Moore, F.C., J.S. MANKIN, and A.H. Becker (2015). Disciplines: Integrating Climate and Social Sciences, Chapter 4 in, Climate Cultures: Anthropological Perspectives on Climate Change , Yale University Press | Email to request copy


Christopher Callahan is a PhD student in Dartmouth's Ecology, Evolution, Ecosystems, and Society (EEES) program. His research focuses on the possible impacts of climate change on human and natural systems and the uncertainties associated with projecting those impacts.

He's from the suburbs of Chicago, and he graduated from Northwestern University in 2018 with a BA in Environmental Science, where he also led Northwestern's award-winning debate team and collaborated with researchers at the University of Chicago.

Ethan Coffel is a Neukom Postdoctoral Fellow in the Climte Modeling & Impacts Group. Ethan studies how climate change is affecting extreme weather and how to quantify the impacts of these changes on human societies and natural ecosystems. He strives to understand the physical mechanisms driving changes in the climate and to clearly communicate climate change projections and their uncertainty.

He's from Iowa, has a BA from Northwestern University, and received his PhD from Columbia University, where he studied extreme heat and its impacts on human health and infrastructure.

You can find more about Ethan at his webiste.

Yaqian He is a Postdoctoral Research Fellow in the Climate Modeling & Impacts Group. She uses remote sensing, statistics, and climate science to explore the effects of human-induced land use and land cover changes on monsoon climates, including the West Africa monsoon and the East Asia monsoon. In particular, she applies remote sensing to classify the land surface and statistical and climate models to examine the underlying physical mechanisms.

Yaqian holds a Bachelors in Survey Engineering from China University of Mining and Technology, an M.S. in Cartography and GIS from the School of Geography at Beijing Normal University, China, and a PhD from the Climatology Lab in the Department of Geography at West Virginia University.

You can find more about Yaqian at her webiste.

Justin Mankin is a climate scientist, assistant professor in the Department of Geography at Dartmouth College, and PI of the Dartmouth Climate Modeling & Impacts Group. He also holds a courtesy appointment in the Department of Earth Sciences (EARS) and the Ecology, Evolution, Ecosystems, & Society (EEES) graduate program, and is an Adjunct Research Scientist in the Division of Ocean & Climate Physics at Lamont-Doherty Earth Observatory of Columbia University. His interdisciplinary research constrains the uncertainty essential to understanding and responding to climate change’s impacts on people and ecosystems.

His previous career was as an intelligence officer working in South Asia and the Middle East. He's from Vermont and holds degrees from Columbia (BA, MPA), the London School of Economics (MSc), and Stanford (PhD).


Join our dynamic and inclusive group!

Postdoctoral Research

There are a number of postdoc possibilities to work with our group beyond NOAA and NSF programs:

1. The Neukom Postdoctoral Research Fellowship

This is an interdsiciplinary computational postdoctoral fellowship sponsored by the Neukom Institute, based around an original proposal. If you have an interest in applying and being a postdoc in our group, this is one avenue to do so. Applications completed by November 15 receive full consideration. Email Justin to discuss.

2. Geography Postdoctoral Fellowship

Dartmouth's Department of Geography has a postdoctoral fellowship program based around an original proposal. Email Justin to discuss.

3. Dartmouth Society of Fellows

This is a fellowship where applicants identify at least one Dartmouth faculty member with similar scholarship. Email Justin to discuss.

Graduate Student Research

Graduate students can join the lab via two pathways, EEES and Earth Sciences. Please email Justin briefly stating your research interests and CV if you'd like to apply.

1. The Ecology, Evolution, Ecosystems & Society (EEES) PhD program at Dartmouth College. See our group advertisement here. (The deadline is December 1, though it is somewhat flexible.)

2. The Department of Earth Sciences (EARS) at Dartmouth College. (Deadline January 15th.)

Undergraduate Research

If you are a Dartmouth undergraduate student, a geography department honors thesis student, or interested in working with the group on climate research send Justin an email briefly outlining your research interests and we can set up a time to discuss research projects beginning in the fall of 2018.


Department of Geography
Dartmouth College
6017 Fairchild
Hanover, NH 03755
Phone: (603) 646-9957
mankin [at] dartmouth [dot] edu
Ocean and Climate Physics
Lamont-Doherty Earth Observatory
Columbia University
61 Route 9W, P.O. Box 1000
Palisades, NY 10964
Phone: (845) 365-8373
jsmankin [at] ldeo [dot] columbia [dot] edu