People_title

DGE Researcher Profile


Julia Pongratz

Title: Post-doctoral research scientist
Lab: Caldeira
Phone: +1-650-223-6947
Email: pongratz[at]carnegie[dot]stanford[dot]edu
curriculum vitae

Research Summary

General interest

- Earth system modeling
- Climate change
- Biosphere-atmosphere interactions
- Carbon cycle
- Remote sensing of land cover
- Food security
- Geoengineering

Current research

The vegetation covering the continents has decisive influence on climate, and humans are interfering substantially by agricultural expansion and deforestation. For example, about one third of past anthropogenic CO2 emissions has been caused by anthropogenic land cover change. In my research I investigate the effects of land cover change on global and regional carbon fluxes, but also the effects of changes in the physical properties of the land surface on climate. The timescales considered cover the last millennium to the near future, addressing questions on the beginning of human-induced climate change as well as possible future mitigation strategies by reforestation. The main tools for my research are comprehensive Earth system models.

As of March, 2012, I hold the Klaus Hasselmann fellowship at the Max Planck Institute for Meteorology in Hamburg, Germany.

Publications

2012

J. Pongratz, D.B. Lobell, L. Cao, and K. Caldeira: Crop yields in a geoengineered climate, Nature Climate Change, doi:10.1038/nclimate1373. Press: NPR The Salt, Nature Climate Change

J. Pongratz and K. Caldeira: Attribution of atmospheric CO2 and temperature increases to regions: importance of preindustrial land use change, Environmental Research Letters 7(034001) doi: 10.1088/1748-9326/7/034001.

2011

J. Pongratz, C.H. Reick, T. Raddatz, K. Caldeira, and M. Claussen: Past land use decisions have increased mitigation potential of reforestation, Geophys. Res. Lett. 38, L15701, doi:10.1029/2011GL047848. Press: GRL Editors' highlight, EOS Research Spotlight

J. Pongratz, K. Caldeira, C.H. Reick, and M. Claussen: Coupled climate-carbon simulations indicate minor global effects of wars and epidemics on atmospheric CO2 between AD 800 and 1850, The Holocene, doi: 10.1177/0959683610386981. Press: Handelsblatt, BBC World Service

G.A. Schmidt, J.H. Jungclaus, C.M. Ammann, E. Bard, P. Braconnot, T.J. Crowley, G. Delaygue, F. Joos, N.A. Krivova, R. Muscheler, B.L. Otto-Bliesner, J. Pongratz, D.T. Shindell, S.K. Solanki, F. Steinhilber, and L.E.A. Vieira: Climate forcing reconstructions for use in PMIP simulations of the last millennium (v1.0), Geosci. Model Dev., 4, pp. 33–45, doi: 10.1177/0959683610386981.

G.A. Ban-Weiss, G. Bala, L. Cao, J. Pongratz, and K. Caldeira: Climate forcing and response to idealized changes in surface latent and sensible heat, Environ. Res. Lett., 6, 034032, doi:10.1088/1748-9326/6/3/034032.

G.A. Schmidt, J.H. Jungclaus, C.M. Ammann, E. Bard, P. Braconnot, T.J. Crowley, G. Delaygue, F. Joos, N.A. Krivova, R. Muscheler, B.L. Otto-Bliesner, J. Pongratz, D.T. Shindell, S.K. Solanki, F. Steinhilber, and L.E.A. Vieira: Climate forcing reconstructions for use in PMIP simulations of the last millennium (v1.1), Geosci. Model Dev. Discuss, 4, pp. 2451–2467, doi:10.5194/gmdd-4-2451-2011.

R.A. Houghton, G.R. van der Werf, R.S. DeFries, M.C. Hansen, J.I. House, J. Pongratz, and N. Ramankutty: Regional Carbon Cycle Assessment and Processes (RECCAP) Synthesis Chapter G2: Carbon emissions from land use and land-cover change, submitted.

K. Caldeira and J. Pongratz: Expecting cooling from deforestation, Comment in Nature on Lee et al, Observed increase in local cooling effect of deforestation at higher latitudes, Nature 479(384-387), 2011.

2010

J. Pongratz, C.H. Reick, T. Raddatz, and M. Claussen: Biogeophysical versus biogeochemical climate response to historical anthropogenic land cover change, Geophys. Res. Lett. 37, L08702, doi:10.1029/2010GL043010.

K. Hibbard, A. Janetos, D. van Vuuren, J. Pongratz, S. Rose, R. Betts, M. Herold, and J. Feddema: Research priorities in land use and land-cover change for the Earth System and Integrated Assessment Modelling, International Journal of Climatology, doi:10.1002/joc.2150.

J.H. Jungclaus, S.J. Lorenz, C. Timmreck, C.H. Reick, V. Brovkin, K. Six, J. Segschneider, M.A. Giorgetta, T.J. Crowley, J. Pongratz, N.A. Krivova, L.E. Vieira, S.K. Solanki, D. Klocke, M. Botzet, M. Esch, V. Gayler, H. Haak, T.J. Raddatz, E. Röckner, R. Schnur, H. Widmann, M. Claussen, B. Stevens, and J. Marotzke: Climate and carbon-cycle variability over the last millennium, Clim. Past 6, pp. 723–737, doi:10.5194/cp-6-723- 2010.

C. Reick, T. Raddatz, J. Pongratz, and M. Claussen: Contribution of anthropogenic land cover change emissions to pre-industrial atmospheric CO2, Tellus, doi:10.1111/j.1600-0889.2010.00479.x.

E. Röckner, M. Giorgetta, T. Crüger, M. Esch, and J. Pongratz: Historical and future anthropogenic emission pathways derived from coupled climate-carbon cycle simulations, Climatic Change, doi:10.1007/s10584-010-9886-6.

J. Pongratz: Global warming or cooling from historical land-cover change? iLEAPS Newsletter 10.

2009

J. Pongratz, C.H. Reick, T. Raddatz, and M. Claussen: Effects of anthropogenic land cover change on the carbon cycle of the last millennium, Global Biogeochem. Cycles 23, GB4001, doi:10.1029/2009GB003488. Press: Nature

J. Pongratz, T. Raddatz, C.H. Reick, M. Esch, and M. Claussen: Radiative forcing from anthropogenic land cover change since A.D. 800, Geophys. Res. Lett. 36, L02709, doi:10.1029/2008GL036394.

J. Pongratz and C.H. Reick: Vorindustrielle Landwirtschaft: Klimawandel ohne Öl und Kohle, Jahrbuch der Max-Planck-Gesellschaft 2009.

J. Pongratz and C.H. Reick: Landwirtschaft pflügt das Klima um, MaxPlanckForschung 4.2009.

J. Pongratz: A model estimate on the effect of anthropogenic land cover change on the climate of the last millennium, Ph.D. Thesis, Reports on Earth System Science 68, ISSN 1614-1199.

2008

J. Pongratz, C. Reick, T. Raddatz, and M. Claussen: A reconstruction of global agricultural areas and land cover for the last millennium, Global Biogeochem. Cycles 22, GB3018, doi:10.1029/2007GB003153

J. Pongratz, C. Reick, T. Raddatz, and M. Claussen: A Global Land Cover Reconstruction AD 800 to 1992 – Technical Description, Reports on Earth System Science 51, ISSN 1614-1199.

2006

J. Pongratz, L. Bounoua, R. DeFries, D.C. Morton, L.O. Anderson, W. Mauser, and C. Klink: The impact of land cover change on surface energy and water balance in Mato Grosso, Brazil, Earth Interactions 10 (19).