Kirsten Zickfeld

Associate Professor

Employment History

  • Associate Professor, Simon Fraser University, Department of Geography, September 2015 - Present
  • Assistant Professor, Simon Fraser University, Department of Geography, August 2010 - August 2015
  • Adjunct Assistant Professor, University of Victoria, School of Earth and Ocean Sciences, Victoria, BC,
    July 2009 - June 2014
  • Research Scientist, Environment Canada, Canadian Centre for Climate Modelling and Analysis, Victoria, BC, November 2008 - July 2010


  • Postdoctoral Research Associate, University of Victoria, School of Earth and Ocean Sciences, Victoria, BC (2006-2008)
  • Postdoctoral Research Associate, Potsdam Institute for Climate Impact Research, Potsdam, Germany (2005)
  • Ph.D., Physics, Potsdam University, Potsdam, Germany (2004)
  • M.Sc., Physics, Free University Berlin, Berlin, Germany (1998)

Research Interests 

My research focuses on the effects of anthropogenic emissions of greenhouse gases and aerosols on climate on multi-centennial timescales. The goal is to better understand the response of the climate system to forcing and the interactions between climate system components (the atmosphere, ocean, land surface, biosphere and cryosphere) in order to improve predictions for the future. To achieve this objective, I use climate models of different complexity, from simple conceptual models to complex Earth System models. My current research focuses on four broad themes:

Reversibility of human-induced climate change 

Is global warming reversible, i.e. is it possible to restore the climate system to a desired state if human-induced emissions of greenhouse gases are reduced or completely eliminated? Climate change is potentially irreversible because of the long (centennial to millennial) time carbon dioxide (CO2) remains in the atmosphere, and the long reaction timescales of the deep ocean and ice sheets. Recent research has shown that human-induced climate change is largely irreversible (i.e. temperature will remain elevated and sea level will continue to rise) for several centuries even after emissions of greenhouse gases are stopped entirely. Against this evidence, technology that seeks to artificially remove CO2 from the atmosphere (which would slow the rate of increase of CO2 in the atmosphere and accelerate the atmospheric CO2 concentration decrease after a peak has been reached) is increasingly discussed. Research in my group explores whether carbon dioxide removal technology has the potential to enhance the reversibility of different components of the climate system (e.g. ocean, permafrost), given realistic constraints on the rate and scale this technology can be applied at.

Carbon cycle response to carbon dioxide removal 

Under the 2015 Paris Agreement nations committed to “holding the increase in the global average surface temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5°C”. Meeting the temperature target in the Paris Agreement presents the enormous challenge of reducing CO2 emissions to zero within this century. Artificial removal of CO2 from the atmosphere (referred to as “carbon dioxide removal” or CDR) is a key mitigation measure in greenhouse gas emission scenarios that seek to limit global warming to 1.5°C or 2°C. Yet, our understanding of the carbon cycle response to CDR is limited. Research in my group seeks to better understand the processes that determine the response of the coupled climate-carbon cycle to CDR both at the global and regional scale, and their uncertainty in models. We also seek to develop metrics to quantify the effectiveness of CDR in lowering atmospheric CO2 and reversing human-induced warming.

Carbon budgets consistent with climate targets  

Recent research has established that global warming at a given point in time is determined by the total amount of CO2 emissions emitted up to that time, and is independent of the emission trajectory. The proportional relationship between global warming and total or “cumulative” CO2 emissions arises because of compensation of different processes within the coupled climate-carbon cycle system. The total CO2 emissions that can be emitted over all times in order to limit global warming to a given level – e.g. the 1.5°C and 2°C limits mentioned in the Paris Agreement – is referred to as “carbon budget”. Carbon budgets are uncertain because the physical and biogeochemical response to CO2 emissions is not well constrained, and because it is uncertain how emissions of other greenhouse gases will evolve in the future. The method of quantification also influences the magnitude of carbon budgets. Research in my group investigates the physical and biogeochemical processes underlying the carbon budget concept, and seeks to quantify carbon budgets consistent with climate targets under consideration of a range of uncertainties.

Feedbacks between climate and the carbon cycle 

A range of feedbacks operate in the climate system, which have the potential attenuate or exacerbate global warming. One class of feedbacks involves the carbon cycle, and determines how much of the carbon dioxide (CO2) emitted by human activities remains in the atmosphere. For example, the solubility of CO2 in seawater decreases with temperature. Therefore, if the temperature of seawater rises, the ocean will be able to absorb less CO2. Similar feedbacks operate in the terrestrial carbon cycle. A prominently discussed feedback is the permafrost-carbon feedback, whereby permanently frozen soils thaw due to warming, releasing CO2 and methane into the atmosphere. These gases, in turn, amplify the greenhouse effect, leading to additional warming. Research suggests that the total effect of carbon-climate feedbacks is to amplify global warming (i.e a positive feedback), but no runaway carbon-climate feedbacks are anticipated, at least this century. Research in my group seeks to better understand the physical and biogeochemical processes that generate these feedbacks, and quantify them.

Graduate student and post-doc opportunities

The Climate Research Lab invites applications from prospective Master’s and Doctoral students and postdocs interested in pursuing research on past and future climate change using Earth System models.

Information on potential research projects, required qualifications and application procedure can be found here:

Current and previous graduate students  


  • Mehdi Aminipouri, PhD candidate, Modelling impact of increased tree cover on pedestrian thermal comfort.
  • Claude-Michel Nzotungicimpaye, PhD candidate, Modelling wetland methane emissions and the permafrost carbon feedback.
  • Margaret Valerio, MSc candidate, Effect of mixing on Southern Ocean water mass volume and production.
  • Nesha Wright, MSc candidate, Reversibility of permafrost thaw in temperature overshoot scenarios.


  • Dana Ehlert, PhD, Climate response to anthropogenic carbon dioxide emissions: time-dependent processes, commitment, and reversibility; currently post-doc at GEOMAR - Helmholtz Centre for Ocean Research Kiel.
  • Tyler Herrington, MSc, Dependence of regional climate change on greenhouse gas emission pathway, currently PhD student at the University of Waterloo.
  • Xinru Li, MSc, Reversibility of marine climate change impacts, currently PhD student at the University of British Columbia.
  • Katarzyna Tokarska, MSc, Role of artificial atmospheric CO2 removal for climate stabilization, currently post-doc at the University of Edinburgh.

Publications in refereed journals

Google Scholar Profile

45. Smith, C.J, P.M. Forster, M. Allen, J. Fuglestvedt, R. Millar, J. Rogelj and K. Zickfeld, 2018, 1.5°C - Are we there yet? Nature Communications, in revision.

44. Keller, D., A. Lenton, V. Scott, N. Vaughan, N. Bauer, D. Ji, C. Jones, B. Kravitz, H. Muri, K. Zickfeld, 2018, The Carbon Dioxide Removal Model Intercomparison Project (CDR-MIP): Rationale and experimental design, Geoscientific Model Development, 11, 1133–1160,

43. Tokarska, K., N.P. Gillett, V.K. Arora, W. Lee, and K. Zickfeld, 2018, The influence of non-CO2 forcings on cumulative carbon emissions budgets, Environmental Research Letters, 13, 034039,

42. *Ehlert, D., K. Zickfeld, 2018, Irreversible ocean thermal expansion under carbon dioxide removal, Earth System Dynamics, 9, 197–210, 2018,

41. Matthews, H.D., K. Zickfeld, R. Knutti, and M. Allen, 2018, Focus on Cumulative Emissions, Global Carbon Budgets and the Implications for Climate Mitigation Targets, Environmental Research Letters, 13, 010201, doi: 10.1088/1748-9326/aa98c.

40. Ehlert, D., K. Zickfeld, M. Eby, N. Gillett, 2017, The effect of variations in ocean mixing on the proportionality between temperature change and cumulative CO2 emissions, Journal of Climate, 30(8), 2921-2935, doi:10.1175/JCLI-D-16-0247.1

39. Matthews, H.D., J.-S. Landry, A.-I. Partanen, M. Allen, M. Eby, P.M. Forster, P. Friedlingstein,  K. Zickfeld, 2017, Estimating carbon budgets for ambitious climate targets, Current Climate Change Reports, 3, 69-77, doi:10.1007/s40641-017-0055-0.

38.  Nzotungicimpaye, C.-M., K. Zickfeld, 2017, The contribution from methane to the permafrost carbon feedback, Current Climate Change Reports, 3, 58–68, doi:10.1007/s40641-017-0054-1 .

37. Ehlert, D., K. Zickfeld, 2017, What determines the warming commitment after cessation of CO2 emissions? Environmental Research Letters, 12, 015002, doi:10.1088/1748-9326/aa564a.

36. Zickfeld, K., S. Solomon, D.M. Gilford, 2017, Centuries of Thermal Sea Level Rise Due to Anthropogenic Emissions of Short-Lived Greenhouse Gases, Proceedings National Academy of Sciences USA, 114, 657-662, doi:10.1073/pnas.1612066114.

35. Zickfeld, K., A.H. MacDougall and H.D. Matthews, 2016, On the proportionality between global temperature change and cumulative CO2 emissions during periods of net negative CO2 emissions, Environmental Research Letters, 11, 055006.

34. MacDougall, A.H., K. Zickfeld, R. Knutti, and H.D. Matthews, 2015, Sensitivity of carbon budgets to permafrost carbon feedbacks and non-CO2 forcings, Environmental Research Letters, 10, 125003, doi:10.1088/1748-9326/10/12/125003.

33. Tokarska, K.B., and Zickfeld, K., 2015, The effectiveness of net negative carbon dioxide emissions in reversing anthropogenic climate change, Environmental Research Letters, 10, 094013, doi:10.1088/1748-9326/10/9/094013.

32. Zickfeld, K., and T. Herrington, 2015, The time lag between a carbon dioxide emission and maximum warming increases with the size of the emission, Environmental Research Letters, 10, 031001, doi:10.1088/1748-9326/10/3/031001.

31. Herrington, T., and K. Zickfeld, 2014, Path independence of climate and carbon cycle response over a broad range of cumulative carbon emissions, Earth Syst.   Dynam., 5: 409-422.

30. Eby, M., A.J. Weaver, K. Alexander, K. Zickfeld et al., 2013, Historical and idealized climate model experiments: An intercomparison of Earth system models of intermediate complexity, Climate of the Past 9(3): 1111-1140, doi: 10.5194/cp-9-1111-2013.

29. Zickfeld, K., M. Eby, K. Alexander, A.J. Weaver et al., 2013, Long-term climate change commitment and reversibility: An EMIC intercomparison, Journal of Climate 26(16):5782-5809, doi: 10.1175/JCLI-D-12-00584.1.

28. Weaver, A.J., Jan Sedlácek, M. Eby, K. Alexander, E. Crespin, T. Fichefet, G. Philippon-Berthier, F. Joos, M. Kawamiya, K. Matsumoto, M. Steinacher, K. Tachiiri, K. Tokos, M. Yoshimori, K. Zickfeld, 2012, Stability of the Atlantic Meridional Overturning Circulation: A Model Intercomparison, Geophysical Research Letters, 39, L20709, doi:10.1029/2012GL053763.

27. Kvale, K.F., K. Zickfeld, T. Bruckner, K.J. Meissner, K. Tanaka, and A.J. Weaver, 2012, Carbon dioxide emissions pathways avoiding dangerous ocean impacts, Weather, Climate and Society, 4, 212-292, doi: 10.1175/WCAS-D-11-00030.1.

26. Zickfeld, K., V.K Arora, and N.P. Gillett, 2012, Is the climate response to carbon emissions path dependent? Geophysical Research Letters. 39, L05703, doi:10.1029/2011GL050205.

25. Matthews, H.D., and K. Zickfeld, 2012, Climate response to zeroed emissions of greenhouse gases and aerosols, Nature Climate Change 2, 338-341.

24. Zickfeld, K., M. Eby, H.D. Matthews, A. Schmittner, and A.J. Weaver, 2011, Nonlinearity of carbon cycle feedbacks, Journal of Climate 24(6): 4254-4274.

23. Gillett, N.P., V. Arora, K. Zickfeld, S. Marshall, and B. Merryfield, 2011, Ongoing climate change following a complete cessation of carbon dioxide emissions, Nature Geoscience, 4:83–87.

22. Zickfeld, K. , M.G. Morgan, D.J. Frame, and D.W. Keith, 2010, Expert judgments about transient climate response to alternative future trajectories of radiative forcing, Proceedings of the National Academy of Science, 107 (28): 12451-12456.

21. Kuhlbrodt, T., S. Rahmstorf, K. Zickfeld, F. Vikebø, S. Sundby, M. Hofmann, P.M. Link, A. Bondeau, W. Cramer, and C. Jaeger, 2009, An Integrated Assessment of Changes in the Thermohaline Circulation,Climatic Change, 96, 489-537

20. Zickfeld, K., M. Eby, H.D. Matthews, and A.J. Weaver, 2009, Setting cumulative emissions targets to reduce the risk of dangerous climate change, Proceedings of the National Academy of Science, 106(38): 16129-16134.

19. Eby, M., K. Zickfeld, A. Montenegro, D. Archer, K.J. Meissner, and A.J. Weaver, 2009, Lifetime of anthropogenic climate change: Millennial life-times of potential CO2 and temperature perturbations,Journal of Climate, 22: 2501-2511.

18. Matthews, H.D., N. Gillett, P. A. Stott, and K. Zickfeld, 2009, The proportionality of global warming to cumulative carbon emissions, Nature, 459: 829-833.

17. Bruckner, T., and K. Zickfeld, 2009, Low risk emissions corridors for safeguarding the Atlantic thermohaline circulation, Mitigation and Adaptation Strategies for Global Change, 14, 61-83.

16. Zickfeld, K., and T. Bruckner, 2008, Reducing the risk of Atlantic thermohaline circulation collapse: sensitivity analysis of emissions corridors. Climatic Change, 91, 291-315.

15. Zickfeld, K. , M. Eby, and A.J. Weaver, 2008, Carbon-cycle feedbacks of changes in the Atlantic meridional overturning circulation under future atmospheric CO2, Global Biogeochem. Cycles, 22, GB3024.

14. Zickfeld, K., J.C. Fyfe, M. Eby, and A.J. Weaver, 2008, Comment on “Saturation of the Southern Ocean CO2 sink due to recent climate change”. Science, 319, 570b.

13. Knopf, B., K. Zickfeld, M. Flechsig, and V. Petoukhov, 2008, Sensitivity of the Indian monsoon to human activities. Advances of Atmospheric Sciences, 25(6), 932-945.

12. Weaver, A.J., K. Zickfeld, A. Montenegro, and M. Eby, 2007, Long term climate implications of 2050 emission reduction targets. Geophysical Research Letters, 34, L19703.

11. Zickfeld, K., O.A. Saenko, M. Eby, J.C. Fyfe, and A.J. Weaver, 2007, Response of the global carbon cycle to human-induced changes in Southern Hemisphere winds. Geophysical Research Letters, 34, L12712.

10. Fyfe, J.C., O.A. Saenko, K. Zickfeld, M. Eby, and A.J. Weaver, 2007, The role of poleward intensifying winds on Southern Ocean warming. Journal of Climate, 20: 5391-5400.

9. Zickfeld, K., A. Levermann, M.G. Morgan, T. Kuhlbrodt, S. Rahmstorf, and D.W. Keith, 2007, Expert judgments on the response of the Atlantic meridional overturning circulation to climate change. Climatic Change, 82(3-4): 235-265.

8. Knopf, B., M. Flechsig, and K. Zickfeld, 2006, Multi parameter uncertainty analysis of a bifurcation point. Nonlinear Processes in Geophysics, 13: 531-540.

7. Kropp, J.P., A. Block, F. Reusswig, K Zickfeld, and H.-J. Schellnhuber, 2006, Semiquantitative Assessment of Regional Climate Vulnerability: The North Rhine - Westphalia Study. Climatic Change, 76(3-4): 265-290.

6. Zickfeld, K., B. Knopf, V. Petoukhov, and H.-J. Schellnhuber, 2005, Is the Indian summer monsoon stable against global change?, Geophysical Research Letters, 32, L15707.

5. Rahmstorf, S., and K. Zickfeld, 2005, Thermohaline circulation changes: a question of risk assessment, Climatic Change, 68 (1-2): 241-247.

4. Zickfeld, K., T. Slawig and S. Rahmstorf, 2004, A low-order model for the response of the Atlantic thermohaline circulation to climate change, Ocean Dynamics, 54(1): 8-26.

3. Slawig, T., and K. Zickfeld, 2004, Parameter optimization using algorithmic differentiation in a reduced-form model of the Atlantic thermohaline circulation, Nonlinear Analysis: Real World Applications, 5(3): 501-518.

2. Zickfeld, K., and T. Bruckner, 2003, Reducing the risk of abrupt climate change: emissions corridors preserving the Atlantic thermohaline circulation, Integrated Assessment, 4(2): 106-115.

1. Zickfeld, K., M.E. Garcia, and K.H. Bennemann, 1999, Theoretical study of the laser-induced femtosecond dynamics of small Sin clusters, Phys. Rev. B, 59(20): 13422-13430.

Intergovernmental Panel on Climate Change (IPCC)

Lead Author of:

  • Canadell, J., P. Scheel Monteiro et al., 2021, Chapter 5: Global carbon and other biogeochemical cycles and feedbacks, in: V. Masson-Delmotte and P. Zhai (Eds.): Climate Change 2021: The Physical Science Basis, Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change.
  • Allen, M., O.P. Dube, B. Solecki et al., 2018, Chapter 1: Framing and Context, in: Special Report of the Intergovernmental Panel on Climate Change on the global warming of 1.5 degrees.

Contributing author to:

  • Church, J.A., P.U. Clark et al., 2013, Chapter 13: Sea Level Change, in: T.F. Stocker and D. Qin (Eds.): Climate Change 2013: The Physical Science Basis, Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, 1137-1216.
  • Collins, M., R. Knutti et al., 2013, Chapter 12: Long-term Climate Change: Projections, Commitments and Irreversibility, in: T.F. Stocker and D. Qin (Eds.): Climate Change 2013: The Physical Science Basis, Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, 1029-1136.
  • Smith, J.B., H.-J. Schellnhuber, M.Q. Mirza, S. Fankhauser, R. Leemans, L. Erda, L. Ogallo, B. Pittock, R. Richels, C. Rosenzweig, U. Safriel, R.S.J. Tol, J. Weyant, G. Yohe, 2001, Vulnerability to Climate Change and Reasons for Concern: A Synthesis, in: J.J. McCarthy, O.F. Canziani, N.A. Leary, D.J. Dokken, K.S. White (Eds.): Climate Change 2001: Impacts, Adaptation, and Vulnerability, Contribution of Working Group II to the Third Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, 913-967.

Book chapters

  • Kropp, J., K. Zickfeld, and K. Eisenack, 2002, Assessment and management of critical events: The breakdown of marine fisheries and the North Atlantic thermohaline circulation. In: A. Bunde, J. Kropp, H.J. Schellnhuber (Eds.), The science of disaster: climate disruptions, heart attacks, and market crashes, Springer, Berlin Heidelberg, 193-216.

Articles in conference proceedings

  • Bruckner, T., and K. Zickfeld, 2008, Inverse integrated assessment of climate change: the guardrail approach, International conference on policy modelling, July 2-4 2008, Berlin, Germany.
  • Bruckner, T., and K. Zickfeld, 2004, Low risk emissions corridors for safeguarding the Atlantic thermohaline circulation, Expert Workshop on “Greenhouse gas emissions and abrupt climate change: positive options and robust policy”, October 30 – October 1, 2004, Paris, France.
  • Zickfeld, K., and T. Bruckner, 2002, Emissions corridors preserving the Atlantic Ocean thermohaline circulation, In: A. E. Rizzoli, A.J. Jakeman (Eds.), Integrated assessment and decision support - Proceedings of the 1st biennial meeting of the International Environmental Modelling and Software Society, 24-27 June 2002, Lugano, Switzerland, 145-150.


GEOG 214 Weather and Climate

This course provides an introduction to the fundamental principles and processes governing the Earth’s weather and climate. Topics include radiation, energy balance, greenhouse effect, clouds, precipitation, atmospheric circulation, mid-latitudes cyclones, thunderstorms, tornadoes, climate change, air pollution and ozone hole.

GEOG 314 The Climate System

This course examines the climate system and its components – the atmosphere, ocean and land surface. Emphasis will be placed on the physical and biogeochemical interactions between these components. Topics to be covered include: atmospheric processes relevant to climate, role of the ocean and land surface in climate, carbon cycle, climate feedbacks, history and evolution of Earth’s climate, global warming, climate models.

GEOG 414 Climate Change

This course provides an overview of the climate change/global warming issue, with focus on the scientific foundations but also consideration of its societal implications. Topics to be discussed include observations of climate changes, attribution of climate changes to natural and/or anthropogenic causes, climate models, sources of greenhouse gas emissions, 21st century projections of future climate changes at regional and global scales, long-term climate changes, biophysical and socio-economic impacts, vulnerability, adaptation to climate change, mitigation of greenhouse gas emissions, geoengineering, climate stabilization, international climate policy.


Future courses may be subject to change.