1 / 15

Uncertainties in soil and terrestrial carbon response to 20th century human CO 2 emissions

Uncertainties in soil and terrestrial carbon response to 20th century human CO 2 emissions. J.-F. Exbrayat 1 , Q. Zhang 2 , A. J. Pitman 3 , G. Abramowitz 1 and Y.-P. Wang 4. 1 Climate Change Research Centre, UNSW Sydney

darci
Download Presentation

Uncertainties in soil and terrestrial carbon response to 20th century human CO 2 emissions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Uncertainties in soil and terrestrial carbon response to 20th century human CO2 emissions J.-F. Exbrayat1, Q. Zhang2, A. J. Pitman3, G. Abramowitz1 and Y.-P. Wang4 1 Climate Change Research Centre, UNSW Sydney 2 College of Global Change and Earth System, Beijing Normal University, Beijing, China 3 ARC Centre of Excellence for Climate System Science, UNSW, Sydney 4 Centre for Australian Weather and Climate Research, CSIRO Marine and Atmospheric Research CoE CSS Annual Workshop, Hobart 26/09/2012

  2. Global carbon cycle Source: IPCC AR4 (image downloaded from http://www.gfdl.noaa.gov/anthropogenic-carbon-cycle)

  3. Terrestrial Carbon Budget in a nutshell Homeostatic pre-industrial conditions: carbon uptake = release (GPP ~ Rh) GPP enhanced by anthropogenic increase in atmospheric CO2 (fertilisation) Release (Rh) favoured by increasing temperatures Up to now, the gain in GPP is higher than the gain in Rh= net uptake From Wania et al. [2012 GMD]

  4. Sources of uncertainty • Limitations in nutrient availability slow down the carbon cycle • Rh response to soil temperature and soil moisture From Zhang et al. [2011 GRL] From Exbrayat et al. [2012 under review]

  5. CASA-CNP model • Biogeochemical model within CABLE • Coupled to CSIRO Mk3L GCM (3.2 lat x 5.6 lon) [Phipps et al., 2011 GMD] • Several nutrient modes with corresponding limitations on C cycle: C-only, CN, CNP From Wang et al. [2010 BG]

  6. Rh parameterisation in soil biogeochemical models

  7. Experiments 27 model versions: each combination of a moisture response function, a temperature response function and a nutrient mode Spin-up all model versions with pre-industrial atmospheric CO2 (284.7 ppmv) Transient runs of increasing atmospheric CO2 from 1850 to 2005 Prescribed SSTs from CSIRO Mk3.6 driven by CMIP5 historical emission data [Rotstayn et al., 2012 ACP]

  8. Simulated 20th century NEA Emission data from Carbon Dioxide Information Analysis Center [Boden et al., 2010]

  9. Comparison with independent estimates

  10. Regional impact Regions in CDIAC data [Boden et al., 2010]

  11. Regional offset

  12. Conclusion Introducing NP limitations reduces the NEA but also narrows the uncertainty introduced by different parameterisations of Rh NP limited models are well in agreement with independent estimates when considering different time windows of the period 1959-2005 NP limitations reduce or even cancel the capability of regions to offset their emissions

  13. Way forward What are the policy / trade scheme relevant implications of the regional results? Will the land surface remain a net sink? What is the effect of a more detailed N cycle (with separation of different inorganic N species) within CASA-CNP?

  14. Thank you for your attention Questions? e: j.exbrayat@unsw.edu.au

More Related