dr andrew rawson: soil carbon sequestration in a changing climate

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Dr Andrew Rawson of the NSW Department of the Environment and Climate Change, explains why climate change is blamed for more than it can be held to have caused. This presentation was given at the Carbon farming Expo & Conference in Orange NSW Australia in November 2008.


  • 1. Soil Carbon Sequestration in a Changing Climate Dr Andrew Rawson NSW Dept of Environment and Climate Change

2. Source: NOAA (2007) Global Climate Change is Real 3. Greenhouse gas concentrations have skyrocketed since the industrial revolution

  • Greenhouse gases are currently at a higher concentration than at any time in the last million years and human activity is responsible

4. Global Climate Change

  • Climate trends aremeasurable , and have beenobserved .
  • The global instrumental record of these changes represents the output of the most comprehensive network of data gathering in history, for any scientific discipline or endeavour.
  • The observed rate of change isfasterthan anything previously experienced, and it isaccelerating .
  • The processes that govern climate are relatively well understood by scientists, and global climatic models (GCMs) have improved to the extent that we can have great confidence in using them to predict future scenarios.

5. Global Climate Change

  • Outputs of anthropogenic GHGs are measureable, and their impact on temperatures are consistent with the observed climate changes.
  • Known natural forcings of climate (including water vapour, solar inputs, volcanoes) cannot explain the observed changes.
  • Ancillary evidence of climate change is abundant around the world. This includes sealevel rises, changes in animal behaviour, reductions in sea ice extent, reductions in snow cover and glacier size, increases in extreme weather events.
  • Modelling shows that the changes will continue to accelerate towards a rate of change that we can no longer control.Now is the time to address the issue, not in 50 years time .

6. Increasing Certainty: IPCC

  • IPCC (1995):
  • Balance of evidencesuggestsdiscernible
  • human influence
  • IPCC (2001):
  • Most of global warming of past 50 yearslikely(odds 2 out of 3) due to human activities
  • IPCC (2007):
  • Most of global warming of past 50 yearsvery
  • likely (odds 9 out of 10) due to greenhouse
  • gases

Completed February 2007 152 Authors ~450 contributors ~600 expert reviewers 30,000+ review comments ~5000 literature references ~1000 pages 7. To adequately inform adaptation, information must be regionally explicit: Aim: to remove uncertainty in climate projections 8. Refined Climate Change Projections for NSW

  • Commissioned by DECC for adaptation planning purposes
  • UNSW Prof Andy Pitman
  • Uses IPCC AR4 GCMs
  • Only one scenario (A2)
  • Uses 4 best models based on skill at predicting current climate
  • Interpolated down to 50km grid
  • In general, this approach appears to accentuate the published trends

9. 10. 11. 12. September 2008 13. NSW annual rainfall time-series 14. Regional climate change North Coast 15. Riverina Murray Regional climate change 16. Climate Change over next 50 years and beyond

  • Increased temperature
  • Increased extremes
  • Increased evaporation
  • Changed seasonality of rainfall (summer dominance) and reductions in many areas
  • Significant imbalance in environmental systems (ecological agricultural social - financial)
  • Many changes outside our experience

17. Whats needed to adapt?

  • greater emphasis on RESILIENT natural and agricultural systems
  • greater emphasis on BUFFERING change,
    • increasing soil OMby any means possible ,
    • restoration of floodplains, swampy meadows,
    • revegetation of catchments,
    • keeping water higher in catchments;
    • reducing flashiness of fluvial systems.

18. Whats needed?

  • Soften the landscape to soften the blow
  • Soil carbon sequestration increasingly important in a changing climate:
    • Mitigation need to draw down CO 2from atmosphere
    • Long term storage
    • Adaptation and resilience

19. However..

  • It will become increasingly difficult to sequester soil carbon in a changed climate, esp. in south of the State
  • Thereforeincreased urgencyto sequester now to:
    • Build in resilience
    • Prepare the landscape for the changes

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