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.
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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