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

Source: NOAA (2007) Global Climate Change is Real

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

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

Global Climate Change Climate trends are measurable , and have been observed . 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 is faster than anything previously experienced, and it is accelerating . 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.

Climate trends are measurable , and have been observed .

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 is faster than anything previously experienced, and it is accelerating .

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.

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 .

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 .

Increasing Certainty: IPCC IPCC (1995): “ Balance of evidence suggests discernible human influence” IPCC (2001): “ Most of global warming of past 50 years likely (odds 2 out of 3) due to human activities” IPCC (2007): “ Most of global warming of past 50 years very 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

IPCC (1995):

“ Balance of evidence suggests discernible

human influence”

IPCC (2001):

“ Most of global warming of past 50 years likely (odds 2 out of 3) due to human activities”

IPCC (2007):

“ Most of global warming of past 50 years very

likely (odds 9 out of 10) due to greenhouse

gases”

To adequately inform adaptation, information must be regionally explicit: Aim: to remove uncertainty in climate projections

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

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

September 2008

NSW annual rainfall time-series

Regional climate change North Coast

Riverina Murray Regional climate change

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

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

What’s needed to adapt? greater emphasis on RESILIENT natural and agricultural systems greater emphasis on BUFFERING change, increasing soil OM by any means possible , restoration of floodplains, swampy meadows, revegetation of catchments, keeping water higher in catchments; reducing “flashiness” of fluvial systems.

greater emphasis on RESILIENT natural and agricultural systems

greater emphasis on BUFFERING change,

increasing soil OM by any means possible ,

restoration of floodplains, swampy meadows,

revegetation of catchments,

keeping water higher in catchments;

reducing “flashiness” of fluvial systems.

What’s needed? “ Soften the landscape to soften the blow” Soil carbon sequestration increasingly important in a changing climate: Mitigation – need to draw down CO 2 from atmosphere Long term storage Adaptation and resilience

“ Soften the landscape to soften the blow”

Soil carbon sequestration increasingly important in a changing climate:

Mitigation – need to draw down CO 2 from atmosphere

Long term storage

Adaptation and resilience

However…….. It will become increasingly difficult to sequester soil carbon in a changed climate, esp. in south of the State Therefore increased urgency to sequester now to: Build in resilience Prepare the landscape for the changes

It will become increasingly difficult to sequester soil carbon in a changed climate, esp. in south of the State

Therefore increased urgency to sequester now to:

Build in resilience

Prepare the landscape for the changes