Theme 5-1: Drought Management and Climate Change--Oral Sessions

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Globally, pressure to ensure future food security is being challenged by competing needs for multiple land-uses in agricultural systems. Rangelands are both a source of greenhouse gas emissions as well as providing opportunities for emissions reduction. Carbon farming is a new land-use option that sequesters carbon in vegetation and soils. National incentive programs in Australia for this option have resulted in significant recent land-use change across Australian rangelands.

Beyond the mitigation benefits, the potential for carbon farming income to enhance socio-ecological resilience in rangelands has been identified. However, there are major uncertainties about the impacts of climate change on sequestration rates and trade-offs between land-use for carbon and pastoral production. The AUD$2.45 billion Commonwealth Emissions Reduction Fund has driven recent land-use change and a further AUD$2 billion over the next 10 years, coupled with a fast-growing secondary carbon market is continuing to drive demand for carbon credits. The ability to supply these carbon credits and meet international emissions reduction obligations but limit the trade-offs with pastoral production can be supported through an identification of spatial prioritisation and optimisation at a landscape scale.

We use a case study of New South Wales where ~3 million ha of traditional rangeland pastoralism is currently delivering ~27% of the national land sector abatement. Priority areas and optimisation of land-use for carbon farming and production under current and future climates were determined by developing a Carbon Optimisation Model (COM). This high-resolution integrated environmental-economic model provides predictions of spatiotemporal dynamics of land-use options for variations of incentive payment levels and policy settings. Regional downscaling of an ensemble of global circulation models (GCMs) were used to predict the climate impacts on future sequestration rates derived from 3PG forest growth model to quantify carbon supply under future climates. The COM can be used to produce spatial maps to underpin strategic prioritisation abatement activities and allow abatement opportunities to be incorporated into regional NRM planning.

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Trade-offs and Optimisation of Land-Use for Pastoralism and Carbon in Southeastern Australia

Globally, pressure to ensure future food security is being challenged by competing needs for multiple land-uses in agricultural systems. Rangelands are both a source of greenhouse gas emissions as well as providing opportunities for emissions reduction. Carbon farming is a new land-use option that sequesters carbon in vegetation and soils. National incentive programs in Australia for this option have resulted in significant recent land-use change across Australian rangelands.

Beyond the mitigation benefits, the potential for carbon farming income to enhance socio-ecological resilience in rangelands has been identified. However, there are major uncertainties about the impacts of climate change on sequestration rates and trade-offs between land-use for carbon and pastoral production. The AUD$2.45 billion Commonwealth Emissions Reduction Fund has driven recent land-use change and a further AUD$2 billion over the next 10 years, coupled with a fast-growing secondary carbon market is continuing to drive demand for carbon credits. The ability to supply these carbon credits and meet international emissions reduction obligations but limit the trade-offs with pastoral production can be supported through an identification of spatial prioritisation and optimisation at a landscape scale.

We use a case study of New South Wales where ~3 million ha of traditional rangeland pastoralism is currently delivering ~27% of the national land sector abatement. Priority areas and optimisation of land-use for carbon farming and production under current and future climates were determined by developing a Carbon Optimisation Model (COM). This high-resolution integrated environmental-economic model provides predictions of spatiotemporal dynamics of land-use options for variations of incentive payment levels and policy settings. Regional downscaling of an ensemble of global circulation models (GCMs) were used to predict the climate impacts on future sequestration rates derived from 3PG forest growth model to quantify carbon supply under future climates. The COM can be used to produce spatial maps to underpin strategic prioritisation abatement activities and allow abatement opportunities to be incorporated into regional NRM planning.