Evaluating transformative adaptation options for Australian extensive farming – a cross-transect analyses of systemic adaptations - July 2016 supplementary report

Evaluating transformative adaptation options for Australian extensive farming – a cross-transect analyses of systemic adaptations - July 2016 supplementary report

This supplementary report contains results from a project that has conducted research across Australia’s extensive farming systems to examine adaptation options that provide resilience to likely climate change by 2030. We have identified and evaluated the effectiveness of a range of options for land managers with grazing, mixed grazing/cropping and cropping enterprises that maintain or boost profitability in a climate that is changing and becoming increasingly variable, whilst reducing
greenhouse gas (GHG) emissions (CH4, N2O and CO2). We have considered the effectiveness of these options at multiple scales (farm, community and region) and against multiple criteria (profit, risk, environmental impacts, GHG emissions and community impacts). This provides key insights into the challenges associated with managing land use change and transition resulting from climate change variability) as well as the range of systematic adaptation options available across corridors that include both rangeland and mixed cropping/grazing and cropping land use to support such change.

More systemic and transformative adaptation options derived from effective packaging of multiple incremental changes are the focus of this study (e.g. perennialisation of the landscape, effective cropping and grazing mix, opportunistic farming, and synergic combinations of options). Evaluation and engagement activities have been undertaken along transects that include both rangeland and mixed cropping/grazing and cropping land use (Figure 1). These include:

WA – Transect 1 (Katanning, Cunderdin, Merredin, Mullewa)
SA - Transect 2 (Quorn in the north to Maitland in the South
VIC - Transect 3 (Birchip in the North to Warrnambool in the south)
NSW - Transect 4 (Goolgowi, Condobolin, Walgett, Trangie, Moree)

Across each transect two adaptation packages were compared against a business as usual management (BAU) strategy. This comparison was undertaken for a period of recent history as well as for the near future, namely a 30 year period centred on 2030. The effectiveness of the adaptation ptions was evaluated in terms of changes to farm cash returns, greenhouse gas emissions and NRM issues, such as cover, runoff and drainage.

Table 1 represents a synthesis of the median percentage change in farm profitability and greenhouse gas emissions for all case study sites across each of the transects. The results show, that the strategy of shifting to summer-active perennial pastures and separating them from cropping appears not to be a widely-applicable adaptation to climate change. It proves to be financially advantageous at only a minority of locations, and at those locations the simulations estimate that separated annual pastures have nearly the same or better financial outcomes.

At the 5 locations, where separating crops and pastures produced an expected financial benefit at 2030, the size of this benefit was relatively small ($5-11 per farm hectare) except at Quorn, where it was $21 per farm hectare. The main reason for this is that pastures occupy relatively little of the land at the other 4 locations, and so the gains from changing pasture and livestock management are strongly diluted at the farm scale. At Quorn, however, the livestock enterprise is proportionally much more important and the marginal effect of more-reliable production from separated pastures is therefore greater.

Table 1. A synthesis of cases study simulation results for each transect. Each value represents the median percentage
change in either farm profitability or greenhouse gas emissions.

The option of changing the cropping and livestock mix, to a more livestock dominated farming system, appears to be a more effective adaptation option, in response to 2030 climate conditions, than the perennialisation option. On average this option provides a net benefit of between $9 and $42 per hectare mean cash margin advantage over the BAU strategy, for two (NSW and WA) of the three transects examined. Across the SA transect this option proved to be ineffective and resulted in a mean farm cash margin of $11 per hectare lower than the BAU strategy. In broad terms the shift towards a more livestock dominated farming system was better able to provide profitability in years with below average growing conditions (i.e. more frequent in each of the future climate scenarios).

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