Climate change reduces the mitigation obtainable from sequestration in an Australian farming system

Abstract

Agricultural research on climate change generally follows two themes: (i) impact and adaptation or (ii) mitigation and emissions. Despite both being simultaneously relevant to future agricultural systems, the two are usually studied separately. By contrast, this study jointly compares the potential impacts of climate change and the effects of mitigation policy on farming systems in the central region of Western Australia's grainbelt, using the results of several biophysical models integrated into a whole-farm bioeconomic model. In particular, we focus on the potential for interactions between climate impacts and mitigation activities. Results suggest that, in the study area, farm profitability is much more sensitive to changes in climate than to a mitigation policy involving a carbon price on agricultural emissions. Climate change reduces the profitability of agricultural production and, as a result, reduces the opportunity cost of reforesting land for carbon sequestration. Nonetheless, the financial attractiveness of reforestation does not necessarily improve because climate change also reduces tree growth and, therefore, the income from sequestration. Consequently, at least for the study area, climate change has the potential to reduce the amount of abatement obtainable from sequestrationa result potentially relevant to the debate about the desirability of sequestration as a mitigation option. * We thank Jenny Carter for her assistance with the 3PG modelling and Brett Bryan for his feedback on drafts of this manuscript.

Agriculture’s carbon neutral challenge: The case of Western Australia*

“…The need for caution arises from acknowledging that once the most cost-effective shire locations for sequestration are identified (and assuming it is legally and politically permissible to switch large swathes of farmland into forestry) then the price of land in those shires would be bid up, increasing the cost of sequestration and potentially making those shires no longer part of the set of shires that are cost-effective providers of abatement. Moreover, if future climate change is even more adverse than the warmer, drier climate observed since the 1970s, upon which this study's tree growth estimates are based, then future sequestration rates in many shires may be lower (Thamo et al 2019) which will increase the cost of sequestration. Moreover, if innovation in dryland agriculture continues to underpin the profitability of farming, particularly in medium and high rainfall regions (Hochman & Horan, 2018), then further real appreciation in land prices for agriculture is feasible, raising the opportunity cost of land committed for abatement.…”

“…Enteric emissions in 1990 were responsible for 75 per cent of all emissions; but by 2015, this figure had fallen to 63 per cent. This change was mostly caused by declining sheep numbers and reflected the move into more intensive cropping systems in WA agriculture (Kingwell & Pannell, 2005;Thamo et al 2019).…”

A club model of nature‐smart agriculture for biodiversity, climate, and productivity enhancements

“…The club approach could provide a framework for striking a balance in the trade-off between agriculture adaptation to climate change and climate mitigation measures on the climate front observed in some parts of the world (see, e.g., Hertzler et al, 2013). Potentially, the NSCF could extend the whole-farm bioeconomic models (such as the one used by Thamo et al, 2019) to examine the potential for fostering positive synergies between adapting to climate change and adopting mitigating practices at the whole-ecosystem level.…”

Making Agriculture Carbon Neutral Amid a Changing Climate: The Case of South-Western Australia

“…Often these contractual investments stretch over several decades, yet there are few longitudinal studies of abatement or offset activities in Australia that factor in the impact of climate change. A few studies do examine, mostly at the farm-level, the trade-off between farm profit and emission levels [26][27][28], but the cost to an Australian farm business or farming region of becoming carbon neutral against the backdrop of a changing climate is not reported in the literature, as far as the authors are aware.…”