Rebecca K Runting, Darran King, Martin Nolan, Javier Navarro, Raymundo Marcos-Martinez, Jonathan R Rhodes, Lei Gao, Ian Watson, Andrew Ash, April E Reside, Jorge G Álvarez-Romero, Jessie A Wells, Euan G. Ritchie, Michalis Hadjikakou , Don A Driscoll, Jeffery D Connor, Jonathan Garber, Brett A. Bryan

Livestock production is an integral part of the global food system and the livelihoods of local people, but it also raises issues of environmental sustainability due to issues such as greenhouse gas (GHG) emissions, biodiversity decline, land degradation, and water use. Further challenges to the social and environmental sustainability of extensive livestock systems may arise from changes in climate and the global economy (e.g., changing livestock demand and carbon prices). However, significant potential exists for both mitigating these impacts and adapting to change via altering stocking rates, managing fire, improving pastures, and supplementing cattle to reduce methane emissions. We developed an integrated, spatio-temporal modelling approach to assess the effectiveness of these different options for land management in Australia’s tropical savanna under different global change scenarios. Performance was measured against a range of sustainability indicators, including environmental outcomes (GHG emissions, biodiversity, water intake, and land condition) and production (profit, beef production). We find that maintaining baseline stocking rates is not environmentally sustainable due to the accelerated land degradation exacerbated by a changing climate. Alternatively, planned early dry season burning resulted in substantial emissions reductions, and in our simulations became profitable under all global change scenarios that included a carbon price. Although there were no perfect win-wins, the balance between production and environmental outcomes could be improved by stocking at modelled carrying capacity and implementing fire management. This scenario was the most profitable (with a four-fold increase from the historic baseline), prevented land degradation, and reduced GHG emissions by 15%. As climate change is likely to reduce the potential for cattle production in Australia and elsewhere, the opportunity to diversify income streams may prove vital in a changing climate.