Promoting co-benefits of carbon farming in Oceania: Applying and adapting approaches and metrics from existing market-based schemes

Carbon farming in its various forms has the potential to deliver a range of ecosystem services in addition to climate regulation. In Australia, the main public 'co-benefits' that could result from carbon farming are conservation of biodiversity, increases in soil and water quality, productivity increases, and economic and cultural services for Indigenous communities. While there is a lack of empirical evidence that carbon farming is delivering these ecosystem services to date, various metrics have been developed by researchers and through other payment for ecosystem services schemes that may enable effective targeting of these co-benefits. In this article, we review previous studies and schemes and identify four main approaches for metrics that could be applied to carbon farming in Australia: (1) spatial modelling, (2) benchmarks; (3) environmental benefit indices; and (4) indicators. The relative value of each of these approaches varies, depending on the objectives of policy-makers. Spatial modelling and benchmarks can play a key role in decision support systems for landholders who may be interested in carbon farming. Indices are valuable for the development of new or modified market-based schemes that weigh up different co-benefits. Indicators are critical for outcome-based payment schemes and for verifying the effectiveness of co-benefit policies overall.