How to make land use policy decisions: Integrating science and economics to deliver connected climate, biodiversity and food objectives

Land use change is crucial to addressing the existential threats of climate change and biodiversity loss while enhancing food security(1). However, the interconnected and spatially varying nature of the impacts of land use change means that these challenges must be addressed simultaneously(2). Despite this, governments around the world commonly focus on single issues, incentivizing land use change via ‘Flat-Rate’ subsidies offering constant per hectare payments, uptake of which is determined by the economic circumstances of landowners rather than the integrated environmental outcomes that will be delivered(3-5). Here we compare this common approach to allocating subsidies to two increasingly popular alternatives: ‘Land Use Scenario’ allocation of subsidies through consultation across stakeholders and interested parties (6); and a ‘Natural Capital’ approach which targets subsidies according to expected ecosystem service response(7, 8). A comparison of outcomes across the three approaches is achieved by developing a novel and comprehensive decision support system, integrating new and existing natural, physical and economic science models to quantify environmental, agricultural and economic outcomes. Applying this system to the UK net zero commitment to increase carbon storage via afforestation, we show that the three approaches result in significantly different outcomes in terms of where planting occurs, their environmental consequences, and economic costs and benefits. Analysis reveals that the dominant Flat-Rate approach actually increases net carbon emissions while Land Use Scenario allocation of subsidies yield poor economic outcomes. In contrast, the Natural Capital targeted approach outperforms both of these alternatives, providing the highest possible social values while satisfying net zero commitments.