Meeting global land restoration and protection targets: What would the world look like in 2050?

Land restoration has received increased attention recently as a tool to counteract negative externalities of unsustainable land management on human well-being. This is reflected in targets of the Sustainable Development Goals (SDGs), the Convention on Biological Diversity (CBD), the United Nations Framework of the Convention on Climate Change (UNFCCC) and the United Nations Convention to Combat Desertification (UNCCD). However, the implications of these targets for land use, especially considering their potential conflict with growing food production demands, are largely unexplored. We study the potential and aggregated consequences of meeting these targets on land cover and land system change. We do so by analyzing targets originating from these global commitments towards land restoration and protection and implement them in a global land system change model. We compare this Restoration and Protection scenario with simulation results of two plausible pathways of socio-economic development in the absence of these targets, following the Shared Socio-Economic Pathway (SSP) storylines. We find that meeting global land restoration and protection targets would increase global tree cover by 4 million km², increasing forest carbon stocks by 50 Gt and protecting 28% of the terrestrial area with the highest value of both biodiversity and carbon storage. Gains in tree cover and natural land systems would cause a contraction of crop, pasture- and bare land. This results in further cropland intensification and the expansion of land systems that are combining land use demands in mosaics of forest and agriculture. Without these targets, land system architecture tends to become more specialized, while many carbon and biodiversity hotspots, such as in the Americas, India, and Indonesia would be lost. Grassland-agriculture mosaics were threatened by land use change under all scenarios, requiring greater consideration in research and environmental policy. Our results emphasize the need for targeted land management in line with the analyzed policy targets if global restoration and protection targets are to be achieved.