Forging the path to achieving land degradation neutrality: Global patterns and drivers of land degradation at global scales

Land degradation – the reduction or loss of the productive potential of land – is a global challenge. More than 20% of the Earth’s vegetated surface is estimated to be degraded, affecting over 1.3 billion people, with an economic impact of up to US$10.6 trillion. Land degradation reduces agricultural productivity and increases the vulnerability of those areas already at risk of impacts from climate variability and change. Addressing land degradation, Sustainable Development Goal (SDG) target 15.3, is essential to improve the livelihoods of those most affected, and to build resilience to safeguard against the most extreme effects of climate change. Drivers of land degradation include natural processes and human activities, and understanding such drivers is key for deploying effective interventions for addressing it. The parties to the United Nations Convention to Combat Desertification (UNCCD) have adopted a framework for assessing and monitoring land degradation at national scale, by measuring three sub-indicators: Changes in land cover, changes in soil organic carbon, and changes in primary productivity. In this study, we use the framework developed by the UNCCD and Trends.Earth, the most widely tool used for producing such indicators, to assess land condition globally for the period 2001-2015, the SDG 15.3.1 baseline period. Using a Bayesian hierarchical model, we then assessed the contribution of 12 drivers of land degradation, including key biophysical and anthropogenic variables, to the observed patterns to provide insight into the main drivers of land degradation at global, regional, and national scales. These results are critical for designing locally relevant plans for assessing land degradation contributing to the global goal of achieving a land degradation neutral world by 2030. The results of this analysis allow identification of not only the significant drivers in a given region, but also of those areas where unexpected trends (either improvement or degradation) are indicative of potential policy successes or failures.