Land-use spillovers from environmental policy interventions

• Spillovers are widely recognized but lack common frameworks and methods. • Most spillovers arise where enforcement is weak and frontier land is accessible. • Spillover research focuses on climate; biodiversity frameworks are overlooked. • Spillovers are rarely assessed across local-to-global scales in policy studies. • Addressing spillovers needs shared tools, cross-scale methods, and integration. Environmental policy interventions are crucial for addressing biodiversity loss and climate change, yet their effectiveness can be compromised by land-use spillovers, where efforts to reduce impacts in one place displace them elsewhere. Despite growing recognition of spillovers, they remain unevenly defined, inconsistently measured, and poorly integrated into policy evaluation and accountability frameworks. This systematic review synthesizes current research on land-use spillovers triggered by environmental policies, including carbon pricing, protected areas, supply chain interventions, and payments for ecosystem services. We identify three dominant pathways: leakage, indirect land use change (iLUC), and positive spillovers, emerging under common conditions such as weak enforcement, market integration, limited livelihood alternatives, and accessible frontier lands. These conditions are shaped by broader institutional, economic, demographic, and biophysical drivers, yet are rarely integrated into policy design and evaluation. While methods to evaluate spillover effects range from global scale ex ante models to local ex post spatial and econometric analyses, few studies bridge scales or connect findings to international policy frameworks such as the Convention on Biological Diversity (CBD) or the United Nations Framework Convention on Climate Change (UNFCCC). Cases are concentrated in climate-linked interventions and in South America, leaving important geographic and sectoral blind spots. This limits their relevance for designing policies that minimize displaced impacts and foster more durable outcomes. Advancing spillover research will require common frameworks, more consistent methodologies, and multi-scale tools that can enhance comparability, attribution, and integration into environmental governance.