Abstract
Abstract
Smallholder farmers’ ability to adapt to socio-environmental changes strongly relies on crop diversity and composition. Yet, how crop portfolios change over time and affect nutrition and climate adaptability remains poorly understood. We address this gap by combining 1,748 surveys of smallholder farmers across 15 globally distributed sites with climate suitability projections and nutritional profiles of 158 crop species. Farmers reported 6,234 crop abandonment and adoption events over the past half-century, highlighting highly dynamic crop portfolios. Although changes varied across sites, five showed a consistent shift from cereals (e.g., maize, sorghum) towards vegetables and fruits. Climate change was the dominant driver of abandonment (25%), particularly for drought-sensitive staples, while markets and value chains primarily shaped adoption (22%). Changes in crop portfolios revealed a trade-off between nutritional diversity and future climate suitability: vegetable adoption may improve dietary quality but increase climate vulnerability through higher water requirements. These findings highlight the need to reconcile immediate nutritional and economic needs with long-term climate adaptation.