This paper provides an overview of the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new pathways designed for climate modeling. The RCPs, developed through a collaboration between integrated assessment modelers, climate modelers, terrestrial ecosystem modelers, and emission inventory experts, span a range of radiative forcing values from 2.6 to 8.5 W/m² by 2100. They are intended to serve as a comprehensive dataset with high spatial and sectoral resolutions, covering land use, air pollutant emissions, and greenhouse gas concentrations up to 2100. The RCPs are harmonized across models and scenarios to ensure consistency with historical observations while preserving individual scenario trends. They are supplemented with extensions (Extended Concentration Pathways, ECPs) for the period up to 2300. The development process involved selecting existing scenarios, updating them to reflect advances in modeling, harmonizing and downsizing data, and extending the pathways beyond 2100. The RCPs are designed to facilitate climate research and assessment, providing a foundation for further studies on emissions mitigation and impact analysis.This paper provides an overview of the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new pathways designed for climate modeling. The RCPs, developed through a collaboration between integrated assessment modelers, climate modelers, terrestrial ecosystem modelers, and emission inventory experts, span a range of radiative forcing values from 2.6 to 8.5 W/m² by 2100. They are intended to serve as a comprehensive dataset with high spatial and sectoral resolutions, covering land use, air pollutant emissions, and greenhouse gas concentrations up to 2100. The RCPs are harmonized across models and scenarios to ensure consistency with historical observations while preserving individual scenario trends. They are supplemented with extensions (Extended Concentration Pathways, ECPs) for the period up to 2300. The development process involved selecting existing scenarios, updating them to reflect advances in modeling, harmonizing and downsizing data, and extending the pathways beyond 2100. The RCPs are designed to facilitate climate research and assessment, providing a foundation for further studies on emissions mitigation and impact analysis.