GreenArch 2026 is the first ICSA26 workshop dedicated to green, carbon-aware software architecture. It brings together researchers and practitioners to explore architectural principles, patterns, and tools for energy-efficient, carbon-aware software systems. The workshop addresses the urgent challenge that software systems now contribute significantly to global energy use and carbon emissions. By focusing on software architecture – the primary driver of system-level efficiency and sustainability – GreenArch aims to align software design with global climate goals.