This document provides an overview of climate variability and climate change impacts on agriculture in the Greater Mekong Sub-region. It discusses observed changes in temperature and precipitation trends based on historical data. Climate models project further increases in temperatures and changes in precipitation patterns, which could impact agriculture through changes in climate suitability and more frequent extreme weather events. The document emphasizes understanding historical climate variability and using downscaled climate projections to better assess impacts and develop adaptation strategies for agricultural systems in the region.