Climate change-induced drought and implications on maize cultivation area in the upper Nan River Basin, Thailand

The escalating frequency of climate change-induced droughts poses a severe threat to rainfed maize cultivation in Thailand’s upper Nan River Basin (NRB). Utilizing the standardized precipitation evapotranspiration index, this study comprehensively examines spatial and temporal drought patterns and their potential agricultural impact. Findings indicate a significant shift in precipitation patterns with wetter wet seasons, drier dry seasons and rising temperatures. The upper NRB experiences prolonged and severe droughts, while the lower region faces higher drought intensity, signalling an increased likelihood of extended and severe drought episodes in the upper region. Assessing maize cultivation suitability, factoring in environmental variables and drought impact under observed and climate change scenarios, reveals the current moderate suitability at 42.2%, projected to expand, and unsuitable regions expected to double. Different shared socioeconomic pathways (SSPs) show varied outcomes, with SSP5-8.5 indicating increased suitability in highly suitable areas and SSP2-4.5 demonstrating improvements in moderately suitable areas. The study underscores the need for tailored adaptation strategies in water management during droughts to enhance crop production, especially in dry seasons, in the upper NRB amid a changing climate.